Sample records for airframes

  1. Airframe/TPS Session (United States)

    Welch, Sharon; Bowles, David


    This viewgraph presentation gives an overview of the second generation Reusable Launch Vehicle (RLV) airframe configuration, including details on the structures and materials, tanks, airframe/cryotank demonstrations, internal assemblies, weight growth and margin, and safety and cost requirements.

  2. Fuel Efficiencies Through Airframe Improvements (United States)

    Bezos-O'Connor, Gaudy M.; Mangelsdorf, Mark F.; Maliska, Heather A.; Washburn, Anthony E.; Wahls, Richard A.


    The factors of continuing strong growth in air traffic volume, the vital role of the air transport system on the economy, and concerns about the environmental impact of aviation have added focus to the National Aeronautics Research Policy. To address these concerns in the context of the National Policy, NASA has set aggressive goals in noise reduction, emissions, and energy consumption. With respect to the goal of reducing energy consumption in the fleet, the development of promising airframe technologies is required to realize the significant improvements that are desired. Furthermore, the combination of advances in materials and structures with aerodynamic technologies may lead to a paradigm shift in terms of potential configurations for the future. Some of these promising airframe technologies targeted at improved efficiency are highlighted.

  3. Proceedings of the Airframe Icing Workshop (United States)

    Colantonio, Ron O. (Editor)


    The NASA Glenn Research Center (GRC) has a long history of working with its partners towards the understanding of ice accretion formation and its associated degradation of aerodynamic performance. The June 9, 2009, Airframe Icing Workshop held at GRC provided an opportunity to examine the current NASA airframe icing research program and to dialogue on remaining and emerging airframe icing issues and research with the external community. Some of the airframe icing gaps identified included, but are not limited to, ice accretion simulation enhancements, three-dimensional benchmark icing database development, three-dimensional iced aerodynamics modeling, and technology development for a smart icing system.

  4. Airframe-Jet Engine Integration Noise (United States)

    Tam, Christopher; Antcliff, Richard R. (Technical Monitor)


    It has been found experimentally that the noise radiated by a jet mounted under the wing of an aircraft exceeds that of the same jet in a stand-alone environment. The increase in noise is referred to as jet engine airframe integration noise. The objectives of the present investigation are, (1) To obtain a better understanding of the physical mechanisms responsible for jet engine airframe integration noise or installation noise. (2) To develop a prediction model for jet engine airframe integration noise. It is known that jet mixing noise consists of two principal components. They are the noise from the large turbulence structures of the jet flow and the noise from the fine scale turbulence. In this investigation, only the effect of jet engine airframe interaction on the fine scale turbulence noise of a jet is studied. The fine scale turbulence noise is the dominant noise component in the sideline direction. Thus we limit out consideration primarily to the sideline.

  5. Control strategies for aircraft airframe noise reduction

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Xunnian; Zhang Dejiu


    With the development of low-noise aircraft engine,airframe noise now represents a major noise source during the commercial aircraft's approach to landing phase.Noise control efforts have therefore been extensively focused on the airframe noise problems in order to further reduce aircraft overall noise.In this review,various control methods explored in the last decades for noise reduction on airframe components including high-lift devices and landing gears are summarized.We introduce recent major achievements in airframe noise reduction with passive control methods such as fairings,deceleration plates,splitter plates,acoustic liners,slat cove cover and side-edge replacements,and then discuss the potential and control mechanism of some promising active flow control strategies for airframe noise reduction,such as plasma technique and air blowing/suction devices.Based on the knowledge gained throughout the extensively noise control testing,a few design concepts on the landing gear,high-lift devices and whole aircraft are provided for advanced aircraft low-noise design.Finally,discussions and suggestions are given for future research on airframe noise reduction.

  6. Airframe Noise Prediction by Acoustic Analogy: Revisited (United States)

    Farassat, F.; Casper, Jay H.; Tinetti, A.; Dunn, M. H.


    The present work follows a recent survey of airframe noise prediction methodologies. In that survey, Lighthill s acoustic analogy was identified as the most prominent analytical basis for current approaches to airframe noise research. Within this approach, a problem is typically modeled with the Ffowcs Williams and Hawkings (FW-H) equation, for which a geometry-independent solution is obtained by means of the use of the free-space Green function (FSGF). Nonetheless, the aeroacoustic literature would suggest some interest in the use of tailored or exact Green s function (EGF) for aerodynamic noise problems involving solid boundaries, in particular, for trailing edge (TE) noise. A study of possible applications of EGF for prediction of broadband noise from turbulent flow over an airfoil surface and the TE is, therefore, the primary topic of the present work. Typically, the applications of EGF in the literature have been limited to TE noise prediction at low Mach numbers assuming that the normal derivative of the pressure vanishes on the airfoil surface. To extend the application of EGF to higher Mach numbers, the uniqueness of the solution of the wave equation when either the Dirichlet or the Neumann boundary condition (BC) is specified on a deformable surface in motion. The solution of Lighthill s equation with either the Dirichlet or the Neumann BC is given for such a surface using EGFs. These solutions involve both surface and volume integrals just like the solution of FW-H equation using FSGF. Insight drawn from this analysis is evoked to discuss the potential application of EGF to broadband noise prediction. It appears that the use of a EGF offers distinct advantages for predicting TE noise of an airfoil when the normal pressure gradient vanishes on the airfoil surface. It is argued that such an approach may also apply to an airfoil in motion. However, for the prediction of broadband noise not directly associated with a trailing edge, the use of EGF does not

  7. 2nd Generation RLV Airframe Structures and Materials (United States)

    Johnson, Theodore F.


    The goals and objectives of the project summarized in this viewgraph presentation are the following: (1) Develop and demonstrate verified airframe and cryotank structural design and analysis technologies, including damage tolerance, safety, reliability, and residual strength technologies, robust nonlinear shell and cryotank analysis technologies, high-fidelity analysis and design technologies for local structural detail features and joints, and high-fidelity analysis technologies for sandwich structures; (2) Demonstrate low cost, robust materials and processing, including polymeric matrix composite (PMC) and metallic materials and processing, and refractory composite and metallic hot structures materials and processing; (3) Develop and demonstrate robust airframe structures and validated integrated airframe structural concepts, including low cost fabrication and joining, operations efficient designs and inspection techniques (non-destructive evaluation), scale-up and integrated thermal structure tests, and airframe structures IVHM; (4) Demonstrate low cost, robust repair techniques; and (5) Develop verified integrated airframe structural concepts, including integrated structural concepts.

  8. Optimization of helicopter airframe structures for vibration reduction considerations, formulations and applications (United States)

    Murthy, T. Sreekanta


    Several key issues involved in the application of formal optimization technique to helicopter airframe structures for vibration reduction are addressed. Considerations which are important in the optimization of real airframe structures are discussed. Considerations necessary to establish relevant set of design variables, constraints and objectives which are appropriate to conceptual, preliminary, detailed design, ground and flight test phases of airframe design are discussed. A methodology is suggested for optimization of airframes in various phases of design. Optimization formulations that are unique to helicopter airframes are described and expressions for vibration related functions are derived. Using a recently developed computer code, the optimization of a Bell AH-1G helicopter airframe is demonstrated.

  9. The Study of Tactical Missile's Airframe Digital Optimization Design

    Institute of Scientific and Technical Information of China (English)

    LUO Zhiqing; QIAN Airong; LI Xuefeng; GAO Lin; LEI Jian


    Digital design and optimal are very important in modern design. The traditional design methods and procedure are not fit for the modern missile weapons research and development. Digital design methods and optimal ideas were employed to deal with this problem. The disadvantages of the traditional missile's airframe design procedure and the advantages of the digital design methods were discussed. A new concept of design process reengineering (DPR) was put forward. An integrated missile airframe digital design platform and the digital design procedure, which integrated the optimization ideas and methods, were developed. Case study showed that the design platform and the design procedure could improve the efficiency and quality of missile's airframe design, and get the more reasonable and optimal results.

  10. 14 CFR 43.7 - Persons authorized to approve aircraft, airframes, aircraft engines, propellers, appliances, or... (United States)


    ..., airframes, aircraft engines, propellers, appliances, or component parts for return to service after... Administrator, may approve an aircraft, airframe, aircraft engine, propeller, appliance, or component part for..., airframe, aircraft engine, propeller, appliance, or component part for return to service as provided...

  11. Airframe technology for aircraft energy efficiency. [economic factors (United States)

    James, R. L., Jr.; Maddalon, D. V.


    The economic factors that resulted in the implementation of the aircraft energy efficiency program (ACEE) are reviewed and airframe technology elements including content, progress, applications, and future direction are discussed. The program includes the development of laminar flow systems, advanced aerodynamics, active controls, and composite structures.

  12. Computational Structures Technology for Airframes and Propulsion Systems (United States)

    Noor, Ahmed K. (Compiler); Housner, Jerrold M. (Compiler); Starnes, James H., Jr. (Compiler); Hopkins, Dale A. (Compiler); Chamis, Christos C. (Compiler)


    This conference publication contains the presentations and discussions from the joint University of Virginia (UVA)/NASA Workshops. The presentations included NASA Headquarters perspectives on High Speed Civil Transport (HSCT), goals and objectives of the UVA Center for Computational Structures Technology (CST), NASA and Air Force CST activities, CST activities for airframes and propulsion systems in industry, and CST activities at Sandia National Laboratory.

  13. Airframe and Powerplant Mechanics Certification Guide. Revised 1971. (United States)

    Federal Aviation Administration (DOT), Washington, DC. Flight Standards Service.

    The guide was prepared to provide information to prospective airframe and powerplant mechanics and other persons interested in the certification of mechanics. The requirements for a mechanic certificate are concerned with age, language ability, experience, knowledge, and skill. The sections of the guide explain the procedure for either…

  14. Avionics and airframe options: current usage and future plans. (United States)

    Mayfield, T; Cady, G


    The 1994 Avionics and Airframe Survey was sent to 178 chief or lead pilots of helicopter emergency medical services (HEMS) programs in October 1993, and 100 (56%) were returned. Sixty-four programs (64%) reported that they operate one helicopter exclusively for EMS, 24 (24%) operate two, and 12 (12%) reported using three or more aircraft. Interestingly, the reported percentage of programs with two or more exclusive helicopters continues to rise, increasing by 5.6% to 36%.

  15. Topology Optimization as a Conceptual Tool for Designing New Airframes



    During the two last decades, topology optimization has grown to be an accepted and used method to produce conceptual designs. Topology optimization is traditionally carried out on a component level, but in this project, the possibility to apply it to airframe design on a full scale aeroplane model is evaluated. The project features a conceptual flying-wing design on which the study is to be carried out. Inertia Relief is used to constrain the aeroplane instead of traditional single point cons...

  16. Construction and materials of airframe resisting severer fleight environment

    Energy Technology Data Exchange (ETDEWEB)

    Sanbongi, Shigeo


    It is unavoidable for any spaceplane to encounter mechanically and thermally severe conditions regardless of the type when taking off and asecending or reentering the atmosphere. The nose part and other parts of smaller curvature are heated to about 1,500/sup 0/C by the friction between air and the airframe. The minimum temperature in the airframe is -253/sup 0/C in the liquid hydrogen tank and it is required for the construction to resist this larger temperature difference and severe mechanical outside load. For these reasons, the airframe side wall is constructed by thermal protection system(PTS), main construction material and insulating material; and suitable materials and constructions must be selected to respective parts. In addition to using different heat resistant materials for PTS, an active mean to cool heated parts with a coolant can be thought. There are much technical accumulations in the USA, and there is large technological gap between Japan and the USA but Japan may display the power with advanced materials. (9 figs, 6 refs)

  17. Fluidic actuators for active flow control on airframe (United States)

    Schueller, M.; Weigel, P.; Lipowski, M.; Meyer, M.; Schlösser, P.; Bauer, M.


    One objective of the European Projects AFLoNext and Clean Sky 2 is to apply Active Flow Control (AFC) on the airframe in critical aerodynamic areas such as the engine/wing junction or the outer wing region for being able to locally improve the aerodynamics in certain flight conditions. At the engine/wing junction, AFC is applied to alleviate or even eliminate flow separation at low speeds and high angle of attacks likely to be associated with the integration of underwing- mounted Ultra High Bypass Ratio (UHBR) engines and the necessary slat-cut-outs. At the outer wing region, AFC can be used to allow more aggressive future wing designs with improved performance. A relevant part of the work on AFC concepts for airframe application is the development of suitable actuators. Fluidic Actuated Flow Control (FAFC) has been introduced as a Flow Control Technology that influences the boundary layer by actively blowing air through slots or holes out of the aircraft skin. FAFC actuators can be classified by their Net Mass Flux and accordingly divided into ZNMF (Zero Net Mass Flux) and NZNMF (Non Zero Net-Mass-Flux) actuators. In the frame of both projects, both types of the FAFC actuator concepts are addressed. In this paper, the objectives of AFC on the airframe is presented and the actuators that are used within the project are discussed.

  18. Should we attempt global (inlet engine airframe) control design? (United States)

    Carlin, C. M.


    The feasibility of multivariable design of the entire airplane control system is briefly addressed. An intermediate step in that direction is to design a control for an inlet engine augmentor system by using multivariable techniques. The supersonic cruise large scale inlet research program is described which will provide an opportunity to develop, integrate, and wind tunnel test a control for a mixed compression inlet and variable cycle engine. The integrated propulsion airframe control program is also discussed which will introduce the problem of implementing MVC within a distributed processing avionics architecture, requiring real time decomposition of the global design into independent modules in response to hardware communication failures.

  19. Development, documentation and correlation of a NASTRAN vibration model of the AH-1G helicopter airframe (United States)

    Cronkhite, J. D.


    NASTRAN was evaluated for vibration analysis of the helicopter airframe. The first effort involved development of a NASTRAN model of the AH-1G helicopter airframe and comprehensive documentation of the model. The next effort was to assess the validity of the NASTRAN model by comparisons with static and vibration tests.

  20. Airframe Noise from a Hybrid Wing Body Aircraft Configuration (United States)

    Hutcheson, Florence V.; Spalt, Taylor B.; Brooks, Thomas F.; Plassman, Gerald E.


    A high fidelity aeroacoustic test was conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel to establish a detailed database of component noise for a 5.8% scale HWB aircraft configuration. The model has a modular design, which includes a drooped and a stowed wing leading edge, deflectable elevons, twin verticals, and a landing gear system with geometrically scaled wheel-wells. The model is mounted inverted in the test section and noise measurements are acquired at different streamwise stations from an overhead microphone phased array and from overhead and sideline microphones. Noise source distribution maps and component noise spectra are presented for airframe configurations representing two different approach flight conditions. Array measurements performed along the aircraft flyover line show the main landing gear to be the dominant contributor to the total airframe noise, followed by the nose gear, the inboard side-edges of the LE droop, the wing tip/LE droop outboard side-edges, and the side-edges of deployed elevons. Velocity dependence and flyover directivity are presented for the main noise components. Decorrelation effects from turbulence scattering on spectral levels measured with the microphone phased array are discussed. Finally, noise directivity maps obtained from the overhead and sideline microphone measurements for the landing gear system are provided for a broad range of observer locations.

  1. Investigation on the use of optimization techniques for helicopter airframe vibrations design studies (United States)

    Sreekanta Murthy, T.


    Results of the investigation of formal nonlinear programming-based numerical optimization techniques of helicopter airframe vibration reduction are summarized. The objective and constraint function and the sensitivity expressions used in the formulation of airframe vibration optimization problems are presented and discussed. Implementation of a new computational procedure based on MSC/NASTRAN and CONMIN in a computer program system called DYNOPT for optimizing airframes subject to strength, frequency, dynamic response, and dynamic stress constraints is described. An optimization methodology is proposed which is thought to provide a new way of applying formal optimization techniques during the various phases of the airframe design process. Numerical results obtained from the application of the DYNOPT optimization code to a helicopter airframe are discussed.

  2. Integrating CFD, CAA, and Experiments Towards Benchmark Datasets for Airframe Noise Problems (United States)

    Choudhari, Meelan M.; Yamamoto, Kazuomi


    Airframe noise corresponds to the acoustic radiation due to turbulent flow in the vicinity of airframe components such as high-lift devices and landing gears. The combination of geometric complexity, high Reynolds number turbulence, multiple regions of separation, and a strong coupling with adjacent physical components makes the problem of airframe noise highly challenging. Since 2010, the American Institute of Aeronautics and Astronautics has organized an ongoing series of workshops devoted to Benchmark Problems for Airframe Noise Computations (BANC). The BANC workshops are aimed at enabling a systematic progress in the understanding and high-fidelity predictions of airframe noise via collaborative investigations that integrate state of the art computational fluid dynamics, computational aeroacoustics, and in depth, holistic, and multifacility measurements targeting a selected set of canonical yet realistic configurations. This paper provides a brief summary of the BANC effort, including its technical objectives, strategy, and selective outcomes thus far.

  3. High Order Wavelet-Based Multiresolution Technology for Airframe Noise Prediction Project (United States)

    National Aeronautics and Space Administration — An integrated framework is proposed for efficient prediction of rotorcraft and airframe noise. A novel wavelet-based multiresolution technique and high-order...

  4. Propulsion airframe integration session overview and review of Lewis PAI efforts (United States)

    Batterton, Peter G.


    Propulsion/Airframe Integration (PAI) is a key issue for the High Speed Civil Transport. The aircraft performance, economics, and environmental acceptability can be adversely affected if the integration of the propulsion system and the airframe is not addressed properly or in a timely manner. Some of the goals are listed in this figure. In particular, these goals are highly influenced by how successfully the propulsion system and airframe are integrated. These goals were grouped by the 'Aero' and 'Propulsion' categories to suggest which group of technologists will likely be addressing them. In terms of the NASA High Speed Research Program, the ultimate objective for propulsion/airframe integration is to demonstrate the technologies for achievement of these goals on a 'single' integrated configuration.

  5. High Order Wavelet-Based Multiresolution Technology for Airframe Noise Prediction Project (United States)

    National Aeronautics and Space Administration — We propose to develop a novel, high-accuracy, high-fidelity, multiresolution (MRES), wavelet-based framework for efficient prediction of airframe noise sources and...

  6. Design and Test of an Improved Crashworthiness Small Composite Airframe (United States)

    Terry, James E.; Hooper, Steven J.; Nicholson, Mark


    The purpose of this small business innovative research (SBIR) program was to evaluate the feasibility of developing small composite airplanes with improved crashworthiness. A combination of analysis and half scale component tests were used to develop an energy absorbing airframe. Four full scale crash tests were conducted at the NASA Impact Dynamics Research Facility, two on a hard surface and two onto soft soil, replicating earlier NASA tests of production general aviation airplanes. Several seat designs and restraint systems including both an air bag and load limiting shoulder harnesses were tested. Tests showed that occupant loads were within survivable limits with the improved structural design and the proper combination of seats and restraint systems. There was no loss of cabin volume during the events. The analysis method developed provided design guidance but time did not allow extending the analysis to soft soil impact. This project demonstrated that survivability improvements are possible with modest weight penalties. The design methods can be readily applied by airplane designers using the examples in this report.

  7. Towards an Airframe Noise Prediction Methodology: Survey of Current Approaches (United States)

    Farassat, Fereidoun; Casper, Jay H.


    In this paper, we present a critical survey of the current airframe noise (AFN) prediction methodologies. Four methodologies are recognized. These are the fully analytic method, CFD combined with the acoustic analogy, the semi-empirical method and fully numerical method. It is argued that for the immediate need of the aircraft industry, the semi-empirical method based on recent high quality acoustic database is the best available method. The method based on CFD and the Ffowcs William- Hawkings (FW-H) equation with penetrable data surface (FW-Hpds ) has advanced considerably and much experience has been gained in its use. However, more research is needed in the near future particularly in the area of turbulence simulation. The fully numerical method will take longer to reach maturity. Based on the current trends, it is predicted that this method will eventually develop into the method of choice. Both the turbulence simulation and propagation methods need to develop more for this method to become useful. Nonetheless, the authors propose that the method based on a combination of numerical and analytical techniques, e.g., CFD combined with FW-H equation, should also be worked on. In this effort, the current symbolic algebra software will allow more analytical approaches to be incorporated into AFN prediction methods.

  8. Calculation of rotor impedance for use in design analysis of helicopter airframe vibrations (United States)

    Nygren, Kip P.


    Excessive vibration is one of the most prevalent technical obstacles encountered in the development of new rotorcraft. The inability to predict these vibrations is primarily due to deficiencies in analysis and simulation tools. The Langley Rotorcraft Structural Dynamics Program was instituted in 1984 to meet long term industry needs in the area of rotorcraft vibration prediction. As a part of the Langley program, this research endeavors to develop an efficient means of coupling the rotor to the airframe for preliminary design analysis of helicopter airframe vibrations. The main effort was to modify the existing computer program for modeling the dynamic and aerodynamic behavior of rotorcraft called DYSCO (DYnamic System COupler) to calculate the rotor impedance. DYSCO was recently developed for the U.S. Army and has proven to be adaptable for the inclusion of new solution methods. The solution procedure developed to use DYSCO for the calculation of rotor impedance is presented. Verification of the procedure by comparison with a known solution for a simple wind turbine model is about 75 percent completed, and initial results are encouraging. After the wind turbine impedance is confirmed, the verification effort will continue by comparison to solutions of a more sophisticated rotorcraft model. Future work includes determination of the sensitivity of the rotorcraft airframe vibrations to helicopter flight conditions and rotor modeling assumptions. When completed, this research will ascertain the feasibility and efficiency of the impedance matching method of rotor-airframe coupling for use in the analysis of airframe vibrations during the preliminary rotorcraft design process.

  9. Overview of the Transport Rotorcraft Airframe Crash Testbed (TRACT) Full Scale Crash Tests (United States)

    Annett, Martin; Littell, Justin


    The Transport Rotorcraft Airframe Crash Testbed (TRACT) full-scale tests were performed at NASA Langley Research Center's Landing and Impact Research Facility in 2013 and 2014. Two CH-46E airframes were impacted at 33-ft/s forward and 25-ft/s vertical combined velocities onto soft soil, which represents a severe, but potentially survivable impact scenario. TRACT 1 provided a baseline set of responses, while TRACT 2 included retrofits with composite subfloors and other crash system improvements based on TRACT 1. For TRACT 2, a total of 18 unique experiments were conducted to evaluate Anthropomorphic Test Devices (ATD) responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and activation of emergency locator transmitters and crash sensors. Combinations of Hybrid II, Hybrid III, and ES-2 ATDs were placed in forward and side facing seats and occupant results were compared against injury criteria. The structural response of the airframe was assessed based on accelerometers located throughout the airframe and using three-dimensional photogrammetric techniques. Analysis of the photogrammetric data indicated regions of maximum deflection and permanent deformation. The response of TRACT 2 was noticeably different in the horizontal direction due to changes in the cabin configuration and soil surface, with higher acceleration and damage occurring in the cabin. Loads from ATDs in energy absorbing seats and restraints were within injury limits. Severe injury was likely for ATDs in forward facing passenger seats.

  10. Global-local Knowledge Coupling Approach to Support Airframe Structural Design

    NARCIS (Netherlands)

    Wang, H.


    The outsourcing that has taken place in the aircraft industry over the last few decades has created a globalized supply chain from and to a limited number of original equipment manufacturers (OEMs). This has led to multi-level design due to the shift from airframe subsystem design to suppliers. Incr

  11. Evaluation of the First Transport Rotorcraft Airframe Crash Testbed (TRACT 1) Full-Scale Crash Test (United States)

    Annett, Martin S.; Littell, Justin D.; Jackson, Karen E.; Bark, Lindley W.; DeWeese, Rick L.; McEntire, B. Joseph


    In 2012, the NASA Rotary Wing Crashworthiness Program initiated the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program by obtaining two CH-46E helicopters from the Navy CH-46E Program Office (PMA-226) at the Navy Flight Readiness Center in Cherry Point, North Carolina. Full-scale crash tests were planned to assess dynamic responses of transport-category rotorcraft under combined horizontal and vertical impact loading. The first crash test (TRACT 1) was performed at NASA Langley Research Center's Landing and Impact Research Facility (LandIR), which enables the study of critical interactions between the airframe, seat, and occupant during a controlled crash environment. The CH-46E fuselage is categorized as a medium-lift rotorcraft with fuselage dimensions comparable to a regional jet or business jet. The first TRACT test (TRACT 1) was conducted in August 2013. The primary objectives for TRACT 1 were to: (1) assess improvements to occupant loads and displacement with the use of crashworthy features such as pre-tensioning active restraints and energy absorbing seats, (2) develop novel techniques for photogrammetric data acquisition to measure occupant and airframe kinematics, and (3) provide baseline data for future comparison with a retrofitted airframe configuration. Crash test conditions for TRACT 1 were 33-ft/s forward and 25-ft/s vertical combined velocity onto soft soil, which represent a severe, but potentially survivable impact scenario. The extraordinary value of the TRACT 1 test was reflected by the breadth of meaningful experiments. A total of 8 unique experiments were conducted to evaluate ATD responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and photogrammetric techniques. A combination of Hybrid II, Hybrid III, and ES-2 Anthropomorphic Test Devices (ATDs) were placed in forward and side facing seats and occupant results were compared against injury criteria. Loads from ATDs in energy

  12. Environmental effects on composite airframes: A study conducted for the ARM UAV Program (Atmospheric Radiation Measurement Unmanned Aerospace Vehicle)

    Energy Technology Data Exchange (ETDEWEB)

    Noguchi, R.A.


    Composite materials are affected by environments differently than conventional airframe structural materials are. This study identifies the environmental conditions which the composite-airframe ARM UAV may encounter, and discusses the potential degradation processes composite materials may undergo when subjected to those environments. This information is intended to be useful in a follow-on program to develop equipment and procedures to prevent, detect, or otherwise mitigate significant degradation with the ultimate goal of preventing catastrophic aircraft failure.

  13. Plan, formulate, discuss and correlate a NASTRAN finite element vibrations model of the Boeing Model 360 helicopter airframe (United States)

    Gabel, R.; Lang, P. F.; Smith, L. A.; Reed, D. A.


    Boeing Helicopter, together with other United States helicopter manufacturers, participated in a finite element applications program to emplace in the United States a superior capability to utilize finite element analysis models in support of helicopter airframe design. The activities relating to planning and creating a finite element vibrations model of the Boeing Model 36-0 composite airframe are summarized, along with the subsequent analytical correlation with ground shake test data.

  14. The Engineering Design of Engine/Airframe Integration for the SAENGER Fully Reusable Space Transportation System (United States)


    Z39-18 1.0 THE GERMAN HYPERSONICS TECHNOLOGY PROGRAM (1988-1995) Fig. 01 SÄNGER/ HTP : Schedule of the German Hypersonics Activities In Germany...Concept Study Preliminary Study  System Study  Propulsion Study  Concept Studies  Basic Technologies  Test facilities  Techn. Dev.+Verific. Concept...Flight Test Vehicle Study  RAM-Engine Dev./Ground Test , SCRAM  Materials/Structures Technology The Engineering Design of Engine/Airframe

  15. Clustering of Parameter Sensitivities: Examples from a Helicopter Airframe Model Updating Exercise


    Shahverdi, H.; C. Mares; W. Wang; J. E. Mottershead


    The need for high fidelity models in the aerospace industry has become ever more important as increasingly stringent requirements on noise and vibration levels, reliability, maintenance costs etc. come into effect. In this paper, the results of a finite element model updating exercise on a Westland Lynx XZ649 helicopter are presented. For large and complex structures, such as a helicopter airframe, the finite element model represents the main tool for obtaining accurate models which could pre...

  16. Experiences at Langley Research Center in the application of optimization techniques to helicopter airframes for vibration reduction (United States)

    Murthy, T. Sreekanta; Kvaternik, Raymond G.


    A NASA/industry rotorcraft structural dynamics program known as Design Analysis Methods for VIBrationS (DAMVIBS) was initiated at Langley Research Center in 1984 with the objective of establishing the technology base needed by the industry for developing an advanced finite-element-based vibrations design analysis capability for airframe structures. As a part of the in-house activities contributing to that program, a study was undertaken to investigate the use of formal, nonlinear programming-based, numerical optimization techniques for airframe vibrations design work. Considerable progress has been made in connection with that study since its inception in 1985. This paper presents a unified summary of the experiences and results of that study. The formulation and solution of airframe optimization problems are discussed. Particular attention is given to describing the implementation of a new computational procedure based on MSC/NASTRAN and CONstrained function MINimization (CONMIN) in a computer program system called DYNOPT for the optimization of airframes subject to strength, frequency, dynamic response, and fatigue constraints. The results from the application of the DYNOPT program to the Bell AH-1G helicopter are presented and discussed.

  17. FAA/NASA International Symposium on Advanced Structural Integrity Methods for Airframe Durability and Damage Tolerance (United States)

    Harris, Charles E. (Editor)


    International technical experts in durability and damage tolerance of metallic airframe structures were assembled to present and discuss recent research findings and the development of advanced design and analysis methods, structural concepts, and advanced materials. The symposium focused on the dissemination of new knowledge and the peer-review of progress on the development of advanced methodologies. Papers were presented on: structural concepts for enhanced durability, damage tolerance, and maintainability; new metallic alloys and processing technology; fatigue crack initiation and small crack effects; fatigue crack growth models; fracture mechanics failure, criteria for ductile materials; structural mechanics methodology for residual strength and life prediction; development of flight load spectra for design and testing; and advanced approaches to resist corrosion and environmentally assisted fatigue.

  18. Toward Improved CFD Predictions of Slender Airframe Aerodynamics Using the F-16XL Aircraft (CAWAPI-2) (United States)

    Luckring, James M.; Rizzi, Arthur; Davis, M. Bruce


    A coordinated project has been underway to improve CFD predictions of slender airframe aerodynamics. The work is focused on two flow conditions and leverages a unique flight data set obtained with an F-16XL aircraft. These conditions, a low-speed high angleof- attack case and a transonic low angle-of-attack case, were selected from a prior prediction campaign wherein the CFD failed to provide acceptable results. In this paper the background, objectives and approach to the current project are presented. The work embodies predictions from multiple numerical formulations that are contributed from multiple organizations, and the context of this campaign to other multi-code, multiorganizational efforts is included. The relevance of this body of work toward future supersonic commercial transport concepts is also briefly addressed.

  19. Fabrication and development of several heat pipe honeycomb sandwich panel concepts. [airframe integrated scramjet engine (United States)

    Tanzer, H. J.


    The feasibility of fabricating and processing liquid metal heat pipes in a low mass honeycomb sandwich panel configuration for application on the NASA Langley airframe-integrated Scramjet engine was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts was evaluated within constraints dictated by existing manufacturing technology and equipment. The chosen design consists of an all-stainless steel structure, sintered screen facesheets, and two types of core-ribbon; a diffusion bonded wire mesh and a foil-screen composite. Cleaning, fluid charging, processing, and process port sealing techniques were established. The liquid metals potassium, sodium and cesium were used as working fluids. Eleven honeycomb panels 15.24 cm X 15.24 cm X 2.94 cm were delivered to NASA Langley for extensive performance testing and evaluation; nine panels were processed as heat pipes, and two panels were left unprocessed.

  20. Numerical investigation of tandem-cylinder aerodynamic noise and its control with application to airframe noise (United States)

    Eltaweel, Ahmed

    Prediction and reduction of airframe noise are critically important to the development of quieter civil transport aircraft. The key to noise reduction is a full understanding of the underlying noise source mechanisms. In this study, tandem cylinders in cross-flow as an idealization of a complex aircraft landing gear configuration are considered to investigate the noise generation and its reduction by flow control using single dielectric barrier discharge plasma actuators. The flow over tandem cylinders at ReD = 22, 000 with and without plasma actuation is computed using large-eddy simulation. The plasma effect is modeled as a body force obtained from a semi-empirical model. The flow statistics and surface pressure frequency spectra show excellent agreement with previous experimental measurements. For acoustic calculations, a boundary-element method is implemented to solve the convected Lighthill equation. The solution method is validated in a number of benchmark problems including flows over a cylinder, a rod-airfoil configuration, and a sphere. With validated flow field and acoustic solver, acoustic analysis is performed for the tandem-cylinder configuration to extend the experimental results and understand the mechanisms of noise generation and its control. Without flow control, the acoustic field is dominated by the interaction between the downstream cylinder and the upstream wake. Through suppression of vortex shedding from the upstream cylinder, the interaction noise is reduced drastically by the plasma flow control, and the vortex-shedding noise from the downstream cylinder becomes equally important. At a free-stream Mach number of 0.2, the peak sound pressure level is reduced by approximately 16 dB. This suggests the viability of plasma actuation for active control of airframe noise. The numerical investigation is extended to the noise from a realistic landing gear experimental model. Coarse-mesh computations are performed, and preliminary results are

  1. State of the Art in Beta Titanium Alloys for Airframe Applications (United States)

    Cotton, James D.; Briggs, Robert D.; Boyer, Rodney R.; Tamirisakandala, Sesh; Russo, Patrick; Shchetnikov, Nikolay; Fanning, John C.


    Beta titanium alloys were recognized as a distinct materials class in the 1950s, and following the introduction of Ti-13V-11Cr-3Al in the early 1960s, intensive research occurred for decades thereafter. By the 1980s, dozens of compositions had been explored and sufficient work had been accomplished to warrant the first major conference in 1983. Metallurgists of the time recognized beta alloys as highly versatile and capable of remarkable property development at much lower component weights than steels, coupled with excellent corrosion resistance. Although alloys such as Ti-15V-3Al-3Sn-3Cr, Ti-10V-2Fe-3Al and Ti-3AI-8V-6Cr-4Mo-4Zr (Beta C) were commercialized into well-known airframe systems by the 1980s, Ti-13V-11Cr-3Al was largely discarded following extensive employment on the SR-71 Blackbird. The 1990s saw the implementation of specialty beta alloys such as Beta 21S and Alloy C, in large part for their chemical and oxidation resistance. It was also predicted that by the 1990s, cost would be the major limitation on expansion into new applications. This turned out to be true and is part of the reason for some stagnation in commercialization of new such compositions over the past two decades, despite a good understanding of the relationships among chemistry, processing, and performance and some very attractive offerings. Since then, only a single additional metastable beta alloy, Ti-5Al-5V-5Mo-3Cr-0.5Fe, has been commercialized in aerospace, although low volumes of other chemistries have found a place in the biomedical implant market. This article examines the evolution of this important class of materials and the current status in airframe applications. It speculates on challenges for expanding their use.

  2. Development of a SMA-Based, Slat-Gap Filler for Airframe Noise Reduction (United States)

    Turner, Travis L.; Long, David L.


    Noise produced by unsteady flow around aircraft structures, termed airframe noise, is an important source of aircraft noise during the approach and landing phases of flight. Conventional leading-edge-slat devices for high lift on typical transport aircraft are a prominent source of airframe noise. Many concepts for slat noise reduction have been investigated. Slat-cove fillers have emerged as an attractive solution, but they maintain the gap flow, leaving some noise production mechanisms unabated, and thus represent a nonoptimal solution. Drooped-leading-edge (DLE) concepts have been proposed as "optimal" because the gap flow is eliminated. The deployed leading edge device is not distinct and separate from the main wing in DLE concepts and the high-lift performance suffers at high angles of attack (alpha) as a consequence. Elusive high-alpha performance and excessive weight penalty have stymied DLE development. The fact that high-lift performance of DLE systems is only affected at high alpha suggests another concept that simultaneously achieves the high-lift of the baseline airfoil and the noise reduction of DLE concepts. The concept involves utilizing a conventional leading-edge slat device and a deformable structure that is deployed from the leading edge of the main wing and closes the gap between the slat and main wing, termed a slat-gap filler (SGF). The deployable structure consists of a portion of the skin of the main wing and it is driven in conjunction with the slat during deployment and retraction. Benchtop models have been developed to assess the feasibility and to study important parameters. Computational models have assisted in the bench-top model design and provided valuable insight in the parameter space as well as the feasibility.

  3. The NASA/Industry Design Analysis Methods for Vibrations (DAMVIBS) Program - Boeing helicopters airframe finite element modeling (United States)

    Gabel, R.; Lang, P.; Reed, D.


    Finite-element modeling of the airframe vibration of the Army/Boeing CH-47D helicopter is conducted with comparisons to experimental data in an effort to improve the design process. A NASTRAN FEM is developed that is fully representative of the test configuration and includes the support fixture, shakers, and the aircraft/shaker suspension system. The analysis is conducted with specific attention given to the prediction of reasonable forced amplitudes throughout the airframe. Reasonable correlation is noted between the FEM and experimental results, although improved correlation can be obtained by including more accurate damping values and secondary effects such as stringer shear loading. It is shown that the general stress model does not provide an adequate dynamic analysis on which to base design improvements. A more detailed model is required that emphasizes highly detailed helicopter elements and employs a finer mesh particularly in the description of the mass distribution.

  4. Toward Establishing a Realistic Benchmark for Airframe Noise Research: Issues and Challenges (United States)

    Khorrami, Mehdi R.


    The availability of realistic benchmark configurations is essential to enable the validation of current Computational Aeroacoustic (CAA) methodologies and to further the development of new ideas and concepts that will foster the technologies of the next generation of CAA tools. The selection of a real-world configuration, the subsequent design and fabrication of an appropriate model for testing, and the acquisition of the necessarily comprehensive aeroacoustic data base are critical steps that demand great care and attention. In this paper, a brief account of the nose landing-gear configuration, being proposed jointly by NASA and the Gulfstream Aerospace Company as an airframe noise benchmark, is provided. The underlying thought processes and the resulting building block steps that were taken during the development of this benchmark case are given. Resolution of critical, yet conflicting issues is discussed - the desire to maintain geometric fidelity versus model modifications required to accommodate instrumentation; balancing model scale size versus Reynolds number effects; and time, cost, and facility availability versus important parameters like surface finish and installation effects. The decisions taken during the experimental phase of a study can significantly affect the ability of a CAA calculation to reproduce the prevalent flow conditions and associated measurements. For the nose landing gear, the most critical of such issues are highlighted and the compromises made to resolve them are discussed. The results of these compromises will be summarized by examining the positive attributes and shortcomings of this particular benchmark case.

  5. Clustering of Parameter Sensitivities: Examples from a Helicopter Airframe Model Updating Exercise

    Directory of Open Access Journals (Sweden)

    H. Shahverdi


    Full Text Available The need for high fidelity models in the aerospace industry has become ever more important as increasingly stringent requirements on noise and vibration levels, reliability, maintenance costs etc. come into effect. In this paper, the results of a finite element model updating exercise on a Westland Lynx XZ649 helicopter are presented. For large and complex structures, such as a helicopter airframe, the finite element model represents the main tool for obtaining accurate models which could predict the sensitivities of responses to structural changes and optimisation of the vibration levels. In this study, the eigenvalue sensitivities with respect to Young's modulus and mass density are used in a detailed parameterisation of the structure. A new methodology is developed using an unsupervised learning technique based on similarity clustering of the columns of the sensitivity matrix. An assessment of model updating strategies is given and comparative results for the correction of vibration modes are discussed in detail. The role of the clustering technique in updating large-scale models is emphasised.

  6. Unsteady Flowfield Around Tandem Cylinders as Prototype for Component Interaction in Airframe Noise (United States)

    Khorrami, Meldi R.; Choudhari, Meelan M.; Jenkins, Luther N.; McGinley, Catherine B.


    Synergistic application of experiments and numerical simulations is crucial to understanding the underlying physics of airframe noise sources. The current effort is aimed at characterizing the details of the flow interaction between two cylinders in a tandem configuration. This setup is viewed to be representative of several component-level flow interactions that occur when air flows over the main landing gear of large civil transports. Interactions of this type are likely to have a significant impact on the noise radiation associated with the aircraft undercarriage. The paper is focused on two-dimensional, time-accurate flow simulations for the tandem cylinder configuration. Results of the unsteady Reynolds Averaged Navier-Stokes (URANS) computations with a two-equation turbulence model, at a Reynolds number of 0.166 million and a Mach number of 0.166, are presented. The experimental measurements of the same flow field are discussed in a separate paper by Jenkins, Khorrami, Choudhari, and McGinley (2005). Two distinct flow regimes of interest, associated with short and intermediate separation distances between the two cylinders, are considered. Emphasis is placed on understanding both time averaged and unsteady flow features between the two cylinders and in the wake of the rear cylinder. Predicted mean flow quantities and vortex shedding frequencies show reasonable agreement with the measured data for both cylinder spacings. Computations for short separation distance indicate decay of flow unsteadiness with time, which is not unphysical; however, the predicted sensitivity of mean lift coefficient to small angles of attack explains the asymmetric flowfield observed during the experiments.

  7. Calibration of Airframe and Occupant Models for Two Full-Scale Rotorcraft Crash Tests (United States)

    Annett, Martin S.; Horta, Lucas G.; Polanco, Michael A.


    Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. Accelerations and kinematic data collected from the crash tests were compared to a system integrated finite element model of the test article. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the second full-scale crash test. This combination of heuristic and quantitative methods was used to identify modeling deficiencies, evaluate parameter importance, and propose required model changes. It is shown that the multi-dimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were compared to test results and the original model results. There was a noticeable improvement in the pilot and co-pilot region, a slight improvement in the occupant model response, and an over-stiffening effect in the passenger region. This approach should be adopted early on, in combination with the building-block approaches that are customarily used, for model development and test planning guidance. Complete crash simulations with validated finite element models can be used

  8. Insights into Airframe Aerodynamics and Rotor-on-Wing Interactions from a 0.25-Scale Tiltrotor Wind Tunnel Model (United States)

    Young, L. A.; Lillie, D.; McCluer, M.; Yamauchi, G. K.; Derby, M. R.


    A recent experimental investigation into tiltrotor aerodynamics and acoustics has resulted in the acquisition of a set of data related to tiltrotor airframe aerodynamics and rotor and wing interactional aerodynamics. This work was conducted in the National Full-scale Aerodynamics Complex's (NFAC) 40-by-80 Foot Wind Tunnel, at NASA Ames Research Center, on the Full-Span Tilt Rotor Aeroacoustic Model (TRAM). The full-span TRAM wind tunnel test stand is nominally based on a quarter-scale representation of the V-22 aircraft. The data acquired will enable the refinement of analytical tools for the prediction of tiltrotor aeromechanics and aeroacoustics.

  9. The NASA/industry Design Analysis Methods for Vibrations (DAMVIBS) program: Boeing Helicopters airframe finite element modeling (United States)

    Gabel, R.; Lang, P.; Reed, D.


    Mathematical models based on the finite element method of structural analysis, as embodied in the NASTRAN computer code, are routinely used by the helicopter industry to calculate airframe static internal loads used for sizing structural members. Historically, less reliance has been placed on the vibration predictions based on these models. Beginning in the early 1980's NASA's Langley Research Center initiated an industry wide program with the objective of engendering the needed trust in vibration predictions using these models and establishing a body of modeling guides which would enable confident future prediction of airframe vibration as part of the regular design process. Emphasis in this paper is placed on the successful modeling of the Army/Boeing CH-47D which showed reasonable correlation with test data. A principal finding indicates that improved dynamic analysis requires greater attention to detail and perhaps a finer mesh, especially the mass distribution, than the usual stress model. Post program modeling efforts show improved correlation placing key modal frequencies in the b/rev range with 4 percent of the test frequencies.

  10. An artificial neural network approach for aerodynamic performance retention in airframe noise reduction design of a 3D swept wing model

    Directory of Open Access Journals (Sweden)

    Tao Jun


    Full Text Available With the progress of high-bypass turbofan and the innovation of silencing nacelle in engine noise reduction, airframe noise has now become another important sound source besides the engine noise. Thus, reducing airframe noise makes a great contribution to the overall noise reduction of a civil aircraft. However, reducing airframe noise often leads to aerodynamic performance loss in the meantime. In this case, an approach based on artificial neural network is introduced. An established database serves as a basis and the training sample of a back propagation (BP artificial neural network, which uses confidence coefficient reasoning method for optimization later on. Then the most satisfactory configuration is selected for validating computations through the trained BP network. On the basis of the artificial neural network approach, an optimization process of slat cove filler (SCF for high lift devices (HLD on the Trap Wing is presented. Aerodynamic performance of both the baseline and optimized configurations is investigated through unsteady detached eddy simulations (DES, and a hybrid method, which combines unsteady DES method with acoustic analogy theory, is employed to validate the noise reduction effect. The numerical results indicate not merely a significant airframe noise reduction effect but also excellent aerodynamic performance retention simultaneously.

  11. An artificial neural network approach for aerodynamic performance retention in airframe noise reduction design of a 3D swept wing model

    Institute of Scientific and Technical Information of China (English)

    Tao Jun; Sun Gang


    With the progress of high-bypass turbofan and the innovation of silencing nacelle in engine noise reduction, airframe noise has now become another important sound source besides the engine noise. Thus, reducing airframe noise makes a great contribution to the overall noise reduction of a civil aircraft. However, reducing airframe noise often leads to aerodynamic perfor-mance loss in the meantime. In this case, an approach based on artificial neural network is intro-duced. An established database serves as a basis and the training sample of a back propagation (BP) artificial neural network, which uses confidence coefficient reasoning method for optimization later on. Then the most satisfactory configuration is selected for validating computations through the trained BP network. On the basis of the artificial neural network approach, an optimization pro-cess of slat cove filler (SCF) for high lift devices (HLD) on the Trap Wing is presented. Aerody-namic performance of both the baseline and optimized configurations is investigated through unsteady detached eddy simulations (DES), and a hybrid method, which combines unsteady DES method with acoustic analogy theory, is employed to validate the noise reduction effect. The numerical results indicate not merely a significant airframe noise reduction effect but also excel-lent aerodynamic performance retention simultaneously.

  12. Summary of the Tandem Cylinder Solutions from the Benchmark Problems for Airframe Noise Computations-I Workshop (United States)

    Lockard, David P.


    Fifteen submissions in the tandem cylinders category of the First Workshop on Benchmark problems for Airframe Noise Computations are summarized. Although the geometry is relatively simple, the problem involves complex physics. Researchers employed various block-structured, overset, unstructured and embedded Cartesian grid techniques and considerable computational resources to simulate the flow. The solutions are compared against each other and experimental data from 2 facilities. Overall, the simulations captured the gross features of the flow, but resolving all the details which would be necessary to compute the noise remains challenging. In particular, how to best simulate the effects of the experimental transition strip, and the associated high Reynolds number effects, was unclear. Furthermore, capturing the spanwise variation proved difficult.

  13. Plan, execute, and discuss vibration measurements and correlations to evaluate a NASTRAN finite element model of the AH-64 helicopter airframe (United States)

    Ferg, D.; Foote, L.; Korkosz, G.; Straub, F.; Toossi, M.; Weisenburger, R.


    A ground vibration test was performed on the AH-64 (Apache) helicopter to determine the frequency response of the airframe. The structure was excited at both the main and tail rotor hubs, separately, and response measurements were taken at 102 locations throughout the fuselage structure. Frequency responses were compared and correlated with results from a NASTRAN finite element model of AH-64. In addition, natural frequencies and mode shapes were estimated from the frequency response data and were correlated with analytical results.

  14. Technology transfer and other public policy implications of multi-national arrangements for the production of commercial airframes (United States)

    Gellman, A. J.; Price, J. P.


    A study to examine the question of technology transfer through international arrangements for production of commercial transport aircraft is presented. The likelihood of such transfer under various representative conditions was determined and an understanding of the economic motivations for, effects of, joint venture arrangements was developed. Relevant public policy implications were also assessed. Multinational consortia with U.S. participation were focused upon because they generate the full range of pertinent public issues (including especially technology transfer), and also because of recognized trends toward such arrangements. An extensive search and analysis of existing literature to identify the key issues, and in-person interviews with executives of U.S. and European commercial airframe producers was reviewed. Distinctions were drawn among product-embodied, process, and management technologies in terms of their relative possibilities of transfer and the significance of such transfer. Also included are observations on related issues such as the implications of U.S. antitrust policy with respect to the formation of consortia and the competitive viability of the U.S. aircraft manufacturing industry.

  15. Development and Calibration of a Field-Deployable Microphone Phased Array for Propulsion and Airframe Noise Flyover Measurements (United States)

    Humphreys, William M., Jr.; Lockard, David P.; Khorrami, Mehdi R.; Culliton, William G.; McSwain, Robert G.; Ravetta, Patricio A.; Johns, Zachary


    A new aeroacoustic measurement capability has been developed consisting of a large channelcount, field-deployable microphone phased array suitable for airframe noise flyover measurements for a range of aircraft types and scales. The array incorporates up to 185 hardened, weather-resistant sensors suitable for outdoor use. A custom 4-mA current loop receiver circuit with temperature compensation was developed to power the sensors over extended cable lengths with minimal degradation of the signal to noise ratio and frequency response. Extensive laboratory calibrations and environmental testing of the sensors were conducted to verify the design's performance specifications. A compact data system combining sensor power, signal conditioning, and digitization was assembled for use with the array. Complementing the data system is a robust analysis system capable of near real-time presentation of beamformed and deconvolved contour plots and integrated spectra obtained from array data acquired during flyover passes. Additional instrumentation systems needed to process the array data were also assembled. These include a commercial weather station and a video monitoring / recording system. A detailed mock-up of the instrumentation suite (phased array, weather station, and data processor) was performed in the NASA Langley Acoustic Development Laboratory to vet the system performance. The first deployment of the system occurred at Finnegan Airfield at Fort A.P. Hill where the array was utilized to measure the vehicle noise from a number of sUAS (small Unmanned Aerial System) aircraft. A unique in-situ calibration method for the array microphones using a hovering aerial sound source was attempted for the first time during the deployment.

  16. Airframe/Propulsion Interference (United States)


    Ij % R 5 T Tc V Ifevre de sortie de la tuyfere secondaire, coefficient de frottement parietal. " d1 injection g&ieralis^. " de poussee...dufrottement sur la tuyere seocndaire est base sur la relation de Ludwieg et Tlllman aui donne le coefficient de frottement incompressible T/i en...fuseau d’une soufflante miniaturiste entrafnee par une turbine k air comprimt ; dans ce cas l’ecart des coefficients de dibit captes entre la maquette

  17. Corrosion in airframes




    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...





    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  19. Ramjets: Airframe integration

    NARCIS (Netherlands)

    Moerel, J.L.; Halswijk, W.


    These notes deal with the integration of a (sc)ramjet engine in either an axisymmetric or a waverider type of cruise missile configuration. The integration aspects relate to the integration of the external and internal flow paths in geometrical configurations that are being considered worldwide. Int

  20. 利用机体遮挡实现机载抗干扰通信%Airborne Anti-jamming Communication by Airframe Antenna Shading

    Institute of Scientific and Technical Information of China (English)

    曹劲; 彭笠


    According to the engineering requirement of airborne anti-jamming communication design,the airframe shading effect on typical forward,rear,left and right distributed VHF/UHF and L-band antennas on the airplane is analyzed. Based on the principle of signal suppression by airframe shading,an anti-jam-ming communication method is proposed by smartly using the left or right wing mounted antenna which faces the communication signal when communication and interference signal comes from different sides of the airplane respectively. The method can be realized easily in engineering because it only needs two new installed wing mounted antennas and two RF switches. The simulation result shows that the method can ef-fectively suppress the interference signal reception from the side of the airplane and the maximal suppres-sion can reach 35 dB. The method provides a new technical solution and theoretical implemental guide for airborne anti-jamming communication design.%结合机载通信抗干扰设计的工程应用需求,分析了机体遮挡对机身前后左右典型安装位置VHF/UHF和L频段通信天线的影响程度,提出了一种当通信信号和干扰信号分别位于机身两侧时,应用机体遮挡对信号接收的抑制原理,通过选择指向通信信号一侧的左或右机翼天线实现抗干扰通信的方法。该方法仅需新增两副机翼天线和两个射频开关,具备较强的工程可实现性。仿真结果表明该方法能够有效抑制来自机身侧面干扰信号的接收,最大抑制达到35 dB,为机载通信抗干扰能力提升设计提供了新的技术途径和理论指导。

  1. Small Airframe Manufacturer's Icing Perspective (United States)

    Hoppins, Jim


    This viewgraph presentation describes the icing effects, risk mitigation practices, and icing certifications for various Cessna small aircraft models. NASA's role in the development of simulation tools for icing certifications is also discussed.

  2. Multi-Layered Integrated Airframe System Project (United States)

    National Aeronautics and Space Administration — This proposed Phase II program builds on the Phase I effort addressing NASA's future mission requirements by: 1) developing higher performing TPS materials capable...

  3. Airframe noise measurements by acoustic imaging (United States)

    Kendall, J. M.


    Studies of the noise produced by flow past wind tunnel models are presented. The central objective of these is to find the specific locations within a flow which are noisy, and to identify the fluid dynamic processes responsible, with the expectation that noise reduction principles will be discovered. The models tested are mostly simple shapes which result in types of flow that are similar to those occurring on, for example, aircraft landing gear and wheel cavities. A model landing gear and a flap were also tested. Turbulence has been intentionally induced as appropriate in order to simulate full-scale effects more closely. The principal technique involves use of a highly directional microphone system which is scanned about the flow field to be analyzed. The data so acquired are presented as a pictorial image of the noise source distribution. An important finding is that the noise production is highly variable within a flow field and that sources can be attributed to various fluid dynamic features of the flow. Flow separation was not noisy, but separation closure usually was.

  4. Multi-Layered Integrated Airframe System Project (United States)

    National Aeronautics and Space Administration — NASA has a need to develop higher performance ablative thermal protection systems (TPS) than is currently available for future exploration of our solar system's...

  5. A Critique of Aircraft Airframe Cost Models. (United States)


    rframes Aircraft Cost Analysis 2C *3Si PACT [’Cor.rinu* an r+vrmm »lam ti omc +mmmfy mr.J tffonUtf t>f Met.* riutnfcor) see reverse side...numbers, however, the ASD Cost Escalation Re- ft port 110-C would give a factor of 1.44.) 6 Historiaal and Forecasted Aeronautical Cost Indices

  6. Toward the direct design of waverider airframes (United States)

    Kinsey, Dawn Daniel


    A waverider is a hypersonic vehicle that keeps the bow shock attached to its leading edges. This class of vehicles originated in the late 1950's as a theoretical construct. Since the late 1980's there has been a resurgence of waverider research and an explosion of waverider applications. Waveriders have traditionally been and are still primarily designed using inverse methods, wherein the flowfield is known and the body surfaces are formed by collecting streamlines or streamsurfaces out of the flowfield. In the work presented here, the advantages of using a more conventional direct-design method for waveriders are investigated. The tools necessary to construct a practical Computational Fluid Dynamics design code are evaluated. As a start, a 3-D steady Euler code is built. The code uses an adaptive Cartesian mesh which allows arbitrary body shapes. The strengths and weaknesses of the code and direct-design method will be discussed. Several test cases and a simple design study are performed. These show that off-design conditions are easily simulated. A case study reveals that small changes in the body shape can significantly impact the lift-to-drag ratio. This points to an advantage of the direct-design method. Because the direct method does not constrain the design space, it can be used to look for optimum shapes between those found using inverse methods.

  7. 14 CFR Appendix C to Part 147 - Airframe Curriculum Subjects (United States)


    ..., service, and repair heating, cooling, air conditioning, pressurization systems, and air cycle machines. (1) 34. Inspect, check, troubleshoot, service, and repair heating, cooling, air-conditioning, and... systems and both mechanical and electrical heading, speed, altitude, temperature, pressure, and...

  8. Multifunctional Core Materials for Airframe Primary Structures Project (United States)

    National Aeronautics and Space Administration — As the use of composite materials on commercial airlines grows the technology of the composites must grow with it. Presently the efficiency gained by the utilization...

  9. Bird or bat: comparing airframe design and flight performance. (United States)

    Hedenström, Anders; Johansson, L Christoffer; Spedding, Geoffrey R


    Birds and bats have evolved powered flight independently, which makes a comparison of evolutionary 'design' solutions potentially interesting. In this paper we highlight similarities and differences with respect to flight characteristics, including morphology, flight kinematics, aerodynamics, energetics and flight performance. Birds' size range is 0.002-15 kg and bats' size range is 0.002-1.5 kg. The wingbeat kinematics differ between birds and bats, which is mainly due to the different flexing of the wing during the upstroke and constraints by having a wing of feathers and a skin membrane, respectively. Aerodynamically, bats appear to generate a more complex wake than birds. Bats may be more closely adapted for slow maneuvering flight than birds, as required by their aerial hawking foraging habits. The metabolic rate and power required to fly are similar among birds and bats. Both groups share many characteristics associated with flight, such as for example low amounts of DNA in cells, the ability to accumulate fat as fuel for hibernation and migration, and parallel habitat-related wing shape adaptations.

  10. Study to Improve Airframe Turbine Engine Rotor Blade Containment (United States)


    high turbine, and low turbine were determined.* It was assumed that multiple blade fragments behaved as a single mass equivalent to the mass sum of in the low turbine area generally produces detectable noise, thrust losses and vibration and in all probability the engine would be shut down

  11. Parallel Tracking and Mapping for Controlling VTOL Airframe

    Directory of Open Access Journals (Sweden)

    Michal Jama


    Full Text Available This work presents a vision based system for navigation on a vertical takeoff and landing unmanned aerial vehicle (UAV. This is a monocular vision based, simultaneous localization and mapping (SLAM system, which measures the position and orientation of the camera and builds a map of the environment using a video stream from a single camera. This is different from past SLAM solutions on UAV which use sensors that measure depth, like LIDAR, stereoscopic cameras or depth cameras. Solution presented in this paper extends and significantly modifies a recent open-source algorithm that solves SLAM problem using approach fundamentally different from a traditional approach. Proposed modifications provide the position measurements necessary for the navigation solution on a UAV. The main contributions of this work include: (1 extension of the map building algorithm to enable it to be used realistically while controlling a UAV and simultaneously building the map; (2 improved performance of the SLAM algorithm for lower camera frame rates; and (3 the first known demonstration of a monocular SLAM algorithm successfully controlling a UAV while simultaneously building the map. This work demonstrates that a fully autonomous UAV that uses monocular vision for navigation is feasible.

  12. Aircraft Scheduled Airframe Maintenance and Downtime Integrated Cost Model

    Directory of Open Access Journals (Sweden)

    Remzi Saltoğlu


    Full Text Available Aviation industry has grown rapidly since the first scheduled commercial aviation started one hundred years ago. There is a fast growth in the number of passengers, routes, and frequencies, with high revenues and low margins, which make this industry one of the most challenging businesses in the world. Every operator aims to undertake the minimum operating cost and gain profit as much as possible. One of the significant elements of operator’s operating cost is the maintenance cost. During maintenance scheduling, operator calculates the maintenance cost that it needs to budget. Previous works show that this calculation includes only costs that are directly related to the maintenance process such as cost of labor, material, and equipment. In some cases, overhead cost is also included. Some of previous works also discuss the existence of another cost throughout aircraft downtime, which is defined as cost of revenue loss. Nevertheless, there is not any standard model that shows how to define and calculate downtime cost. For that reason, the purpose of this paper is to introduce a new model and analysis technique that can be used to calculate aircraft downtime cost due to maintenance.

  13. Landing Gear Door Liners for Airframe Noise Reduction (United States)

    Jones, Michael G. (Inventor); Howerton, Brian M. (Inventor); Van De Ven, Thomas (Inventor)


    A landing gear door for retractable landing gear of aircraft includes an acoustic liner. The acoustic liner includes one or more internal cavities or chambers having one or more openings that inhibit the generation of sound at the surface and/or absorb sound generated during operation of the aircraft. The landing gear door may include a plurality of internal chambers having different geometries to thereby absorb broadband noise.

  14. Structural-Acoustic Simulations in Early Airframe Design Project (United States)

    National Aeronautics and Space Administration — The structural design during the early development of an aircraft focuses on strength, fatigue, corrosion, maintenance, inspection, and manufacturing. Usually the...

  15. Feedback strategies for visual search in airframe structural inspection. (United States)

    Gramopadhye, A K; Drury, C G; Sharit, J


    Feedback of information has consistently shown positive results in human inspection, provided it is given in a timely and appropriate manner. Feedback serves as the basis of most training schemes; traditionally this has been performance feedback. Other forms of feedback which provide strategy information rather than performance information may have a role in improving inspection. This study compared performance feedback and cognitive feedback in a realistic simulation of an aircraft structural inspection task. Performance (time, errors) feedback showed the greatest improvements in performance measures. Cognitive feedback enhanced efficiency measures of search strategy. When cognitive feedback consisted of visual representations of the path and the coverage of the search sequence, subjects also were able to use this task information to improve their search performance.

  16. Low-frequency noise reduction of lightweight airframe structures (United States)

    Getline, G. L.


    The results of an experimental study to determine the noise attenuation characteristics of aircraft type fuselage structural panels were presented. Of particular interest was noise attenuation at low frequencies, below the fundamental resonances of the panels. All panels were flightweight structures for transport type aircraft in the 34,050 to 45,400 kg (75,000 to 100,000 pounds) gross weight range. Test data include the results of vibration and acoustic transmission loss tests on seven types of isotropic and orthotropically stiffened, flat and curved panels. The results show that stiffness controlled acoustically integrated structures can provide very high noise reductions at low frequencies without significantly affecting their high frequency noise reduction capabilities.

  17. Characterization of Unsteady Flow Structures Around Tandem Cylinders for Component Interaction Studies in Airframe Noise (United States)

    Jenkins, Luther N.; Khorrami, Mehdi R.; Choudhari, Meelan M.; McGinley, Catherine B.


    A joint computational and experimental study has been performed at NASA Langley Research Center to investigate the unsteady flow generated by the components of an aircraft landing gear system. Because the flow field surrounding a full landing gear is so complex, the study was conducted on a simplified geometry consisting of two cylinders in tandem arrangement to isolate and characterize the pertinent flow phenomena. This paper focuses on the experimental effort where surface pressures, 2-D Particle Image Velocimetry, and hot-wire anemometry were used to document the flow interaction around the two cylinders at a Reynolds Number of 1.66 x 10(exp 5), based on cylinder diameter, and cylinder spacing-todiameter ratios, L/D, of 1.435 and 3.70. Transition strips were applied to the forward cylinder to produce a turbulent boundary layer upstream of the flow separation. For these flow conditions and L/D ratios, surface pressures on both the forward and rear cylinders show the effects of L/D on flow symmetry, base pressure, and the location of flow separation and attachment. Mean velocities and instantaneous vorticity obtained from the PIV data are used to examine the flow structure between and aft of the cylinders. Shedding frequencies and spectra obtained using hot-wire anemometry are presented. These results are compared with unsteady, Reynolds-Averaged Navier-Stokes (URANS) computations for the same configuration in a companion paper by Khorrami, Choudhari, Jenkins, and McGinley (2005). The experimental dataset produced in this study provides information to better understand the mechanisms associated with component interaction noise, develop and validate time-accurate computer methods used to calculate the unsteady flow field, and assist in modeling of the radiated noise from landing gears.

  18. Evaluation of Airframe Noise Reduction Concepts via Simulations Using a Lattice Boltzmann Approach (United States)

    Fares, Ehab; Casalino, Damiano; Khorrami, Mehdi R.


    Unsteady computations are presented for a high-fidelity, 18% scale, semi-span Gulfstream aircraft model in landing configuration, i.e. flap deflected at 39 degree and main landing gear deployed. The simulations employ the lattice Boltzmann solver PowerFLOW® to simultaneously capture the flow physics and acoustics in the near field. Sound propagation to the far field is obtained using a Ffowcs Williams and Hawkings acoustic analogy approach. In addition to the baseline geometry, which was presented previously, various noise reduction concepts for the flap and main landing gear are simulated. In particular, care is taken to fully resolve the complex geometrical details associated with these concepts in order to capture the resulting intricate local flow field thus enabling accurate prediction of their acoustic behavior. To determine aeroacoustic performance, the farfield noise predicted with the concepts applied is compared to high-fidelity simulations of the untreated baseline configurations. To assess the accuracy of the computed results, the aerodynamic and aeroacoustic impact of the noise reduction concepts is evaluated numerically and compared to experimental results for the same model. The trends and effectiveness of the simulated noise reduction concepts compare well with measured values and demonstrate that the computational approach is capable of capturing the primary effects of the acoustic treatment on a full aircraft model.

  19. ICAM Manufacturing Cost/Design Guide. Volume 3. Airframes. User’s Manual. (United States)



  20. A Comparative Study of Learning Curve Models in Defense Airframe Cost Estimating (United States)


    high end sports car . The level of precision and craftsmanship required eliminates the use for certain automated 64 processes that may be present in...production process that is automated . A Bureau of Labor Statistics report identifies that percentage as very low but does not give an exact number...production of an automobile. While the process and parts are always the same, a savvy car buyer may want to avoid cars that were built on a Monday or

  1. Top 10 Airframe MROs%世界机体维修企业排行榜

    Institute of Scientific and Technical Information of China (English)

    Lee Ann Tegtmeier



  2. Tension and Bending Testing of an Integral T-Cap for Stitched Composite Airframe Joints (United States)

    Lovejoy, Andrew E.; Leone, Frank A., Jr.


    The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a structural concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body aircraft configuration. An important design feature required for assembly is the integrally stitched T-cap, which provides connectivity of the corner (orthogonal) joint between adjacent panels. A series of tests were conducted on T-cap test articles, with and without a rod stiffener penetrating the T-cap web, under tension (pull-off) and bending loads. Three designs were tested, including the baseline design used in large-scale test articles. The baseline had only the manufacturing stitch row adjacent to the fillet at the base of the T-cap web. Two new designs added stitching rows to the T-cap web at either 0.5- or 1.0-inch spacing along the height of the web. Testing was conducted at NASA Langley Research Center to determine the behavior of the T-cap region resulting from the applied loading. Results show that stitching arrests the initial delamination failures so that the maximum strength capability exceeds the load at which the initial delaminations develop. However, it was seen that the added web stitching had very little effect on the initial delamination failure load, but actually decreased the initial delamination failure load for tension loading of test articles without a stiffener passing through the web. Additionally, the added web stitching only increased the maximum load capability by between 1% and 12.5%. The presence of the stiffener, however, did increase the initial and maximum loads for both tension and bending loading as compared to the stringerless baseline design. Based on the results of the few samples tested, the additional stitching in the T-cap web showed little advantage over the baseline design in terms of structural failure at the T-cap web/skin junction for the current test articles.

  3. Digital Load Control Applied to Full-Scale Airframe Fatigue Tests (United States)


    77 ’ iELT A19 AFFDL-TR-79-3011 The zero steady-state error is consistent with the model even with the bias, i.e.: REF KpS + Ki K C The response of...TASK COMMUNICATIONS BCS ERR3 IF ERROR LEAVE .GTJB #AREA,#JOE:BLK ;GET JOE: PARAMS .DEYICE #AREA,#DEYE-LK PREPARE "C RETURN: MOY ERRCNT, R@ UPDATE ISTAT

  4. Weapon System Costing Methodology for Aircraft Airframes and Basic Structures. Volume I. Technical Volume (United States)


    specifications, or other data, is not to be regarded by implication or otherwise as in any manner licensing the holder or any other person or...COSTl COSTC CObTC COSTC CÜSTC COSTC COSTC COsTo CObTC CObTC CObTC CObTC >- COSTC ( J" I i,. 1L CObTC. ,n .,-L I 1 W i> 1 u , fl

  5. A NASTRAN Vibration Model of the AH-1G Helicopter Airframe. Volume 2 (United States)


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  6. Micro-mechanical damage accumulation in airframe materials and structural components (United States)

    Tiku, Sanjay

    A simple and flexible ACPD probe design methodology incorporating current focusing technique was developed for on-line as well as off-line measurements in laboratory and industrial scale test environments. The effectiveness of the current focusing technique and the resulting three-dimensional control of the current density distribution was demonstrated. The ACPD technique was successfully used to obtain strain calibration and crack calibration curves in 7075 Al alloys. This also included quantifying the effect of residual stresses on ACPD signal. The smallest crack depth detected was 140 mum at 120 kHz, 5 amp. and 3000 gain. A quadratic relation was found to correlate crack depth with potential change. The ACPD sensors were installed on a F-18 aircraft undergoing full scale test at Canadair. The sensors were able to measure the response of the structure to spectrum loading. A crack was detected by the ACPD sensors only after 3400 SFH and it was established that ACPD probes were able to detect the crack long before (˜2500 SFH) any other established techniques utilized by DND/Canadair was able to detect the crack. The technique was successfully used to characterize short crack growth behaviour of naturally initiated fatigue cracks in Al alloys from 40 mum crack depth onwards. The cracks were semi-elliptical in shape and crack growth along the notch root was faster than crack growth into the specimen. The effect of various grain orientations on short crack growth behaviour was studied. The crack tip interactions with grain boundaries were shown to control the SCG behaviour of Al alloys even at notch root peak stresses close to yield stress of the material. This effect was less prominent at notch root peak stresses considerably higher than yield stresses. The fatigue crack growth rates were correlated with the SIF (K) calculated using Newman's model for thumb nail cracks. This correlation resulted in a very large scatter in the data. The fatigue crack growth rate data were better correlated using modified parameters, DeltaK2 /sigma and DeltaK/C.

  7. Mechanical Properties and Fatigue Behavior of Unitized Composite Airframe Structures at Elevated Temperature (United States)


    T5 T5-8 25 MS3-2 ±45° T6 T6-2 19 After labeling, the gage section width and thickness was measured using a Mitutoyo Absolute Solar Digimatic Caliper...solution of soap and water and thoroughly rinsed with distilled water in order to remove contaminants from the machining process. After cleaning, specimens...section width and thickness was measured using a Mitutoyo Absolute Solar Digimatic Caliper, Model N0. CD-S6”CT. Specimen thickness varied slightly from

  8. Integrated Airframe Design Technology (Les Technologies pour la Conception Integree des Cellules) (United States)


    influencing the variables such as frequencies, system outcome. Each participant can displacements, and cyclic strains, are provide information on the...18E/F Optimized Wing Thickness The system was also used by MDC during the proposal phase of the Single Stage Rocket Technology ( SSRT ) program. The

  9. A NASTRAN Vibration Model of the AH-1G Helicopter Airframe. Volume 1 (United States)


    9303 ... 456 AAA . . 123 DCC 9307 456 AAA - - 123 DCC 1 9313 456 AAA - - 123 DCC 9317 456 AAA - 13 OC 9331 456 AAA - - 123 DC 9333 456 AAA...DCC 9313 456 AAA - - 123 DCC 11503 3456 AAAA - - 12 DC 13801 456 AAA - 123 DCC 13803 456 AAA - - 123 DCC 13821 456 AAA - - 123 DCC , 14801...TO300— -«^*6 -11. .4M 8 0.0 -3. 276 -13, .452 9 0.0 5. 174 -13. ,472 10 n _ ft o en 13,274 -11. ,622 11 0.0 19. 194 -3. ,?62 SECTICN PPQofRTlES A^ EA

  10. High Maneuverability Airframe: Investigation of Fin and Canard Sizing for Optimum Maneuverability (United States)


    mass properties, and aerodynamics were perturbed. Monte Carlo techniques were applied in the simulations. 46 The trajectory and aerodynamic angle...Projectile 82 1 DEFENSE TECHNICAL (PDF) INFORMATION CTR DTIC OCA 2 DIRECTOR (PDF) US ARMY RESEARCH LAB RDRL CIO LL IMAL HRA MAIL

  11. Mesh Independent Probabilistic Residual Life Prediction of Metallic Airframe Structures Project (United States)

    National Aeronautics and Space Administration — Global Engineering and Materials, Inc. (GEM) along with its team members, Clarkson University and LM Aero, propose to develop a mesh independent probabilistic...

  12. Source Book of World War II Basic Data - Airframe Industry. Volume 1. Direct Man-Hours - Progress Curves (United States)


    13333 8300 1 01 2941 16000 6 17021 7S00 2 18 • ISO 35000» 2 35714 11500 3 11 IS 16000 7 17204 7800 2 21 蛷 15500 S 16818 7S00 2...281938 31 412954 48100 8.59 10 1407 22 ISO ! 1300 1.39 5518 230171 31 333581 4S100 0.94 15 1389 22 17S1 1300 1 37 5S23 199523...210 15350 75 01100 23200 2.05 91 11350 25 15133 4500 3 36 365 12250 75 49000 23200 2.11 141 10000

  13. Multidimensional Aptitude Battery-Second Edition Intelligence Testing of Remotely Piloted Aircraft Training Candidates Compared with Manned Airframe Training Candidates (United States)


    schizophrenia, attention deficit hyperactivity disorder , and autism spectrum disorders ) and not on very high functioning populations such as aviators...pilots and to the development of a U.S. Air Force (USAF) RPA pilot career field. Effective recruitment into this new career field is critical to...high levels of intelligence, dexterity, visual-spatial abilities, memory, attention /concentration, psychomotor reaction time, as well as speed and

  14. Airframe RDT&E Cost Estimating: A Justification for and Development of Unique Cost Estimating Relationships According to Aircraft Type. (United States)


    736 19.297 .ni 7050:7061 1670.7676. C 70. 71105 VARIAILE(S) ENTERED ON STEP 4 711 TTL 7325s 7136, NILTIPLE R .9421 AUG OF SI SUARES NEAN SO. F 7141m...RESIDUAL. S. .424 .478SIC. .%4 7869 AN R SUARE .8179 COEFF OF VARIAILITY 7.SPCT 79011- VARIABLE a S.E. I F SIC. ETA ELASTICITY 7910s 7929. TOCUAl 1.389

  15. Inlet and airframe compatibility for a V/STOL fighter/attack aircraft with top-mounted inlets (United States)

    Durston, D. A.; Smeltzer, D. B.


    Aerodynamic force and inlet pressure data are obtained for 9.5% force and pressure models of a V/STOL fighter/attack aircraft configuration with top mounted twin inlets. Data are presented from tests conducted in the Ames Unitary Wind Tunnels at Mach numbers of 0.6, 0.9, and 1.2 at angles of attack up to 27 deg. and angles of sideslip up to 12 deg. Trimmed aerodynamic characteristics and inlet performance are compared for three different leading edge extension (LEX) configurations. The effects of wing leading and trailing-edge flaps on the inlet are also determined. Maneuver perfromance is calculated form combined force and inlet pressure data. The largest of the three LEX sizes tested gives the best airplane maneuver performance. Wing flap deflections improved inlet recovery at all Mach numbers.

  16. F-111D, DT and E Evaluation of Environmental Control, Airframe, Flight Control, and Secondary Power Subsystems. Appendix 1 (United States)


    i/ n T ■ r x ^ [■ f ►■ al r u i ■ ► _i s- ►■ - IJ (^ f T • c c » t 0 ^ _■ o o o c- o t c t CTOÜC. tot fsdocroocrc^ ecc -oe C...o. o ^MU u; ft 3 m « ft «4 U O K ft U O UJ N- X ft Z M z Ü Ut 3 »-* T UJ tLt t- W X l^ O «Kisj«’WfgK* HOMo ^i#*«M^r\\;nMrf’MCrK.«w

  17. Computational Aeroacoustics Using the Generalized Lattice Boltzmann Equation Project (United States)

    National Aeronautics and Space Administration — The research proposed targets airframe noise (AFN) prediction and reduction. AFN originates from complex interactions of turbulent flow with airframe components that...

  18. Hybrid-Electric Aircraft TOGW Development Tool with Empirically-Based Airframe and Physics-Based Hybrid Propulsion System Component Analysis Project (United States)

    National Aeronautics and Space Administration — Hybrid-Electric distributed propulsion (HEDP) is becoming widely accepted and new tools will be required for future development. This Phase I SBIR proposal creates a...

  19. Weapon System Costing Methodology for Aircraft Airframes and Basic Structures Volume II - Estimating Handbook and User’s Manual, Part 2 (United States)


    asic structure. b. Material costs for secondary structure. c. Basic structure assembly material costs. c. ("om]X)nent assembly material costs. The...LAGS till GFrtf-’ ^Y^M HOURS ? " ASIC STOUCTURt TnoLIMG u t, 6 7 8 HAS 1 £ 3 (♦ F 7 «i R.I T TP? MTL • 7r. O.𔃻...UJ O O O l ( o tJ o «■ J O CJ ’t.- (Ji I J O O C) O cni en tjoD«JtTCJ o C3c_itr»f)t3t3t3tj c czt j in U"- Uŕ i.^ iD

  20. A Two-level Optimization Design Approach for Low RCS Airframe Shapes%基于二级优化的低RCS外形设计方法

    Institute of Scientific and Technical Information of China (English)

    胡添元; 余雄庆



  1. 14 CFR 91.1413 - CAMP: Responsibility for airworthiness. (United States)


    ..., including airframes, aircraft engines, propellers, rotors, appliances, and parts. (2) Maintaining its..., including airframes, aircraft engines, propellers, rotors, appliances, emergency equipment and parts, under... Ownership Operations Program Management § 91.1413 CAMP: Responsibility for airworthiness. (a) For...

  2. Joint Collaborative Technology Experiment (JCTE) (United States)


    Technologies (CCT) flown first in a Caliber airframe and then in a Bergen airframe . SSC successfully demonstrated auto takeoff, auto landing, and MOCU...Bergen suffered airframe reliability issues. The current development airframe supporting JCTE efforts is the Mongoose UAS (Figure 5). The Mongoose is...hills, ditches , etc.). The LMS Phase 1 capability does not make use of DTED information and thus works in an ideal environment where there are no hills

  3. Aerodynamic Engine/Airframe Integration for High Performance Aircraft and Missiles (L’Integration Aerodynamique des Moteurs et des Cellules dans les Avions et les Missiles a Hautes Performances) (United States)


    contact entre ]a maquetle et les patois , tout en emptchant urt rdpanitions de pression mesurdes (Fig.8). La nacelle seule provoque unec 6eoulement...8217occupation de la maquente dans ]a seine, des fotrnes intettne, ’decan maximal ye situars a 40% de 1’envergute du tron~on d’aile. En de patois haute

  4. Behaviour of Short Cracks in Airframe Components, Conference Proceedings of the Meeting of the AGARD Structures and Materials Panel (55th) Held at Toronto, Canada on 19-24 September 1982. (United States)


    20-22,24,26-28). Using arguments based on microplastic - ity and crack closure effects, Morris and co-workers [22,26) have modelled the process in terms...deceleration "well," shown in this figure, appeared to be determined by the degree of microplasticity involved in the crack traversing the boundary...need to be performed to better understand the average parameter values and variances and the impact of these parameters on the IFQ for different

  5. 机体/动力装置一体化分析中的动力影响效应数值模拟%Numerical simulation method for the powered effects in airframe/propulsion integration analysis

    Institute of Scientific and Technical Information of China (English)

    谭兆光; 陈迎春; 李杰; 张淼


    采用合适的进、排气边界条件,对带动力的单独涡扇发动机模型和带动力的DLR-F6翼身架舱复杂组合体(WBPN)模型的流场进行了数值模拟和分析.运用Roe三阶迎风偏置通量差分裂方法和隐式近似因子分解方法求解雷诺平均Navier-Stokes方程,基于点搭接多块网格技术生成高质量计算网格,通过多重网格技术来加速收敛.着重对动力发动机进、排气边界条件的给定进行了推导,以准确地模拟发动机动力效应.计算结果与实验值吻合良好,验证了所采用计算方法、网格分块策略和边界条件处理方法的正确性.%The flow-fields around powered isolated turbofan engine model and powered DLR-F6 wing/body/pylon/nacelle (WBPN) model were numerically simulated and analyzed by the appropriate fan inlet face and jet-exit boundary conditions.Three-dimensional time-dependent compressible Reynolds-averaged Navier-Stokes equations were solved with third-order upwind-biased flux-difference splitting method and approximate factorization method.The point-to-point patched multi-block technology was used to generate high quality grid.The multi-grid technique was employed to accelerate the convergence.For a better simulation of the powered effects,the fan inlet face boundary conditions and jet-exit boundary conditions were determined.Computational results and comparisons with experimental data were presented.The good agreement indicates that the numerical method,grid blocking strategy and management of boundary conditions are validated.


    Directory of Open Access Journals (Sweden)

    Sergiy Ishchenko


    Full Text Available Abstract. The influence of residual strain on the airframe aerodynamic characteristics of aircraft wasconsidered. The possibility of estimation of changes in deformation of airframe using data of leveling wasshown. The method of estimating the change of aerodynamic characteristics caused by the influence ofresidual strain airframe was proposed. Technique can be used in the operation and overhaul of aircraft withlarge operating time.Keywords: aerodynamic characteristics, residual strain construction asymmetric moments, thedistribution of circulation, the scheme of leveling, trigonometric series.



    Ishchenko, Sergiy; Tofil, Arkadiush


    Abstract. The influence of residual strain on the airframe aerodynamic characteristics of aircraft wasconsidered. The possibility of estimation of changes in deformation of airframe using data of leveling wasshown. The method of estimating the change of aerodynamic characteristics caused by the influence ofresidual strain airframe was proposed. Technique can be used in the operation and overhaul of aircraft withlarge operating time.Keywords: aerodynamic characteristics, residual strain constr...

  8. 14 CFR 65.92 - Inspection authorization: Duration. (United States)


    ... (CONTINUED) AIRMEN CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics § 65.92 Inspection... effective mechanic certificate with both a currently effective airframe rating and a currently...

  9. Broadband Trailing-Edge Noise Predictions - Overview of BANC-III Results

    DEFF Research Database (Denmark)

    Herr, M.; Ewert, R.; Rautmann, C.


    The Third Workshop on Benchmark Problems for Airframe Noise Computations, BANCIII, was held on 14-15 June 2014 in Atlanta, Georgia, USA. The objective of this workshop was to assess the present computational capability in the area of physics-based prediction of different types of airframe noise...

  10. Aircraft Fuel, Hydraulic and Pneumatic Systems (Course Outlines), Aviation Mechanics 3 (Air Frame): 9067.01. (United States)

    Dade County Public Schools, Miami, FL.

    This document presents an outline for a 135-hour course designed to familiarize the student with the operation, inspection, and repair of aircraft fuel, hydraulic, and pneumatic systems. It is designed to help the trainee master the knowledge and skills necessary to become an aviation airframe mechanic. The aviation airframe maintenance technician…

  11. 75 FR 82333 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F... (United States)


    ... FURTHER INFORMATION CONTACT: Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles...-5234; fax: (562) 627-5210; e-mail: . SUPPLEMENTARY INFORMATION: Comments Invited... 39.19. Send information to ATTN: Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L,...

  12. 77 FR 5386 - Airworthiness Directives; The Boeing Company Airplanes (United States)


    .... FOR FURTHER INFORMATION CONTACT: Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los...: (562) 627-5234; fax: (562) 627-5210; email: . ] SUPPLEMENTARY INFORMATION...: Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 3960...

  13. Air Force Flight Evaluation (Systems) of the A-10A Prototype Aircraft (United States)


    any manner licensing the holder or any other person or corporation , or conveying aNy rights or perpission to manufacture, use, or sell any patented...susceptibility 6. Detection susceptibility p Engine/Airframe Compatibility Test Results: The comnatibility of the YTF34/F5 engine with the A-10A airframe was

  14. 14 CFR 65.73 - Ratings. (United States)


    ... CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Mechanics § 65.73 Ratings. (a) The following ratings are issued under this subpart: (1) Airframe. (2) Powerplant. (b) A mechanic certificate with an aircraft or... mechanic certificate with an airframe or powerplant rating, or both, as the case may be, and may...

  15. The NASA/Industry Design Analysis Methods for Vibrations (DAMVIBS) Program - A government overview. [of rotorcraft technology development using finite element method (United States)

    Kvaternik, Raymond G.


    An overview is presented of government contributions to the program called Design Analysis Methods for Vibrations (DAMV) which attempted to develop finite-element-based analyses of rotorcraft vibrations. NASA initiated the program with a finite-element modeling program for the CH-47D tandem-rotor helicopter. The DAMV program emphasized four areas including: airframe finite-element modeling, difficult components studies, coupled rotor-airframe vibrations, and airframe structural optimization. Key accomplishments of the program include industrywide standards for modeling metal and composite airframes, improved industrial designs for vibrations, and the identification of critical structural contributors to airframe vibratory responses. The program also demonstrated the value of incorporating secondary modeling details to improving correlation, and the findings provide the basis for an improved finite-element-based dynamics design-analysis capability.

  16. Overview of mechanics of materials branch activities in the computational structures area (United States)

    Poe, C. C., Jr.


    Base programs and system programs are discussed. The base programs include fundamental research of composites and metals for airframes leading to characterization of advanced materials, models of behavior, and methods for predicting damage tolerance. Results from the base programs support the systems programs, which change as NASA's missions change. The National Aerospace Plane (NASP), Advanced Composites Technology (ACT), Airframe Structural Integrity Program (Aging Aircraft), and High Speed Research (HSR) programs are currently being supported. Airframe durability is one of the key issues in each of these system programs. The base program has four major thrusts, which will be reviewed subsequently. Additionally, several technical highlights will be reviewed for each thrust.

  17. Overview of mechanics of materials branch activities in the computational structures area (United States)

    Poe, C. C., Jr.


    Base programs and system programs are discussed. The base programs include fundamental research of composites and metals for airframes leading to characterization of advanced materials, models of behavior, and methods for predicting damage tolerance. Results from the base programs support the systems programs, which change as NASA's missions change. The National Aerospace Plane (NASP), Advanced Composites Technology (ACT), Airframe Structural Integrity Program (Aging Aircraft), and High Speed Research (HSR) programs are currently being supported. Airframe durability is one of the key issues in each of these system programs. The base program has four major thrusts, which will be reviewed subsequently. Additionally, several technical highlights will be reviewed for each thrust.

  18. 26 CFR 1.1031(a)-2 - Additional rules for exchanges of personal property. (United States)


    ... freight, and all helicopters (airframes and engines) (asset class 00.21), (v) Automobiles, taxis (asset... construction (asset class 00.28), and (xiii) Industrial steam and electric generation and/or...

  19. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project (United States)

    National Aeronautics and Space Administration — A major component of airframe noise for commercial transport aircraft is the deployed landing gear. The noise from the gear originates due to complex, unsteady bluff...

  20. Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 2 (United States)

    Adams, K. M.; Lucas, J. J.


    The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacturer of larger helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D, was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR R-49/epoxy skin and graphite/epoxy frames and stringers. The single cure concept is made possible by the utilization of pre-molded foam cores, over which the graphite/epoxy pre-impregnated frame and stringer reinforcements are positioned. Bolted composite channel sections were selected as the optimum joint construction. The applicability of the single cure concept to larger realistic curved airframe sections, and the durability of the composite structure in a realistic spectrum fatigue environment, was described.

  1. Unstructured, High-Order Scheme Module with Low Dissipation Flux Difference Splitting for Noise Prediction Project (United States)

    National Aeronautics and Space Administration — Thorough understanding of aircraft airframe and engine noise mechanisms and the subsequent acoustic propagation to the farfield is necessary to develop and evaluate...

  2. RIDES: Raman Icing Detection System Project (United States)

    National Aeronautics and Space Administration — Inflight icing of engines and airframe presents a significant hazard to air transport, especially at lower flight elevations during take-off or on approach. Ice...

  3. Effect of Engine Installation on Jet Noise using a Hybrid LES/RANS Approach Project (United States)

    National Aeronautics and Space Administration — Installation effects arising from propulsion airframe interaction are known to produce substantial variations in the in-situ jet noise. A hybrid LES/RANS...

  4. Environmental Assessment for Installation of a New Jet Engine Test Cell, Edwards Air Force Base, California (United States)


    airflow noise generated as the airframe passes through the air. The same noise sources are present with supersonic flights, but the aircraft are... ditches and retention ponds. Additionally, during construction of new facilities, Edwards AFB requires contractors to implement construction

  5. 76 FR 31451 - Special Conditions: Boeing Model 747-8 Airplanes; Stairway Between the Main Deck and Upper Deck (United States)


    ... FURTHER INFORMATION CONTACT: Jayson Claar, FAA, Airframe and Cabin Safety Branch, ANM-115, Transport... designed and located to minimize damage to its structure during an emergency landing or ditching. ]...

  6. 76 FR 14819 - Special Conditions: Boeing Model 747-8 Series Airplanes; Stairway Between the Main Deck and Upper... (United States)


    ... holidays, between 7:30 a.m. and 4 p.m. FOR FURTHER INFORMATION CONTACT: Jayson Claar, FAA, Airframe and... minimize damage to its structure during an emergency landing or ditching. 7. General illumination must...

  7. Revolution in airplane construction? Grob G110: The first modern fiber glass composition airplane shortly before its maiden flight (United States)

    Dorpinghaus, R.


    A single engine two passenger airplane, constructed completely from fiber reinforced plastic materials is introduced. The cockpit, controls, wing profile, and landing gear are discussed. Development of the airframe is also presented.

  8. Damage Adaptation Using Integrated Structural, Propulsion, and Aerodynamic Control Project (United States)

    National Aeronautics and Space Administration — The proposed SBIR Phase I plan of research seeks to develop and demonstrate an integrated architecture designed to compensate for combined propulsion, airframe,...

  9. Reduction of Flight Control System/Structural Mode Interaction Project (United States)

    National Aeronautics and Space Administration — A novel approach is proposed for reducing the degree of interaction of a high gain flight control system with the airframe structural vibration modes, representing a...

  10. Multifunctional Aerogel Thermal Protection Systems for Hypersonic Vehicles Project (United States)

    National Aeronautics and Space Administration — The push to hypersonic flight regimes requires novel materials that are lightweight as well as thermally and structurally efficient for airframes and thermal...

  11. Forecast Icing Product (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Forecast Icing Product (FIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The FIP algorithm uses...

  12. 77 FR 37879 - 36(b)(1) Arms Sales Notification (United States)


    ... provide greater security for its critical oil and natural gas infrastructure, and significant national... survivability equipment, displays, and sensors. The airframe itself does not contain sensitive technology...), Electro-Optic Missile Sensors (EOMSs), and Sequencer and Improved Countermeasures Dispenser (ICMD)....

  13. All-Fiber-Optic Ultrasonic Health Management System Project (United States)

    National Aeronautics and Space Administration — Health management of composite airframe components is essential for safety and reliability of future aircrafts. It reduces the risk of catastrophic failures and...

  14. 75 FR 35611 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F... (United States)


    ... Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Nenita Odesa, Aerospace... procedures found in 14 CFR 39.19. Send information to ATTN: Nenita Odesa, Aerospace Engineer, Airframe...

  15. Fault Tolerance, Diagnostics, and Prognostics in Aircraft Flight (United States)

    National Aeronautics and Space Administration — Abstract In modern fighter aircraft with statically unstable airframe designs, the flight control system is considered flight critical, i.e. the aircraft will...

  16. AGARD Flight Test Techniques Series. Volume 14. Introduction to Flight Test Engineering (Introduction a la Technique d’essais en vol) (United States)


    34Demonstration Requirements", 18 Mar 1971 with Amendment 1 of 30 Jun 1983 MIL-D-8708A( WEP ), "Demonstration Requirements for Airplanes", 13 Sep 1960 DoD...executed on full-scale airframes, mockups or airframe sections mounted atop heavy 3-axis positioners on outdoor antenna test ranges. The advantages...various design phases are subject to human engineering verification and validation tests beginning with rapid prototyping and mockups , extending through

  17. Introduction to Flight Test Engineering (Introduction aux techniques des essais en vol) (United States)


    34, 18 Mar 1971 with Amendment 1 of 30 Jun 1983. MIL-D-8708A( WEP ), "Demonstration Requirements for Airplanes", 13 Sep 1960. DoD Directive (DoDD) 5000.3...this, static ARP tests can be executed on full- scale airframes, mockups or airframe sections mounted atop heavy 3-axis positioners on outdoor antenna...and mockups , extending through partial and full simulations, and continuing through on-aircraft ground and flight test missions in operationally

  18. The Advanced Surface Force Fleet: A Proposal for an Alternate Surface Force Structure and Its Impact in the Asian Pacific Theater (United States)


    compatibility of rail guns , lasers, unmanned aerial vehicles, unmanned surface vehicles, and other future weapons aboard the eLPD 17. In support of...cushions (LCAC) or one landing craft utility (LCU).31 It is armed with two 30mm guns and two rolling airframe missile (RAMs) launchers.32 The...Additionally, it is armed with two 30mm guns and two rolling airframe missile (RAMs) launchers.38 Figure 1 is a picture of the USS San Antonio, the

  19. How Funding Instability Affects Army Programs (United States)


    other D models are remanufactured A-, B-, and C-model Chinooks. Compared with its predecessors, the CH-47D features composite rotor blades, an...Aviation Intermediate Maintenance. Comanche’s advanced airframe design incorporates composite airframe structures, a bearingless main rotor system...that significantly improves airlift responsiveness. Significant features of the C-17 include: super-critical wing design and winglets to reduce drag

  20. Proceedings: Annual Workshop on Meteorological and Environmental Inputs to Aviation Systems (5th) Held on 31 March-2 April 1981. (United States)


    of training people. Such a meeting of the effects of airframe and nacelle (or pro- would allow us to discuss available technology peller) icing upon...Doppler radar in thunderstorm detection airframe and nacelle icinq upon the aero- and lightning forecasting. dyrjmic coefficients and engine parameters...head- Global wind sensing from satellites using laser on and should be by an interagency effort in radar ( lidar ) is feasible. The Wave Propagation

  1. How Will Emerging Aerial Surveillance and Detection Technology Contribute to the Mission of U.S. Customs and Border Protection (United States)


    appropriate to this thesis. Beyond the traditional airframes , CBP relies on two unmanned aircraft platforms, the MQ-9 Predator B Unmanned Aircraft System...along America’s coastline and land borders. The operation of LSA’s away from land would be highly unsafe if the pilot were forced to ditch the...and infrared camera mounted or affixed on the airframe , remotely monitored and controlled in order to conduct surveillance. This technology is

  2. The Littoral Combat Ship: How We Got Here, and Why (United States)


    to be a ‘seaframe’ serving much the same purpose as an airframe for a reconfigurable aircraft or helicopter (or as an aircraft carrier with its...considered a top priority, and the Phalanx Close-in Weapon System, Rolling Airframe Missile (RAM) anti-missile system, and Nulka decoy were all on...command, as a last- ditch defense against incoming missiles and other targets. It has been a staple on U.S. warships since its fleet introduction in 1980

  3. NASA's Reusable Launch Vehicle Technologies: A Composite Materials Overview (United States)

    Clinton, R. G., Jr.; Cook, Steve; Effinger, Mike; Smith, Dennis; Swint, Shayne


    A materials overview of the NASA's Earth-to-Orbit Space Transportation Program is presented. The topics discussed are: Earth-to-Orbit Goals and Challenges; Space Transportation Program Structure; Generations of Reusable Launch Vehicles; Space Transportation Derived Requirements; X 34 Demonstrator; Fastrac Engine System; Airframe Systems; Propulsion Systems; Cryotank Structures; Advanced Materials, Fabrication, Manufacturing, & Assembly; Hot and Cooled Airframe Structures; Ceramic Matrix Composites; Ultra-High Temp Polymer Matrix Composites; Metal Matrix Composites; and PMC Lines Ducts and Valves.

  4. An Analysis of the U.S. Navy P-3C Orion Service Life Extension Program (United States)


    service life assessment program ( SLAP ) to determine not only the severity of the corrosion problem, but also the structural life remaining on the...airframe. In addition, SLAP offered corrective structural remedies if the aircraft were suitable for SLEP. SLAP results were promising: The airframe...a third of its fleet on the ramp. This thesis analyzes the challenges of SLEP. 14. SUBJECT TERMS P-3C Orion, SLEP, SLAP , SRP 15

  5. The Model Of One-Type Aircraft Fleet Behaviour While Service And Advantages SHM V. NDT Implementation

    Directory of Open Access Journals (Sweden)

    Lewitowicz Jerzy


    Full Text Available The paper defines the essence of durability characteristics of the designing structure of an airframe in terms of flight safety. Particular attention is drawn to one of the main factors influencing the durability characteristics of the airframe – diagnostics system for the health assessment of the airframe during the process of operation. The effectiveness of the use of integrated solutions to the structure of the airframe providing a continuous assessment of the technical condition is presented. Continuous diagnostics system integrated with the airframe, SHM, is classified as an intelligent solution. This paper presents a model of the behavior of one-type aircraft operating in the air operator’s fleet in terms of susceptibility to failure. Justified assumption in the description of this behavior, in the form of a “bathtub curve”. The analysis is supported by real data of failures. The benefits of using a continuous diagnostics system integrated with the airframe, SHM, is interpreted in relation to the classical approach with the use of non-destructive testing, NDT, for the three phases of the bathtub curve.

  6. Distributed Turboelectric Propulsion for Hybrid Wing Body Aircraft (United States)

    Kim, Hyun Dae; Brown, Gerald V.; Felder, James L.


    Meeting future goals for aircraft and air traffic system performance will require new airframes with more highly integrated propulsion. Previous studies have evaluated hybrid wing body (HWB) configurations with various numbers of engines and with increasing degrees of propulsion-airframe integration. A recently published configuration with 12 small engines partially embedded in a HWB aircraft, reviewed herein, serves as the airframe baseline for the new concept aircraft that is the subject of this paper. To achieve high cruise efficiency, a high lift-to-drag ratio HWB was adopted as the baseline airframe along with boundary layer ingestion inlets and distributed thrust nozzles to fill in the wakes generated by the vehicle. The distributed powered-lift propulsion concept for the baseline vehicle used a simple, high-lift-capable internally blown flap or jet flap system with a number of small high bypass ratio turbofan engines in the airframe. In that concept, the engine flow path from the inlet to the nozzle is direct and does not involve complicated internal ducts through the airframe to redistribute the engine flow. In addition, partially embedded engines, distributed along the upper surface of the HWB airframe, provide noise reduction through airframe shielding and promote jet flow mixing with the ambient airflow. To improve performance and to reduce noise and environmental impact even further, a drastic change in the propulsion system is proposed in this paper. The new concept adopts the previous baseline cruise-efficient short take-off and landing (CESTOL) airframe but employs a number of superconducting motors to drive the distributed fans rather than using many small conventional engines. The power to drive these electric fans is generated by two remotely located gas-turbine-driven superconducting generators. This arrangement allows many small partially embedded fans while retaining the superior efficiency of large core engines, which are physically separated

  7. Approach to Modeling Boundary Layer Ingestion using a Fully Coupled Propulsion-RANS Model (United States)

    Gray, Justin; Martins, Joaquim R. R.


    Although boundary layer ingestion (BLI), or wake ingestion, is commonly applied in marine propulsion applications, it has not yet seen wide-spread adoption in aircraft applications. However, recent studies have predicted that BLI offers a potential for a 10 reduction in aircraft fuel burn, even on a fairly traditional aircraft configuration. This dramatic reduction in fuel burn is achieved via tight integration of the propulsion system and airframe aerodynamics, but actually realizing such large performance gains will require modifying the aircraft design process to account for this integration. Traditionally, in aircraft design, the airframe and the propulsion system are designed separately and then the engine sizing is managed with a rubber-engine approach. This works when the propulsion system is placed in the free-stream air, away from the aerodynamic influence of the airframe, and it is reasonable to assume that small changes to either system won't have a strong impact on the other.

  8. Computational Modeling of a Mechanized Benchtop Apparatus for Leading-Edge Slat Noise Treatment Device Prototypes (United States)

    Turner, Travis L.; Moore, James B.; Long, David L.


    Airframe noise is a growing concern in the vicinity of airports because of population growth and gains in engine noise reduction that have rendered the airframe an equal contributor during the approach and landing phases of flight for many transport aircraft. The leading-edge-slat device of a typical high-lift system for transport aircraft is a prominent source of airframe noise. Two technologies have significant potential for slat noise reduction; the slat-cove filler (SCF) and the slat-gap filler (SGF). Previous work was done on a 2D section of a transport-aircraft wing to demonstrate the implementation feasibility of these concepts. Benchtop hardware was developed in that work for qualitative parametric study. The benchtop models were mechanized for quantitative measurements of performance. Computational models of the mechanized benchtop apparatus for the SCF were developed and the performance of the system for five different SCF assemblies is demonstrated.

  9. The NASA/industry Design Analysis Methods for Vibrations (DAMVIBS) program: McDonnell-Douglas Helicopter Company achievements (United States)

    Toossi, Mostafa; Weisenburger, Richard; Hashemi-Kia, Mostafa


    This paper presents a summary of some of the work performed by McDonnell Douglas Helicopter Company under NASA Langley-sponsored rotorcraft structural dynamics program known as DAMVIBS (Design Analysis Methods for VIBrationS). A set of guidelines which is applicable to dynamic modeling, analysis, testing, and correlation of both helicopter airframes and a large variety of structural finite element models is presented. Utilization of these guidelines and the key features of their applications to vibration modeling of helicopter airframes are discussed. Correlation studies with the test data, together with the development and applications of a set of efficient finite element model checkout procedures, are demonstrated on a large helicopter airframe finite element model. Finally, the lessons learned and the benefits resulting from this program are summarized.

  10. British government, industry agree to fund Hotel launcher studies (United States)

    Brown, D. A.


    A program status assessment is presented for the horizontal takeoff and landing 'Hotol' single-stage-to-orbit space launcher, for which parallel, two-year airframe and propulsion system proof-of-concept studies have been approved. A two-year initial development program for the airframe would be followed by a four-year development and manufacturing phase that would begin upon the propulsion system concept's successful demonstration. Flight trials could begin in 1996. A number of significant modifications have already been made to the initial design concept, such as to the foreplanes, afterbody, engine intake, and orbital control system.

  11. Status of 3D Ice Shape Measurement Effort (United States)

    Lee, Sam


    (1) Main goal of the Airframe Icing Technical Challenge is to achieve acceptance of experimental and computational icing simulation tools -SupercooledLarge Droplet Icing (SLD) conditions -3D airframe components including swept wings; (2) It is necessary to develop suitable means of recording and archiving fully 3D descriptions of experimental ice accretion geometry; (3) Past research has shown that commercial laser scanners have the potential to be adapted to this task; and (4) A research plan has been developed to implement and validate the use of this technology for experimental ice accretions.

  12. Evaluation of Sc-Bearing Aluminum Alloy C557 for Aerospace Applications (United States)

    Domack, Marcia S.; Dicus, Dennis L.


    The performance of the Al-Mg-Sc alloy C557 was evaluated to assess its potential for a broad range of aerospace applications, including airframe and launch vehicle structures. Of specific interest were mechanical properties at anticipated service temperatures and thermal stability of the alloy. Performance was compared with conventional airframe aluminum alloys and with other emerging aluminum alloys developed for specific service environments. Mechanical properties and metallurgical structure were evaluated for commercially rolled sheet in the as-received H116 condition and after thermal exposures at 107 C. Metallurgical analyses were performed to grain morphology and texture, strengthening precipitates, and to assess the effect of thermal exposure.

  13. Aeroacoustic Research Techniques: Jets to Autos (United States)

    Soderman, Paul T.


    Aeroacoustic research has benefited from the development of advanced techniques for the study of fluid mechanically generated noise New instrumentation; methodologies, information technologies, and facilities have evolved to help researchers investigate the complexities of aircraft and automobile noise. In this paper, research techniques are reviewed with emphasis on the subject closest to the author s experience: aircraft propulsion and airframe noise in simulated flight. A new technology developed for the study of aircraft airframe noise is described as a potential tool for the study of automobile noise. The important role of information technology in aeroacoustic research is discussed.

  14. Technology challenges for the National Aero-Space Plane (United States)

    Piland, William M.


    The National Aerospace Plane (NASP) will require an exceptionally high degree of integration between propulsion and aerodynamic configuration, in order to achieve the requisite specific impulse and low structural weight. This is to be achieved through the use of forebody shock compression and afterbody exhaust expansion. Attention is presently given to the materials and structural concepts required for the realization of these NASP airframe functions, in view of the exceptionally high aerothermodynamic loads that will be experienced at hypersonic speeds. Active cooling will have to be used in certain critical airframe and propulsion components. CFD characterizations of these processes must be carefully developed and fully validated.

  15. Aviation Safety Program Atmospheric Environment Safety Technologies (AEST) Project (United States)

    Colantonio, Ron


    Engine Icing: Characterization and Simulation Capability: Develop knowledge bases, analysis methods, and simulation tools needed to address the problem of engine icing; in particular, ice-crystal icing Airframe Icing Simulation and Engineering Tool Capability: Develop and demonstrate 3-D capability to simulate and model airframe ice accretion and related aerodynamic performance degradation for current and future aircraft configurations in an expanded icing environment that includes freezing drizzle/rain Atmospheric Hazard Sensing and Mitigation Technology Capability: Improve and expand remote sensing and mitigation of hazardous atmospheric environments and phenomena

  16. Finite element model reduction application to parametric studies and optimization of rotorcraft structures (United States)

    Hashemi-Kia, M.; Toossi, M.


    As a result of this work, a reduction procedure has been developed which can be applied to large finite element model of airframe type structures. This procedure, which is tailored to be used with MSC/NASTRAN finite element code, is applied to the full airframe dynamic finite element model of AH-64A Attack Helicopter. The applicability of the resulting reduced model to parametric and optimization studies is examined. Through application of the design sensitivity analysis, the viability and efficiency of this reduction technique has been demonstrated in a vibration reduction study.

  17. Investigation of difficult component effects on FEM vibration prediction for the AH-1G helicopter (United States)

    Dompka, Robert V.


    Under the NASA-sponsored Design Analysis Methods for Vibrations program, a series of ground vibration tests and NASTRAN finite element model correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Secondary structure and damping were found to have significant effects on the frequency response of the airframe above 15 Hz. The nonlinear effects of thrust stiffening and elastomeric mounts on the low-frequency pylon modes below the main rotor were also significant.

  18. Deployed Flight Test of the Iraqi Air Force Comp Air 7SLX (CA-7) (United States)


    airframe, performance, flying qualities, and avionics . The program was highly visible, drawing the interest of the commander of AFMC, 3 General Bruce...Air Force Historical Research Agency, Maxwell Air Force Base, Ala . (hereafter AFHRA). 2 Brfg (U), “Coordination/Approval Briefing for the Limited

  19. Expanding the Targeting Process into the Space Domain (United States)


    representation of that service but also allows a cross- pollenization of knowledge between the services. These personnel issues are made even more challenging...activities of headquarters, barracks, commissary, motor pool, and airfield would constitute an Installation; an airframe production plant and all...maintain a space targeting cell. Navy: The Navy currently has approximately 1000 Space Operations and Engineering Officers (active and reserve

  20. 78 FR 26280 - Special Conditions: Embraer, S.A., Model EMB-550 Airplane; Side-Facing Seats; Installation of... (United States)


    ... owner operations. The aircraft has a conventional configuration with low wing and T-tail empennage. The...: Jayson Claar, FAA, Airframe and Cabin Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft.... applied for a type certificate for their new Model EMB-550 airplane. The Model EMB-550 airplane is...

  1. 14 CFR Appendix A to Part 43 - Major Alterations, Major Repairs, and Preventive Maintenance (United States)


    ... following types, when not listed in the aircraft specifications issued by the FAA, are airframe major... surfaces. (iii) Wing stringers or chord members. (iv) Spars. (v) Spar flanges. (vi) Members of truss-type... of fuel tank filler openings provided the specific device has been made a part of the aircraft...

  2. 77 FR 70362 - Airworthiness Directives; The Boeing Company Airplanes (United States)


    .... FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle...; fax: (425) 917-6590; email: . SUPPLEMENTARY INFORMATION: Discussion We issued a... 1-``MED 1 Upper Main Sill web'' or a method approved in accordance with the procedures specified...

  3. 75 FR 39189 - Airworthiness Directives; The Boeing Company Model 747 Airplanes (United States)


    ... inspections for cracking of the bulkhead frame web and body skin; and corrective actions if necessary. This... after receipt. FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S... detailed inspections for cracking of the bulkhead frame web and body skin, and corrective actions...

  4. Active noise control in fuselage design

    NARCIS (Netherlands)

    Krakers, L.A.; Tooren, M.J.L. van; Beukers, A.; Berkhof, A.P.; Goeje, M.P. de


    To achieve comfortable noise levels inside the passenger cabin, sound damping measures have to be taken to improve the sound insulation properties of the bare airframe. Usually the sound insulation requirements of a passenger cabin are met after the mechanical design of the fuselage structure is alr

  5. Study of Helicopter Roll Control Effectiveness Criteria. (United States)


    variety of helicopter configurations and control system types , and a wide range of flight tasks and maneuvers. The basis of the experimental design...represent a wide range of basic helicopter rotor hub and airframe designs and flight control system types . It was intended to generally limit

  6. The National Aeronautics and Space Administration’s FY2006 Budget Request: Description, Analysis, and Issues for Congress (United States)


    displays, gauges, and instruments • First flight test of winglets (small wings at the end of each main wing) to reduce aerodynamic drag, improving fuel...technologies such as composite airframe materials, but program cancelled in 1994. 1990-1999 • Continued flights of the Space Shuttle: - 64 successful

  7. 14 CFR 125.243 - Certificate holder's responsibilities. (United States)


    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Certificate holder's responsibilities. 125... Certificate holder's responsibilities. (a) With regard to airplanes, including airframes, aircraft engines, propellers, appliances, and survival and emergency equipment, operated by a certificate holder,...

  8. F-35 Joint Strike Fighter (JSF) Program: Background and Issues for Congress (United States)


    suitability include, among other things, strengthened landing gear, a strengthened airframe, and an arresting hook so as to permit catapult launches and...Jane’s Defence Weekly, November 10, 2004. 79 Barbara Opall- Rome and David Pugliese, “Israeli Clarification Calms Canada’s Ire on Offsets,” Defense News

  9. F-35 Joint Strike Fighter (JSF) Program (United States)


    strengthened airframe, and an arresting hook so as to permit catapult launches and arrested landings, as well as folding wing tips for more compact storage...80 Barbara Opall- Rome and David Pugliese, “Israeli Clarification Calms Canada’s Ire on Offsets

  10. Adaptive Control and Guidance for Tactical Missiles. Volume 1: Parts 1 and 2. Introduction and Adaptive Control Theory (United States)

    varying airframe dynamics. Guidance techniques for tactical missiles are also reviewed and a number of steering laws, derived from optimal control ... theory , are evaluated. Quantitative comparisons are made between different guidance laws on the basis of intercept accuracy and control effort expended.

  11. F-35 Joint Strike Fighter: Preliminary Observations on Program Progress (United States)


    inefficiencies and requiring workarounds. Engine manufacturing deliveries remain steady and 218 engines have been delivered to date. The labor that build the F-35 airframes and engines continue to report improved manufacturing efficiency and supply chain performance. The F-35...program’s (1) future modernization (2) affordability, remaining development, and ongoing manufacturing plans. GAO analyzed program documentation

  12. The Residual Strength Failure Sequence in Fibre Metal Laminates

    NARCIS (Netherlands)

    Rodi, R.


    The concept of damage tolerance is a key aspect in ensuring and maintaining safety of an airframe structure over its design life. Developments in materials and structural design have both contributed to improvements in the damage tolerance of modern aircraft structures. Indeed, new developments in

  13. Applications of Composite Materials in Helicopter Construction (Les Applications des Materiaux Composite dans la Construction des Helicopteres), (United States)


    suspension J. Fuel tank k. Landing gear 1. Cabin vibration absorbers m. Main rotor hub vibration absorbers n. Main rotor hub o. Main rotor shaft p. Cyclic...filters Hub vibration absorbers Suspensions between gearbox and airframe Cabin vibration absorbers --Engines --Transmissions /23 Main gearbox Rotor shaft

  14. Elasto-Plastic 3D Finite Element Contact Analysis of a Hole Containing a Circular Insert in a Fatigue Test Coupon (United States)


    stresses would be developed, making the job of stress visualisation somewhat more straightforward. Figure 7 shows the Abaqus finite element mesh that...1 S&T Program Air Force Scientific Adviser 1 Navy Scientific Adviser 1 Chief of Aerospace Division 1 Research Leader, Airframe Technology and

  15. 14 CFR 65.91 - Inspection authorization. (United States)


    ..., for at least the 2-year period before the date he applies, in maintaining aircraft certificated and... necessary to properly inspect airframes, powerplants, propellers, or any related part or appliance; and (5) Pass a written test on his ability to inspect according to safety standards for returning aircraft...

  16. 78 FR 33012 - Airworthiness Directives; The Boeing Company Airplanes (United States)


    ... the AD docket shortly after receipt. FOR FURTHER INFORMATION CONTACT: Roger Caldwell, Aerospace... ties, located between longitudinal stringers, are an integral part of the load-bearing airframe... Caldwell, Aerospace Engineer, Technical Operations Center, ANM-100D, FAA, Denver ACO, 26805 East...

  17. 76 FR 9982 - Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 Series Airplanes (United States)


    ... INFORMATION CONTACT: James Delisio, Aerospace Engineer, Airframe and Mechanical Systems Branch, ANE-171, FAA, New York Aircraft Certification Office (ACO), 1600 Stewart Avenue, Suite 410, Westbury, New York 11590...: Program Manager, Continuing Operational Safety, FAA, New York ACO, 1600 Stewart Avenue, Suite...

  18. Are Pilots Graduating SUPT Today Meeting AMC’s Current and Future Needs (United States)


    airframe is slightly larger and the AF claims it is 70 percent newer than the previous versions. The cockpit is composed of a digital instrumentation...consideration identified by NASA, is human factors training. The ditching of US Airways Airbus A320 in the Hudson River following a bird strike and

  19. The Need to Ensure Training Readiness in the Total Force (United States)


    Iraqi Army over the period of several months, consisting of mines, wire and tank ditches . Prior to the ground war, other activities included tactical...for ship space or airframes to move the roundouts to the Gulf. The Army did not share this omission with the roundouts, with National Guard

  20. Ultraviolet (UV)-Curable Coatings for Aerospace Applications (United States)


    production and reduced airframe availability to the Warfighter. Ultraviolet- (UV-) curable coatings are a potential alternative to conventional isocyanate...last ditch effort to achieve some coating cure. Observations Post-Cure: Too aggressive a mixture of Prekote was used; the team were later told that a

  1. Environmental Assessment Stockbridge Research Facility (United States)


    1Sllflg Drainage Ditches 42 Recreational Facilities 43 Stormwater Management Facilittcs 44_ Mining Activities 45 Repair of Uplands Damaged by...E lectronic Counter Measure (ECM) threat response on large airframes , including the B-52, KC-135, C-130 and B-B I Bs. Modifications included the

  2. U.S. Air Force Environmental Assessment, Add To and Alter Type III Hydrant Fueling System, Tinker Air Force Base, Oklahoma (United States)


    provides a vital, secure communications link to the submerged fleet of ballistic missile submarines. OC-ALC airframe artisans perform depot work on the...wetland areas no longer existed or were actually drainage ditches or wet-weather conveyances that did not function as wetlands or aquatic habitat

  3. Impact Analysis on the Removal of Filter/Monitors from USN/USMC Helicopter in Flight Refueling Systems (United States)


    water/contamination from being introduced into the airframe fuel system during HIFR from the air capable ships. Although fuel quality assurance...purposes, and in emergency situations to avoid ditching (e.g. a fouled deck, deck unsuitable for landing, aircraft too heavy, etc). At most

  4. Air Force Journal of Logistics. Volume 34, Numbers 3 and 4, 2011 (United States)


    Logistics made to the airframe . which further slowed production and deployment. Specifically, the munitions stations on the aircraft were of British...Southern England, some written-off, whilst others ditched in the Channel or crashed on landing in France. The pilots involved fared little better, suffering

  5. The sail wing windmill and its adaptation for use in rural India (United States)

    Sherman, M. M.


    An 8 meter-diameter prototype sail wing windmill is reported that uses a one meter-diameter bullock cartwheel to which three bamboo poles are latched in a triangular pattern with overlapping ends, to form the airframe for cloth sails. This device lifts 300 pounds to a height of 20 feet in one minute in a 10 mph wind.

  6. Shape Optimisation of Holes in Loaded Plates by Minimisation of Multiple Stress Peaks (United States)


    September, San Francisco , USA. Heller M, Burchill M, Wescott R, Waldman W, Kaye R, Evans R, McDonald M, 2009: Airframe life extension by optimised...9. TASK NUMBER AIR 07/283 10. TASK SPONSOR OIC- ASI -DGTA 11. NO. OF PAGES 123 12. NO. OF REFERENCES 35 13. DSTO PUBLICATIONS

  7. Haptic Interface for UAV Teleoperation

    NARCIS (Netherlands)

    Lam, T.M.


    In the teleoperation of an uninhabited aerial vehicle (UAV), the human operator is physically separated from the vehicle and lacks various multiple-sensory information such as sound, motions, and vibrations of the airframe. The operator is usually only provided with visual information, e.g., from ca

  8. Russia’s Air Power at the Crossroads, (United States)


    and even the civilian waitresses in the officer’s dining hall. The intent was to simulate a unit rotation to the Warsaw Pact forward area during a...a factory or hangar floor . There has been no shortage of authoritative comment, however, to the effect that some such Russian airframe exists, with

  9. 75 FR 53851 - Airworthiness Directives; Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701 & 702... (United States)


    ... discovered that when the outflow valve (OFV) manual mode connector is not connected, the manual mode motor... control] backup/safety functions, including OFV manual control, altitude limitation, emergency...., Washington, DC. FOR FURTHER INFORMATION CONTACT: Fabio Buttitta, Aerospace Engineer, Airframe and...

  10. Effects of Temperature and Environment on Creep Behavior of an Oxide-Oxide Ceramic Matrix Composite (United States)


    resistant ceramic matrix composites by a precursor infiltration and pyrolysis method,” Materials Science and Engineering, A195:145-150 (1995). 33...the B-52 and F-16 airframes. He also spent a year as the Air Force Tire Engineer. In August 2005 he began graduate school work at the Air Force

  11. 14 CFR 21.93 - Classification of changes in type design. (United States)


    ... engine and nacelle carriage external to the skin of the airplane (and return of the pylon or other external mount), or (iii) Time-limited engine and/or nacelle changes, where the change in type design... flight and is not part of an airframe or engine. An “acoustical change” does not include: (A) Addition...

  12. 78 FR 41684 - Special Conditions: Embraer S.A. Model EMB-550 Airplanes, Sudden Engine Stoppage (United States)


    ...-engine installations, the engine mounts, pylons, and adjacent supporting airframe structure must be... are to be multiplied by a factor of 1.0 when applied to engine mounts and pylons, and multiplied by a..., Sudden Engine Stoppage AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final...

  13. 78 FR 67323 - Special Conditions: Airbus, Model A350-900 Series Airplane; Transient Engine Failure Loads (United States)


    ...: 1. For turbine engine installations, the engine mounts, pylons, and adjacent supporting airframe... multiplied by a factor of 1.0 when applied to engine mounts and pylons and multiplied by a factor of 1.25...; Transient Engine Failure Loads AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice...

  14. 76 FR 10213 - Special Conditions: Embraer Model EMB-135BJ (Legacy 650) Airplanes, Limit Engine Torque Loads for... (United States)


    ... engine mounts, pylons and adjacent supporting airframe structure must be designed to withstand 1g level... developed from these conditions are to be multiplied by a factor of 1.0 when applied to engine mounts and... 650) Airplanes, Limit Engine Torque Loads for Sudden Engine Stoppage AGENCY: Federal...

  15. 78 FR 31851 - Harmonization of Airworthiness Standards-Gust and Maneuver Load Requirements (United States)


    ... turbulence design loads criteria; revise the application of gust loads to engine mounts, high lift devices.... 25.362) We propose to revise the engine loads design requirements for engine mounts, auxiliary power unit mounts, engine pylons, and adjacent supporting airframe structures. The proposed amendment...

  16. An Analysis of the Manpower Impact of Unmanned Aerial Vehicles on Subsurface Platforms (United States)


    gear systems including wheels and tires, brakes , and emergency systems, pneumatic power, storage and distribution systems, hoists and winches, wing...Mechanic—Hydraulics: AMs maintain aircraft airframe and structural components, flight surfaces and controls, hydraulic and pneumatic control...61 Ibid., AE-3 62 Ibid., AM-3 30 pneumatic systems, steering and suspension systems, cryogenic systems, electrical systems, gas turbine

  17. Detection of aeroacoustic sound sources on aircraft and wind turbines

    NARCIS (Netherlands)

    Oerlemans, Stefan


    This thesis deals with the detection of aeroacoustic sound sources on aircraft and wind turbines using phased microphone arrays. First, the reliability of the array technique is assessed using airframe noise measurements in open and closed wind tunnels. It is demonstrated that quantitative acoustic

  18. Pilot Cognitive Functioning and Training Outcomes (United States)


    reducing physical stress and damage to the airframe. In summary, there has been extensive research in the USAF on the use of cognitive ability tests...has amassed a body of knowledge about many topics Comprehension Measures “social acculturation ,” “social intelligence,” and the conventional

  19. The NASA/industry Design Analysis Methods for Vibrations (DAMVIBS) program : Bell Helicopter Textron accomplishments (United States)

    Cronkhite, James D.


    Accurate vibration prediction for helicopter airframes is needed to 'fly from the drawing board' without costly development testing to solve vibration problems. The principal analytical tool for vibration prediction within the U.S. helicopter industry is the NASTRAN finite element analysis. Under the NASA DAMVIBS research program, Bell conducted NASTRAN modeling, ground vibration testing, and correlations of both metallic (AH-1G) and composite (ACAP) airframes. The objectives of the program were to assess NASTRAN airframe vibration correlations, to investigate contributors to poor agreement, and to improve modeling techniques. In the past, there has been low confidence in higher frequency vibration prediction for helicopters that have multibladed rotors (three or more blades) with predominant excitation frequencies typically above 15 Hz. Bell's findings under the DAMVIBS program, discussed in this paper, included the following: (1) accuracy of finite element models (FEM) for composite and metallic airframes generally were found to be comparable; (2) more detail is needed in the FEM to improve higher frequency prediction; (3) secondary structure not normally included in the FEM can provide significant stiffening; (4) damping can significantly affect phase response at higher frequencies; and (5) future work is needed in the areas of determination of rotor-induced vibratory loads and optimization.

  20. Investigation of difficult component effects on finite element model vibration prediction for the Bell AH-1G helicopter. Volume 1: Ground vibration test results (United States)

    Dompka, R. V.


    Under the NASA-sponsored Design Analysis Methods for VIBrationS (DAMVIBS) program, a series of ground vibration tests and NASTRAN finite element model (FEM) correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Previous correlations of the AH-1G showed good agreement between NASTRAN and tests through 15 to 20 Hz, but poor agreement in the higher frequency range of 20 to 30 Hz. Thus, this effort emphasized the higher frequency airframe vibration response correlations and identified areas that need further R and T work. To conduct the investigations, selected difficult components (main rotor pylon, secondary structure, nonstructural doors/panels, landing gear, engine, fuel, etc.) were systematically removed to quantify their effects on overall vibratory response of the airframe. The entire effort was planned and documented, and the results reviewed by NASA and industry experts in order to ensure scientific control of the testing, analysis, and correlation exercise. In particular, secondary structure and damping had significant effects on the frequency response of the airframe above 15 Hz. Also, the nonlinear effects of thrust stiffening and elastomer mounts were significant on the low frequency pylon modes below main rotor 1p (5.4 Hz). The results of the ground vibration testing are presented.

  1. Investigation of difficult component effects on finite element model vibration prediction for the Bell AG-1G helicopter. Volume 2: Correlation results (United States)

    Dompka, R. V.


    Under the NASA-sponsored DAMVIBS (Design Analysis Methods for VIBrationS) program, a series of ground vibration tests and NASTRAN finite element model (FEM) correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Previous correlations of the AG-1G showed good agreement between NASTRAN and tests through 15 to 20 Hz, but poor agreement in the higher frequency range of 20 to 30 Hz. Thus, this effort emphasized the higher frequency airframe vibration response correlations and identified areas that need further R and T work. To conduct the investigations, selected difficult components (main rotor pylon, secondary structure, nonstructural doors/panels, landing gear, engine, furl, etc.) were systematically removed to quantify their effects on overall vibratory response of the airframe. The entire effort was planned and documented, and the results reviewed by NASA and industry experts in order to ensure scientific control of the testing, analysis, and correlation exercise. In particular, secondary structure and damping had significant effects on the frequency response of the airframe above 15 Hz. Also, the nonlinear effects of thrust stiffening and elastomer mounts were significant on the low frequency pylon modes below main rotor 1p (5.4 Hz). The results of the NASTRAN FEM correlations are given.

  2. Women in Combat Arms: A Study of the Global War on Terror (United States)


    and, depending on the mission profile, night vision goggles and...pain.113 These injuries are attributed to a combination of several factors: whole-body vibration (WBV) caused by the airframe, use of night - vision ...also become relevant when looking at the specifics of injuries among helicopter pilots . Health Concerns There are three areas are examined here that

  3. 77 FR 40828 - Airworthiness Directives; The Boeing Company Airplanes (United States)


    ... available in the AD docket shortly after receipt. FOR FURTHER INFORMATION CONTACT: Nenita Odesa, Aerospace... Boulevard, Lakewood, CA 90712-4137; phone: (562) 627-5234; fax: (562) 627-5210; email: Information (1) For more information about this AD, contact Nenita Odesa, Aerospace Engineer, Airframe...

  4. 78 FR 61161 - Airworthiness Directives; The Boeing Company Airplanes (United States)


    ...-140, 1200 New Jersey Avenue SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Nenita . SUPPLEMENTARY INFORMATION: Discussion We issued a notice of proposed rulemaking (NPRM..., contact Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles...

  5. 76 FR 73491 - Airworthiness Directives; McDonnell Douglas Corporation Airplanes (United States)


    ... Jersey Avenue SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Nenita Odesa, Aerospace... Boulevard, Lakewood, California 90712-4137; phone: (562) 627-5234; fax: (562) 627-5210; email: nenita.odesa... procedures found in 14 CFR 39.19. Send information to ATTN: Nenita Odesa, Aerospace Engineer, Airframe...

  6. Protection of Advanced Electrical Power Systems from Atmospheric Electromagnetic Hazards. (United States)


    Total Charge = 41 Coulombs Poderate : Peak current = 20 kA Peak rate-of-rise = 5.4 x 1010 A/sec Total Charge = 1.6 Coulombs These two trreats are...the inherent airframe shielding for equipment location and wire routing, the design engineer will be better prepared for judicious usage of shielding

  7. JPRS Report, Science & Technology Japan. (United States)


    insulating materia ^ Side support L^Sfh of ’&r airframe (Gr/Pl) Figure 2.3 Example of Trial-Manufactured Nickel TPS 103 Figure 2 3 shows a, equipment and systems in order to keep its balance with GNP. Construction results are shown in Figure 12. (*) s Optoelectronization index

  8. F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force Fitness Test Scores (United States)


    mood, hormonal status, drugs , and eating habits also affect HR response. Maximal vs. submaximal muscular contraction of the AGSM also might affect...HR response. AGSM muscle contraction was not assessed. Genetics contribute to cardiac size and predisposition for certain sports or airframes and


    Directory of Open Access Journals (Sweden)

    P. Reidelstürz


    The airframe´s wingspan is about 3,45m weighting 4.2 kg, ready to fly. The hand launchable UAV can start from any place in agricultural regions. The wing is configured with flaps, allowing steep approaches and short landings using a „butterfly“ brake configuration. In spite of the lightweight configuration the UAV yet proves its worth under windy baltic wether situations by collecting regular sharp images of fields under wind speed up to 15m/s (Beaufort 6 –7. In further projects the development of further payload modules and a user friendly flight planning tool is scheduled considering different payload – and airframe requirements for different precision farming purposes and forest applications. Data processing and workflow will be optimized. Cooperation with further partners to establish UAV systems in agricultural, forest and geodata aquisition is desired.

  10. Nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel and stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.G.; Sorensen, N.R.


    This report presents a nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel alloys from stainless steel alloys as well as an evaluation of cleaning techniques to remove a thermal oxide layer on aircraft exhaust components. The results of this assessment are presented in terms of how effective each technique classifies a known exhaust material. Results indicate that either inspection technique can separate inconel and stainless steel alloys. Based on the experiments conducted, the electrochemical spot test is the optimum for use by airframe and powerplant mechanics. A spot test procedure is proposed for incorporation into the Federal Aviation Administration Advisory Circular 65-9A Airframe & Powerplant Mechanic - General Handbook. 3 refs., 70 figs., 7 tabs.

  11. Use of LS-DYNA(Registered TradeMark) to Assess the Energy Absorption Performance of a Shell-Based Kevlar(TradeMark)/Epoxy Composite Honeycomb (United States)

    Polanco, Michael


    The forward and vertical impact stability of a composite honeycomb Deployable Energy Absorber (DEA) was evaluated during a full-scale crash test of an MD-500 helicopter at NASA Langley?s Landing and Impact Research Facility. The lower skin of the helicopter was retrofitted with DEA components to protect the airframe subfloor upon impact and to mitigate loads transmitted to Anthropomorphic Test Device (ATD) occupants. To facilitate the design of the DEA for this test, an analytical study was conducted using LS-DYNA(Registered TradeMark) to evaluate the performance of a shell-based DEA incorporating different angular cell orientations as well as simultaneous vertical and forward impact conditions. By conducting this study, guidance was provided in obtaining an optimum design for the DEA that would dissipate the kinetic energy of the airframe while maintaining forward and vertical impact stability.

  12. Robotic inspection of fiber reinforced composites using phased array UT (United States)

    Stetson, Jeffrey T.; De Odorico, Walter


    Ultrasound is the current NDE method of choice to inspect large fiber reinforced airframe structures. Over the last 15 years Cartesian based scanning machines using conventional ultrasound techniques have been employed by all airframe OEMs and their top tier suppliers to perform these inspections. Technical advances in both computing power and commercially available, multi-axis robots now facilitate a new generation of scanning machines. These machines use multiple end effector tools taking full advantage of phased array ultrasound technologies yielding substantial improvements in inspection quality and productivity. This paper outlines the general architecture for these new robotic scanning systems as well as details the variety of ultrasonic techniques available for use with them including advances such as wide area phased array scanning and sound field adaptation for non-flat, non-parallel surfaces.

  13. A study of the prediction of cruise noise and laminar flow control noise criteria for subsonic air transports (United States)

    Swift, G.; Mungur, P.


    General procedures for the prediction of component noise levels incident upon airframe surfaces during cruise are developed. Contributing noise sources are those associated with the propulsion system, the airframe and the laminar flow control (LFC) system. Transformation procedures from the best prediction base of each noise source to the transonic cruise condition are established. Two approaches to LFC/acoustic criteria are developed. The first is a semi-empirical extension of the X-21 LFC/acoustic criteria to include sensitivity to the spectrum and directionality of the sound field. In the second, the more fundamental problem of how sound excites boundary layer disturbances is analyzed by deriving and solving an inhomogeneous Orr-Sommerfeld equation in which the source terms are proportional to the production and dissipation of sound induced fluctuating vorticity. Numerical solutions are obtained and compared with corresponding measurements. Recommendations are made to improve and validate both the cruise noise prediction methods and the LFC/acoustic criteria.

  14. Vibration analysis of the SA349/2 helicopter (United States)

    Heffernan, Ruth; Precetti, Dominique; Johnson, Wayne


    Helicopter airframe vibration is examined using calculations and measurements for the SA349/2 research helicopter. The hub loads, which transmit excitations to the fuselage, are predicted using a comprehensive rotorcraft analysis and correlated with measuring hub loads. The predicted and measured hub loads are then coupled with finite element models representing the SA349/2 fuselage. The resulting vertical acceleration at the pilot seat is examined. Adjustments are made to the airframe structural models to examine the sensitivity of predicted vertical acceleration to the model. Changes of a few percent to the damping and frequency of specific models lead to large reductions in predicted vibration, and to major improvements in the correlations with measured pilot-seat vertical acceleration.

  15. Analysis and correlation of SA349/2 helicopter vibration (United States)

    Heffernan, Ruth; Precetti, Dominique; Johnson, Wayne


    Helicopter airframe vibration is examined using calculation and measurements for the SA349/2 research helicopter. The hub loads, which transmit excitation to the fuselage, are predicted using a comprehensive rotorcraft analysis and correlated with measured hub loads. The predicted and measured hub loads are then coupled with finite element models representing the SA349/2 fuselage. The resulting vertical acceleration at the pilot seat is examined. Adjustments are made to the airframe structural models to examine the sensitivity of predicted vertical acceleration to the model. Changes of a few percent to the damping and frequency of specific modes lead to large reductions in predicted vibration and to major improvements in the correlations with measured pilot seat vertical acceleration.

  16. Designs and Technology Requirements for Civil Heavy Lift Rotorcraft (United States)

    Johnson, Wayne; Yamauchi, Gloria K.; Watts, Michael E.


    The NASA Heavy Lift Rotorcraft Systems Investigation examined in depth several rotorcraft configurations for large civil transport, designed to meet the technology goals of the NASA Vehicle Systems Program. The investigation identified the Large Civil Tiltrotor as the configuration with the best potential to meet the technology goals. The design presented was economically competitive, with the potential for substantial impact on the air transportation system. The keys to achieving a competitive aircraft were low drag airframe and low disk loading rotors; structural weight reduction, for both airframe and rotors; drive system weight reduction; improved engine efficiency; low maintenance design; and manufacturing cost comparable to fixed-wing aircraft. Risk reduction plans were developed to provide the strategic direction to support a heavy-lift rotorcraft development. The following high risk areas were identified for heavy lift rotorcraft: high torque, light weight drive system; high performance, structurally efficient rotor/wing system; low noise aircraft; and super-integrated vehicle management system.

  17. Correlation of finite-element structural dynamic analysis with measured free vibration characteristics for a full-scale helicopter fuselage (United States)

    Kenigsberg, I. J.; Dean, M. W.; Malatino, R.


    The correlation achieved with each program provides the material for a discussion of modeling techniques developed for general application to finite-element dynamic analyses of helicopter airframes. Included are the selection of static and dynamic degrees of freedom, cockpit structural modeling, and the extent of flexible-frame modeling in the transmission support region and in the vicinity of large cut-outs. The sensitivity of predicted results to these modeling assumptions are discussed. Both the Sikorsky Finite-Element Airframe Vibration analysis Program (FRAN/Vibration Analysis) and the NASA Structural Analysis Program (NASTRAN) have been correlated with data taken in full-scale vibration tests of a modified CH-53A helicopter.

  18. The design of a wind tunnel VSTOL fighter model incorporating turbine powered engine simulators (United States)

    Bailey, R. O.; Maraz, M. R.; Hiley, P. E.


    A wind-tunnel model of a supersonic VSTOL fighter aircraft configuration has been developed for use in the evaluation of airframe-propulsion system aerodynamic interactions. The model may be employed with conventional test techniques, where configuration aerodynamics are measured in a flow-through mode and incremental nozzle-airframe interactions are measured in a jet-effects mode, and with the Compact Multimission Aircraft Propulsion Simulator which is capable of the simultaneous simulation of inlet and exhaust nozzle flow fields so as to allow the evaluation of the extent of inlet and nozzle flow field coupling. The basic configuration of the twin-engine model has a geometrically close-coupled canard and wing, and a moderately short nacelle with nonaxisymmetric vectorable exhaust nozzles near the wing trailing edge, and may be converted to a canardless configuration with an extremely short nacelle. Testing is planned to begin in the summer of 1982.

  19. Flight and analytical investigations of a structural mode excitation system on the YF-12A airplane (United States)

    Goforth, E. A.; Murphy, R. C.; Beranek, J. A.; Davis, R. A.


    A structural excitation system, using an oscillating canard vane to generate force, was mounted on the forebody of the YF-12A airplane. The canard vane was used to excite the airframe structural modes during flight in the subsonic, transonic, and supersonic regimes. Structural modal responses generated by the canard vane forces were measured at the flight test conditions by airframe-mounted accelerometers. Correlations of analytical and experimental aeroelastic results were made. Doublet lattice, steady state double lattice with uniform lag, Mach box, and piston theory all produced acceptable analytical aerodynamic results within the restrictions that apply to each. In general, the aerodynamic theory methods, carefully applied, were found to predict the dynamic behavior of the YF-12A aircraft adequately.

  20. Check Six: Take a Look Back (Again) to Ensure Future Fighter Success (United States)


    I1.. .... ,; ........................... : .. 29 . Appendix B: USAF Analysis of AlA results of the Vietnam Conflict...replications to Marine aircrews with the obsolete F-5E/N Tiger II. Despite flying aging airframes with outdated avionics and weapons Campbell 1...the conflict. As a result, Navy and Marine aircrews flew fewer AlA missions than the Air Force due to their hodgepodge of aircraft, which included

  1. FAA debris mitigation phase I impact test report

    Energy Technology Data Exchange (ETDEWEB)

    Couch, R


    The goal of the study is the accurate prediction of the effect of uncontained engine debris on aircraft structures. This will provide airframe engineers the information required to design for damage mitigation and improved safety. The basis for predictive simulation tools lies in the experimental data, which motivates the initial development and application of codes that can adequately describe past experiments. This in turn validates the predictive capability of the codes to simulate future experiments.

  2. Prolonged Cycle Times and Schedule Growth in Defense Acquisition: A Literature Review (United States)


    commercial experience, an example being Boeing’s recent experience developing the 787 Dreamliner . The Dream- liner was designed to improve fuel...composite materials relative to older airframes, as well as new manufacturing techniques. At the same time, in an effort to cut costs, Boeing ...2011/01/20/ us- boeing - dreamliner -idUSTRE70J2UX20110120 Portier, Bertrand, “SOA Terminology Overview, Part 1: Service, Architecture, Governance, and

  3. Integrating Pavement Crack Detection and Analysis Using Autonomous Unmanned Aerial Vehicle Imagery (United States)


    the- art status in pavement health classification, UAV technology, and computer vision. Pavement Health Pavement repair has been a concern since... photography is uses an f-number. Each time the f- number is doubled, twice the rate of light is allowed onto the image sensor. A camera with a higher... photography in support of this research. Table 2 lists these airframes tested and applicable attributes examined in the selection process. Table 2

  4. Experimental Investigation of Fan Rotor Response to Inlet Swirl Distortion


    Frohnapfel, Dustin Joseph


    Next generation aircraft design focuses on highly integrated airframe/engine architectures that exploit advantages in system level efficiency and performance. One such design concept incorporates boundary layer ingestion which locates the turbofan engine inlet near enough to the lifting surface of the aircraft skin that the boundary layer is ingested and reenergized. This process reduces overall aircraft drag and associated required thrust, resulting in fuel savings and decreased emissions;...

  5. Matlab as a robust control design tool (United States)

    Gregory, Irene M.


    This presentation introduces Matlab as a tool used in flight control research. The example used to illustrate some of the capabilities of this software is a robust controller designed for a single stage to orbit air breathing vehicles's ascent to orbit. The global requirements of the controller are to stabilize the vehicle and follow a trajectory in the presence of atmospheric disturbances and strong dynamic coupling between airframe and propulsion.

  6. Design Concepts for Helicopter Pallets and Gondolas (United States)


    Vertical Bounce 44 Materials and Method of Construction 44 Methods of Construction 45 Materials 46 Strength-to-Weight Ratios 47...Stability System Excitation " Vertical Bounce " System excitation or vertical bounce is a phenomenon whereby the airframe body bending and rotor RPM become...reduced accordingly.’ VERTICAL BOUNCE Vertical bounce was investigated to determine what effect, if any, the gondola structure might

  7. Ready for TFI Prime Time? A Closer Examination of the Dual Component Commander and the Integrated Wing (United States)


    grievances by some guardsmen who were frustrated with the style and inexperience of some AC supervisors in dealing with union rules. 21 As before, GANG...command relationship between the AC and NG forces. 14 “Hurricane Katrina. Better Plans and Exercises Need to Guide the Military’s Response to...Tight budgets compel the USAF to create associations with Active Component ( AC ) and Air Reserve Component forces that can share airframes, resources

  8. Best Value Analysis of Tool/Individual Material Readiness List (IMRL) Items for Carrier Air Wing Five (CVW-5) F/A-18 Hornet Squadrons from NAF Atsugi to MCAS Iwakuni, Japan (United States)


    Coleman, & Hodge , 2011). We use some of their findings for transportation and shipping costs to determine whether there is a cost savings to the Naval...relational map of U.S. military bases in Japan. 13 Figure 10. Relational Map of U.S. Military Bases in Japan (From Debord, Coleman, & Hodge , 2011...aviation accidents since the earliest days of flight, whether it was propeller nicks , tire damage, or tears to airframe fabric, but FOD actually

  9. Structural design and analysis of a Mach zero to five turbo-ramjet system (United States)

    Spoth, Kevin A.; Moses, Paul L.


    The paper discusses the structural design and analysis of a Mach zero to five turbo-ramjet propulsion system for a Mach five waverider-derived cruise vehicle. The level of analysis detail necessary for a credible conceptual design is shown. The results of a finite-element failure mode sizing analysis for the engine primary structure is presented. The importance of engine/airframe integration is also discussed.

  10. Probable Impacts of Space Operations on Air Force Civil Engineering (United States)


    University, Air Command and Staff College, Research Report). Bierling , James R ., Space Operations Professional Development Guide, Maxwell AFB, Alabama, April...basing containerized payloads self ferry Table S. NASP Technical Challenges and Confidence Factors4 1986 1988 1990 Airframe Structures and Materials R ...Y B Thermal Management Y G B Flight Vehicle Integration R G G Inlet/Nozzle Performane R Y 6 Slush Hydrogen Y Y 6 Propulsion Ramjet Y 6 B Scramjet

  11. Spin Forming of Aluminum Metal Matrix Composites (United States)

    Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)


    An exploratory effort between NASA-Marshall Space Flight Center (MSFC) and SpinCraft, Inc., to experimentally spin form cylinders and concentric parts from small and thin sheets of aluminum Metal Matrix Composites (MMC), successfully yielded good microstructure data and forming parameters. MSFC and SpinCraft will collaborate on the recent technical findings and develop strategy to implement this technology for NASA's advanced propulsion and airframe applications such as pressure bulkheads, combustion liner assemblies, propellant tank domes, and nose cone assemblies.

  12. A historical perspective of aircrew systems effects on aircraft design


    Bauer, David O.


    Approved for public release; distribution in unlimited. The design of the aircrew workstation often has not been an orderly part of the overall aircraft design process but rather of much lower priority than the integration of the airframe and powerplant. However, the true test of the aircraft is how well the aircrew can use the aircraft for mission performance. NAVAIR has been seeking the establishment of an Aircrew Centered System Design discipline, to be addressed as an integral part of ...

  13. CFD Analysis of a T-38 Wing Fence (United States)


    or making major adjustments to the existing airframe. The answer lies in flow control. Flow control devices like vortex generators, winglets , and wing...proposed by the Air Force Test Pilot School. The driving force for considering a wing fence as opposed to vane vortex generators or winglets 3 was a row of...devices are vortex generators, fences, high lift flaps, and winglets . Active flow control injects the boundary layer with energy from small jets of

  14. European Scientific Notes. Volume 34, Number 11, (United States)


    combined effect of moisture, heat , and results of a major study which concluded mechanical stress; impact behavior; and that the degree of risk was low...from a lightning strike arcs across the Weinstock stated that it has been demon- joint, and the resulting ohmic heating strated that CFRP airframe...100 MW(e) plant has 28,600 heliostats earthquakes. The risk from Canvey Is- with surfaces of 30.4m 2. Each plant land is a couple of orders of


    Directory of Open Access Journals (Sweden)

    Kamal S. Ali


    Full Text Available This study describes a Multi-Agent Hardware In the Loop Simulator (HILS for Unmanned Aerial Vehicles’ (UAV autopilots. This HILS system allows multiple autopilots to fly multiple virtual airframes in the same virtual environment allowing these agents to interact as a swarm. This system makes the exploration and evaluation of Multi Agent Systems (MAS possible at minimal cost.

  16. Efficient Aviation Security: Strengthening the Analytic Foundation for Making Air Transportation Security Decisions (United States)


    Keeney, 2007; Parnell, Smith, and Moxley, 2010). Approaching the problem from a different direction, ana - lysts have also developed more approximate...reasonable adaptation paths could include use of alternative methods to damage airframes in flight (e.g., incen- diaries ) or to injure the passengers or crew...Aviation Terrorism and Security, London, UK: Frank Cass, 1999. Willis, Henry H., and Tom LaTourrette, “Using Probabilistic Terrorism Risk Modeling for

  17. Aircraft Noise Prediction



    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper add...

  18. Development of a dynamic calculation tool forsimulation of ditching


    Pilorget, Marc


    The present document is the final master thesis report written by Marc PILORGET,student at SUPAERO (home institution) and KTH (Royal Institute of Technology,Exchange University). This six months internship was done at DASSAULT AVIATION(Airframe engineering department) based in Saint-Cloud, France. It spanned from the 5thof July to the 23rd of December. The thesis work aims at developing an SPH (SmoothParticle Hydrodynamics) calculation method for ditching and implementing it in the finiteelem...

  19. Maritime Mass Rescue Interventions: Availability and Associated Technology (United States)


    Hudson River, New York, NY [ Ditching , January 2009] Multiple resources working together. Survivor accountability, manifest uncertainties ?N...multiple airframes Vessel deployable - multiple vessel sizes/types Land deployable - e.g., from a cliff, remote area Long range deployable Multiple...approximately 3 nm outside the immediate harbor, is the designated " ditch zone" for Toronto Pearson International Airport. The Marine Unit is

  20. Chromium and Cadmium Replacement Options for Advanced Aircraft (United States)


    also laser glazing, LISI, etc.) Electrospark deposition (alloying) Localized repair and build-up Explosive cladding Wide area bonding – IDs, gun tubes... deposition Does not seem to cause embrittlement Bath must be dumped periodically Keith Legg, Data available Like EHC...reliability, accuracy Beware – most data will be for heat treated state, but most airframe usage will be as- deposited Wear not as good, corrosion better

  1. System Testing in the Avionics Domain



    When developing a new aircraft, the airframer encounters various (partly contradictory) demands and requirements. To deal with them, current avionics systems are based on the framework of integrated modular electronics which allows to use COTS products for less critical functions and uses integrated modular avionics (IMA) technology for safety-critical avionics functions. Since this evolution affects the entire development, new processes and means for the development and the verification and ...

  2. Flight Dynamics Simulation Modeling and Control of a Large Flexible Tiltrotor Aircraft (United States)


    spectrum active control, including flight control systems, rotor load limiting, and vibration and noisetiltion [1]. The development of a high-order...done on tiltrotors to determine the piloted preferred response types. Bare-airframe single main rotor helicopters exhibit a rate command (RC) re...were used to reduce loads in cruise. It was noted that in piloted simulations, load amplification was observed in maneuvers not accounted for during

  3. Improving Air Support for Wildfire Management in the United States (United States)


    an aircraft’s airframe or load bearing internal framework can only withstand a certain tolerance to massive pressures, vibrations , and other...2012, FS began to collect information for the effectiveness of large airtankers, but FS has failed to gather metrics on helicopters and single engine...27. 20“ Fire Improvements Needed,” 15. 21“Fire Improvements Needed,” 16. In British Columbia, Canadian wildfire pilots complete after action

  4. Determination of Minimised Kt Values and Boundary Shapes for a Class of Quasi-Rectangular Holes in Infinite Plates (United States)


    September, San Francisco , USA. Heller M, Burchill M, Wescott R, Waldman W, Kaye R, Evans R, McDonald M, 2009: Airframe life extension by optimised...Waldman AUSTRALIA DEFENCE ORGANISATION No. of Copies Task Sponsor OIC- ASI -DGTA 1 S&T Program Air Force Scientific Adviser 1 Navy...AIR 07/283 10. TASK SPONSOR OIC- ASI -DGTA 11. NO. OF PAGES 50 12. NO. OF REFERENCES 25 13. DST GROUP PUBLICATIONS REPOSITORY http

  5. Sea-Based Automated Launch and Recovery System Virtual Testbed (United States)


    will explore the performance of sensors in degraded environments, including electro-optic/infra-red (EO/IR), radar, LIDAR /LADAR, beacon tracking and...linked with other simulation codes, including Matlab Simulink via an S-function allowing any Simulink model to be used with any CASTLE airframe model...processed using in-built CASTLE plotting and analysis functions or exported to Matlab . The desktop simulation supports multiple ship-aircraft

  6. Applications of numerical optimization methods to helicopter design problems - A survey (United States)

    Miura, H.


    A survey of applications of mathematical programming methods is used to improve the design of helicopters and their components. Applications of multivariable search techniques in the finite dimensional space are considered. Five categories of helicopter design problems are considered: (1) conceptual and preliminary design, (2) rotor-system design, (3) airframe structures design, (4) control system design, and (5) flight trajectory planning. Key technical progress in numerical optimization methods relevant to rotorcraft applications are summarized.

  7. Applications of numerical optimization methods to helicopter design problems: A survey (United States)

    Miura, H.


    A survey of applications of mathematical programming methods is used to improve the design of helicopters and their components. Applications of multivariable search techniques in the finite dimensional space are considered. Five categories of helicopter design problems are considered: (1) conceptual and preliminary design, (2) rotor-system design, (3) airframe structures design, (4) control system design, and (5) flight trajectory planning. Key technical progress in numerical optimization methods relevant to rotorcraft applications are summarized.

  8. The Rest of the C2 Iceberg (United States)


    operational C2—hence, the AOC and AFFOR con- struct. However, few senior leaders have an emotional attachment to C2 in the same way they do airframes... Klein , Streetlights and Shadows: Searching for the Keys to Adaptive Decision Making (Cambridge, MA: MIT Press, 2009). 20. For the classic analysis of...American Military Styles in Strategy and Analysis (Baltimore: John Hopkins University Press, 1989). 21. See Gary Klein , Sources of Power: How

  9. AGARD Index of Publications 1974-1976 (United States)


    Netherlands) of the required elevator control input end to teach the pilot to ADVANCED FLIGHT TEST INSTRUMENTATIONe DESIGN generate the signal...and predicted results are In good K. N Ghis, U Ghla and W. A. Teach (GE. Co.. Evendale. Ohio) agreentant. Aulhor 33 02 AERODYNAMICS N76.17039 Ohio...detectinn and suppression systems are examined along with N76,t4069 05-03) airframe design constraints. The primary and secondary fire The thermochemistry

  10. Report of the Acquisition Cycle Task Force. 1977 Summer Study (United States)


    cial programs which, if not respondrd to tffectively, may result in the markut perishing or preormptiin of the existing market by competitors. The...of the market . Very low rates (A production substantially increase labor costs of airframe cuanstruction and assembly, As illustrated in Fig- ure 10, of progranm overlap or concurrency, Computer systerms, automobiles, and many other commercial producto are developed and produced on a

  11. Development of the TFX F-111 in the Department of Defense’s Search for Multi-Mission, Joint-Service Aerial Platforms (United States)


    entrenched and involved in development decisions. On 1 September, General Dynamics completed the first mock -up for production. The F-111 was finally...aircraft for fleet defense. Experience had shown that any aircraft would only last for a few years as a fleet defense bird and the F-4 was scheduled to...The Navy recommended General Dynamics add more artificial drag to the aircraft, which would kill all supersonic capabilities of the airframe.61

  12. Design Oriented Structural Modeling for Airplane Conceptual Design Optimization (United States)

    Livne, Eli


    The main goal for research conducted with the support of this grant was to develop design oriented structural optimization methods for the conceptual design of airplanes. Traditionally in conceptual design airframe weight is estimated based on statistical equations developed over years of fitting airplane weight data in data bases of similar existing air- planes. Utilization of such regression equations for the design of new airplanes can be justified only if the new air-planes use structural technology similar to the technology on the airplanes in those weight data bases. If any new structural technology is to be pursued or any new unconventional configurations designed the statistical weight equations cannot be used. In such cases any structural weight estimation must be based on rigorous "physics based" structural analysis and optimization of the airframes under consideration. Work under this grant progressed to explore airframe design-oriented structural optimization techniques along two lines of research: methods based on "fast" design oriented finite element technology and methods based on equivalent plate / equivalent shell models of airframes, in which the vehicle is modelled as an assembly of plate and shell components, each simulating a lifting surface or nacelle / fuselage pieces. Since response to changes in geometry are essential in conceptual design of airplanes, as well as the capability to optimize the shape itself, research supported by this grant sought to develop efficient techniques for parametrization of airplane shape and sensitivity analysis with respect to shape design variables. Towards the end of the grant period a prototype automated structural analysis code designed to work with the NASA Aircraft Synthesis conceptual design code ACS= was delivered to NASA Ames.

  13. Electronics plus fluidics for V/STOL flight control (United States)

    Hendrick, R. C.


    The redundant digital fly by wire flight control system coupled with a fluidic system, which uses hydraulic pressure as its signal transmission means to provide pilot and feedback sensor control of airframe forcing functions is considered for application to the V/STOL aircraft. A potential fluidics system is introduced, and anticipated performance, weight, and reliability is discussed. Integration with the redundant electronic channels is explored, with the safety and mission reliability of alternate configurations estimated.

  14. Joint Communications Support Element: The Voice Heard Round the World (United States)


    selected STEP locations. In the airborne domain, JCSE enables mobility through its Joint Airborne Com- munications System ( JACS ) and Joint Air- borne...Communications Center/Command Post (JACC/CP). JACS provides an airborne radio relay connection for VHF and UHF communications range extension and...relay. JACS Version 2 operates from either a C-12 or C-130 airframe. JACS Version 3 (V3) increases operational flexibility by operating from an

  15. Meeting the Challenge of Distributed Real-Time & Embedded (DRE) Systems (United States)


    Services COTS & standards-based middleware, language, OS, network, & hardware platforms • Real-time CORBA (TAO) middleware • ADAPTIVE Communication...Airframe, Navigation, & Display components • Common middleware infrastructure • e.g., Real-time CORBA & Lightweight CORBA ...OMG Real-time CORBA & DDS, Sun RMI, Microsoft DCOM, W3C SOAP Client OBJ REF Object (Servant) in args operation() out args + return IDL STUBS IDL

  16. Assessing/Optimising Bio-fuel Combustion Technologies for Reducing Civil Aircraft Emissions


    Mazlan, Nurul Musfirah


    Gas turbines are extensively used in aviation because of their advantageous volume as weight characteristics. The objective of this project proposed was to look at advanced propulsion systems and the close coupling of the airframe with advanced prime mover cycles. The investigation encompassed a comparative assessment of traditional and novel prime mover options including the design, off-design, degraded performance of the engine and the environmental and economic analysis of the system. The ...

  17. Classification Trees and the Analysis of Helicopter Vibration Data


    Larson, Harold J.


    Health and Usage Monitoring Systems are receiving a great deal of interest, in an attempt to increase the safety and operational readiness of helicopters, and to minimize maintenance costs. These systems monitor (and can record) various flight parameters, pilot conversations, engine exhaust debris, metallic chip detector levels in the lubrication system, rotor track and balance, as well as vibration levels at selected locations throughout the airframe and the power drive system. Vibration lev...

  18. F-35 Sustainment: DOD Needs a Plan to Address Risks Related to Its Central Logistics System (United States)


    Office of the Secretary of Defense SCM Supply Chain Management SOU Standard Operating Unit TMS Training Management System This is a work... components that make up the F-35, along with the airframe and engine. However, ALIS has experienced developmental issues, including system functionality...of the F-35 fleet. It comprises both hardware and software. The hardware consists of three main components : • The Autonomic Logistics Operating Unit

  19. Automatic Operational Modal Analysis for Aeroelastic Applications


    Schwochow, Jan; Jelicic, G.


    The development of new aircraft requires the evaluation of the aeroelastic stability to avoid the phenomenon of flutter, a self-excited oscillation of the airframe. Since the rational analysis of the flutter stability comprises coupled simulations using numerical structural models and unsteady aerodynamic loads, the accomplishment is complex and the implementations must be checked for their validity by comparison of analytical and experimental results. In the so-called Ground Vibration Test (...

  20. A Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics. Part 1. Analysis Development (United States)


    The perturbation velozity components are due to the blade degrees of freedom, the shaft motion, and the aerodynamic gust velocity: -tA 4- + V(. o ) -A...gimballed, and teetering rotors with an arbitrary number of blades. The rotor degrees of freedom included are blade flap/lag bending, rigid pitch and elastic...tunnel is also covered. The aircraft degrees of freedom included are the six rigid body motions, elastic airframe motions, and the rotor/engine speed

  1. Tribology of Ceramics (United States)


    Research and Development of Airframe Bearings for Aerospace Vehicles. Technical Documentary Report ASD-TRD-63-716 (September). Rabinowicz , E., and M. Imai...chemically stable compared to metals. Metals in close contact have a strong tendency to adhere through the formation of chemical bonds. Rabinowicz (1984...of Rabinowicz (1971) on the sliding wear of metals. Rabinowicz studied the binary phase diagrams of the metals and developed criteria for grouping

  2. Influence of environmental factors on corrosion damage of aircraft structure

    Institute of Scientific and Technical Information of China (English)


    Corrosion is one of the important structural integrity concerns of aging aircraft, and it is estimated that a significant portion of airframe maintenance budgets is directed towards corrosion-related problems for both military and commercial aircraft. In order to better understand how environmental factors influence the corrosion damage initiation and propagation on aircraft structure and to predict pre-corrosion test pieces of fatigue life and structural integrity of an effective approach, this paper uses ...

  3. Intelligence Support for the F-35A Lightning II (United States)


    106 | Air & Space Power Journal Intelligence Support for the F-35A Lightning II Capt Stephanie Anne Fraioli, USAF Disclaimer: The views and opinions...the first joint fifth-generation fighter aircraft; there-fore, the Air Force, Navy, and Marine Corps need to codify the requirements for intelligence to fifth-generation airframes. Making informed deci- sions necessitates an operational understanding of current intelligence gaps, short

  4. Calcul direct du rayonnement acoustique généré par une cavité cylindrique sous une aile d'avion



    Aerodynamically generated noise sources are multiple for an airplane. During the landing phase, airframe noise is the main source. At the instigation of Airbus, the project AEROCAV (Aeroacoustics of cavities) deals with the noise produced by cylindrical burst-disk cavities located under the wings. An intense tonal noise is emitted. Numerical simulations of the noise generated by these cylindrical cavities are performed to investigate the noise source mechanisms by using Direct Noise Computati...

  5. A Comparative Analysis of Enlisted Career Progression Systems. (United States)


    Promotional Requirements to Airframe Foreman . . . .. .. .. .. .. .. .. .. 119 xi LIST OF FIGURES Figure Page 1-1. Pyramid of Proposed Research...PERSPECTIVE AND OPINION• /SYSTEMS SURVE Y Fig. 1-1. Pyramid of Proposed Research-- USA? Enlisted Career Progression System 13 3. An examination of believe (28:2). McIntire focuses on two of the experts in the field of job motivation and enrichment, Dr. Abraham Maslow and Frederick Herzberg

  6. Computer prediction of three-dimensional potential flow fields in which aircraft propellers operate. M.S. Thesis (United States)

    Jumper, S. J.


    A computer program was developed to calculate the three dimensional, steady, incompressible, inviscid, irrotational flow field at the propeller plane (propeller removed) located upstream of an arbitrary airframe geometry. The program uses a horseshoe vortex of known strength to model the wing. All other airframe surfaces are modeled by a network source panels of unknown strength which is exposed to a uniform free stream and the wing-induced velocity field. By satisfying boundary conditions on each panel (the Neumann problem), relaxed boundary conditions being used on certain panels to simulate inlet inflow, the source strengths are determined. From the known source and wing vortex strengths, the resulting velocity fields on the airframe surface and at the propeller plane are obtained. All program equations are derived in detail, and a brief description of the program structure is presented. A user's manual which fully documents the program is cited. Computer predictions of the flow on the surface of a sphere and at a propeller plane upstream of the sphere are compared with the exact mathematical solutions. Agreement is good, and correct program operation is verified.

  7. A summary of recent NASA/Army contributions to rotorcraft vibrations and structural dynamics technology (United States)

    Kvaternik, Raymond G.; Bartlett, Felton D., Jr.; Cline, John H.


    The requirement for low vibrations has achieved the status of a critical design consideration in modern helicopters. There is now a recognized need to account for vibrations during both the analytical and experimental phases of design. Research activities in this area were both broad and varied and notable advances were made in recent years in the critical elements of the technology base needed to achieve the goal of a jet smooth ride. The purpose is to present an overview of accomplishments and current activities of govern and government-sponsored research in the area of rotorcraft vibrations and structural dynamics, focusing on NASA and Army contributions over the last decade or so. Specific topics addressed include: airframe finite-element modeling for static and dynamic analyses, analysis of coupled rotor-airframe vibrations, optimization of airframes subject to vibration constraints, active and passive control of vibrations in both the rotating and fixed systems, and integration of testing and analysis in such guises as modal analysis, system identification, structural modification, and vibratory loads measurement.

  8. Near-field commercial aircraft contribution to nitrogen oxides by engine, aircraft type, and airline by individual plume sampling. (United States)

    Carslaw, David C; Ropkins, Karl; Laxen, Duncan; Moorcroft, Stephen; Marner, Ben; Williams, Martin L


    Nitrogen oxides (NOx) concentrations were measured in individual plumes from aircraft departing on the northern runway at Heathrow Airport in west London. Over a period of four weeks 5618 individual plumes were sampled by a chemiluminescence monitor located 180 m from the runway. Results were processed and matched with detailed aircraft movement and aircraft engine data using chromatographic techniques. Peak concentrations associated with 29 commonly used engines were calculated and found to have a good relationship with N0x emissions taken from the International Civil Aviation Organization (ICAO) databank. However, it is found that engines with higher reported NOx emissions result in proportionately lower NOx concentrations than engines with lower emissions. We show that it is likely that aircraft operational factors such as takeoff weight and aircraftthrust setting have a measurable and important effect on concentrations of N0x. For example, NOx concentrations can differ by up to 41% for aircraft using the same airframe and engine type, while those due to the same engine type in different airframes can differ by 28%. These differences are as great as, if not greater than, the reported differences in NOx emissions between different engine manufacturers for engines used on the same airframe.

  9. Calculation of flight vibration levels of the AH-1G helicopter and correlation with existing flight vibration measurements (United States)

    Sopher, R.; Twomey, W. J.


    NASA-Langley is sponsoring a rotorcraft structural dynamics program with the objective to establish in the U.S. a superior capability to utilize finite element analysis models for calculations to support industrial design of helicopter airframe structures. In the initial phase of the program, teams from the major U.S. manufacturers of helicopter airframes will apply extant finite element analysis methods to calculate loads and vibrations of helicopter airframes, and perform correlations between analysis and measurements. The aforementioned rotorcraft structural dynamics program was given the acronym DAMVIBS (Design Analysis Method for Vibrations). Sikorsky's RDYNE Rotorcraft Dynamics Analysis used for the correlation study, the specifics of the application of RDYNE to the AH-1G, and comparisons of the predictions of the method with flight data for loads and vibrations on the AH-1G are described. RDYNE was able to predict trends of variations of loads and vibrations with airspeed, but in some instances magnitudes differed from measured results by factors of two or three to one. Sensitivities were studied of predictions to rotor inflow modeling, effects of torsional modes, number of blade bending modes, fuselage structural damping, and hub modal content.

  10. Comparison of induced velocity models for helicopter flight mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.E.; Houston, S.S.


    Modeling of rotor-induced velocity receives continued attention in the literature as the rotorcraft community addresses limitations in the fidelity of simulations of helicopter stability, control, and handling qualities. A comparison is presented of results obtained using a rigid-blade rotor-fuselage model configured with two induced velocity models: a conventional, first-order, finite state, dynamic inflow model and a wake model that solves a vorticity transport equation on a computational mesh enclosing the rotorcraft. Differences between the two models are quantified by comparing predictions of trimmed rotor blade flap, lag and feather angles, airframe pitch and roll attitudes, cross-coupling derivatives, response to control inputs, and airframe vibration. Results are presented in the context of measurements taken on a Puma aircraft in steady flight from hover to high speed. More accurate predictions of the cross-coupling derivatives, response to control, and airframe vibration obtained using the vorticity transport model suggest that incorporation of real flowfield effects is important to extending the bandwidth of applicability of helicopter simulation models. Unexpectedly small differences in some of the trim predictions obtained using the two wake models suggest that an overall improvement in simulation fidelity may not be achieved without equivalent attention to the rotor dynamic model. (Author)

  11. Multidisciplinary design optimization of low-noise transport aircraft (United States)

    Leifsson, Leifur Thor

    The objective of this research is to examine how to design low-noise transport aircraft using Multidisciplinary Design Optimization (MDO). The subject is approached by designing for low-noise both implicitly and explicitly. The explicit design approach involves optimizing an aircraft while explicitly constraining the noise level. An MDO framework capable of optimizing both a cantilever wing and a Strut-Braced-Wing (SBW) aircraft was developed. The objective is to design aircraft for low-airframe-noise at the approach conditions and quantify the change in weight and performance with respect to a traditionally designed aircraft. The results show that reducing airframe noise by reducing approach speed alone, will not provide significant noise reduction without a large performance and weight penalty. Therefore, more dramatic changes to the aircraft design are needed to achieve a significant airframe noise reduction. Another study showed that the trailing-edge flap can be eliminated, as well as all the noise associated with that device, without incurring a significant weight and performance penalty. Lastly, an airframe noise analysis showed that a SBW aircraft with short fuselage-mounted landing gear could have a similar or potentially a lower airframe noise level than a comparable cantilever wing aircraft. The implicit design approach involves selecting a configuration that supports a low-noise operation, and optimizing for performance. In this study a Blended-Wing-Body (BWB) transport aircraft, with a conventional and a distributed propulsion system, was optimized for minimum take-off gross weight. The effects of distributed propulsion were studied using an MDO framework previously developed at Virginia Tech. The results show that more than two thirds of the theoretical savings of distributed propulsion are required for the BWB designs with a distributed propulsion system to have comparable gross weight as those with a conventional propulsion system. Therefore

  12. 大型客机发动机振动载荷传递特性研究%Exploring Wing-Mounted Engine Vibration Transmission for New Generation Airplanes with Turbofan Engines of High Bypass Ratio

    Institute of Scientific and Technical Information of China (English)

    陈熠; 贺尔铭; 扈西枝; 韩峰


    The use of turbofan engines of high bypass ratio has caused the low-frequency structure-borne noise. To investigate the medium and low frequency vibration transmission through wing structure to airframe, we introduce the double-beam dynamic model of a wing and build the "pylon-wing-airframe" dynamic half model of a full airplane, which takes into account the dynamics of an actual airplane. Sections 1 through 4 of the full paper explain the exploration mentioned in the title; their core consists of; ( 1) we use the vibration spectrum of the turbofan engines to calculate the vibration load of the airplane at each section of the airframe transmitted from wing to the air-frame , which provides the input data for estimating the noise level of the pressurized cabin; (2) through simulation , we identify the main path of engines' vibration transmission to the airframe; the simulation results, given in Figs. 6 and 7, and their analysis form, in our opinion, a useful preparation for pylon structure vibration reduction, engine vibration isolation mounting and the acoustic design inside the cabin.%高涵道比涡扇发动机的振动冲击频段向低频转移,使得飞机舱内噪声频率分布中的低频结构传递噪声变得更加突出.为了研究发动机振动载荷通过机翼向机身传递的中低频振动特性,文章针对真实客机的结构动力特性,创新地提出了机翼双梁动力学模型概念,建立了“吊架-机翼-机身”全机动力学有限元模型;基于发动机的振动载荷谱,分析了发动机振动通过机翼向机身结构传递的载荷特性,为后续舱内噪声预计提供了数据输入;并仿真辨识了发动机振动传递的主路径,为舱内声学设计及发动机隔振安装提供了基础数据.文中研究结果对我国大型客机的减振降噪设计工作有重要的工程参考价值.

  13. High Bypass Ratio Jet Noise Reduction and Installation Effects Including Shielding Effectiveness (United States)

    Thomas, Russell H.; Czech, Michael J.; Doty, Michael J.


    An experimental investigation was performed to study the propulsion airframe aeroacoustic installation effects of a separate flow jet nozzle with a Hybrid Wing Body aircraft configuration where the engine is installed above the wing. Prior understanding of the jet noise shielding effectiveness was extended to a bypass ratio ten application as a function of nozzle configuration, chevron type, axial spacing, and installation effects from additional airframe components. Chevron types included fan chevrons that are uniform circumferentially around the fan nozzle and T-fan type chevrons that are asymmetrical circumferentially. In isolated testing without a pylon, uniform chevrons compared to T-fan chevrons showed slightly more low frequency reduction offset by more high frequency increase. Phased array localization shows that at this bypass ratio chevrons still move peak jet noise source locations upstream but not to nearly the extent, as a function of frequency, as for lower bypass ratio jets. For baseline nozzles without chevrons, the basic pylon effect has been greatly reduced compared to that seen for lower bypass ratio jets. Compared to Tfan chevrons without a pylon, the combination with a standard pylon results in more high frequency noise increase and an overall higher noise level. Shielded by an airframe surface 2.17 fan diameters from nozzle to airframe trailing edge, the T-fan chevron nozzle can produce reductions in jet noise of as much as 8 dB at high frequencies and upstream angles. Noise reduction from shielding decreases with decreasing frequency and with increasing angle from the jet inlet. Beyond an angle of 130 degrees there is almost no noise reduction from shielding. Increasing chevron immersion more than what is already an aggressive design is not advantageous for noise reduction. The addition of airframe control surfaces, including vertical stabilizers and elevon deflection, showed only a small overall impact. Based on the test results, the best

  14. Noise Scaling and Community Noise Metrics for the Hybrid Wing Body Aircraft (United States)

    Burley, Casey L.; Brooks, Thomas F.; Hutcheson, Florence V.; Doty, Michael J.; Lopes, Leonard V.; Nickol, Craig L.; Vicroy, Dan D.; Pope, D. Stuart


    An aircraft system noise assessment was performed for the hybrid wing body aircraft concept, known as the N2A-EXTE. This assessment is a result of an effort by NASA to explore a realistic HWB design that has the potential to substantially reduce noise and fuel burn. Under contract to NASA, Boeing designed the aircraft using practical aircraft design princip0les with incorporation of noise technologies projected to be available in the 2020 timeframe. NASA tested 5.8% scale-mode of the design in the NASA Langley 14- by 22-Foot Subsonic Tunnel to provide source noise directivity and installation effects for aircraft engine and airframe configurations. Analysis permitted direct scaling of the model-scale jet, airframe, and engine shielding effect measurements to full-scale. Use of these in combination with ANOPP predictions enabled computations of the cumulative (CUM) noise margins relative to FAA Stage 4 limits. The CUM margins were computed for a baseline N2A-EXTE configuration and for configurations with added noise reduction strategies. The strategies include reduced approach speed, over-the-rotor line and soft-vane fan technologies, vertical tail placement and orientation, and modified landing gear designs with fairings. Combining the inherent HWB engine shielding by the airframe with added noise technologies, the cumulative noise was assessed at 38.7 dB below FAA Stage 4 certification level, just 3.3 dB short of the NASA N+2 goal of 42 dB. This new result shows that the NASA N+2 goal is approachable and that significant reduction in overall aircraft noise is possible through configurations with noise reduction technologies and operational changes.

  15. Wind Tunnel Testing of a 120th Scale Large Civil Tilt-Rotor Model in Airplane and Helicopter Modes (United States)

    Theodore, Colin R.; Willink, Gina C.; Russell, Carl R.; Amy, Alexander R.; Pete, Ashley E.


    In April 2012 and October 2013, NASA and the U.S. Army jointly conducted a wind tunnel test program examining two notional large tilt rotor designs: NASA's Large Civil Tilt Rotor and the Army's High Efficiency Tilt Rotor. The approximately 6%-scale airframe models (unpowered) were tested without rotors in the U.S. Army 7- by 10-foot wind tunnel at NASA Ames Research Center. Measurements of all six forces and moments acting on the airframe were taken using the wind tunnel scale system. In addition to force and moment measurements, flow visualization using tufts, infrared thermography and oil flow were used to identify flow trajectories, boundary layer transition and areas of flow separation. The purpose of this test was to collect data for the validation of computational fluid dynamics tools, for the development of flight dynamics simulation models, and to validate performance predictions made during conceptual design. This paper focuses on the results for the Large Civil Tilt Rotor model in an airplane mode configuration up to 200 knots of wind tunnel speed. Results are presented with the full airframe model with various wing tip and nacelle configurations, and for a wing-only case also with various wing tip and nacelle configurations. Key results show that the addition of a wing extension outboard of the nacelles produces a significant increase in the lift-to-drag ratio, and interestingly decreases the drag compared to the case where the wing extension is not present. The drag decrease is likely due to complex aerodynamic interactions between the nacelle and wing extension that results in a significant drag benefit.

  16. Future Jet Technologies. Part B. F-35 Future Risks v. JS-Education of Pilots & Engineers (United States)

    Gal-Or, Benjamin


    Design of “Next-Generation” airframes based on supermarket-jet-engine-components is nowadays passé. A novel integration methodology [Gal-Or, “Editorial-Review, Part A”, 2011, Gal-Or, “Vectored Propulsion, Supermaneuverability and Robot Aircraft”, Springer Verlag, Gal-Or, Int'l. J. of Thermal and Fluid Sciences 7: 1-6, 1998, “Introduction”, 2011] is nowadays in. For advanced fighter aircraft it begins with JS-based powerplant, which takes up to three times longer to mature vis-à-vis the airframe, unless “committee's design” enforces a dormant catastrophe. Jet Steering (JS) or Thrust Vectoring Flight Control, is a classified, integrated engine-airframe technology aimed at maximizing post-stall-maneuverability, flight safety, efficiency and flight envelopes of manned and unmanned air vehicles, especially in the “impossible-to-fly”, post-stall flight domains where the 100+ years old, stall-spin-limited, Conventional Flight Control fails. Worldwide success in adopting the post-stall, JS-revolution, opens a new era in aviation, with unprecedented design variables identified here for a critical review of F-35 future risks v. future fleets of jet-steered, pilotless vehicles, like the X-47B/C. From the educational point of view, it is also instructive to comprehend the causes of long, intensive opposition to adopt post-stall, JS ideas. A review of such debates may also curb a future opposition to adopt more advanced, JS-based technologies, tests, strategies, tactics and missions within the evolving air, marine and land applications of JS. Most important, re-education of pilots and engineers requires adding post-stall, JS-based studies to curriculum & R&D.

  17. Active control of counter-rotating open rotor interior noise in a Dornier 728 experimental aircraft (United States)

    Haase, Thomas; Unruh, Oliver; Algermissen, Stephan; Pohl, Martin


    The fuel consumption of future civil aircraft needs to be reduced because of the CO2 restrictions declared by the European Union. A consequent lightweight design and a new engine concept called counter-rotating open rotor are seen as key technologies in the attempt to reach this ambitious goals. Bearing in mind that counter-rotating open rotor engines emit very high sound pressures at low frequencies and that lightweight structures have a poor transmission loss in the lower frequency range, these key technologies raise new questions in regard to acoustic passenger comfort. One of the promising solutions for the reduction of sound pressure levels inside the aircraft cabin are active sound and vibration systems. So far, active concepts have rarely been investigated for a counter-rotating open rotor pressure excitation on complex airframe structures. Hence, the state of the art is augmented by the preliminary study presented in this paper. The study shows how an active vibration control system can influence the sound transmission of counter-rotating open rotor noise through a complex airframe structure into the cabin. Furthermore, open questions on the way towards the realisation of an active control system are addressed. In this phase, an active feedforward control system is investigated in a fully equipped Dornier 728 experimental prototype aircraft. In particular, the sound transmission through the airframe, the coupling of classical actuators (inertial and piezoelectric patch actuators) into the structure and the performance of the active vibration control system with different error sensors are investigated. It can be shown that the active control system achieves a reduction up to 5 dB at several counter-rotating open rotor frequencies but also that a better performance could be achieved through further optimisations.

  18. Variable Geometry Aircraft Wing Supported by Struts And/Or Trusses (United States)

    Melton, John E. (Inventor); Dudley, Michael R. (Inventor)


    The present invention provides an aircraft having variable airframe geometry for accommodating efficient flight. The aircraft includes an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, and a brace operably connected between said oblique wing and said fuselage. The present invention also provides an aircraft having an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, a propulsion system pivotally connected with said oblique wing, and a brace operably connected between said propulsion system and said fuselage.

  19. Conversion of hydrocarbon fuel in thermal protection reactors of hypersonic aircraft (United States)

    Kuranov, A. L.; Mikhaylov, A. M.; Korabelnikov, A. V.


    Thermal protection of heat-stressed surfaces of a high-speed vehicle flying in dense layers of atmosphere is one of the topical issues. Not of a less importance is also the problem of hydrocarbon fuel combustion in a supersonic air flow. In the concept under development, it is supposed that in the most high-stressed parts of airframe and engine, catalytic thermochemical reactors will be installed, wherein highly endothermic processes of steam conversion of hydrocarbon fuel take place. Simultaneously with heat absorption, hydrogen generation will occur in the reactors. This paper presents the results of a study of conversion of hydrocarbon fuel in a slit reactor.

  20. Hypersonic propulsion - Breaking the thermal barrier (United States)

    Weidner, J. P.


    The challenges of hypersonic propulsion impose unique features on the hypersonic vehicle - from large volume requirements to contain cryogenic fuel to airframe-integrated propulsion required to process sufficient quantities of air. Additional challenges exist in the design of the propulsion module that must be capable of efficiently processing air at very high enthalpies, adding and mixing fuel at supersonic speeds and expanding the exhaust products to generate thrust greater than drag. The paper explores the unique challenges of the integrated hypersonic propulsion system, addresses propulsion cycle selection to cope with the severe thermal environment and reviews the direction of propulsion research at hypervelocity speeds.

  1. Predicted thermal superluminescence in low-pressure air

    CERN Document Server

    Aramyan, A R; Galechyan, G A; Mangasaryan, N R; Nersisyan, H B


    It is shown that due to the dissociation of the molecular oxygen it is possible to obtain inverted population in low pressure air by heating. As a result of the quenching of the corresponding levels of the atomic oxygen the thermal superluminescent radiation is generated. It has been found that the threshold of the overpopulation is exceeded at the air temperature 2300-3000 K. Using this effect a possible mechanism for the generation of the flashes of the radiation in air observed on the airframe of the space shuttle during its descent and reentry in the atmosphere is suggested.

  2. Experimental verification of a large flexible manipulator (United States)

    Lee, Jac Won; Huggins, James D.; Book, Wayne J.


    A large experimental lightweight manipulator would be useful for material handling, for welding, or for ultrasonic inspection of a large structure, such as an airframe. The flexible parallel link mechanism is designed for high rigidity without increasing weight. This constrained system is analyzed by singular value decomposition of the constraint Jacobian matrix. A verification of the modeling using the assumed mode method is presented. Eigenvalues and eigenvectors of the linearized model are compared to the measured system natural frequencies and their associated mode shapes. The modeling results for large motions are compared to the time response data from the experiments. The hydraulic actuator is verified.

  3. An Overview of Aircraft Integrated Control Technology (United States)


    and stability augmentation, high hf’ system, steering and brak - ing 22 ’ . An F-15B research aircraft, modified with all-moving canard control...0.2 0.4 0.6 0.8 1.0 1.2 1.4 MACH NUMBER The IFPC system responds to pilot inputs with an automatic blend of aerodynamic control surfaces and thrust...decoupling airframe translation and rotation movements). In general, it was found that a blended combination of direct force and conventional control

  4. A non-linear UAV altitude PSO-PD control (United States)

    Orlando, Calogero


    In this work, a nonlinear model based approach is presented for the altitude stabilization of a hexarotor unmanned aerial vehicle (UAV). The mathematical model and control of the hexacopter airframe is presented. To stabilize the system along the vertical direction, a Proportional Derivative (PD) control is taken into account. A particle swarm optimization (PSO) approach is used in this paper to select the optimal parameters of the control algorithm taking into account different objective functions. Simulation sets are performed to carry out the results for the non-linear system to show how the PSO tuned PD controller leads to zero the error of the position along Z earth direction.

  5. Personality Test Scores that Distinguish U.S. Air Force Remotely Piloted Aircraft Drone Pilot Training Candidates (United States)


    domain. The five domains are as follows: 1. Neuroticism – general tendency to experience negative emotions (e.g., anxiety, hostility, depression) and...Airframe Candidates (n=7,244) Mean (SD) Neuroticism 42.17 (9.35) 42.84 (7.32) 42.88 (9.60) Anxiety 42.71 (8.63) 45.42 (10.16) 43.35 (9.37...effects were identified for one Neuroticism facet: impulsiveness (F = 2.91). Group 2 had higher impulsiveness scores than groups 1 and 3 (g = 0.43 and

  6. Structural requirements and basic design concepts for a two-stage winged launcher system (Saenger) (United States)

    Kuczera, H.; Keller, K.; Kunz, R.


    An evaluation is made of materials and structures technologies deemed capable of increasing the mass fraction-to-orbit of the Saenger two-stage launcher system while adequately addressing thermal-control and cryogenic fuel storage insulation problems. Except in its leading edges, nose cone, and airbreathing propulsion system air intakes, Ti alloy-based materials will be the basis of the airframe primary structure. Lightweight metallic thermal-protection measures will be employed. Attention is given to the design of the large lower stage element of Saenger.

  7. Weight Assessment for Fuselage Shielding on Aircraft With Open-Rotor Engines and Composite Blade Loss (United States)

    Carney, Kelly; Pereira, Michael; Kohlman, Lee; Goldberg, Robert; Envia, Edmane; Lawrence, Charles; Roberts, Gary; Emmerling, William


    The Federal Aviation Administration (FAA) has been engaged in discussions with airframe and engine manufacturers concerning regulations that would apply to new technology fuel efficient "openrotor" engines. Existing regulations for the engines and airframe did not envision features of these engines that include eliminating the fan blade containment systems and including two rows of counter-rotating blades. Damage to the airframe from a failed blade could potentially be catastrophic. Therefore the feasibility of using aircraft fuselage shielding was investigated. In order to establish the feasibility of this shielding, a study was conducted to provide an estimate for the fuselage shielding weight required to provide protection from an open-rotor blade loss. This estimate was generated using a two-step procedure. First, a trajectory analysis was performed to determine the blade orientation and velocity at the point of impact with the fuselage. The trajectory analysis also showed that a blade dispersion angle of 3deg bounded the probable dispersion pattern and so was used for the weight estimate. Next, a finite element impact analysis was performed to determine the required shielding thickness to prevent fuselage penetration. The impact analysis was conducted using an FAA-provided composite blade geometry. The fuselage geometry was based on a medium-sized passenger composite airframe. In the analysis, both the blade and fuselage were assumed to be constructed from a T700S/PR520 triaxially-braided composite architecture. Sufficient test data on T700S/PR520 is available to enable reliable analysis, and also demonstrate its good impact resistance properties. This system was also used in modeling the surrogate blade. The estimated additional weight required for fuselage shielding for a wing- mounted counterrotating open-rotor blade is 236 lb per aircraft. This estimate is based on the shielding material serving the dual use of shielding and fuselage structure. If the

  8. A Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics. Part 2. User’s Manual (United States)


    TGOV governor IGOV Control variables 100 90I 91& 91,---q)Q; rotor #1 ic is 200 a.aas QN2 rotor #2 2C1C 2C1S 2C4 DELF 64airframe ELE St, DELA & DELR ~ CT...rotor sY1 2110 orotor -i2 2C1S DELF aircraft DELE DELA DELR &r - CT a DELO pilot DELC DELS DELP DELT Gust components UG uG VG vG WG wG -75- For the

  9. OVERFLOW Simulations of Space Shuttle Orbiter Reentry Based on As-Built Geometry (United States)

    Ma, Edward C.; Vicker, Darby J.; Campbell, Charles H.; Wilson, Brad; Pavek, Mike; Berger, Karen


    The Space Shuttle Orbiters Discovery and Endeavor have been digitally scanned to obtain outer mold line surfaces. Using these scans, the existing overset computational fluid dynamics (CFD) grid system will be modified by projecting the grid points to the scanned geometry. Simulations will be performed using the OVERFLOW solver and the results compared to previous OVERFLOW results on the theoretical geometry and the aerodynamic databook. The "bent airframe" term will be compared between the aerodynamic databook and the computations over a range of reentry conditions.

  10. A comprehensive vibration analysis of a coupled rotor/fuselage system (United States)

    Yeo, Hyeonsoo

    A comprehensive vibration analysis of a coupled rotor/fuselage system for a two-bladed teetering rotor using finite element methods in space and time is developed which incorporates consistent rotor/fuselage structural, aerodynamic, and inertial couplings and a modern free wake model. A coordinate system is developed to take into account a teetering rotor's unique characteristics, such as teetering motion and undersling. Coupled nonlinear periodic blade and fuselage equations are transformed to the modal space in the fixed frame and solved simultaneously. The elastic line and detailed 3-D NASTRAN finite element models of the AH-1G helicopter airframe from the DAMVIBS program are integrated into the elastic rotor finite element model. Analytical predictions of rotor control angles, blade loads, hub forces, and vibration are compared with AH-1G Operation Load Survey flight test data. The blade loads predicted by present analysis show generally fair agreement with the flight test data, especially blade chord bending moment estimation shows good agreement. Calculated 2/rev vertical vibration levels at pilot seat show good correlation with the flight test data both in magnitude and phase, but 4/rev vibration levels show fair correlation only in magnitude. Lateral vibration results show more disagreement than vertical vibration results. Pylon flexibility effect is essential in the two-bladed teetering rotor vibration analysis. The pylon flexibility increases the first lag frequency by about 14%, and decreases 2/rev longitudinal and lateral hub forces by more than half. Rotor/fuselage coupling reduces 2/rev vertical and lateral vibration levels by 60% to 70% and has a small effect on 4/rev vibration levels. Modeling of difficult components (secondary structures, doors/panels, etc) is essential in predicting airframe natural frequencies. Refined aerodynamics such as free wake and unsteady aerodynamics have an important role in the prediction of vibration. For example, free

  11. 高超声速弹性飞行器前体压缩性能分析%Analyzing fore-body compression performance of a flexible hypersonic flight vehicle

    Institute of Scientific and Technical Information of China (English)

    祝强军; 唐硕; 谭艺明


    针对全尺寸的吸气式高超声速飞行器的低阶弹性弯曲模态极易被控制和扰动输入激发的特点,提出了一种基于准定常激波膨胀波理论进行前体处于振动条件下的气流参数计算方法,然后用该方法分析了一个具有二维可调进气道的全尺寸吸气式高超声速飞行器机体弹性弯曲振动对前体压缩性能的影响.分析表明:对于实际飞行中可能发生的小振幅的低频弯曲振动,其最主要的影响是引起头部激波的改变;机体弯曲振动幅值或频率增大都会对超燃冲压发动机进气道调节范围和前体压缩性能产生不利影响.%The control input and disturbance are prone to excite the lower order bending mode of a full-scale airbreathing hypersonic flight vehicle ( AHFV). A method based on the quasi-steady shock-expansion wave theory for calculating the unsteady aerodynamics of airframe under bending vibration was proposed for a full-scale AHFV. The effect of airframe bending on the fore-body compression performance is analyzed with this method. It shows that for the possible low frequency and small amplitude vibration of airframe bending, the change of nose shock wave is identified as the main effect; and if the vibration amplitude or frequency of airframe bending is increased, the scramjet may encounter difficulties in adjusting cowl position and compression performance.

  12. 高超声速弹性飞行器后体/外喷管建模与分析%Modeling and analyzing the afterbody external nozzle of a flexible hypersonic flight vehicle

    Institute of Scientific and Technical Information of China (English)

    祝强军; 唐硕; 谭艺明


    To investigate the influence of airframe bending vibration on external nozzle for full-scale airbreath-ing hypersonic flight vehicles ( AHFV) , a new method is developed for modeling and analyzing the external nozzle of AHFVs under the airframe vibration. The first step of this method is to determine the shear layer position using virtual shock-expansion wave method. After that, the flow in the external nozzle modeled as quasi-one dimensional flow is solved using the influence coefficients method, and the pressure on the lower surface of afterbody is modified by the piston theory. To analyze the influence of airframe bending vibration on external nozzle performance, a simulation is carried out using the new developed method. The results show that the change of an external nozzle performance is not so remarkable, as long as the airframe bending motion is in the range of low frequency and small amplitude.%考虑到全尺寸吸气式高超声速飞行器的机体弹性弯曲振动极易被激发,提出了一种包含机体弹性弯曲影响的外喷管建模和分析方法.该方法首先用虚拟激波膨胀波法确定剪切层的位置,然后用影响系数法求解外喷管中的准一维流,并用活塞理论修正后体下表面的压力.用该方法对一个全尺寸吸气式高超声速飞行器的后体/外喷管进行了仿真分析,结果表明,仅考虑低频、小振幅的后体弹性弯曲运动对外喷管性能的影响并不显著.

  13. Cost Growth Above Inflation (CGAI) in Operating and Support (O&S) Costs in Raw Materials for Air Force Aircraft (United States)


    Table 1 depicts NIIN 004424412, a butterfly valve , used on the C-5. Tracking individual NIIN costs over time allows for insight of price changes...Table 1 NIIN Example NIIN Description Airframe 004424412 Butterfly Valve C-5A The government agencies are interested in understanding how the...1,183.19 2000 A-10 009141329 WHEEL,LANDING GEAR 2 2,416.26 2000 A-10 009611971 TRANSMITTER,ANGLE OF ATTACK 1 2,215.99 2000 A-10 010030909 VALVE ,EMERGENCY

  14. DEBON-air: design, execution and benchmarking of operational networks, airborne (United States)

    Van Brackle, David; Spivey, Kevin; Hein, Carl; Horiatis, Zach; Rosenfeld, Peter; Sinclair, Asher


    This paper will discuss and evaluate the advantages provided by the DEBON-Air simulation environment for effecting communications between UAV airframes in flight. DEBON-Air provides a realistic multi-vehicle simulation environment which models communications complexities. By simulating various operational factors (e.g., bandwidth and reliability), and environmental factors (e.g., weather, altitude, range, and attitude), evaluators can establish the functional and performance characteristics of an Information Management System (IMS) in a simulated tactical environment. The Air Force Research Laboratory (AFRL) Apollo IMS will be used in concert with the DEBON-Air simulation environment for the purposes of these evaluations.

  15. Multidisciplinary Techniques and Novel Aircraft Control Systems (United States)

    Padula, Sharon L.; Rogers, James L.; Raney, David L.


    The Aircraft Morphing Program at NASA Langley Research Center explores opportunities to improve airframe designs with smart technologies. Two elements of this basic research program are multidisciplinary design optimization (MDO) and advanced flow control. This paper describes examples where MDO techniques such as sensitivity analysis, automatic differentiation, and genetic algorithms contribute to the design of novel control systems. In the test case, the design and use of distributed shape-change devices to provide low-rate maneuvering capability for a tailless aircraft is considered. The ability of MDO to add value to control system development is illustrated using results from several years of research funded by the Aircraft Morphing Program.

  16. Research status of key techniques for shock-induced combustion ramjet(shcramjet) engine

    Institute of Scientific and Technical Information of China (English)


    As one of the most promising propulsion systems in the future,shock-induced combustion ramjet engine can remedy the disadvantages in the integrated design of scramjet engine and airframe.It can shorten the length of the combustor,lighten the structure weight of the engine and keep better performance in a broad range of flight Mach number.The elementary principle of shock-induced combustion ramjet engine is introduced.The key technologies of this kind of propulsion system are described,while their research status is presented in detail.Suggestion on the development of shcramjet engine in China is put forward.

  17. Development of an Ultralight with a Ducted Fan

    Directory of Open Access Journals (Sweden)

    Jiří Brabec


    Full Text Available This paper introduces the UL-39 project, an ultralight aircraft with a ducted fan, and some of the problems that have arisen in the course of its development. Several problems with the design of a non-traditional aircraft of this kind are mentioned, e.g. the design of the airframe, and the design of the propulsion unit. The paper describes the specific procedure for determining the basic thrust characteristics of this unusual aircraft concept, and also the experimental determination of these characteristics. Further options for applying the experience gained during the work, and the futurefocus of work on these issues, are outlined at the end of the paper.

  18. Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Mark T. Whittaker


    Full Text Available Although originally discovered in the 18th century [1], the titanium industry did not experience any significant advancement until the middle of the 20th century through the development of the gas turbine engine [2]. Since then, the aerospace sector has dominated worldwide titanium use with applications in both engines and airframe structures [3]. The highly desirable combination of properties, which include excellent corrosion resistance, favourable strength to weight ratios, and an impressive resistance to fatigue, has led to an extensive range of applications [4], with only high extraction and processing costs still restricting further implementation. [...

  19. Computer technology forecast study for general aviation (United States)

    Seacord, C. L.; Vaughn, D.


    A multi-year, multi-faceted program is underway to investigate and develop potential improvements in airframes, engines, and avionics for general aviation aircraft. The objective of this study was to assemble information that will allow the government to assess the trends in computer and computer/operator interface technology that may have application to general aviation in the 1980's and beyond. The current state of the art of computer hardware is assessed, technical developments in computer hardware are predicted, and nonaviation large volume users of computer hardware are identified.

  20. Landing gear noise attenuation (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)


    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  1. Input/output models for general aviation piston-prop aircraft fuel economy (United States)

    Sweet, L. M.


    A fuel efficient cruise performance model for general aviation piston engine airplane was tested. The following equations were made: (1) for the standard atmosphere; (2) airframe-propeller-atmosphere cruise performance; and (3) naturally aspirated engine cruise performance. Adjustments are made to the compact cruise performance model as follows: corrected quantities, corrected performance plots, algebraic equations, maximize R with or without constraints, and appears suitable for airborne microprocessor implementation. The following hardwares are recommended: ignition timing regulator, fuel-air mass ration controller, microprocessor, sensors and displays.

  2. Static strain and vibration characteristics of a metal semimonocoque helicopter tail cone of moderate size (United States)

    Bielawa, Richard L.; Hefner, Rachel E.; Castagna, Andre


    The results are presented of an analytic and experimental research program involving a Sikorsky S-55 helicopter tail cone directed ultimately to the improved structural analysis of airframe substructures typical of moderate sized helicopters of metal semimonocoque construction. Experimental static strain and dynamic shake-testing measurements are presented. Correlation studies of each of these tests with a PC-based finite element analysis (COSMOS/M) are described. The tests included static loadings at the end of the tail cone supported in the cantilever configuration as well as vibrational shake-testing in both the cantilever and free-free configurations.

  3. Revolutionary Aeropropulsion Concept for Sustainable Aviation: Turboelectric Distributed Propulsion (United States)

    Kim, Hyun Dae; Felder, James L.; Tong, Michael. T.; Armstrong, Michael


    In response to growing aviation demands and concerns about the environment and energy usage, a team at NASA proposed and examined a revolutionary aeropropulsion concept, a turboelectric distributed propulsion system, which employs multiple electric motor-driven propulsors that are distributed on a large transport vehicle. The power to drive these electric propulsors is generated by separately located gas-turbine-driven electric generators on the airframe. This arrangement enables the use of many small-distributed propulsors, allowing a very high effective bypass ratio, while retaining the superior efficiency of large core engines, which are physically separated but connected to the propulsors through electric power lines. Because of the physical separation of propulsors from power generating devices, a new class of vehicles with unprecedented performance employing such revolutionary propulsion system is possible in vehicle design. One such vehicle currently being investigated by NASA is called the "N3-X" that uses a hybrid-wing-body for an airframe and superconducting generators, motors, and transmission lines for its propulsion system. On the N3-X these new degrees of design freedom are used (1) to place two large turboshaft engines driving generators in freestream conditions to minimize total pressure losses and (2) to embed a broad continuous array of 14 motor-driven fans on the upper surface of the aircraft near the trailing edge of the hybrid-wing-body airframe to maximize propulsive efficiency by ingesting thick airframe boundary layer flow. Through a system analysis in engine cycle and weight estimation, it was determined that the N3-X would be able to achieve a reduction of 70% or 72% (depending on the cooling system) in energy usage relative to the reference aircraft, a Boeing 777-200LR. Since the high-power electric system is used in its propulsion system, a study of the electric power distribution system was performed to identify critical dynamic and

  4. Analytical and experimental evaluations of the effect of broad property fuels on combustors for commercial aircraft gas turbine engines (United States)

    Smith, A. L.


    Analytical and experimental studies were conducted in three contract activities funded by the National Aeronautics and Space Administration, Lewis Research Center, to assess the impacts of broad property fuels on the design, performance, durability, emissions and operational characteristics of current and advanced combustors for commercial aircraft gas turbine engines. The effect of fuel thermal stability on engine and airframe fuel system was evaluated. Trade-offs between fuel properties, exhaust emissions and combustor life were also investigated. Results indicate major impacts of broad property fuels on allowable metal temperatures in fuel manifolds and injector support, combustor cyclic durability and somewhat lesser impacts on starting characteristics, lightoff, emissions and smoke.

  5. Finite Element Analysis and Test Results Comparison for the Hybrid Wing Body Center Section Test Article (United States)

    Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.


    This report documents the comparison of test measurements and predictive finite element analysis results for a hybrid wing body center section test article. The testing and analysis efforts were part of the Airframe Technology subproject within the NASA Environmentally Responsible Aviation project. Test results include full field displacement measurements obtained from digital image correlation systems and discrete strain measurements obtained using both unidirectional and rosette resistive gauges. Most significant results are presented for the critical five load cases exercised during the test. Final test to failure after inflicting severe damage to the test article is also documented. Overall, good comparison between predicted and actual behavior of the test article is found.

  6. AirGuardian - UAV Hardware and Software System for Small Size UAVs

    Directory of Open Access Journals (Sweden)

    Dániel Stojcsics


    Full Text Available AirGuardian is a complex of an Unmanned Aerial Vehicle and ground station UAV hardware and software systems which has been developed at Obuda University. The hardware and software of the autopilot (AERObot, the antenna tracker station and the ground control station were simultaneously created resulting in the optimal cooperation of the modules. The aim of the research on AERObot ‐ the special autopilot ‐ was to create a generic autopilot which is capable of controlling different designs, weights and structures of airframes without any complex mathematical model recalculation.

  7. Development Of Maneuvering Autopilot For Flight Tests (United States)

    Menon, P. K. A.; Walker, R. A.


    Report describes recent efforts to develop automatic control system operating under supervision of pilot and making airplane follow prescribed trajectories during flight tests. Report represents additional progress on this project. Gives background information on technology of control of test-flight trajectories; presents mathematical models of airframe, engine and command-augmentation system; focuses on mathematical modeling of maneuvers; addresses design of autopilots for maneuvers; discusses numerical simulation and evaluation of results of simulation of eight maneuvers under control of simulated autopilot; and presents summary and discussion of future work.

  8. System Noise Assessment of Blended-Wing-Body Aircraft With Open Rotor Propulsion (United States)

    Guo, Yueping; Thomas, Russell H.


    An aircraft system noise study is presented for the Blended-Wing-Body (BWB) aircraft concept with three open rotor engines mounted on the upper surface of the airframe. It is shown that for such an aircraft, the cumulative Effective Perceived Noise Level (EPNL) is about 24 dB below the current aircraft noise regulations of Stage 4. While this makes the design acoustically viable in meeting the regulatory requirements, even with the consideration of more stringent noise regulations of a possible Stage 5 in the next decade or so, the design will likely meet stiff competitions from aircraft with turbofan engines. It is shown that the noise levels of the BWB design are held up by the inherently high noise levels of the open rotor engines and the limitation on the shielding benefit due to the practical design constraint on the engine location. Furthermore, it is shown that the BWB design has high levels of noise from the main landing gear, due to their exposure to high speed flow at the junction between the center body and outer wing. These are also the reasons why this baseline BWB design does not meet the NASA N+2 noise goal of 42 dB below Stage 4. To identify approaches that may further reduce noise, parametric studies are also presented, including variations in engine location, vertical tail and elevon variations, and airframe surface acoustic liner treatment effect. These have the potential to further reduce noise but they are only at the conceptual stage.

  9. Materials analysis: A key to unlocking the mystery of the Columbia tragedy (United States)

    Mayeaux, Brian M.; Collins, Thomas E.; Jerman, Gregory A.; McDanels, Steven J.; Piascik, Robert S.; Russell, Richard W.; Shah, Sandeep R.


    Materials analyses of key forensic evidence helped unlock the mystery of the loss of space shuttle Columbia that disintegrated February 1, 2003 while returning from a 16-day research mission. Following an intensive four-month recovery effort by federal, state, and local emergency management and law officials, Columbia debris was collected, catalogued, and reassembled at the Kennedy Space Center. Engineers and scientists from the Materials and Processes (M&P) team formed by NASA supported Columbia reconstruction efforts, provided factual data through analysis, and conducted experiments to validate the root cause of the accident. Fracture surfaces and thermal effects of selected airframe debris were assessed, and process flows for both nondestructive and destructive sampling and evaluation of debris were developed. The team also assessed left hand (LH) airframe components that were believed to be associated with a structural breach of Columbia. Analytical data collected by the M&P team showed that a significant thermal event occurred at the left wing leading edge in the proximity of LH reinforced carbon carbon (RCC) panels 8 and 9. The analysis also showed exposure to temperatures in excess of 1,649°C, which would severely degrade the support structure, tiles, and RCC panel materials. The integrated failure analysis of wing leading edge debris and deposits strongly supported the hypothesis that a breach occurred at LH RCC panel 8.

  10. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure . Part II; Severe Damage (United States)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.


    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a finite element analysis and the testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part II of the paper considers the final test to failure of the test article in the presence of an intentionally inflicted severe discrete source damage under the wing up-bending loading condition. Finite element analysis results are compared with measurements acquired during the test and demonstrate that the hybrid wing body test article was able to redistribute and support the required design loads in a severely damaged condition.

  11. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads (United States)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.


    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

  12. Basic research on design analysis methods for rotorcraft vibrations (United States)

    Hanagud, S.


    The objective of the present work was to develop a method for identifying physically plausible finite element system models of airframe structures from test data. The assumed models were based on linear elastic behavior with general (nonproportional) damping. Physical plausibility of the identified system matrices was insured by restricting the identification process to designated physical parameters only and not simply to the elements of the system matrices themselves. For example, in a large finite element model the identified parameters might be restricted to the moduli for each of the different materials used in the structure. In the case of damping, a restricted set of damping values might be assigned to finite elements based on the material type and on the fabrication processes used. In this case, different damping values might be associated with riveted, bolted and bonded elements. The method itself is developed first, and several approaches are outlined for computing the identified parameter values. The method is applied first to a simple structure for which the 'measured' response is actually synthesized from an assumed model. Both stiffness and damping parameter values are accurately identified. The true test, however, is the application to a full-scale airframe structure. In this case, a NASTRAN model and actual measured modal parameters formed the basis for the identification of a restricted set of physically plausible stiffness and damping parameters.

  13. Aviation Trends Related to Atmospheric Environment Safety Technologies Project Technical Challenges (United States)

    Reveley, Mary S.; Withrow, Colleen A.; Barr, Lawrence C.; Evans, Joni K.; Leone, Karen M.; Jones, Sharon M.


    Current and future aviation safety trends related to the National Aeronautics and Space Administration's Atmospheric Environment Safety Technologies Project's three technical challenges (engine icing characterization and simulation capability; airframe icing simulation and engineering tool capability; and atmospheric hazard sensing and mitigation technology capability) were assessed by examining the National Transportation Safety Board (NTSB) accident database (1989 to 2008), incidents from the Federal Aviation Administration (FAA) accident/incident database (1989 to 2006), and literature from various industry and government sources. The accident and incident data were examined for events involving fixed-wing airplanes operating under Federal Aviation Regulation (FAR) Parts 121, 135, and 91 for atmospheric conditions related to airframe icing, ice-crystal engine icing, turbulence, clear air turbulence, wake vortex, lightning, and low visibility (fog, low ceiling, clouds, precipitation, and low lighting). Five future aviation safety risk areas associated with the three AEST technical challenges were identified after an exhaustive survey of a variety of sources and include: approach and landing accident reduction, icing/ice detection, loss of control in flight, super density operations, and runway safety.

  14. A KBE-enabled design framework for cost/weight optimization study of aircraft composite structures (United States)

    Wang, H.; La Rocca, G.; van Tooren, M. J. L.


    Traditionally, minimum weight is the objective when optimizing airframe structures. This optimization, however, does not consider the manufacturing cost which actually determines the profit of the airframe manufacturer. To this purpose, a design framework has been developed able to perform cost/weight multi-objective optimization of an aircraft component, including large topology variations of the structural configuration. The key element of the proposed framework is a dedicated knowledge based engineering (KBE) application, called multi-model generator, which enables modelling very different product configurations and variants and extract all data required to feed the weight and cost estimation modules, in a fully automated fashion. The weight estimation method developed in this research work uses Finite Element Analysis to calculate the internal stresses of the structural elements and an analytical composite plate sizing method to determine their minimum required thicknesses. The manufacturing cost estimation module was developed on the basis of a cost model available in literature. The capability of the framework was successfully demonstrated by designing and optimizing the composite structure of a business jet rudder. The study case indicates the design framework is able to find the Pareto optimal set for minimum structural weight and manufacturing costin a very quick way. Based on the Pareto set, the rudder manufacturer is in conditions to conduct both internal trade-off studies between minimum weight and minimum cost solutions, as well as to offer the OEM a full set of optimized options to choose, rather than one feasible design.

  15. Human and behavioral factors contributing to spine-based neurological cockpit injuries in pilots of high-performance aircraft: recommendations for management and prevention (United States)

    Jones, J. A.; Hart, S. F.; Baskin, D. S.; Effenhauser, R.; Johnson, S. L.; Novas, M. A.; Jennings, R.; Davis, J.


    In high-performance aircraft, the need for total environmental awareness coupled with high-g loading (often with abrupt onset) creates a predilection for cervical spine injury while the pilot is performing routine movements within the cockpit. In this study, the prevalence and severity of cervical spine injury are assessed via a modified cross-sectional survey of pilots of multiple aircraft types (T-38 and F-14, F-16, and F/A-18 fighters). Ninety-five surveys were administered, with 58 full responses. Fifty percent of all pilots reported in-flight or immediate post-flight spine-based pain, and 90% of fighter pilots reported at least one event, most commonly (> 90%) occurring during high-g (> 5 g) turns of the aircraft with the head deviated from the anatomical neutral position. Pre-flight stretching was not associated with a statistically significant reduction in neck pain episodes in this evaluation, whereas a regular weight training program in the F/A-18 group approached a significant reduction (mean = 2.492; p injury from airframe to airframe. Several strategies for prevention are possible from both an aircraft design and a preventive medicine standpoint. Countermeasure strategies against spine injury in pilots of high-performance aircraft require additional research, so that future aircraft will not be limited by the human in control.

  16. SRμCT study of crack propagation within laser-welded aluminum-alloy T-joints (United States)

    Herzen, J.; Beckmann, F.; Riekehr, S.; Bayraktar, F. S.; Haibel, A.; Staron, P.; Donath, T.; Utcke, S.; Kocak, M.; Schreyer, A.


    Using laser welding in fabrication of metallic airframes reduces the weight and hence fuel consumption. Currently only limited parts of the airframes are welded. To increase laser beam welded parts, there is the need for a better understanding of crack propagation and crack-pore interaction within the welds. Laser beam welded Al-alloys may contain isolated small process pores and their role and interaction with growing crack need to be investigated. The present paper presents the first results of a crack propagation study in laser beam welded (LBW) Al-alloy T-joints using synchrotron radiation based micro computed tomography (SRμCT). A region-of-interest technique was used, since the specimens exceeded the field of view of the X-ray detector. As imaging with high density resolution at high photon energies is very challenging, a feasibility measurement on a small laser weld, cut cylindrically from the welded region of a T-joint, was done before starting the crack-propagation study. This measurement was performed at the beamline HARWI-II at DESY to demonstrate the potential of the SRμCT as non-destructive testing method. The result has shown a high density resolution, hence, the different Al alloys used in the T-joint and the weld itself were clearly separated. The quantitative image analysis of the 3D data sets allows visualizing non-destructively and calculating the pore size distribution.

  17. Advanced Concept Studies for Supersonic Commercial Transports Entering Service in the 2018 to 2020 Period (United States)

    Morgenstern, John; Norstrud, Nicole; Sokhey, Jack; Martens, Steve; Alonso, Juan J.


    Lockheed Martin Aeronautics Company (LM), working in conjunction with General Electric Global Research (GE GR), Rolls-Royce Liberty Works (RRLW), and Stanford University, herein presents results from the "N+2 Supersonic Validations" contract s initial 22 month phase, addressing the NASA solicitation "Advanced Concept Studies for Supersonic Commercial Transports Entering Service in the 2018 to 2020 Period." This report version adds documentation of an additional three month low boom test task. The key technical objective of this effort was to validate integrated airframe and propulsion technologies and design methodologies. These capabilities aspired to produce a viable supersonic vehicle design with environmental and performance characteristics. Supersonic testing of both airframe and propulsion technologies (including LM3: 97-023 low boom testing and April-June nozzle acoustic testing) verified LM s supersonic low-boom design methodologies and both GE and RRLW's nozzle technologies for future implementation. The N+2 program is aligned with NASA s Supersonic Project and is focused on providing system-level solutions capable of overcoming the environmental and performance/efficiency barriers to practical supersonic flight. NASA proposed "Initial Environmental Targets and Performance Goals for Future Supersonic Civil Aircraft". The LM N+2 studies are built upon LM s prior N+3 100 passenger design studies. The LM N+2 program addresses low boom design and methodology validations with wind tunnel testing, performance and efficiency goals with system level analysis, and low noise validations with two nozzle (GE and RRLW) acoustic tests.

  18. Frame junction vibration transmission with a modified frame deformation model. (United States)

    Moore, J A


    A previous paper dealt with vibration transmission through junctions of connected frame members where the allowed frame deformations included bending, torsion, and longitudinal motions [J.A. Moore, J. Acoust. Soc. Am. 88, 2766-2776 (1990)]. In helicopter and aircraft structures the skin panels can constitute a high impedance connection along the length of the frames that effectively prohibits in-plane motion at the elevation of the skin panels. This has the effect of coupling in-plane bending and torsional motions within the frame. This paper discusses the transmission behavior through frame junctions that accounts for the in-plane constraint in idealized form by assuming that the attached skin panels completely prohibit inplane motion in the frames. Also, transverse shear deformation is accounted for in describing the relatively deep web frame constructions common in aircraft structures. Longitudinal motion in the frames is not included in the model. Transmission coefficient predictions again show the importance of out-of-plane bending deformation to the transmission of vibratory energy in an aircraft structure. Comparisons are shown with measured vibration transmission data along the framing in the overhead of a helicopter airframe, with good agreement. The frame junction description has been implemented within a general purpose statistical energy analysis (SEA) computer code in modeling the entire airframe structure including skin panels.

  19. HYFLEX (Hypersonic Flight Experiment). Results of flight testing (Navigation, guidance and control of HYFLEX vehicle and actual reentry flight trajectory); Gokuchoonsoku hiko jikken (HYFLEX) ni tsuite. Hiko kekka wo chushin ni (koho yudo seigyo to jitsuhiko keiro)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K.; Takizawa, M. [National Aerospace Laboratory, Tokyo (Japan); Ishimoto, S.; Morito, T. [National Space Development Agency of Japan, Tokyo (Japan); Tsujioka, M.; Shimura, K. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)


    The HYFLEX vehicle is the first reentry testing vehicle with an airframe generating lift in Japan. Establishment of guidance and control technology is one of the purposes. For the design of flight trajectory, in order to satisfy the constraint of J-1 rocket during launching and the heat resistance performance of HYFLEX, the altitude 110 km and ground speed 3.9 km/s were determined as an apogee condition of the reentry trajectory. For the trajectory design on the ground surface, were considered the insurance of radar tracking and telemetry transfer from the Ogasawara Tracking Station and the load reduction for development cost and attitude control system. The navigation, guidance and control system is composed of an inertia sensor unit, an on-board computer, and an on-board software (OBS). The attitude is controlled by the elevon at the rear end of airframe and the gas jet. The design requirements include an accuracy of flight trajectory and a stable flight by attitude control. In response to these requirements, OBS was divided into function units, i.e., navigation, guidance, and control, which were individually designed. The flight experiments were conducted as scheduled. 12 refs., 3 figs., 1 tab.

  20. Analysis of Aviation Safety Reporting System Incident Data Associated with the Technical Challenges of the Atmospheric Environment Safety Technology Project (United States)

    Withrow, Colleen A.; Reveley, Mary S.


    This study analyzed aircraft incidents in the NASA Aviation Safety Reporting System (ASRS) that apply to two of the three technical challenges (TCs) in NASA's Aviation Safety Program's Atmospheric Environment Safety Technology Project. The aircraft incidents are related to airframe icing and atmospheric hazards TCs. The study reviewed incidents that listed their primary problem as weather or environment-nonweather between 1994 and 2011 for aircraft defined by Federal Aviation Regulations (FAR) Parts 121, 135, and 91. The study investigated the phases of flight, a variety of anomalies, flight conditions, and incidents by FAR part, along with other categories. The first part of the analysis focused on airframe-icing-related incidents and found 275 incidents out of 3526 weather-related incidents over the 18-yr period. The second portion of the study focused on atmospheric hazards and found 4647 incidents over the same time period. Atmospheric hazards-related incidents included a range of conditions from clear air turbulence and wake vortex, to controlled flight toward terrain, ground encounters, and incursions.

  1. Analysis-Driven Design Optimization of a SMA-Based Slat-Cove Filler for Aeroacoustic Noise Reduction (United States)

    Scholten, William; Hartl, Darren; Turner, Travis


    Airframe noise is a significant component of environmental noise in the vicinity of airports. The noise associated with the leading-edge slat of typical transport aircraft is a prominent source of airframe noise. Previous work suggests that a slat-cove filler (SCF) may be an effective noise treatment. Hence, development and optimization of a practical slat-cove-filler structure is a priority. The objectives of this work are to optimize the design of a functioning SCF which incorporates superelastic shape memory alloy (SMA) materials as flexures that permit the deformations involved in the configuration change. The goal of the optimization is to minimize the actuation force needed to retract the slat-SCF assembly while satisfying constraints on the maximum SMA stress and on the SCF deflection under static aerodynamic pressure loads, while also satisfying the condition that the SCF self-deploy during slat extension. A finite element analysis model based on a physical bench-top model is created in Abaqus such that automated iterative analysis of the design could be performed. In order to achieve an optimized design, several design variables associated with the current SCF configuration are considered, such as the thicknesses of SMA flexures and the dimensions of various components, SMA and conventional. Designs of experiment (DOE) are performed to investigate structural response to an aerodynamic pressure load and to slat retraction and deployment. DOE results are then used to inform the optimization process, which determines a design minimizing actuator forces while satisfying the required constraints.

  2. Exploring Wing-mounted Engine Vibration Transmission under Windmill Imbalance for New Airplanes%大型客机风车不平衡振动载荷传递特性研究

    Institute of Scientific and Technical Information of China (English)

    白杰; 李广; 王伟


    Based on the dynamic characteristics of real aircraft ,we build the“pylon‐wing‐airframe”dynamic finite element model of a full airplane .Based on the vibration load spectrum of engine windmill imbalance ,we calculate the vibration load on the airplane at each section of the airframe transmitted from wing to the airframe .The results show that the windmill unbalance vibration is generated by the low‐pressure compressor rotor .And the results have important reference for the safety of the aircraft flight when it is in windmill imbalance condition .%依据真实客机的结构动力特性,建立“吊架—机翼—机身”动力学有限元模型;基于实验台测得发动机风车不平衡振动载荷谱,分析风车不平衡振动通过吊架向机翼及机身结构传递的载荷特性。结果表明,风车不平衡振动主要由低压压气机转子产生,飞机机身隔框振动具有明显的离散特性。

  3. Ground vibration tests of a helicopter structure using OMA techniques (United States)

    Ameri, N.; Grappasonni, C.; Coppotelli, G.; Ewins, D. J.


    This paper is focused on an assessment of the state-of-the-art of operational modal analysis (OMA) methodologies in estimating modal parameters from output responses on helicopter structures. For this purpose, a ground vibration test was performed on a real helicopter airframe. In the following stages, several OMA techniques were applied to the measured data and compared with the results from typical input-output approach. The results presented are part of a more general research activity carried out in the Group of Aeronautical Research and Technology in Europe (GARTEUR) Action Group 19, helicopter technical activity, whose overall objective is the improvement of the structural dynamic finite element models using in-flight test data. The structure considered is a medium-size helicopter, a time-expired Lynx Mk7 (XZ649) airframe. In order to have a comprehensive analysis, the behaviour of both frequency- and time-domain-based OMA techniques are considered for the modal parameter estimates. An accuracy index and the reliability of the OMA methods with respect to the standard EMA procedures, together with the evaluation of the influence of the experimental setup on the estimate of the modal parameters, will be presented in the paper.

  4. Hydrodynamic impact analysis and testing of an unmanned aerial vehicle (United States)

    Bird, Isabel

    Analysis and testing have been conducted to assess the feasibility of a small UAV that can be landed in the water and recovered for continued use. Water landings may be desirable in a number of situations, for example when testing UAVs outside of the territorial waters of the US to avoid violating FAA regulations. Water landings may also be desirable when conducting surveillance missions in marine environments. Although the goal in landing is to have the UAV lightly set down on the water, rough seas or gusty winds may result in a nose-in landing where the UAV essentially impacts the surface of the water. The tested UAV is a flying wing design constructed of expanded polypropylene foam wings with a hollowed out center-section for the avionics. Acceleration data was collected by means of LIS331 3-axis accelerometers positioned at five locations, including the wingtips. This allowed conclusions to be drawn with respect to the loads experienced on impact throughout the airframe. This data was also used to find loads corresponding to the maximum decelerations experienced during impact. These loads were input into a finite element analysis model of the wing spars to determine stress in the wing spars. Upon impact, the airframe experienced high-frequency oscillation. Surprisingly, peak accelerations at the wingtips were observed at up to 15g greater than corresponding accelerations at the center of the fuselage.

  5. Development of a SMA-Based Slat-Cove Filler for Reduction of Aeroacoustic Noise Associated With Transport-Class Aircraft Wings (United States)

    Turner, Travis L.; Kidd, Reggie T.; Hartl, Darren J.; Scholten, William D.


    Airframe noise is a significant part of the overall noise produced by typical, transport-class aircraft during the approach and landing phases of flight. Leading-edge slat noise is a prominent source of airframe noise. The concept of a slat-cove filler was proposed in previous work as an effective means of mitigating slat noise. Bench-top models were deployed at 75% scale to study the feasibility of producing a functioning slat-cove filler. Initial results from several concepts led to a more-focused effort investigating a deformable structure based upon pseudoelastic SMA materials. The structure stows in the cavity between the slat and main wing during cruise and deploys simultaneously with the slat to guide the aerodynamic flow suitably for low noise. A qualitative parametric study of SMA-enabled, slat-cove filler designs was performed on the bench-top. Computational models were developed and analyses were performed to assess the displacement response under representative aerodynamic load. The bench-top and computational results provide significant insight into design trades and an optimal design.

  6. Metallic Thermal Protection System Technology Development: Concepts, Requirements and Assessment Overview (United States)

    Dorsey, John T.; Poteet, Carl C.; Chen, Roger R.; Wurster, Kathryn E.


    A technology development program was conducted to evolve an earlier metallic thermal protection system (TPS) panel design, with the goals of: improving operations features, increasing adaptability (ease of attaching to a variety of tank shapes and structural concepts), and reducing weight. The resulting Adaptable Robust Metallic Operable Reusable (ARMOR) TPS system incorporates a high degree of design flexibility (allowing weight and operability to be traded and balanced) and can also be easily integrated with a large variety of tank shapes, airframe structural arrangements and airframe structure/material concepts. An initial attempt has been made to establish a set of performance based TPS design requirements. A set of general (FARtype) requirements have been proposed, focusing on defining categories that must be included for a comprehensive design. Load cases required for TPS design must reflect the full flight envelope, including a comprehensive set of limit loads, However, including additional loads. such as ascent abort trajectories, as ultimate load cases, and on-orbit debris/micro-meteoroid hypervelocity impact, as one of the discrete -source -damage load cases, will have a significant impact on system design and resulting performance, reliability and operability. Although these load cases have not been established, they are of paramount importance for reusable vehicles, and until properly included, all sizing results and assessments of reliability and operability must be considered optimistic at a minimum.

  7. Elastomeric Structural Attachment Concepts for Aircraft Flap Noise Reduction - Challenges and Approaches to Hyperelastic Structural Modeling and Analysis (United States)

    Sreekantamurthy, Thammaiah; Turner, Travis L.; Moore, James B.; Su, Ji


    Airframe noise is a significant part of the overall noise of transport aircraft during the approach and landing phases of flight. Airframe noise reduction is currently emphasized under the Environmentally Responsible Aviation (ERA) and Fixed Wing (FW) Project goals of NASA. A promising concept for trailing-edge-flap noise reduction is a flexible structural element or link that connects the side edges of the deployable flap to the adjacent main-wing structure. The proposed solution is distinguished by minimization of the span-wise extent of the structural link, thereby minimizing the aerodynamic load on the link structure at the expense of increased deformation requirement. Development of such a flexible structural link necessitated application of hyperelastic materials, atypical structural configurations and novel interface hardware. The resulting highly-deformable structural concept was termed the FLEXible Side Edge Link (FLEXSEL) concept. Prediction of atypical elastomeric deformation responses from detailed structural analysis was essential for evaluating feasible concepts that met the design constraints. The focus of this paper is to describe the many challenges encountered with hyperelastic finite element modeling and the nonlinear structural analysis of evolving FLEXSEL concepts. Detailed herein is the nonlinear analysis of FLEXSEL concepts that emerged during the project which include solid-section, foamcore, hollow, extended-span and pre-stressed concepts. Coupon-level analysis performed on elastomeric interface joints, which form a part of the FLEXSEL topology development, are also presented.

  8. Polymer-matrix Composites for High-temperature Applications

    Directory of Open Access Journals (Sweden)

    P.D. Mangalgiri


    Full Text Available Over the last decade, applications of fibre-reinforced composites using polymer matrices have seen tremendous growth. In spite of the complexity of their behaviour and the unconventionalnature of fabrication and other aspects, the usage of such composites, even for primary loadbearing structures in military fighters and transport aircraft, and satellites and space vehicles has been beneficially realised. Most of such usage constituted structural applications (such as in airframe where service temperatures are not expected to he beyond 120 'C. Attention is now focussed on expanding the usage of such composites to other areas where temperatures could be higher-in the range 200400 "C. The intended applications are structural and non-structural parts on or around the aero-engines and airframe components for supersonic or hypersonic aircraft. The development of polymer matrices-such as bismaleimides, polyimides, cyanates, and liquid crystalline polymers and others-has brought such applications within the realm of practicability. The associated problems have been in terms of suitable processing technologies and in balancing the requirements of the performance with those of the processing. This paper describes briefly such developments and reviews the potential application scenario.

  9. Corrosion detection in multi-layered rotocraft structures

    Energy Technology Data Exchange (ETDEWEB)



    Rotorcraft structures do not readily lend themselves to quantifiable inspection methods due to airframe construction techniques. Periodic visual inspections are a common practice for detecting corrosion. Unfortunately, when the telltale signs of corrosion appear visually, extensive repair or refurbishment is required. There is a need to nondestructively evaluate airframe structures in order to recognize and quantify corrosion before visual indications are present. Nondestructive evaluations of rotorcraft airframes face inherent problems different from those of the fixed wing industry. Most rotorcraft lap joints are very narrow, contain raised fastener heads, may possess distortion, and consist of thinner gage materials ({approximately}0.012--0.125 inches). In addition the structures involve stack-ups of two and three layers of thin gage skins that are separated by sealant of varying thickness. Industry lacks the necessary data techniques, and experience to adequately perform routine corrosion inspection of rotorcraft. In order to address these problems, a program is currently underway to validate the use of eddy current inspection on specific rotorcraft lap joints. Probability of detection (POD) specimens have been produced that simulate two lap joint configurations on a model TH-57/206 helicopter. The FAA's Airworthiness Assurance Center (AANC) at Sandia Labs and Bell Helicopter have applied single and dual frequency eddy current (EC) techniques to these test specimens. The test results showed enough promise to justify beta site testing of the eddy current methods evolved in this study. The technique allows users to distinguish between corrosion signals and those caused by varying gaps between the assembly of skins. Specific structural joints were defined as prime corrosion areas and a series of corrosion specimens were produced with 5--20% corrosion distributed among the layers of each joint. Complete helicopter test beds were used to validate the laboratory

  10. Numerical study of attack angle characteristics for integrated hypersonic vehicle

    Institute of Scientific and Technical Information of China (English)

    Wei HUANG; Zhen-guo WANG


    The two-dimensional coupled implicit Navier-Stokes equations and standard k-ε viscous models are used to simulate the angle of Stack characteristics of an integrated hypersonic vehicle with a hark head configuration under three kinds of working conditions:inlet cut-off,engine through-flow,and engine ignition.Influence of each component on aero-propulsive performance of the vehicle is discussed.It is concluded that the longitudinal static stability of the vehicle is good,and there is enough lift-to-drag ratio to satisfy the flying requirement of the vehicle.At the same time,it is important to change configurations of engine and upper surface of airframe to improve aero-propulsive performance of the vehicle.

  11. Review of the Most Important Design Optimization Technique of Composite Wing

    Directory of Open Access Journals (Sweden)

    Bogdan-Alexandru BELEGA


    Full Text Available The scope of wing optimization is to design a structure that meets all the airworthiness demands while minimizing its weight. This paper introduces a review for the most important optimization design tools of composite wings with multiple load cases and large scale design variables. Each discipline resorts to accurate design to ensure better performance. Accurate design and multidisciplinary optimization design for wings need large scale design variables. The structural design of an airframe is determined by multidisciplinary criteria (stress, fatigue, buckling, control surface effectiveness, flutter and weight etc.. Several thousands of structural sizes of stringers, panels, ribs etc. have to be determined considering hundreds of thousands of requirements to find an optimum solution, i.e. a design fulfilling all requirements with a minimum weight or minimum cost respectively.

  12. Virtual Sensor for Failure Detection, Identification and Recovery in the Transition Phase of a Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Guillermo Heredia


    Full Text Available The Helicopter Adaptive Aircraft (HADA is a morphing aircraft which is able to take-off as a helicopter and, when in forward flight, unfold the wings that are hidden under the fuselage, and transfer the power from the main rotor to a propeller, thus morphing from a helicopter to an airplane. In this process, the reliable folding and unfolding of the wings is critical, since a failure may determine the ability to perform a mission, and may even be catastrophic. This paper proposes a virtual sensor based Fault Detection, Identification and Recovery (FDIR system to increase the reliability of the HADA aircraft. The virtual sensor is able to capture the nonlinear interaction between the folding/unfolding wings aerodynamics and the HADA airframe using the navigation sensor measurements. The proposed FDIR system has been validated using a simulation model of the HADA aircraft, which includes real phenomena as sensor noise and sampling characteristics and turbulence and wind perturbations.

  13. Closing Symposium of the DFG Research Unit FOR 1066

    CERN Document Server

    Niehuis, Reinhard; Kroll, Norbert; Behrends, Kathrin


    The book reports on advanced solutions to the problem of simulating wing and nacelle stall, as presented and discussed by internationally recognized researchers at the Closing Symposium of the DFG Research Unit FOR 1066. Reliable simulations of flow separation on airfoils, wings and powered engine nacelles at high Reynolds numbers represent great challenges in defining suitable mathematical models, computing numerically accurate solutions and providing comprehensive experimental data for the validation of numerical simulations. Additional problems arise from the need to consider airframe-engine interactions and inhomogeneous onset flow conditions, as real aircraft operate in atmospheric environments with often-large distortions. The findings of fundamental and applied research into these and other related issues are reported in detail in this book, which targets all readers, academics and professionals alike, interested in the development of advanced computational fluid dynamics modeling for the simulation of...

  14. UAVs for Glacier Mapping: Lessons Learned (United States)

    McKinnon, T.; McKinnon, K. A.; Anderson, B.


    Using two different unmanned aerial vehicles (UAVs) mounted with cameras, we created a digital elevation model (DEM) of the lower 12 km^2 of Tasman Glacier, South Island, New Zealand in March 2014. The project served primarily as a proof-of-concept, and here we discuss the lessons learned, emphasizing the practical, logistical, and flight issues. We tested two different fixed-wing airframes -- a twin-boom tradition and flying wing; two different camera types, both consumer-grade RGB; and various combinations of RC and telemetry radios. We used both commercial and open-source photogrammetry software to create the mosaic and DEM imagery. Some of the most critical UAV-specific issues are: access to a launch/landing site, adequate landing zones, range, airspace contention with manned aircraft, and hardware reliability. While UAVs provide a lower-cost method for photogrammetry access, it also comes with a unique set of challenges.

  15. Bifilar analysis study, volume 1 (United States)

    Miao, W.; Mouzakis, T.


    A coupled rotor/bifilar/airframe analysis was developed and utilized to study the dynamic characteristics of the centrifugally tuned, rotor-hub-mounted, bifilar vibration absorber. The analysis contains the major components that impact the bifilar absorber performance, namely, an elastic rotor with hover aerodynamics, a flexible fuselage, and nonlinear individual degrees of freedom for each bifilar mass. Airspeed, rotor speed, bifilar mass and tuning variations are considered. The performance of the bifilar absorber is shown to be a function of its basic parameters: dynamic mass, damping and tuning, as well as the impedance of the rotor hub. The effect of the dissimilar responses of the individual bifilar masses which are caused by tolerance induced mass, damping and tuning variations is also examined.

  16. Thermal stress analysis of the NASA Dryden hypersonic wing test structure (United States)

    Morris, Glenn


    Present interest in hypersonic vehicles has resulted in a renewed interest in thermal stress analysis of airframe structures. While there are numerous texts and papers on thermal stress analysis, practical examples and experience on light gage aircraft structures are fairly limited. A research program has been undertaken at General Dynamics to demonstrate the present state of the art, verify methods of analysis, gain experience in their use, and develop engineering judgement in thermal stress analysis. The approach for this project has been to conduct a series of analyses of this sample problem and compare analysis results with test data. This comparison will give an idea of how to use our present methods of thermal stress analysis, and how accurate we can expect them to be.

  17. Personal Aircraft Point to the Future of Transportation (United States)


    NASA's Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs, as well as a number of Agency innovations, have helped Duluth, Minnesota-based Cirrus Design Corporation become one of the world's leading manufacturers of general aviation aircraft. SBIRs with Langley Research Center provided the company with cost-effective composite airframe manufacturing methods, while crashworthiness testing at the Center increased the safety of its airplanes. Other NASA-derived technologies on Cirrus SR20 and SR22 aircraft include synthetic vision systems that help pilots navigate and full-plane parachutes that have saved the lives of more than 30 Cirrus pilots and passengers to date. Today, the SR22 is the world's top-selling Federal Aviation Administration (FAA)-certified single-engine airplane.

  18. Decennial Specialists' Meeting on Rotorcraft Dynamics, 2nd, Moffett Field, CA, November 7-9, 1984, Proceedings (United States)


    Various papers on helicopter rotor technology are presented. The subjects considered include: ground resonance analysis using a substructure modelling approach, aerolastic stability of a bearingless rotor, experimentally determined flutter from two and three-bladed model bearingless rotors in hover, lifting surface theory for a helicopter rotor in forward flight, aeroelastic considerations for torsionally soft rotors, and restructuring of a rotor analysis program. Also discussed are: dynamic inflow and its effect on experimental correlations, flap-lag-torsion instability in forward flight, dynamic stability of a bearingless circulation control rotor blade in hover, dynamic response characteristics of a circulation control rotor model pneumatic system, the relations between vibratory loads and airframe vibrations, coupled rotor body vibrations with in-plane degrees of freedom, helicopter vibration reduction concepts.

  19. Flexible missile autopilot design studies with PC-MATLAB/386 (United States)

    Ruth, Michael J.


    Development of a responsive, high-bandwidth missile autopilot for airframes which have structural modes of unusually low frequency presents a challenging design task. Such systems are viable candidates for modern, state-space control design methods. The PC-MATLAB interactive software package provides an environment well-suited to the development of candidate linear control laws for flexible missile autopilots. The strengths of MATLAB include: (1) exceptionally high speed (MATLAB's version for 80386-based PC's offers benchmarks approaching minicomputer and mainframe performance); (2) ability to handle large design models of several hundred degrees of freedom, if necessary; and (3) broad extensibility through user-defined functions. To characterize MATLAB capabilities, a simplified design example is presented. This involves interactive definition of an observer-based state-space compensator for a flexible missile autopilot design task. MATLAB capabilities and limitations, in the context of this design task, are then summarized.

  20. A Synthesis of Hybrid RANS/LES CFD Results for F-16XL Aircraft Aerodynamics (United States)

    Luckring, James M.; Park, Michael A.; Hitzel, Stephan M.; Jirasek, Adam; Lofthouse, Andrew J.; Morton, Scott A.; McDaniel, David R.; Rizzi, Arthur M.


    A synthesis is presented of recent numerical predictions for the F-16XL aircraft flow fields and aerodynamics. The computational results were all performed with hybrid RANS/LES formulations, with an emphasis on unsteady flows and subsequent aerodynamics, and results from five computational methods are included. The work was focused on one particular low-speed, high angle-of-attack flight test condition, and comparisons against flight-test data are included. This work represents the third coordinated effort using the F-16XL aircraft, and a unique flight-test data set, to advance our knowledge of slender airframe aerodynamics as well as our capability for predicting these aerodynamics with advanced CFD formulations. The prior efforts were identified as Cranked Arrow Wing Aerodynamics Project International, with the acronyms CAWAPI and CAWAPI-2. All information in this paper is in the public domain.

  1. Basic materials and structures aspects for hypersonic transport vehicles (HTV) (United States)

    Steinheil, E.; Uhse, W.

    A Mach 5 transport design is used to illustrate structural concepts and criteria for materials selections and also key technologies that must be followed in the areas of computational methods, materials and construction methods. Aside from the primary criteria of low weight, low costs, and conceivable risks, a number of additional requirements must be met, including stiffness and strength, corrosion resistance, durability, and a construction adequate for inspection, maintenance and repair. Current aircraft construction requirements are significantly extended for hypersonic vehicles. Additional consideration is given to long-duration temperature resistance of the airframe structure, the integration of large-volume cryogenic fuel tanks, computational tools, structural design, polymer matrix composites, and advanced manufacturing technologies.

  2. Prepreg and Melt Infiltration Technology Developed for Affordable, Robust Manufacturing of Ceramic Matrix Composites (United States)

    Singh, Mrityunjay; Petko, Jeannie F.


    Affordable fiber-reinforced ceramic matrix composites with multifunctional properties are critically needed for high-temperature aerospace and space transportation applications. These materials have various applications in advanced high-efficiency and high-performance engines, airframe and propulsion components for next-generation launch vehicles, and components for land-based systems. A number of these applications require materials with specific functional characteristics: for example, thick component, hybrid layups for environmental durability and stress management, and self-healing and smart composite matrices. At present, with limited success and very high cost, traditional composite fabrication technologies have been utilized to manufacture some large, complex-shape components of these materials. However, many challenges still remain in developing affordable, robust, and flexible manufacturing technologies for large, complex-shape components with multifunctional properties. The prepreg and melt infiltration (PREMI) technology provides an affordable and robust manufacturing route for low-cost, large-scale production of multifunctional ceramic composite components.

  3. The damping performance of aluminum-based composites

    Energy Technology Data Exchange (ETDEWEB)

    Updike, C.A.; Bhagat, R.B.; Pechersky, M.J.; Amateau, M.F. (Harris Corp., Government Aerospace Systems Div., Melbourne, FL (USA) Pennsylvania State Univ., University Park (USA))


    Metal-matrix-composites may offer better damping properties than unreinforced alloys. Because damping properties (and metal-matrix composites) are becoming important in airframe design, the damping capabilities of a number of aluminum-matrix composites were measured over a wide range of frequencies at low strain amplitudes, using a new laser vibrometer technique. Silicon carbide and alumina reinforcements resulted in a material with damping properties similar to that of unreinforced aluminum 6061-T6, but unidirectional and planar-random graphite continuous-fiber reinforcements increased the damping by 5 and 14 times, respectively. The increased damping of the continuous fiber composites is attributed to the absence of interfacial reaction resulting from the high-pressure infiltration method used for their manufacture. 25 refs.

  4. Development and testing of the Perseus proof-of-concept aircraft. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Langford, J.S. [Aurora Flight Sciences Corp., Manassas, VA (United States)


    Many areas of global climate change research could benefit from a flexible, affordable, and near-term platform that could provide in situ measurements in the upper troposphere and lower stratosphere. To provide such a capability, the Perseus unmanned science research aircraft was proposed in 1989. As a first step toward the development of Perseus, a proof-of-concept (POC) demonstrator was constructed and tested during 1990 and 1991. The POC was a full scale Perseus airframe intended to validate the structural, aerodynamic, and flight control technologies for the Perseus within a total budget of about $1.5 million. Advanced propulsion systems needed for the operational Perseus were not covered in the POC program due to funding limitations. This report documents the design, development, and testing of the Perseus POC.

  5. Thermal-structural test facilities at NASA Dryden (United States)

    Deangelis, V. Michael; Anderson, Karl F.


    The National Aero-Space Plane (NASP) has renewed interest in hypersonic flight and hot-structures technology development for both the airframe and engine. The NASA Dryden Thermostructures Research Facility is a unique national facility that was designed to conduct thermal-mechanical tests on aircraft and aircraft components by simulating the flight thermal environment in the laboratory. The layout of the facility is presented, which includes descriptions of the high-bay test area, the instrumentation laboratories, the mechanical loading systems, and the state-of-the-art closed-loop thermal control system. The hot-structures test capability of the facility is emphasized by the Mach-3 thermal simulation conducted on the YF-12 airplane. The Liquid-Hydrogen Structural Test Facility, which is presently in the design phase, will provide the capability of thermally testing structures containing hydrogen.

  6. The research of optical windows used in aircraft sensor systems

    Institute of Scientific and Technical Information of China (English)

    Zhou Feng; Li Yan; Tang Tian-Jin


    The optical windows used in aircrafts protect their imaging sensors from environmental effects.Considering the imaging performance,flat surfaces are traditionally used in the design of optical windows.For aircrafts operating at high speeds,the optical windows should be relatively aerodynamic,but a flat optical window may introduce unacceptably high drag to the airframes.The linear scanning infrared sensors used in aircrafts with,respectively,a fiat window,a spherical window and a toric window in front of the aircraft sensors are designed and compared.Simulation results show that the optical design using a toric surface has the integrated advantages of field of regard,aerodynamic drag,narcissus effect,and imaging performance,so the optical window with a toric surface is demonstrated to be suited for this application.

  7. Application of the ABC helicopter to the emergency medical service role (United States)

    Levine, L. S.


    Attention is called to the use of helicopters in transporting the sick and injured to medical facilities. It is noted that the helicopter's speed of response and delivery increases patient survival rates and may reduce the cost of medical care and its burden on society. Among the vehicle characteristics desired for this use are a cruising speed of 200 knots, a single engine hover capability at 10,000 ft, and an absence of a tail rotor. Three designs for helicopters incorporating such new technologies as digital/optical control systems, all composite air-frames, and third-generation airfoils are presented. A sensitivity analysis is conducted to show the effect of design speed, mission radius, and single engine hover capability on vehicle weight, fuel consumption, operating costs, and productivity.

  8. High performance jet-engine flight test data base for HSR (United States)

    Kelly, Jeffrey


    The primary acoustic priority of the flight test data base for HSR is the validation of the NASA Aircraft Noise Prediction Program (ANOPP) and other source noise codes. Also, the noise measurements are an important support function for the High Lift Program devoted to HSR. Another concern that will be addressed is a possible noise problem 7-20 miles from take-off during climbout. The attention arises from the higher speeds envisioned for the HSCT compared to conventional aircraft causing levels to increase because of Doppler amplification in conjunction with high source levels due to jet noise. An attempt may be made to measure airframe noise for the F-16XL test which would provide an assessment of this noise component for delta wing aircraft.

  9. Aqua[4-(hydroxyiminomethylpyridine-κN1](iminodiacetato-κ3O,N,O′copper(II

    Directory of Open Access Journals (Sweden)

    Yisheng Yang


    Full Text Available In the title complex, [Cu(C4H5NO4(C6H6N2O(H2O], conventionally abbreviated Cu(IDA(4-OXPy(H2O, where IDA is iminodiacetate and 4-OXPy is 4-(hydroxyiminomethylpyridine, the CuII atom exhibits a distorted square-pyramidal coordination geometry, which is constructed from two O atoms and one N atom from a IDA ligand, one N atom from 4-OXPy ligand and one O atom from water. This molecule looks like a space shuttle, the IDA ligand is its empennage (tail, and the 4-OXPy ligand is its airframe. The complexes are linked into two-dimensional supramolecular layers parallel to (100 by three pairs of O—H...O hydrogen bonds. Two pairs of N—H...O hydrogen bonds further connect these supramolecular layers, forming a three-dimensional supramolecular network.

  10. Typical High-Temperature Seal Structur of Reusable and Hypersonic Vehicles%飞行器典型热密封结构

    Institute of Scientific and Technical Information of China (English)

    李凡; 王树浩; 陈江涛; 赵光辉; 于焕光


    Reusable and hypersonic vehicles pose an extraordinary challenge for seal structures. Airframes and engines require lightweight, high-temperature seal structural that can withstand the extreme environment of hypersonic flight. This paper reviews relevant seal technology for typical vehicles (e. g. Space Shuttle, X-38 and X-51) and presents several seal technologies for future hypersonic vehicles, foucs on high-temperature seal structural of the space shuttle TPS, vehicle penetrations and control surfaces.%对航天飞机、X-38和X-51等飞行器的热密封结构进行了综合评述.分析了机身TPS、机身开口部位及控制面三个安装部位的热密封结构特点,综述了其热密封组件的研究历程和使用现状.

  11. Superplasticity in Aeroengine Titanium Alloy VT-9 and its Modified Compositions

    Directory of Open Access Journals (Sweden)

    Abhijit Dutta


    Full Text Available The alloy (Ti-6.5AL-3.3 Mo-1.6Zr-O.3Si is a Soviet composition designated VT-9. Excellent superplastic characteristics found by us in this alloy prompted us to explore the possibility of use of Si-free VT-9 in sheet form for superplastic forming. An optimum thermomechanical processing produced a microstructure that resulted in an elongation of 1700 per cent at a fairly high deformation rate (2 X 10-3 set-1. Thus, the same aeroengine alloy (VT-9 can be used for superplastically formed airframe parts in the Si-free condition. The present study also shows that for making the forming process commercially viable, deformation temperature could be lowered by temporarily alloying with hydrogen in a particular concentration range (0.1 to 0.2 wt per cent.

  12. An approximation approach for uncertainty quantification using evidence theory

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Ha-Rok; Grandhi, Ramana V.; Canfield, Robert A


    Over the last two decades, uncertainty quantification (UQ) in engineering systems has been performed by the popular framework of probability theory. However, many scientific and engineering communities realize that there are limitations in using only one framework for quantifying the uncertainty experienced in engineering applications. Recently evidence theory, also called Dempster-Shafer theory, was proposed to handle limited and imprecise data situations as an alternative to the classical probability theory. Adaptation of this theory for large-scale engineering structures is a challenge due to implicit nature of simulations and excessive computational costs. In this work, an approximation approach is developed to improve the practical utility of evidence theory in UQ analysis. The techniques are demonstrated on composite material structures and airframe wing aeroelastic design problem.

  13. The Strategy of Drone Warfare

    Directory of Open Access Journals (Sweden)

    Mike Fowler


    Full Text Available There is a budding controversy with the combat use of Remotely Piloted Aircraft (RPA. Also known as Unmanned Aerial Vehicles (UAV, there is a growing literature critiquing the use of RPAs, often using the pejorative term “drone.” RPAs seem to get the blame for a variety of complaints about policy and employment that have little to do with the airframe or its processes. While all of the military functions of an RPA can and are done by manned aircraft, the RPAs must endure additional scrutiny. The decision to employ RPAs requires additional considerations at both the strategic and operational levels of war. This article explores the strategic issues that govern the decisions to employ RPAs in combat. The decision to employ RPAs involves a variety of strategic and operational concerns involving legal issues, technological constraints, operational efficiency, and an interdependency upon information operations.

  14. Fabrication and development of several heat pipe honeycomb sandwich panel concepts (United States)

    Tanzer, H. J.


    The feasibility of fabricating and processing liquid metal heat pipes in a low mass honeycomb sandwich panel configuration for application on the NASA Langley airframe-integrated Scramjet engine was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts was evaluated within constraints dictated by existing manufacturing technology and equipment. The chosen design consists of an all-stainless steel structure, sintered screen facesheets, and two types of core-ribbon; a diffusion bonded wire mesh and a foil-screen composite. Cleaning, fluid charging, processing, and process port sealing techniques were established. The liquid metals potassium, sodium and cesium were used as working fluids. Eleven honeycomb panels 15.24 cm X 15.24 cm X 2.94 cm were delivered to NASA Langley for extensive performance testing and evaluation; nine panels were processed as heat pipes, and two panels were left unprocessed.

  15. Propulsion Induced Effects (PIE) Test Program (United States)

    Cappuccio, Gelsomina; Won, Mark J.


    The Propulsion Induced Effects (PIE) test program is being lead by NASA Ames for Configuration Aerodynamics (CA). Representatives from CA, Technology Integration (TI), Inlet, and the Nozzle ITD's are working with Ames in defining and executing this test program. The objective of the CA 4-14 milestone is to assess the propulsion/airframe integration characteristics of the Technology Concept Airplane (TCA) and design variations using computational and experimental methods. The experimental aspect includes static calibrations, transonic and supersonic wind tunnel testing. The test program will generate a comprehensive database that will include all appropriate wind tunnel corrections, with emphasis placed on establishing the propulsion induced effects on the flight performance of the TCA.

  16. International SAMPE Technical Conference, 23rd, Kiamesha Lake, NY, Oct. 21-24, 1991, Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Carri, R.L.; Poveromo, L.M.; Gauland, J. (Grumman Aircraft Systems, Bethpage, NY (United States))


    The present conference discusses the cost of composite structures, microwave processing of thermoset resin-matrix composites at high pressure, the impact damage-tolerance of helicopter sandwich structures, novel fluorinated polybenzoxazole thermoplastics, low expansion coefficient polyimides containing metal-ion additives, thermoplastic polyimides for supersonic airframes, material properties and laser cutting of composites, fiber-matrix bond tests in composites, and a global/local stress analysis of stitched composites. Also discussed are moldless composite aircraft wing structural design modifications, advances in anhydride epoxy systems, medical applications of advanced composites, metal-joining processes for space fabrication, close-tolerance plastic master molds, the ballistic energy absorption of composites, soft and hard composite armors, resin-transfer molding of 3D composites, toughened cyanate ester resins, and thermoforming of thermoplastics.

  17. HYTEX - Saenger trailblazer (United States)

    Bulloch, Chris

    The Hypersonic Technology Experimental, or 'HYTEX' vehicle is a proof-of-concept aircraft for the more ambitious Saenger two-stage-to-orbit reusable launch vehicle being developed by the DLR; in this, it mirrors NASA's intention to build the X-30 hypersonic test vehicle prior to full scale development of the National Aerospace Plane. Attention is presently given to the variable-geometry features of HYTEX's airframe-integrated propulsion system, which will employ two LH2/kerosene turboramjets. The maximum speed for HYTEX would be Mach 5.6, which is the minimum required for full verification of propulsion and structures technologies intended for use by Saenger's Mach 6.8-maximum-speed lower stage.

  18. Overview of Low-Speed Aerodynamic Tests on a 5.75% Scale Blended-Wing-Body Twin Jet Configuration (United States)

    Vicroy, Dan D.; Dickey, Eric; Princen, Norman; Beyar, Michael D.


    The NASA Environmentally Responsible Aviation (ERA) Project sponsored a series of computational and experimental investigations of the propulsion and airframe integration issues associated with Hybrid-Wing-Body (HWB) or Blended-Wing-Body (BWB) configurations. NASA collaborated with Boeing Research and Technology (BR&T) to conduct this research on a new twin-engine Boeing BWB transport configuration. The experimental investigations involved a series of wind tunnel tests with a 5.75-percent scale model conducted in two low-speed wind tunnels. This testing focused on the basic aerodynamics of the configuration and selection of the leading edge Krueger slat position for takeoff and landing. This paper reviews the results and analysis of these low-speed wind tunnel tests.

  19. F-5M DTA Program

    Directory of Open Access Journals (Sweden)

    Daniel Ferreira V. Mattos


    Full Text Available The Brazilian F-5 was submitted to avionics and weapons upgrade. This “new” aircraft has proven to be heavier and more capable. A comprehensive damage tolerance analysis is being performed to evaluate how the new mission profiles and weight distribution may affect the airframe structural integrity. Operational data were collected at the Brazilian Air Force Bases where the fighter is flown. Software was developed in order to acquire, filter and analyze flight data. This data was used for comparison between the pre and post modernization mission profiles and to determine the stress level in each of the known aircraft fatigue critical locations (FCL. The results show that the change in aircraft weight and balance and the new operational profile can significantly change the inspection intervals of certain fatigue critical locations of the structure. A preliminary result for the horizontal tail has shown that this component will have a much more restrictive maintenance schedule to assure flight safety.

  20. An overview of aeroelasticity studies for the National Aero-Space Plane (United States)

    Ricketts, Rodney H.; Noll, Thomas E.; Whitlow, Woodrow, Jr.; Huttsell, Lawrence J.


    The National Aero-Space Plane (NASP), or X-30, is a single-stage-to-orbit vehicle that is designed to takeoff and land on conventional runways. Research in aeroelasticity was conducted by the NASA and the Wright Laboratory to support the design of a flight vehicle by the national contractor team. This research includes the development of new computational codes for predicting unsteady aerodynamic pressures. In addition, studies were conducted to determine the aerodynamic heating effects on vehicle aeroelasticity and to determine the effects of fuselage flexibility on the stability of the control systems. It also includes the testing of scale models to better understand the aeroelastic behavior of the X-30 and to obtain data for code validation and correlation. This paper presents an overview of the aeroelastic research which has been conducted to support the airframe design.

  1. An overview of aeroelasticity studies for the National Aerospace Plane (United States)

    Ricketts, Rodney H.; Noll, Thomas E.; Huttsell, Lawrence J.; Hutsell, Lawrence J.


    The National Aero-Space Plane (NASP), or X-30, is a single-stage-to-orbit vehicle that is designed to takeoff and land on conventional runways. Research in aeroelasticity was conducted by NASA and the Wright Laboratory to support the design of a flight vehicle by the national contractor team. This research includes the development of new computational codes for predicting unsteady aerodynamic pressures. In addition, studies were conducted to determine the aerodynamic heating effects on vehicle aeroelasticity and to determine the effects of fuselage flexibility on the stability of the control systems. It also includes the testing of scale models to better understand the aeroelastic behavior of the X-30 and to obtain data for code validation and correlation. This paper presents an overview of the aeroelastic research which has been conducted to support the airframe design.

  2. Survey of supersonic combustion ramjet research at Langley (United States)

    Northam, G. B.; Anderson, G. Y.


    The Hypersonic Propulsion Branch at NASA Langley Research Center has maintained an active research program in supersonic combustion ramjet (scramjet) and high speed ramjet propulsion since the 1960s. The focus for this research has centered on propulsion for manned reuseable vehicles with cryogenic hydrogen fuel. This paper presents some highlights of this research. The design philosophy of the Langley fixed-geometry airframe-integrated modular scramjet is discussed. The component development and research programs that have supported the successful demonstration of the engine concept using subscale engine module hardware is reviewed and a brief summary of the engine tests presented. An extensive bibliography of research supported by the Langley program is also included.

  3. Survey of NASA research on crash dynamics (United States)

    Thomson, R. G.; Carden, H. D.; Hayduk, R. J.


    Ten years of structural crash dynamics research activities conducted on general aviation aircraft by the National Aeronautics and Space Administration (NASA) are described. Thirty-two full-scale crash tests were performed at Langley Research Center, and pertinent data on airframe and seat behavior were obtained. Concurrent with the experimental program, analytical methods were developed to help predict structural behavior during impact. The effects of flight parameters at impact on cabin deceleration pulses at the seat/occupant interface, experimental and analytical correlation of data on load-limiting subfloor and seat configurations, airplane section test results for computer modeling validation, and data from emergency-locator-transmitter (ELT) investigations to determine probable cause of false alarms and nonactivations are assessed. Computer programs which provide designers with analytical methods for predicting accelerations, velocities, and displacements of collapsing structures are also discussed.

  4. Adaptive, tolerant and efficient composite structures

    CERN Document Server

    Sinapius, Michael


    Polymer composites offer the possibility for functional integration since the material is produced simultaneously with the product. The efficiency of composite structures raises through functional integration. The specific production processes of composites offer the possibility to improve and to integrate more functions thus making the structure more valuable. Passive functions can be improved by combination of different materials from nano to macro scale, i.e. strength, toughness, bearing strength, compression after impact properties or production tolerances.  Active functions can be realized by smart materials, i.e. morphing, active vibration control, active structure acoustic control or structure health monitoring. The basis is a comprehensive understanding of materials, simulation, design methods, production technologies and adaptronics. These disciplines together deliver advanced lightweight solutions for applications ranging from mechanical engineering to vehicles, airframe and space structures along ...

  5. Adaptive, tolerant and efficient composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, Martin; Sinapius, Michael (eds.) [German Aerospace Center DLR, Braunschweig (Germany). Inst. of Composite Structures and Adaptive Systems


    Polymer composites offer the possibility for functional integration since the material is produced simultaneously with the product. The efficiency of composite structures raises through functional integration. The specific production processes of composites offer the possibility to improve and to integrate more functions thus making the structure more valuable. Passive functions can be improved by combination of different materials from nano to macro scale, i.e. strength, toughness, bearing strength, compression after impact properties or production tolerances. Active functions can be realized by smart materials, i.e. morphing, active vibration control, active structure acoustic control or structure health monitoring. The basis is a comprehensive understanding of materials, simulation, design methods, production technologies and adaptronics. These disciplines together deliver advanced lightweight solutions for applications ranging from mechanical engineering to vehicles, airframe and space structures along the complete process chain. The book provides basics as well as inspiring ideas for engineers working in the field of adaptive, tolerant and robust composite structures.

  6. Structural Load Alleviation Applied to Next Generation Aircraft and Wind Turbines (United States)

    Frost, Susan


    Reducing the environmental impact of aviation is a goal of the Subsonic Fixed Wing Project under the Fundamental Aeronautics Program of NASAs Aeronautics Research Mission Directorate. Environmental impact of aviation is being addressed by novel aircraft configurations and materials that reduce aircraft weight and increase aerodynamic efficiency. NASA is developing tools to address the challenges of increased airframe flexibility created by wings constructed with reduced structural material and novel light-weight materials. This talk will present a framework and demonstration of a flight control system using optimal control allocation with structural load feedback and constraints to achieve safe aircraft operation. As wind turbines age, they become susceptible to many forms of blade degradation. Results will be presented on work in progress that uses adaptive contingency control for load mitigation in a wind turbine simulation with blade damage progression modeled.

  7. NASA-UVa light aerospace alloy and structures technology program supplement: Aluminum-based materials for high speed aircraft (United States)

    Starke, E. A., Jr. (Editor)


    This report on the NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from July 1, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) Ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) Powder metallurgy 2XXX alloys, (3) Rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) Discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  8. Hot gas ingestion characteristics and flow visualization of a vectored thrust STOVL concept (United States)

    Johns, Albert L.; Neiner, George H.; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.; Williams, Ben R.


    The study presents results obtained at the compressor face of a 9.2-percent scale vectored thrust model in ground effects from Phases I and II of a test program to evaluate the hot ingestion phenomena and control techniques, and to conduct flow visualization of the model flowfield in and out of ground effects, respectively. A description of the model, facility, a new model support system, and a sheet laser illumination system are provided. The findings contain the compressor face pressure and temperature distortions, compressor face temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane temperature and pressure distributions, model airframe heating, and the location of the ground flow separation. Results from the sheet laser flow visualization test are also presented.

  9. Performance improvements of a highly integrated digital electronic control system for an F-15 airplane (United States)

    Putnam, T. W.; Burcham, F. W., Jr.; Andries, M. G.; Kelly, J. B.


    The NASA highly integrated digital electronic control (HIDEC) program is structured to conduct flight research into the benefits of integrating an aircraft flight control system with the engine control system. A brief description of the HIDEC system installed on an F-15 aircraft is provided. The adaptive engine control system (ADECS) mode is described in detail, together with simulation results and analyses that show the significant excess thrust improvements achievable with the ADECS mode. It was found that this increased thrust capability is accompanied by reduced fan stall margin and can be realized during flight conditions where engine face distortion is low. The results of analyses and simulations also show that engine thrust response is improved and that fuel consumption can be reduced. Although the performance benefits that accrue because of airframe and engine control integration are being demonstrated on an F-15 aircraft, the principles are applicable to advanced aircraft such as the advanced tactical fighter and advanced tactical aircraft.

  10. Test and evaluation of the HIDEC engine uptrim algorithm. [Highly Integrated Digital Electronic Control for aircraft (United States)

    Ray, R. J.; Myers, L. P.


    The highly integrated digital electronic control (HIDEC) program will demonstrate and evaluate the improvements in performance and mission effectiveness that result from integrated engine-airframe control systems. Performance improvements will result from an adaptive engine stall margin mode, a highly integrated mode that uses the airplane flight conditions and the resulting inlet distortion to continuously compute engine stall margin. When there is excessive stall margin, the engine is uptrimmed for more thrust by increasing engine pressure ratio (EPR). The EPR uptrim logic has been evaluated and implemente into computer simulations. Thrust improvements over 10 percent are predicted for subsonic flight conditions. The EPR uptrim was successfully demonstrated during engine ground tests. Test results verify model predictions at the conditions tested.

  11. The study and design of a national supply chain for the aerospace titanium components manufacturing industry

    Directory of Open Access Journals (Sweden)

    Lene van der Merwe


    Full Text Available Titanium’s strength-to-density ratio, corrosion resistance and high thermal compatibility makes it the perfect metal for aerospace. Titanium is for instance used for the structural airframe, seat tracks, engine components and landing gear of aircraft. The Boeing 787 that had its test flight in 2009 is one of the latest aircraft designs that incorporates a substantially higher percentage of parts manufactured from titanium due to the weight benefit. Titanium’s extensive use in aerospace applications ensures that the aerospace market is the main driver of titanium metal demand. South Africa is the second largest titanium producer in the world after Australia. The abundance of titanium in South Africa together with the growing demand has led it to be identified as a beneficiation priority in a collaborative government initiative, called Titanium Beneficiation Initiative (TBI. The purpose of this paper is to develop a supply chain model for the anticipated South African titanium component manufacturing industry.

  12. Three-Dimensional Cellular Structures Enhanced By Shape Memory Alloys (United States)

    Nathal, Michael V.; Krause, David L.; Wilmoth, Nathan G.; Bednarcyk, Brett A.; Baker, Eric H.


    This research effort explored lightweight structural concepts married with advanced smart materials to achieve a wide variety of benefits in airframe and engine components. Lattice block structures were cast from an aerospace structural titanium alloy Ti-6Al-4V and a NiTi shape memory alloy (SMA), and preliminary properties have been measured. A finite element-based modeling approach that can rapidly and accurately capture the deformation response of lattice architectures was developed. The Ti-6-4 and SMA material behavior was calibrated via experimental tests of ligaments machined from the lattice. Benchmark testing of complete lattice structures verified the main aspects of the model as well as demonstrated the advantages of the lattice structure. Shape memory behavior of a sample machined from a lattice block was also demonstrated.

  13. Periodic Cellular Structure Technology for Shape Memory Alloys (United States)

    Chen, Edward Y.


    Shape memory alloys are being considered for a wide variety of adaptive components for engine and airframe applications because they can undergo large amounts of strain and then revert to their original shape upon heating or unloading. Transition45 Technologies, Inc., has developed an innovative periodic cellular structure (PCS) technology for shape memory alloys that enables fabrication of complex bulk configurations, such as lattice block structures. These innovative structures are manufactured using an advanced reactive metal casting technology that offers a relatively low cost and established approach for constructing near-net shape aerospace components. Transition45 is continuing to characterize these structures to determine how best to design a PCS to better exploit the use of shape memory alloys in aerospace applications.

  14. Design, fabrication and test of liquid metal heat-pipe sandwich panels (United States)

    Basiulis, A.; Camarda, C. J.


    Integral heat-pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich panel construction, were fabricated and tested. The designs utilize two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and potassium or sodium as the working fluid. Panels were tested by radiant heating, and the results indicate successful heat pipe operation at temperatures of approximately 922K (1200F). These panels, in addition to solving potential thermal stress problems in an Airframe-Integrated Scramjet Engine, have potential applications as cold plates for electronic component cooling, as radiators for space platforms, and as low distortion, large area structures.

  15. Dynamics of hypersonic flight vehicles exhibiting significant aeroelastic and aeropropulsive interactions (United States)

    Chavez, Frank R.; Schmidt, David K.


    With analytic expressions previously developed for the forces and moments acting on a generic hypersonic vehicle, it is of interest to investigate the relative importance of the aerodynamic and propulsive effects on the vehicle dynamics. It is shown that the vehicle's aerodynamics and propulsive forces are both very significant in the evaluation of key stability derivatives which dictate the vehicle's dynamic characteristics. It is also shown that the vehicle model selected is unstable in pitch and exhibits strong airframe/engine/elastic coupling. With the use of literal expressions for both the systems poles and zeros, as well as the stability derivatives, key vehicle dynamic characteristics are investigated. For small errors, or uncertainties, in either the aerodynamic or propulsive forces, significant errors in the frequency and damping of the dominant modes and zero locations will arise.

  16. National Cycle Program (NCP) Common Analysis Tool for Aeropropulsion (United States)

    Follen, G.; Naiman, C.; Evans, A.


    Through the NASA/Industry Cooperative Effort (NICE) agreement, NASA Lewis and industry partners are developing a new engine simulation, called the National Cycle Program (NCP), which is the initial framework of NPSS. NCP is the first phase toward achieving the goal of NPSS. This new software supports the aerothermodynamic system simulation process for the full life cycle of an engine. The National Cycle Program (NCP) was written following the Object Oriented Paradigm (C++, CORBA). The software development process used was also based on the Object Oriented paradigm. Software reviews, configuration management, test plans, requirements, design were all apart of the process used in developing NCP. Due to the many contributors to NCP, the stated software process was mandatory for building a common tool intended for use by so many organizations. The U.S. aircraft and airframe companies recognize NCP as the future industry standard for propulsion system modeling.


    Institute of Scientific and Technical Information of China (English)

    F.H. Cao; Z. Zhang; Y.L. Cheng; J.F. Li; J.Q. Zhang; C.N. Cao


    The electrochemical features of commercial airframe material, Al alloy LY12, in 0. 349mol/L neutral sodium chloride (NaCl) and sodium sulfate (Na2SO4) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the Nyquist plots of LY12 at different immersion time displayed different fe atures, indicating that the Cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO2-4 solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in NaCl solution are greater than that in Na2SO4 solution.

  18. SILHIL Replication of Electric Aircraft Powertrain Dynamics and Inner-Loop Control for V&V of System Health Management Routines (United States)

    Bole, Brian; Teubert, Christopher Allen; Cuong Chi, Quach; Hogge, Edward; Vazquez, Sixto; Goebel, Kai; George, Vachtsevanos


    Software-in-the-loop and Hardware-in-the-loop testing of failure prognostics and decision making tools for aircraft systems will facilitate more comprehensive and cost-effective testing than what is practical to conduct with flight tests. A framework is described for the offline recreation of dynamic loads on simulated or physical aircraft powertrain components based on a real-time simulation of airframe dynamics running on a flight simulator, an inner-loop flight control policy executed by either an autopilot routine or a human pilot, and a supervisory fault management control policy. The creation of an offline framework for verifying and validating supervisory failure prognostics and decision making routines is described for the example of battery charge depletion failure scenarios onboard a prototype electric unmanned aerial vehicle.

  19. Investigation of lateral-directional aerodynamic parameters identification method for fly-by-wire passenger airliners

    Institute of Scientific and Technical Information of China (English)

    Wu Zhao; Wang Lixin; Lin Jiaming; Ai Junqiang


    A new identification method is proposed to solve the problem of the influence on the loaded excitation signals brought by high feedback gain augmentation in lateral-directional aerody-namic parameters identification of fly-by-wire (FBW) passenger airliners. Taking for example an FBW passenger airliner model with directional relaxed-static-stability, through analysis of its signal energy distribution and airframe frequency response, a new method is proposed for signal type selec-tion, signal parameters design, and the appropriate frequency relationship between the aileron and rudder excitation signals. A simulation validation is presented of the FBW passenger airliner’s lat-eral-directional aerodynamic parameters identification. The validation result demonstrates that the designed signal can excite the lateral-directional motion mode of the FBW passenger airliner ade-quately and persistently. Meanwhile, the relative errors of aerodynamic parameters are less than 5%.

  20. NASA's Spaceliner 100 Investment Area Technology Activities (United States)

    Hueter, Uwe; Lyles, Garry M. (Technical Monitor)


    NASA's has established long term goals for access-to-space. The third generation launch systems are to be fully reusable and operational around 2025. The goals for the third generation launch system are to reduce cost by a factor of 100 and improve safety by a factor of 10,000 over current conditions. The Advanced Space Transportation Program Office (ASTP) at the NASA's Marshall Space Flight Center in Huntsville, AL has the agency lead to develop space transportation technologies. Within ASTP, under the Spaceliner100 Investment Area, third generation technologies are being pursued in the areas of propulsion, airframes, integrated vehicle health management (IVHM), launch systems, and operations and range. The ASTP program will mature these technologies through ground system testing. Flight testing where required, will be advocated on a case by case basis.

  1. ASTM and VAMAS activities in titanium matrix composites test methods development (United States)

    Johnson, W. S.; Harmon, D. M.; Bartolotta, P. A.; Russ, S. M.


    Titanium matrix composites (TMC's) are being considered for a number of aerospace applications ranging from high performance engine components to airframe structures in areas that require high stiffness to weight ratios at temperatures up to 400 C. TMC's exhibit unique mechanical behavior due to fiber-matrix interface failures, matrix cracks bridged by fibers, thermo-viscoplastic behavior of the matrix at elevated temperatures, and the development of significant thermal residual stresses in the composite due to fabrication. Standard testing methodology must be developed to reflect the uniqueness of this type of material systems. The purpose of this paper is to review the current activities in ASTM and Versailles Project on Advanced Materials and Standards (VAMAS) that are directed toward the development of standard test methodology for titanium matrix composites.

  2. A fuel-efficient cruise performance model for general aviation piston engine airplanes. Ph.D. Thesis. Final Report (United States)

    Parkinson, R. C. H.


    A fuel-efficient cruise performance model which facilitates maximizing the specific range of General Aviation airplanes powered by spark-ignition piston engines and propellers is presented. Airplanes of fixed design only are considered. The uses and limitations of typical Pilot Operating Handbook cruise performance data, for constructing cruise performance models suitable for maximizing specific range, are first examined. These data are found to be inadequate for constructing such models. A new model of General Aviation piston-prop airplane cruise performance is then developed. This model consists of two subsystem models: the airframe-propeller-atmosphere subsystem model; and the engine-atmosphere subsystem model. The new model facilitates maximizing specific range; and by virtue of its implicity and low volume data storge requirements, appears suitable for airborne microprocessor implementation.

  3. An Icing Of Aircraft – Reasons, Consequences, Counteraction

    Directory of Open Access Journals (Sweden)

    Gębura Andrzej


    Full Text Available The article presents reasons of an helicopter’s ising as well as an aircraft’s ising. The maion attention is addressed a conteraction of an ising. Autors divide the problem an two groups: an ising of an airframe – mostly lifting surfaces, an ising of engines. According to authors reasons, an extension (first of all consequences of airframe’s ising considerably differ from seemingly similar events in an engine. The considerable attention is concentrated on a connteraction of consequences of an ising during the flight. The most complicated ising referes to helicopters, considering their particular aerodynamics characteristics. The autors dedicated is greather attention. Results reached during investigations of heating rotor blades in ITWL are presented.

  4. Termovision and electricity capacitance measurements as a evaluation of a helicopter rotor’s blades delamination

    Directory of Open Access Journals (Sweden)

    Gębura Andrzej


    Full Text Available The article presents essential elements reached during investigations of heat section of rotor blades which have been done in AFIT. The investigations were related to a valuation of helicopter’s rotor blades delamination. They used a method of thermal field measurement as well as a electricity capacitance between an airframe and a heat element of the installation. A suggestion of such measurements appeared during the disassembly of rotor blade heat sections when some local unglue of heat element’s tape from the structure of blade’s heating pack has seen. Spots nearby separation of adhesive are a potential area of a local temperature increase, both the electric heating element and the mechanical structure of the blade. This is especially dangerous for composite structures. Overheated composite structures characterized by reduced flexibility and becomes prone to cracking. Therefore, the possibility of non-invasive monitoring adhesive spots, without removing the blades would be particularly useful.

  5. Flying control of small-type helicopter by detecting its in-air natural features

    Directory of Open Access Journals (Sweden)

    Chinthaka Premachandra


    Full Text Available Control of a small type helicopter is an interesting research area in unmanned aerial vehicle development. This study aims to detect a more typical helicopter unequipped with markers as a means by which to resolve the various issues of the prior studies. Accordingly, we propose a method of detecting the helicopter location and pose through using an infrastructure camera to recognize its in-air natural features such as ellipse traced by the rotation of the helicopter's propellers. A single-rotor system helicopter was used as the controlled airframe in our experiments. Here, helicopter location is measured by detecting the main rotor ellipse center and pose is measured following relationship between the main rotor ellipse and the tail rotor ellipse. Following these detection results we confirmed the hovering control possibility of the helicopter through experiments.

  6. Advanced Supersonic Nozzle Concepts: Experimental Flow Visualization Results Paired With LES (United States)

    Berry, Matthew; Magstadt, Andrew; Stack, Cory; Gaitonde, Datta; Glauser, Mark; Syracuse University Team; The Ohio State University Team


    Advanced supersonic nozzle concepts are currently under investigation, utilizing multiple bypass streams and airframe integration to bolster performance and efficiency. This work focuses on the parametric study of a supersonic, multi-stream jet with aft deck. The single plane of symmetry, rectangular nozzle, displays very complex and unique flow characteristics. Flow visualization techniques in the form of PIV and schlieren capture flow features at various deck lengths and Mach numbers. LES is compared to the experimental results to both validate the computational model and identify limitations of the simulation. By comparing experimental results to LES, this study will help create a foundation of knowledge for advanced nozzle designs in future aircraft. SBIR Phase II with Spectral Energies, LLC under direction of Barry Kiel.

  7. Implementation and verification of a comprehensive helicopter coupled rotor - Fuselage analysis (United States)

    Wood, E. R.; Banerjee, D.; Shamie, J.; Straub, F.; Dinyavari, M. A. H.


    The analytical basis and the application of a Rotor/Airframe Comprehensive Aeroelastic Program (RACAP) are described in detail. The rationale behind each analytical choice is outlined and the modular procedure is described. The program is verified by application to the AH-1G helicopter. The applicability of various airload prediction models is examined, and both the steady and vibratory responses of the blade are compared with flight test data. Reasonable correlation is found between measured and calculated blade response, with excellent correlation for vibration amplitudes at various locations on the fuselage such as engine, pilot seat, and gunner. Within the analytical model, comparisons are drawn between an isolated blade analysis and a coupled rotor/fuselage model. The deficiency of the former in the context of the AH-1G is highlighted.

  8. Hybrid upper surface blown flap propulsive-lift concept for the Quiet Short-Haul Research Aircraft (United States)

    Cochrane, J. A.; Carros, R. J.


    The hybrid upper surface blowing concept consists of wing-mounted turbofan engines with a major portion of the fan exhaust directed over the wing upper surface to provide high levels of propulsive lift, but with a portion of the fan airflow directed over selected portions of the airframe to provide boundary layer control. NASA-sponsored preliminary design studies identified the hybrid upper surface blowing concept as the best propulsive lift concept to be applied to the Quiet Short-Haul Research Aircraft (QSRA) that is planned as a flight facility to conduct flight research at low noise levels, high approach lift coefficients, and steep approaches. Data from NASA in-house and NASA-sponsored small and large-scale wind tunnel tests of various configurations using this concept are presented.

  9. Technologies Advance UAVs for Science, Military (United States)


    A Space Act Agreement with Goddard Space Flight Center and West Virginia University enabled Aurora Flight Sciences Corporation, of Manassas, Virginia, to develop cost-effective composite manufacturing capabilities and open a facility in West Virginia. The company now employs 160 workers at the plant, tasked with crafting airframe components for the Global Hawk unmanned aerial vehicle (UAV) program. While one third of the company's workforce focuses on Global Hawk production, the rest of the company develops advanced UAV technologies that are redefining traditional approaches to unmanned aviation. Since the company's founding, Aurora s cutting-edge work has been supported with funding from NASA's Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs.

  10. Performance and Stability Analysis of a Shrouded-Fan UAV

    CERN Document Server

    de Divitiis, Nicola


    This paper deals with the estimation of the performance and stability for a shrouded-fan unmanned rotorcraft whose mission profile also prescribes the flight in ground effect. The not so simple estimation of the aerodynamic coefficients and of the thrust in the various situations makes the performance calculation and the stability analysis difficult tasks. This is due to the strong interaction between the fan flow and shroud that causes quite different flow structures about the airframe depending on flight conditions. A further difficulty is related to the ground effect which produces substantial modifications in the rotor thrust and aerodynamic coefficients. To evaluate performance and stability, two models have been developed. One determines the aerodynamic coefficients of the shroud, whereas the other one calculates thrust and moment of the rotors system. Both models take into account the mutual interference between fan flow and fuselage and ground effect. Performance and stability are then discussed with ...

  11. Interaction of airborne and structure-borne noise radiated by plates (United States)

    Mcgary, M. C.


    The interaction of airborne and structure-borne noise radiated by aircraft structures is studied analytically and experimentally for the case of noise radiating from thin, isotropic, rectangular aluminum plates as a result of fully coherent, combined acoustic and vibrational inputs. Attention is given to the great influence of the relative phase between inputs on the combined noise radiation characteristics of the plates; these phase-dependent effects, which are manifest as cross-terms in both the dynamic and acoustic portions of the analysis, can radically alter the combined sound power radiated by airframe structure plates. Such interactive effects have heretofore been neglected in analyses of results from analytical and experimental studies of propeller-driven aircraft interior noise.

  12. Hybrid Laminates for Application in North Conditions (United States)

    Antipov, V. V.; Oreshko, E. I.; Erasov, V. S.; Serebrennikova, N. Yu.


    A hybrid aluminum-lithium alloy/SIAL laminate as a possible material for application in structures operated in North conditions is considered. The finite-element method is used for a buckling stability analysis of hybrid panels, bars, and plates. A technique allowing one to compare the buckling stability of multilayered hybrid plates is offered. Compression tests were run on a hybrid laminate wing panel as a prototype of the top panel of TU-204SM airplane made from a high-strength B95T2 aluminum alloy. It turned out that the lighter composite panel had a higher load-carrying capacity than the aluminum one. Results of investigation into the properties the hybrid aluminum-lithium alloy/SIAL laminate and an analysis of scientific-technical data on this subject showed that this composite material could be used in the elements of airframes, including those operated in north conditions.

  13. Highly integrated digital engine control system on an F-15 airplane (United States)

    Burcham, F. W., Jr.; Haering, E. A., Jr.


    The Highly Integrated Digital Electronic Control (HIDEC) program will demonstrate and evaluate the improvements in performance and mission effectiveness that result from integrated engine/airframe control systems. This system is being used on the F-15 airplane. An integrated flightpath management mode and an integrated adaptive engine stall margin mode are implemented into the system. The adaptive stall margin mode is a highly integrated mode in which the airplane flight conditions, the resulting inlet distortion, and the engine stall margin are continuously computed; the excess stall margin is used to uptrim the engine for more thrust. The integrated flightpath management mode optimizes the flightpath and throttle setting to reach a desired flight condition. The increase in thrust and the improvement in airplane performance is discussed.

  14. Sliding Mode Control for Mass Moment Aerospace Vehicles Using Dynamic Inversion Approach

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Zhang


    Full Text Available The moving mass actuation technique offers significant advantages over conventional aerodynamic control surfaces and reaction control systems, because the actuators are contained entirely within the airframe geometrical envelope. Modeling, control, and simulation of Mass Moment Aerospace Vehicles (MMAV utilizing moving mass actuators are discussed. Dynamics of the MMAV are separated into two parts on the basis of the two time-scale separation theory: the dynamics of fast state and the dynamics of slow state. And then, in order to restrain the system chattering and keep the track performance of the system by considering aerodynamic parameter perturbation, the flight control system is designed for the two subsystems, respectively, utilizing fuzzy sliding mode control approach. The simulation results describe the effectiveness of the proposed autopilot design approach. Meanwhile, the chattering phenomenon that frequently appears in the conventional variable structure systems is also eliminated without deteriorating the system robustness.

  15. Overview of ERA Integrated Technology Demonstration (ITD) 51A Ultra-High Bypass (UHB) Integration for Hybrid Wing Body (HWB) (United States)

    Flamm, Jeffrey D.; James, Kevin D.; Bonet, John T.


    The NASA Environmentally Responsible Aircraft Project (ERA) was a ve year project broken into two phases. In phase II, high N+2 Technical Readiness Level demonstrations were grouped into Integrated Technology Demonstrations (ITD). This paper describes the work done on ITD-51A: the Vehicle Systems Integration, Engine Airframe Integration Demonstration. Refinement of a Hybrid Wing Body (HWB) aircraft from the possible candidates developed in ERA Phase I was continued. Scaled powered, and unpowered wind- tunnel testing, with and without acoustics, in the NASA LARC 14- by 22-foot Subsonic Tunnel, the NASA ARC Unitary Plan Wind Tunnel, and the 40- by 80-foot test section of the National Full-Scale Aerodynamics Complex (NFAC) in conjunction with very closely coupled Computational Fluid Dynamics was used to demonstrate the fuel burn and acoustic milestone targets of the ERA Project.

  16. 高超声速巡航飞行器纵向气动特性分析%Longitudinal Aerodynamic Characteristics Analysis of Hypersonic Cruise Vehicle

    Institute of Scientific and Technical Information of China (English)

    邢永刚; 唐硕


    The airframe integrated nature of the scramjet engine with airbreathing hypersonic cruise vehicle (HCV) results in a strong couplings between aerodynamics and propulsive system. The couplings have an effect on vehicle aerodynamic performance, stability and control. Aiming at the effects, the model of airframe integrated scramjet engine has been developed and aero-propulsion interface separated. Based on the forgoing work,longitudinal aerodynamic characteristics of HCV inlet open, scramjet engine powered and unpowered have been computed separately. Simulation reveals the couplings between aerodynamics and propulsive system and the effect on vehicle characteristics.%吸气式高超声速巡航飞行器机身/发动机一体化特性使得气动一推进系统之间存在强的耦合作用,这种耦合影响着飞行器气动性能、稳定性和控制.针对耦合对飞行器特性的影响,建立了机身一发动机一体化模型,并进行了气动-推进界面划分.在此基础上,分别计算了高超声速巡航飞行器在进气道打开,发动机不工作以及进气道打开,发动机工作两种状态下的纵向气动特性.仿真结果揭示了高超声速巡航飞行器气动一推进系统之间的耦合以及耦合作用对飞行器气动性能、稳定性的影响.

  17. Comparison of In-Flight Measured and Computed Aeroelastic Damping: Modal Identification Procedures and Modeling Approaches

    Directory of Open Access Journals (Sweden)

    Roberto da Cunha Follador


    Full Text Available The Operational Modal Analysis technique is a methodology very often applied for the identification of dynamic systems when the input signal is unknown. The applied methodology is based on a technique to estimate the Frequency Response Functions and extract the modal parameters using only the structural dynamic response data, without assuming the knowledge of the excitation forces. Such approach is an adequate way for measuring the aircraft aeroelastic response due to random input, like atmospheric turbulence. The in-flight structural response has been measured by accelerometers distributed along the aircraft wings, fuselage and empennages. The Enhanced Frequency Domain Decomposition technique was chosen to identify the airframe dynamic parameters. This technique is based on the hypothesis that the system is randomly excited with a broadband spectrum with almost constant power spectral density. The system identification procedure is based on the Single Value Decomposition of the power spectral densities of system output signals, estimated by the usual Fast Fourier Transform method. This procedure has been applied to different flight conditions to evaluate the modal parameters and the aeroelastic stability trends of the airframe under investigation. The experimental results obtained by this methodology were compared with the predicted results supplied by aeroelastic numerical models in order to check the consistency of the proposed output-only methodology. The objective of this paper is to compare in-flight measured aeroelastic damping against the corresponding parameters computed from numerical aeroelastic models. Different aerodynamic modeling approaches should be investigated such as the use of source panel body models, cruciform and flat plate projection. As a result of this investigation it is expected the choice of the better aeroelastic modeling and Operational Modal Analysis techniques to be included in a standard aeroelastic

  18. Cooperative control theory and integrated flight and propulsion control (United States)

    Schmidt, David K.; Schierman, John D.


    The major contribution of this research was the exposition of the fact that airframe and engine interactions could be present, and their effects could include loss of stability and performance of the control systems. Also, the significance of two directional, as opposed to one-directional, coupling was identified and explained. A multivariable stability and performance analysis methodology was developed, and applied to several candidate aircraft configurations. In these example evaluations, the significance of these interactions was underscored. Also exposed was the fact that with interactions present along with some integrated control approaches, the engine command/limiting logic (which represents an important nonlinear component of the engine control system) can impact closed-loop airframe/engine system stability. Finally, a brief investigation of control-law synthesis techniques appropriate for the class of systems was pursued, and it was determined that multivariable techniques, including model-following formulations of LQG and/or H infinity methods, showed promise. However, for practical reasons, decentralized control architectures are preferred, which is an architecture incompatible with these synthesis methods. The major contributions of the second phase of the grant was the development of conditions under which no decentralized controller could achieve closed loop system requirements on stability and/or performance. Sought were conditions that depended only on properties of the plant and the requirement, and independent of any particular control law or synthesis approach. Therefore, they could be applied a priori, before synthesis of a candidate control law. Under this grant, such conditions were found regarding stability, and encouraging initial results were obtained regarding performance.

  19. Progress in Open Rotor Research: A U.S. Perspective (United States)

    Van Zante, Dale E.


    In response to the 1970s oil crisis, NASA created the Advanced Turboprop Project (ATP) to mature technologies for high-speed propellers to enable large reductions in fuel burn relative to turbofan engines of that era. Both single rotation and contra- rotation concepts were designed and tested in ground based facilities as well as flight. Some novel concepts/configurations were proposed as part of the effort. The high-speed propeller concepts did provide fuel burn savings, albeit with some acoustics and structural challenges to overcome. When fuel prices fell, the business case for radical new engine configurations collapsed and the research emphasis returned to high bypass ducted configurations. With rising oil prices and increased environmental concerns there is renewed interest in high-speed propeller based engine architectures. Contemporary analysis tools for aerodynamics and aeroacoustics have enabled a new era of blade designs that have both high efficiency and lower noise characteristics. A recent series of tests in the U.S. have characterized the aerodynamic performance and noise from these modern contra-rotating propeller designs. Additionally the installation and noise shielding aspects for conventional airframes and blended wing bodies have been studied. Historical estimates of 'propfan' performance have relied on legacy propeller performance and acoustics data. Current system studies make use of the modern propeller data and higher fidelity installation effects data to estimate the performance of a contemporary aircraft system. Contemporary designs have demonstrated high net efficiency, approximately 86%, at 0.78 Mach, and low noise, greater than 15 EPNdB cumulative margin to Chapter 4 when analyzed on a NASA derived aircraft/mission. This paper presents the current state of high-speed propeller/open rotor research within the U.S. from an overall viewpoint of the various efforts ongoing. The remaining technical challenges to a production engine include

  20. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure (United States)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter


    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  1. Mission Analysis and Aircraft Sizing of a Hybrid-Electric Regional Aircraft (United States)

    Antcliff, Kevin R.; Guynn, Mark D.; Marien, Ty V.; Wells, Douglas P.; Schneider, Steven J.; Tong, Michael T.


    The purpose of this study was to explore advanced airframe and propulsion technologies for a small regional transport aircraft concept (approximately 50 passengers), with the goal of creating a conceptual design that delivers significant cost and performance advantages over current aircraft in that class. In turn, this could encourage airlines to open up new markets, reestablish service at smaller airports, and increase mobility and connectivity for all passengers. To meet these study goals, hybrid-electric propulsion was analyzed as the primary enabling technology. The advanced regional aircraft is analyzed with four levels of electrification, 0 percent electric with 100 percent conventional, 25 percent electric with 75 percent conventional, 50 percent electric with 50 percent conventional, and 75 percent electric with 25 percent conventional for comparison purposes. Engine models were developed to represent projected future turboprop engine performance with advanced technology and estimates of the engine weights and flowpath dimensions were developed. A low-order multi-disciplinary optimization (MDO) environment was created that could capture the unique features of parallel hybrid-electric aircraft. It is determined that at the size and range of the advanced turboprop: The battery specific energy must be 750 watt-hours per kilogram or greater for the total energy to be less than for a conventional aircraft. A hybrid vehicle would likely not be economically feasible with a battery specific energy of 500 or 750 watt-hours per kilogram based on the higher gross weight, operating empty weight, and energy costs compared to a conventional turboprop. The battery specific energy would need to reach 1000 watt-hours per kilogram by 2030 to make the electrification of its propulsion an economically feasible option. A shorter range and/or an altered propulsion-airframe integration could provide more favorable results.

  2. 采用捷联激光探测器的制导火箭比例导引实现方法%PNG law analysis for strapdown laser detector guided rocket

    Institute of Scientific and Technical Information of China (English)

    王磊; 朱伯立


    A guidance control scheme based on strapdown laser detector and proportional navigation guidance (PNG) for rocket projectile was presented in details since the precise guidance improvement requirement. Because the strapdown detector can only measure the error angle between airframe axis and target directly and could not provide the inertial line-of-sight (LOS) angular rate necessarily to PNG, a LOS rate algorithm using detector′s error angle and airframe attitude rate from onboard gyro was proposed. A two-loop acceleration autopilot was designed with respect to the autopilot-guidance match principle. The non-dimensional miss distance analysis and trajectory simulation results validate that the proposed approach is feasible.%围绕制式火箭弹精确制导改造的需求,提出了一种采用捷联激光探测器和比例导引的火箭弹制导控制方案。针对捷联探测器只能测量弹轴相对于目标的偏差角而无法提供比例导引所需的惯性视线角速度信号的难题,研究了基于捷联探测器测量的误差角和弹体姿态角速度信号的弹目视线角速度信号提取算法。在制导控制系统内部,基于自动驾驶仪与制导律相匹配的原则,设计了两回路过载自动驾驶仪。无量纲脱靶量分析与攻击静止目标的弹道仿真结果验证了所提方案的可行性。

  3. Uav for Geodata Acquisition in Agricultureal and Forestal Applications (United States)

    Reidelstürz, P.; Schrenk, L.; Littmann, W.


    of German Armed Forces in Neubiberg/Munich and the well-established precision farming company "Konsultationszentrum Liepen" to develop an applicable UAV for precision farming purposes. Currently Cis GmbH and Technologie Campus Freyung, with intense contact to the „flying robot"- team of DLR Oberpfaffenhofen, collaborate to optimize the existing UAV and to extend the applications from data aquisition for biomass diversity up to detect the water supply situation in agricultural fields, to support pest management systems as much as to check the possibilities to detect bark beetle attacks in european spruce in an early stage of attack (green attack phase) by constructing and integrating further payload modules with different sensors in the existing UAV airframe. Also effective data processing workflows are to be worked out. Actually in the existing UAV autopilotsystem "piccolo" (cloudcaptech) is integrated and also a replaceable payload module is available, carrying a VIS and a NIR camera to calculate maps of NDVI diversity as indicator of biomass diversity. Further modules with a 6 channel multispectral still camera and with a spectrometer are planned. The airframe's wingspan is about 3,45m weighting 4.2 kg, ready to fly. The hand launchable UAV can start from any place in agricultural regions. The wing is configured with flaps, allowing steep approaches and short landings using a „butterfly" brake configuration. In spite of the lightweight configuration the UAV yet proves its worth under windy baltic wether situations by collecting regular sharp images of fields under wind speed up to 15m/s (Beaufort 6 -7). In further projects the development of further payload modules and a user friendly flight planning tool is scheduled considering different payload - and airframe requirements for different precision farming purposes and forest applications. Data processing and workflow will be optimized. Cooperation with further partners to establish UAV systems in agricultural

  4. Aeroacoustic characterization of scaled canonical nose landing gear configurations (United States)

    Zawodny, Nikolas S.

    Aircraft noise is a critical issue in the commercial airline industry. Airframe noise is a subcomponent of aircraft noise and is generally dominant over jet engine noise during approach conditions, which can lead to high community impact. Landing gears have been identified as major components of airframe noise during landing configurations for commercial aircraft. They are perhaps the least understood contributors to airframe noise due to complex flow patterns associated with intricate gear component geometries. Nose landing gear in particular have received much attention in recent years, exhibiting acoustic signatures on the order of the main landing gear assembly of an aircraft, while simultaneously being more amenable to scaled wind tunnel testing. In order to characterize the acoustic signature of a complex geometry such as a nose landing gear, it is important to isolate, study, and understand the acoustic contributions of individual component geometries. The purpose of this dissertation is to develop a correlation between the complex flow field nature and far-field acoustic signature of a nose landing gear sub-system. The model under investigation is a 1/2-scale shock-strut cylinder coupled with an adjustable torque link apparatus. This geometry was chosen due to its fundamental importance and implementation across a wide span of commercial aircraft. The fluid dynamic (surface pressure and stereoscopic particle image velocimety) and aeroacoustic (far-field microphone and phased array) experiments were performed in the University of Florida Aeroacoustic Flow Facility. The experimental data compare favorably with the results of a numerical simulation using PowerFLOW, a lattice-Boltzmann solver developed by the Exa Corporation. The far-field acoustic results of this dissertation have shown non-uniform scaling behavior as a function of frequency for the different model configurations tested. For frequencies that appropriately satisfied the condition of acoustic

  5. 盒式机翼布局大型飞机横航向飞行品质研究%Lateral-directional flying qualities research of large aircraft with box-wing configuration

    Institute of Scientific and Technical Information of China (English)

    吕新波; 刘振钦


    Compared with a large aircraft with conventional configuration, the aerodynamic characteristics of large aircraft with box-wing configuration were calculated and showed in this paper. The lateral-directional airframe flying qualities of the large aircraft with box-wing configuration were researched. The lateral-directional airframe flying qualities of the large aircraft with box-wing configuration will be deteriorated, so the effective measures which can improve flying qualities of large aircraft with box-wing configuration would be researched. The results show that the large aircraft with box-wing configuration has a larger ratio of lift to drag and special lateral-directional aerodynamic characteristics. Modifying configuration parameters are limited to improve the lateral-directional flying qualities of large aircraft with box-wing configuration and the design of control laws can assure satisfied flying qualities.%经计算并和常规布局大型飞机对比分析,给出了盒式机翼布局大型飞机的气动特点;然后研究了盒式机翼布局大型飞机本体横航向飞行品质;针对盒式机翼布局本体飞机横航向飞行品质较差的问题,研究了提高盒式机翼布局飞机横航向飞行品质的有效方法.研究结果表明:盒式机翼布局大型飞机具有良好的升阻特性和特殊的横航向气动特性;修改布局参数对提高盒式机翼布局飞机横航向飞行品质是有限的,控制律的设计可以保证其具有满意的横航向飞行品质.

  6. Prediction of jet noise shielding with forward flight effects (United States)

    Mayoral, Salvador

    Aircraft noise continues to be a major concern among airport-neighboring communities. A strong component of aircraft noise is the jet noise that is generated from the turbulent mixing between the jet exhaust and ambient medium. The hybrid wing body aircraft suppresses jet noise by mounting the engines over-the-wing so that the airframe may shield ground observers from jet noise sources. Subscale jet noise shielding measurements of a scaled-down turbofan nozzle and a model of the hybrid wing body planform are taken with two 12-microphone polar arrays. Chevrons and wedge-type fan flow deflectors are integrated into the baseline bypass ratio 10 (BPR10) nozzle to modify the mean flow and alter the noise source behavior. Acoustic results indicate that the baseline BPR10 nozzle produces a long noise source region that the airframe has difficulty shielding, even when the nozzle is translated two fan diameters upstream of its nominal position. The integration of either chevrons or fan flow deflectors into the nozzle is essential for jet noise shielding because they translate peak intensities upstream, closer to the fan exit plane. The numerical counterpart of this study transforms the system of equations governing the acoustic diffraction with forward flight into the wave equation. Two forward flight formulations are considered: uniform flow over slender body; and non-uniform potential flow at low Mach number. The wave equation is solved numerically in the frequency domain using the boundary element method. The equivalent jet noise source is modeled using the combination of a wavepacket and a monopole. The wavepacket is parameterized using the experimental far-field acoustic autospectra of the BPR10 jets and knowledge of their peak noise locations. It is shown that the noise source compacts with increasing Mach number and consequently there is an increase in shielding. An assessment of the error associated with the non-uniform formulation for forward flight shows that the

  7. Effect of noise reducing components on nose landing gear stability for a mid-size aircraft coupled with vortex shedding and freeplay (United States)

    Eret, Petr; Kennedy, John; Bennett, Gareth J.


    In the pursuit of quieter aircraft, significant effort has been dedicated to airframe noise identification and reduction. The landing gear is one of the main sources of airframe noise on approach. The addition of noise abatement technologies such as fairings or wheel hub caps is usually considered to be the simplest solution to reduce this noise. After touchdown, noise abatement components can potentially affect the inherently nonlinear and dynamically complex behaviour (shimmy) of landing gear. Moreover, fairings can influence the aerodynamic load on the system and interact with the mechanical freeplay in the torque link. This paper presents a numerical study of nose landing gear stability for a mid-size aircraft with low noise solutions, which are modelled by an increase of the relevant model structural parameters to address a hypothetical effect of additional fairings and wheel hub caps. The study shows that the wheel hub caps are not a threat to stability. A fairing has a destabilising effect due to the increased moment of inertia of the strut and a stabilising effect due to the increased torsional stiffness of the strut. As the torsional stiffness is dependent on the method of attachment, in situations where the fairing increases the torsional inertia with little increase to the torsional stiffness, a net destabilising effect can result. Alternatively, it is possible that for the case that if the fairing were to increase equally both the torsional stiffness and the moment of inertia of the strut, then their effects could be mutually negated. However, it has been found here that for small and simple fairings, typical of current landing gear noise abatement design, their implementation will not affect the dynamics and stability of the system in an operational range (Fz ≤ 50 000 N, V ≤ 100 m/s). This generalisation is strictly dependent on size and installation methods. The aerodynamic load, which would be influenced by the presence of fairings, was modelled

  8. Further Evolution of Composite Doubler Aircraft Repairs Through a Focus on Niche Applications

    Energy Technology Data Exchange (ETDEWEB)



    The number of commercial airframes exceeding twenty years of service continues to grow. A typical aircraft can experience over 2,000 fatigue cycles (cabin pressurizations) and even greater flight hours in a single year. An unavoidable by-product of aircraft use is that crack and corrosion flaws develop throughout the aircraft's skin and substructure elements. Economic barriers to the purchase of new aircraft have created an aging aircraft fleet and placed even greater demands on efficient and safe repair methods. The use of bonded composite doublers offers the airframe manufacturers and aircraft maintenance facilities a cost effective method to safety extend the lives of their aircraft. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure. The FAA's Airworthiness Assurance Center at Sandia National Labs (AANC) is conducting a program with Boeing and Federal Express to validate and introduce composite doubler repair technology to the US commercial aircraft industry. This project focuses on repair of DC-10 structure and builds on the foundation of the successful L-1011 door corner repair that was completed by the AANC, Lockheed-Martin, and Delta Air Lines. The L-1011 composite doubler repair was installed in 1997 and has not developed any flaws in over three years of service, As a follow-on effort, this DC-1O repair program investigated design, analysis, performance (durability, flaw containment, reliability), installation, and nondestructive inspection issues. Current activities are demonstrating regular use of composite doubler repairs on commercial aircraft. The primary goal of this program is to move the technology into niche applications and to streamline the design-to-installation process. Using the data accumulated to date, the team has designed, analyzed, and developed inspection techniques for an array of composite doubler

  9. On Noise Assessment for Blended Wing Body Aircraft (United States)

    Guo, Yueping; Burley, Casey L; Thomas, Russell H.


    A system noise study is presented for the blended-wing-body (BWB) aircraft configured with advanced technologies that are projected to be available in the 2025 timeframe of the NASA N+2 definition. This system noise assessment shows that the noise levels of the baseline configuration, measured by the cumulative Effective Perceived Noise Level (EPNL), have a large margin of 34 dB to the aircraft noise regulation of Stage 4. This confirms the acoustic benefits of the BWB shielding of engine noise, as well as other projected noise reduction technologies, but the noise margins are less than previously published assessments and are short of meeting the NASA N+2 noise goal. In establishing the relevance of the acoustic assessment framework, the design of the BWB configuration, the technical approach of the noise analysis, the databases and prediction tools used in the assessment are first described and discussed. The predicted noise levels and the component decomposition are then analyzed to identify the ranking order of importance of various noise components, revealing the prominence of airframe noise, which holds up the levels at all three noise certification locations and renders engine noise reduction technologies less effective. When projected airframe component noise reduction is added to the HWB configuration, it is shown that the cumulative noise margin to Stage 4 can reach 41.6 dB, nearly at the NASA goal. These results are compared with a previous NASA assessment with a different study framework. The approaches that yield projections of such low noise levels are discussed including aggressive assumptions on future technologies, assumptions on flight profile management, engine installation, and component noise reduction technologies. It is shown that reliable predictions of component noise also play an important role in the system noise assessment. The comparisons and discussions illustrate the importance of practical feasibilities and constraints in aircraft

  10. NASA Langley's AirSTAR Testbed: A Subscale Flight Test Capability for Flight Dynamics and Control System Experiments (United States)

    Jordan, Thomas L.; Bailey, Roger M.


    As part of the Airborne Subscale Transport Aircraft Research (AirSTAR) project, NASA Langley Research Center (LaRC) has developed a subscaled flying testbed in order to conduct research experiments in support of the goals of NASA s Aviation Safety Program. This research capability consists of three distinct components. The first of these is the research aircraft, of which there are several in the AirSTAR stable. These aircraft range from a dynamically-scaled, twin turbine vehicle to a propeller driven, off-the-shelf airframe. Each of these airframes carves out its own niche in the research test program. All of the airplanes have sophisticated on-board data acquisition and actuation systems, recording, telemetering, processing, and/or receiving data from research control systems. The second piece of the testbed is the ground facilities, which encompass the hardware and software infrastructure necessary to provide comprehensive support services for conducting flight research using the subscale aircraft, including: subsystem development, integrated testing, remote piloting of the subscale aircraft, telemetry processing, experimental flight control law implementation and evaluation, flight simulation, data recording/archiving, and communications. The ground facilities are comprised of two major components: (1) The Base Research Station (BRS), a LaRC laboratory facility for system development, testing and data analysis, and (2) The Mobile Operations Station (MOS), a self-contained, motorized vehicle serving as a mobile research command/operations center, functionally equivalent to the BRS, capable of deployment to remote sites for supporting flight tests. The third piece of the testbed is the test facility itself. Research flights carried out by the AirSTAR team are conducted at NASA Wallops Flight Facility (WFF) on the Eastern Shore of Virginia. The UAV Island runway is a 50 x 1500 paved runway that lies within restricted airspace at Wallops Flight Facility. The

  11. Three-dimensional finite element analyses of the local mechanical behavior of riveted lap joints (United States)

    Iyer, Kaushik Arjunan

    Three-dimensional elastic-plastic finite element models of single and double rivet-row lap joints have been developed to evaluate local distortions and the mechanics of airframe-type 7075-T6 aluminum alloy riveted assemblies. Loading induced distortion features such as the excess assembly compliance, rivet tilt, local in- and out-of-plane slips and stress concentration factors are evaluated as functions of rivet countersinking, rivet material and friction coefficient. Computed features are examined to identify alterations in the proportions of in-plane and out-of-plane load transmission across rivet-panel interfaces and isolate global and lower-order effects present in the complex response of these multi-body assemblies. Analytical procedures are validated by comparing calculated and measured values of excess assembly compliance and local panel bending. Direct out-of-plane load transmission between the rivet heads and panels affects global deformation features such as remote panel bending and local features such as the panel stress concentration factor. The increase in stress concentration due to panel bending is self-limiting owing to decreasing in-plane load bearing with increasing rivet tilt, which is a composite reflection of the basic rivet deformation modes of shear and rotation. Calculations have also been performed to define approximate steady-state fretting fatigue conditions that lead to crack initiation at a panel hole surface in single and double rivet-row assemblies for countersunk and non-countersunk rivets. These account for and isolate effects of interference and clamping forces on fatigue performance by comparing computed circumferential variations of bulk residual stresses, cyclic stress range and mean stress. With interference, a non-countersunk assembly is shown to be as prone to crack initiation as a countersunk assembly. Frictional work due to fretting is evaluated and the physical location of fretting fatigue crack initiation is predicted by

  12. Jet Engine Powerloss in Ice Particle Conditions: An Aviation Industry Problem (United States)

    Strapp, J. W.


    Since about the 1990, there have been in excess of 100 engine powerloss events in jet aircraft that have now been attributed to the ingestion of ice particles. These powerloss events are observed in essentially all engine types, and on all airframes. Almost all cases have occurred in the vicinity of deep convection usually associated with warm and moist atmospheres. Events have occurred all throughout the world, although there is a somewhat higher concentration in the area of southeast Asia. Powerloss can result from stall, surge, flameout and rollback events in the engine. Many are momentary, with engines relighting automatically, while others require a manual engine relight. In some cases, particularly in rollback cases on smaller commuter-transport aircraft, engine power has only been recovered by melting of ice buildup in the engine below the freezing level. There have been cases of multiple simultaneous engine powerloss, and one case of a landing with no engine power. The frequency of the events, and the potential for multiple-engine powerloss, has led the FAA to note that that these occurrences constitute a significant safety issue. Analysis of the events using aircraft flight data recorder information, pilot interviews, standard meteorological radar and satellite data, and information from several past flight test programs, have led to the conclusion that the powerloss is due to ice buildup in the engine from high concentrations of ice particles in the atmosphere, and that supercooled LWC is not required. This is an unconventional form of icing that had not been previously considered possible by engine designers. The Engine Harmonization Working Group (EHWG), an industry-led committee composed of engine manufacturers, airframe manufacturers, regulators, and government agencies have been studying the powerloss issue since 2004, and have suggested a 4-part technical plan to resolve the issue, which includes improvement of instrumentation to measure high ice

  13. The Role of Aircraft Motion in Airborne Gravity Data Quality (United States)

    Childers, V. A.; Damiani, T.; Weil, C.; Preaux, S. A.


    Many factors contribute to the quality of airborne gravity data measured with LaCoste and Romberg-type sensors, such as the Micro-g LaCoste Turnkey Airborne Gravity System used by the National Geodetic Survey's GRAV-D (Gravity for the Redefinition of the American Vertical Datum) Project. For example, it is well documented that turbulence is a big factor in the overall noise level of the measurement. Turbulence is best controlled by avoidance; thus flights in the GRAV-D Project are only undertaken when the predicted wind speeds at flight level are ≤ 40 kts. Tail winds are known to be particularly problematic. The GRAV-D survey operates on a number of aircraft in a variety of wind conditions and geographic locations, and an obvious conclusion from our work to date is that the aircraft itself plays an enormous role in the quality of the airborne gravity measurement. We have identified a number of features of the various aircraft which can be determined to play a role: the autopilot, the size and speed of the aircraft, inherent motion characteristics of the airframe, tip tanks and other modifications to the airframe to reduce motion, to name the most important. This study evaluates the motion of a number of the GRAV-D aircraft and looks at the correlation between this motion and the noise characteristics of the gravity data. The GRAV-D Project spans 7 years and 42 surveys, so we have a significant body of data for this evaluation. Throughout the project, the sensor suite has included an inertial measurement unit (IMU), first the Applanix POSAv, and then later the Honeywell MicroIRS IMU as a part of a NovAtel SPAN GPS/IMU system. We compare the noise characteristics of the data with measures of aircraft motion (via pitch, roll, and yaw captured by the IMU) using a variety of statistical tools. It is expected that this comparison will support the conclusion that certain aircraft tend to work well with this type of gravity sensor while others tend to be problematic in

  14. High-Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement (United States)

    Quackenbush, Todd R.; McKillip, Robert M., Jr.


    One of key NASA goals is to develop and integrate noise reduction technology to enable unrestricted air transportation service to all communities. One of the technical priorities of this activity has been to account for and reduce noise via propulsion/airframe interactions, identifying advanced concepts to be integrated with the airframe to mitigate these noise-producing mechanisms. An adaptive geometry chevron using embedded smart structures technology offers the possibility of maximizing engine performance while retaining and possibly enhancing the favorable noise characteristics of current designs. New high-temperature shape memory alloy (HTSMA) materials technology enables the devices to operate in both low-temperature (fan) and high-temperature (core) exhaust flows. Chevron-equipped engines have demonstrated reduced noise in testing and operational use. It is desirable to have the noise benefits of chevrons in takeoff/landing conditions, but have them deployed into a minimum drag position for cruise flight. The central feature of the innovation was building on rapidly maturing HTSMA technology to implement a next-generation aircraft noise mitigation system centered on adaptive chevron flow control surfaces. In general, SMA-actuated devices have the potential to enhance the demonstrated noise reduction effectiveness of chevron systems while eliminating the associated performance penalty. The use of structurally integrated smart devices will minimize the mechanical and subsystem complexity of this implementation. The central innovations of the effort entail the modification of prior chevron designs to include a small cut that relaxes structural stiffness without compromising the desired flow characteristics over the surface; the reorientation of SMA actuation devices to apply forces to deflect the chevron tip, exploiting this relaxed stiffness; and the use of high-temperature SMA (HTSMA) materials to enable operation in the demanding core chevron environment

  15. Mitigating crack propagation in a highly maneuverable flight vehicle using life extending control logic (United States)

    Elshabasy, Mohamed Mostafa Yousef Bassyouny

    In this research, life extending control logic is proposed to reduce the cost of treating the aging problem of military aircraft structures and to avoid catastrophic failures and fatal accidents due to undetected cracks in the airframe components. The life extending control logic is based on load tailoring to facilitate a desired stress sequence that prolongs the structural life of the cracked airframe components by exploiting certain nonlinear crack retardation phenomena. The load is tailored to include infrequent injections of a single-cycle overload or a single-cycle overload and underload. These irregular loadings have an anti-intuitive but beneficial effect, which has been experimentally validated, on the extension of the operational structural life of the aircraft. A rigid six-degree-of freedom dynamic model of a highly maneuverable air vehicle coupled with an elastic dynamic wing model is used to generate the stress history at the lower skin of the wing. A three-dimensional equivalent plate finite element model is used to calculate the stress in the cracked skin. The plate is chosen to be of uniform chord-wise and span-wise thickness where the mechanical properties are assigned using an ad-hoc approach to mimic the full scale wing model. An in-extensional 3-node triangular element is used as the gridding finite element while the aerodynamic load is calculated using the vortex-lattice method where each lattice is laid upon two triangular finite elements with common hypotenuse. The aerodynamic loads, along with the base-excitation which is due to the motion of the rigid aircraft model, are the driving forces acting on the wing finite element model. An aerodynamic control surface is modulated based on the proposed life extending control logic within an existing flight control system without requiring major modification. One of the main goals of life extending control logic is to enhance the aircraft's service life, without incurring significant loss of vehicle

  16. Multi-Fuel Rotary Engine for General Aviation Aircraft (United States)

    Jones, C.; Ellis, D. R.; Meng, P. R.


    Design studies, conducted for NASA, of Advanced Multi-fuel General Aviation and Commuter Aircraft Rotary Stratified Charge Engines are summarized. Conceptual design studies of an advanced engine sized to provide 186/250 shaft KW/HP under cruise conditions at 7620/25,000 m/ft. altitude were performed. Relevant engine development background covering both prior and recent engine test results of the direct injected unthrottled rotary engine technology, including the capability to interchangeably operate on gasoline, diesel fuel, kerosene, or aviation jet fuel, are presented and related to growth predictions. Aircraft studies, using these resultant growth engines, define anticipated system effects of the performance and power density improvements for both single engine and twin engine airplanes. The calculated results indicate superior system performance and 30 to 35% fuel economy improvement for the Rotary-engine airplanes as compared to equivalent airframe concept designs with current baseline engines. The research and technology activities required to attain the projected engine performance levels are also discussed.

  17. 高超声速飞行器的自抗扰控制器设计%Active Disturbance Rejection Control Design for Hypersonic Vehicle

    Institute of Scientific and Technical Information of China (English)

    闫斌斌; 闫杰


    This paper proposes the implementation of active disturbance rejection control C ADRC) for altitude and velocity tracking control of the longitudinal model of hypersonic vehicle which has an integrated airframe-propulsion system configuration. A set of nonlinear longitudinal equations of motion for the vehicle which include the CFD-generated aerodynamic, propulsion, and coupled aero propulsion data are developed. An ADRC controller including velocity and height loop is designed according to the feature of the hypersonic cruise vehicle. Simulation results demonstrate the effectiveness of ADRC design in tracking altitude and velocity commands.%由于采用机体一体化设计,吸气式高超声速飞行器的气动特性难以准确获知,建立的数学模型是极为不准确的;设计了一种自抗扰控制器(ADRC),分别设计了速度回路和高度回路的自抗扰控制器;仿真用高超声速飞行器的纵向模型对该控制器进行了验证,证明该控制方法能够有效地跟踪飞行器的高度和速度指令.

  18. Open Rotor Noise Shielding by Blended-Wing-Body Aircraft (United States)

    Guo, Yueping; Czech, Michael J.; Thomas, Russell H.


    This paper presents an analysis of open rotor noise shielding by Blended Wing Body (BWB) aircraft by using model scale test data acquired in the Boeing Low Speed Aeroacoustic Facility (LSAF) with a legacy F7/A7 rotor model and a simplified BWB platform. The objective of the analysis is the understanding of the shielding features of the BWB and the method of application of the shielding data for noise studies of BWB aircraft with open rotor propulsion. By studying the directivity patterns of individual tones, it is shown that though the tonal energy distribution and the spectral content of the wind tunnel test model, and thus its total noise, may differ from those of more advanced rotor designs, the individual tones follow directivity patterns that characterize far field radiations of modern open rotors, ensuring the validity of the use of this shielding data. Thus, open rotor tonal noise shielding should be categorized into front rotor tones, aft rotor tones and interaction tones, not only because of the different directivities of the three groups of tones, but also due to the differences in their source locations and coherence features, which make the respective shielding characteristics of the three groups of tones distinctly different from each other. To reveal the parametric trends of the BWB shielding effects, results are presented with variations in frequency, far field emission angle, rotor operational condition, engine installation geometry, and local airframe features. These results prepare the way for the development of parametric models for the shielding effects in prediction tools.

  19. Design Comparison Between Metallic and Composite Rear Spar of Center Wing%中央翼后梁复合材料与金属方案对比分析

    Institute of Scientific and Technical Information of China (English)



    Composite material as an excellent aviation material is widely used due to its high intensity, stiffness and designable performance. Metallic material is more widely used in airframe material because of low cost and ex-cellent range of properties , which can meet particular requirements and have experience of manufacturing tech-niques. As an example of some type of aircraft, the design procedure of these two schemes of composite and metal-lic material were analyzed and discussed in detail in this article. It is hopeful to provide technical support for the design on the rear spar of center wing.%复合材料作为一种优良的航空材料,具有比强度高、比刚度大、材料力学性能可设计等优点。金属材料由于成本不高,能够满足不同设计需求而被广泛应用,同时制造加工技术成熟。以某型飞机为例,详细分析和探讨了中央翼后梁采用复合材料和金属材料2套方案,为中央翼后梁结构设计提供支持。

  20. Development of a Two-Phase Model for the Hot Deformation of Highly-Alloyed Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    A. J. Beaudoin; J. A. Dantzig; I. M. Robertson; B. E. Gore; S. F. Harnish; H. A. Padilla


    Conventional processing methods for highly alloyed aluminum consist of ingot casting, followed by hot rolling and thermal treatments. Defects result in lost productivity and wasted energy through the need to remelt and reprocess the material. This research centers on developing a fundamental understanding for deformation of wrought 705X series alloys, a key alloy system used in structural airframe applications. The development of damage at grain boundaries is characterized through a novel test that provides initiation of failure while preserving a controlled deformation response. Data from these mechanical tests are linked to computer simulations of the hot rolling process through a critical measure of damage. Transmission electron microscopy provides fundamental insight into deformation at these high working temperatures, and--in a novel link between microscale and macroscale response--the evolution of microstructure (crystallographic orientation) provides feedback for tuning of friction in the hot rolling process. The key product of this research is a modeling framework for the analysis of industrial hot rolling.

  1. An Assessment of Technical and Production Risks of Candidate Low-Cost Attitude/Heading Reference Systems(AHRS) (United States)

    Yuchnovicz, Daniel; Burgess, Malcolm; Hammers, William


    This report provides an assessment of technical and production risks of candidate low-cost attitude/heading reference systems (AHRS) for use in the Advanced General Aviation Transport Experiments (AGATE) airplanes. A low-cost AHRS is a key component of modem "glass cockpit" flight displays for General Aviation (GA) aircraft. The technical capabilities of several candidate low-cost AHRS were examined and described along with the technical issues involved with using all solid-state components for attitude measurement. An economic model was developed which describes the expected profit, rate of return, and volume requirements for the manufacture of low-cost AHRS for GA aircraft in the 2000 to 2020 time frame. The model is the result of interviews with GA airframe manufacturers, avionics manufacturers and historical analysis of avionics of similar complexity. The model shows that a manufacturer will break even after three years of AHRS production, realizing an 18 percent rate of return (23 percent profit) on an investment of $3.5M over the 20 year period. A start-up production estimate showed costs of $6-12M for a new company to build and certify an AHRS from scratch, considered to be a high-risk proposition, versus $0.25-0.75M for an experienced avionics manufacturer to manufacture a design under license, a low-risk proposition.

  2. Methods for Estimating Environmental Effects and Constraints on NexGen: High Density Case Study (United States)

    Augustine, S.; Ermatinger, C.; Graham, M.; Thompson, T.


    This document provides a summary of the current methods developed by Metron Aviation for the estimate of environmental effects and constraints on the Next Generation Air Transportation System (NextGen). This body of work incorporates many of the key elements necessary to achieve such an estimate. Each section contains the background and motivation for the technical elements of the work, a description of the methods used, and possible next steps. The current methods described in this document were selected in an attempt to provide a good balance between accuracy and fairly rapid turn around times to best advance Joint Planning and Development Office (JPDO) System Modeling and Analysis Division (SMAD) objectives while also supporting the needs of the JPDO Environmental Working Group (EWG). In particular this document describes methods applied to support the High Density (HD) Case Study performed during the spring of 2008. A reference day (in 2006) is modeled to describe current system capabilities while the future demand is applied to multiple alternatives to analyze system performance. The major variables in the alternatives are operational/procedural capabilities for airport, terminal, and en route airspace along with projected improvements to airframe, engine and navigational equipment.

  3. Landing Gear Aerodynamic Noise Prediction Using Building-Cube Method

    Directory of Open Access Journals (Sweden)

    Daisuke Sasaki


    Full Text Available Landing gear noise prediction method is developed using Building-Cube Method (BCM. The BCM is a multiblock-structured Cartesian mesh flow solver, which aims to enable practical large-scale computation. The computational domain is composed of assemblage of various sizes of building blocks where small blocks are used to capture flow features in detail. Because of Cartesian-based mesh, easy and fast mesh generation for complicated geometries is achieved. The airframe noise is predicted through the coupling of incompressible Navier-Stokes flow solver and the aeroacoustic analogy-based Curle’s equation. In this paper, Curle’s equation in noncompact form is introduced to predict the acoustic sound from an object in flow. This approach is applied to JAXA Landing gear Evaluation Geometry model to investigate the influence of the detail components to flows and aerodynamic noises. The position of torque link and the wheel cap geometry are changed to discuss the influence. The present method showed good agreement with the preceding experimental result and proved that difference of the complicated components to far field noise was estimated. The result also shows that the torque link position highly affects the flow acceleration at the axle region between two wheels, which causes the change in SPL at observation point.

  4. Carbon Nanotube/Polymer Nanocomposites Flexible Stress and Strain Sensors (United States)

    Kang, Jin Ho; Sauti, Godfrey; Park, Cheol; Scholl, Jonathan A.; Lowther, Sharon E.; Harrison, Joycelyn S.


    Conformable stress and strain sensors are required for monitoring the integrity of airframe structures as well as for sensing the mechanical stimuli in prosthetic arms. For this purpose, we have developed a series of piezoresistive single-wall carbon nanotube (SWCNT)/polymer nanocomposites. The electromechanical coupling of pressure with resistance changes in these nanocomposites is exceptionally greater than that of metallic piezoresistive materials. In fact, the piezoresistive stress coefficient (pi) of a SWCNT/polymer nanocomposite is approximately two orders of magnitude higher than that of a typical metallic piezoresistive. The piezoresistive stress coefficient is a function of the nanotube concentration wherein the maximum value occurs at a concentration just above the percolation threshold concentration (phi approx. 0.05 %). This response appears to originate from a change in intrinsic resistivity under compression/tension. A systematic study of the effect of the modulus of the polymer matrix on piezoresistivity allowed us to make flexible and conformable sensors for biomedical applications. The prototype haptic sensors using these nanocomposites are demonstrated. The piezocapacitive properties of SWCNT/polymer are also characterized by monitoring the capacitance change under pressure.

  5. Design concept of three-dimensional section controllable internal waverider hypersonic inlet

    Institute of Scientific and Technical Information of China (English)

    YOU YanCheng; LIANG DeWang


    A new hypersonic inlet named three-dimensional section controllable internal waverider inlet is presented in this paper to achieve the goal of section shape geometric transition and complete capture of the upstream mass. On the basis of the association between hypersonic waverider airframe and streamtraced hypersonic inlet, the waverider concept is extended to yield results for the internal flows,namely internal waverider concept. It is proven theoretically that not osculating cones but osculating axisymmetric theory is appropriate for the design of section controllable internal wsverider inlet. And two design methods out of the internal waverider concept are proposed subsequently to construct two inlets with specific section shape request, triangle to ellipse and rectangle to ellipse ones. The calculation results show that the inlets are capable of keeping their shock structures and the main flow characteristics exactly as their derived flowfield. Further, the inlets successfully capture all the upstream mass despite their complicated cross-section transitions. It is believed that the concept proposed explores a new way of designing three-dimensional hypersonic inlets with special demand of section shape transition. However, the detailed flow characteristic and the performance of the internal waverider inlets are still under investigation.

  6. Design concept of three-dimensional section controllable internal waverider hypersonic inlet

    Institute of Scientific and Technical Information of China (English)


    A new hypersonic inlet named three-dimensional section controllable internal waverider inlet is presented in this paper to achieve the goal of section shape geometric transition and complete capture of the upstream mass. On the basis of the association between hypersonic waverider airframe and streamtraced hypersonic inlet, the waverider concept is extended to yield results for the internal flows, namely internal waverider concept. It is proven theoretically that not osculating cones but osculating axisymmetric theory is appropriate for the design of section controllable internal waverider inlet. And two design methods out of the internal waverider concept are proposed subsequently to construct two inlets with specific section shape request, triangle to ellipse and rectangle to ellipse ones. The calculation results show that the inlets are capable of keeping their shock structures and the main flow characteristics exactly as their derived flowfield. Further, the inlets successfully capture all the upstream mass despite their complicated cross-section transitions. It is believed that the concept proposed ex- plores a new way of designing three-dimensional hypersonic inlets with special demand of section shape transition. However, the detailed flow characteristic and the performance of the internal waverider inlets are still under investigation.

  7. Definition of 1992 Technology Aircraft Noise Levels and the Methodology for Assessing Airplane Noise Impact of Component Noise Reduction Concepts (United States)

    Kumasaka, Henry A.; Martinez, Michael M.; Weir, Donald S.


    This report describes the methodology for assessing the impact of component noise reduction on total airplane system noise. The methodology is intended to be applied to the results of individual study elements of the NASA-Advanced Subsonic Technology (AST) Noise Reduction Program, which will address the development of noise reduction concepts for specific components. Program progress will be assessed in terms of noise reduction achieved, relative to baseline levels representative of 1992 technology airplane/engine design and performance. In this report, the 1992 technology reference levels are defined for assessment models based on four airplane sizes - an average business jet and three commercial transports: a small twin, a medium sized twin, and a large quad. Study results indicate that component changes defined as program final goals for nacelle treatment and engine/airframe source noise reduction would achieve from 6-7 EPNdB reduction of total airplane noise at FAR 36 Stage 3 noise certification conditions for all of the airplane noise assessment models.

  8. The impact of materials technology and operational constraints on the economics of cruise speed selection (United States)

    Clauss, J. S., Jr.; Bruckman, F. A.; Horning, D. L.; Johnston, R. H.; Werner, J. V.


    Six material concepts at Mach 2.0 and three material concepts at Mach 2.55 were proposed. The resulting evaluations, based on projected development, production, and operating costs, indicate that aircraft designs with advanced composites as the primary material ingredient have the lowest fare premiums at both Mach 2.0 and 2.55. Designs having advanced metallics as the primary material ingredient are not economical. Advanced titanium, employing advanced manufacturing methods such as SFF/DB, requires a fare premium of about 30 percent at both Mach 2.0 and 2.55. Advanced aluminum, usable only at the lower Mach number, requires a fare premium of 20 percent. Cruise speeds in the Mach 2.0-2.3 regime are preferred because of the better economics and because of the availability of two material concepts to reduce program risk - advanced composites and advanced aluminums. This cruise speed regime also avoids the increase in risk associated with the more complex inlets and airframe systems and higher temperature composite matrices required at the higher Mach numbers typified by Mach 2.55.

  9. Drag prediction method of powered-on civil aircraft based on thrust drag bookkeeping

    Directory of Open Access Journals (Sweden)

    Zhang Yufei


    Full Text Available A drag prediction method based on thrust drag bookkeeping (TDB is introduced for civil jet propulsion/airframe integration performance analysis. The method is derived from the control volume theory of a powered-on nacelle. Key problem of the TDB is identified to be accurate prediction of velocity coefficient of the powered-on nacelle. Accuracy of CFD solver is validated by test cases of the first AIAA Propulsion Aerodynamics Workshop. Then the TDB method is applied to thrust and drag decomposing of a realistic aircraft. A linear relation between the computations assumed free stream Mach number and the velocity coefficient result is revealed. The thrust losses caused by nozzle internal drag and pylon scrubbing are obtained by the isolated nacelle and mapped on to the in-flight whole configuration analysis. Effects of the powered-on condition are investigated by comparing through-flow configuration with powered-on configuration. The variance on aerodynamic coefficients and pressure distribution is numerically studied.

  10. Large Eddy Simulation of Airfoil Self-Noise at High Reynolds Number (United States)

    Kocheemoolayil, Joseph; Lele, Sanjiva


    The trailing edge noise section (Category 1) of the Benchmark Problems for Airframe Noise Computations (BANC) workshop features five canonical problems. No first-principles based approach free of empiricism and tunable coefficients has successfully predicted trailing edge noise for the five configurations to date. Our simulations predict trailing edge noise accurately for all five configurations. The simulation database is described in detail, highlighting efforts undertaken to validate the results through systematic comparison with dedicated experiments and establish insensitivity to grid resolution, domain size, alleatory uncertainties such as the tripping mechanism used to force transition to turbulence and epistemic uncertainties such as models for unresolved near-wall turbulence. Ongoing efforts to extend the predictive capability to non-canonical configurations featuring flow separation are summarized. A novel, large-span calculation that predicts the flow past a wind turbine airfoil in deep stall with unprecedented accuracy is presented. The simulations predict airfoil noise in the near-stall regime accurately. While the post-stall noise predictions leave room for improvement, significant uncertainties in the experiment might preclude a fair comparison in this regime. We thank Cascade Technologies Inc. for providing access to the CharLES toolkit - a massively-parallel, unstructured large eddy simulation framework.

  11. An experimental investigation into the damage resistance and compression-after-impact strength of T800H/3900-2 (United States)

    Vietinghoff, H.; Poon, C.; Straznicky, P. V.; Gould, R.


    An experimental investigation was conducted into impact behavior of a Toray T800H/3900-2 material system, a system representative of the most recent generation of toughened graphite-epoxy composites selected for use in several new airframes. In the investigation, test specimens featuring quasi-isotropic and midplane symmetric layup with 24 plies were fabricated and impacted at five different impact energy levels, resulting in damage ranging from barely visible to severe. Damage was characterized using nondestructive and destructive inspection, including ultrasound and x-ray techniques, and the specimens were then compressively loaded to failure. The carefully controlled set of experiments resulted in a detailed three dimensional characterization of the damage induced in the selected laminate layup for a range of impact energies. Compression after impact testing resulted in a correlation of impact energy and damage area with residual compressive strength. The results will be used to calibrate and test the analytical prediction methods being developed as part of a project on impact resistance and tolerance of composite materials, and as reference data on the material system.

  12. A Collection of Nonlinear Aircraft Simulations in MATLAB (United States)

    Garza, Frederico R.; Morelli, Eugene A.


    Nonlinear six degree-of-freedom simulations for a variety of aircraft were created using MATLAB. Data for aircraft geometry, aerodynamic characteristics, mass / inertia properties, and engine characteristics were obtained from open literature publications documenting wind tunnel experiments and flight tests. Each nonlinear simulation was implemented within a common framework in MATLAB, and includes an interface with another commercially-available program to read pilot inputs and produce a three-dimensional (3-D) display of the simulated airplane motion. Aircraft simulations include the General Dynamics F-16 Fighting Falcon, Convair F-106B Delta Dart, Grumman F-14 Tomcat, McDonnell Douglas F-4 Phantom, NASA Langley Free-Flying Aircraft for Sub-scale Experimental Research (FASER), NASA HL-20 Lifting Body, NASA / DARPA X-31 Enhanced Fighter Maneuverability Demonstrator, and the Vought A-7 Corsair II. All nonlinear simulations and 3-D displays run in real time in response to pilot inputs, using contemporary desktop personal computer hardware. The simulations can also be run in batch mode. Each nonlinear simulation includes the full nonlinear dynamics of the bare airframe, with a scaled direct connection from pilot inputs to control surface deflections to provide adequate pilot control. Since all the nonlinear simulations are implemented entirely in MATLAB, user-defined control laws can be added in a straightforward fashion, and the simulations are portable across various computing platforms. Routines for trim, linearization, and numerical integration are included. The general nonlinear simulation framework and the specifics for each particular aircraft are documented.

  13. Impact of aviation upon the atmosphere. Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Carpentier, J. [Comite Avion-Ozone, 75 - Paris (France)


    The commercial air traffic, either for business or for tourism will induce a special increase of long haul flights, with cruising altitudes of about 10 to 12 km. These altitudes correspond to the upper troposphere for the low latitudes (tropical zones) and to the lower stratosphere for middle and high latitudes. The prospect of a world air traffic multiplied by a factor 2 within the next fifteen years, with an increasing part of the long-haul flights, raises the problem of the impact of aircraft emissions on the upper troposphere and on the lower stratosphere. The air traffic growth which is forecast for the next two decades as well as for long term will be larger than the GDP growth. But technical progress concerning airframes, engines, navigation systems and improvements of air traffic control and airports will keep the aircraft emissions growth at a rate which will not exceed the GDP growth rate. The aviation`s share of global anthropogenic emissions will remain lower than 3 percent. The regulations related to NO{sub x} emissions from aircraft will reduce the aviation`s share of nitrogen oxides from human sources at a level of 1 percent. (R.P.)

  14. Computational and Experimental Fluid-Structure Interaction Analysis of a High-Lift Wing with a Slat-Cove Filler for Noise Reduction (United States)

    Scholten, William D.; Patterson, Ryan D.; Hartl, Darren J.; Strganac, Thomas W.; Chapelon, Quentin H. C.; Turner, Travis


    Airframe noise is a significant component of overall noise produced by transport aircraft during landing and approach (low speed maneuvers). A significant source for this noise is the cove of the leading-edge slat. The slat-cove filler (SCF) has been shown to be effective at mitigating slat noise. The objective of this work is to understand the fluid-structure interaction (FSI) behavior of a superelastic shape memory alloy (SMA) SCF in flow using both computational and physical models of a high-lift wing. Initial understanding of flow around the SCF and wing is obtained using computational fluid dynamics (CFD) analysis at various angles of attack. A framework compatible with an SMA constitutive model (implemented as a user material subroutine) is used to perform FSI analysis for multiple flow and configuration cases. A scaled physical model of the high-lift wing is constructed and tested in the Texas A&M 3 ft-by-4-foot wind tunnel. Initial validation of both CFD and FSI analysis is conducted by comparing lift, drag and pressure distributions with experimental results.

  15. Aircraft Lightning Electromagnetic Environment Measurement (United States)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.


    This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.

  16. Impact dynamics instrumentation (United States)

    Mccormck, R. F.


    One of the tasks specified in the NASA Langley controlled impact demonstration (CID) work package was to furnish dynamic instrumentation sensors. The types of instrumentation sensors required were accelerometers for aircraft structural loads measurements, seat belt load cells to measure anthropomorphic dummy responses to the aircraft impact, and strain gage bending bridges to measure the aircraft fuselage and wing bending during impact. The objective in the selection of dynamic instrumentation for the CID was to provide 352 of the highest quality transducers and remain within budget allocation. The transducers that were selected for the CID evaluation process were each subjected to rigorous laboratory acceptance tests and to aircraft fuselage section drop tests at the LaRC Impact Dynamics Research Facility. Data compiled from this series of tests showed the selected transducers to be best suited for the CID mission requirement. The transducers installation technique on the airframe proved successful. The transducer quality assurance was guaranteed through rigorous acceptance testing. Data acquired was 97.0%.


    Directory of Open Access Journals (Sweden)

    Corneliu STOICA


    Full Text Available Over the last few decades, many approaches have been undertaken in order to asses detailed noise source identification on complex bodies, i.e. aircrafts, cars, machinery. Noise source identification implies to accurately obtain the position and frequency of the dominant noise sources. There are cases where traditional testing methods can not be applied at all or their use involves some limitations. Optical systems used for near field analysis require a line of sight that may not be available. The state-of-the-art technology for this purpose is the use of a large number of microphones whose signals are acquired simultaneously, i.e. microphone phased array. Due to the excessive cost of the instruments and the data acquisition system required, the implementation of this technology was restricted to governmental agencies (NASA, DLR and big companies such as Boeing and Airbus. During the past years, this technique was developed in wind tunnels and some universities to perform noise source identification on scale airframes, main landing gear models, and aerodynamic profiles (used on airplanes, helicopter rotors and wind mills.

  18. Robo-line storage: Low latency, high capacity storage systems over geographically distributed networks (United States)

    Katz, Randy H.; Anderson, Thomas E.; Ousterhout, John K.; Patterson, David A.


    Rapid advances in high performance computing are making possible more complete and accurate computer-based modeling of complex physical phenomena, such as weather front interactions, dynamics of chemical reactions, numerical aerodynamic analysis of airframes, and ocean-land-atmosphere interactions. Many of these 'grand challenge' applications are as demanding of the underlying storage system, in terms of their capacity and bandwidth requirements, as they are on the computational power of the processor. A global view of the Earth's ocean chlorophyll and land vegetation requires over 2 terabytes of raw satellite image data. In this paper, we describe our planned research program in high capacity, high bandwidth storage systems. The project has four overall goals. First, we will examine new methods for high capacity storage systems, made possible by low cost, small form factor magnetic and optical tape systems. Second, access to the storage system will be low latency and high bandwidth. To achieve this, we must interleave data transfer at all levels of the storage system, including devices, controllers, servers, and communications links. Latency will be reduced by extensive caching throughout the storage hierarchy. Third, we will provide effective management of a storage hierarchy, extending the techniques already developed for the Log Structured File System. Finally, we will construct a protototype high capacity file server, suitable for use on the National Research and Education Network (NREN). Such research must be a Cornerstone of any coherent program in high performance computing and communications.

  19. Toward Reduced Aircraft Community Noise Impact Via a Perception-Influenced Design Approach (United States)

    Rizzi, Stephen A.


    This is an exciting time for aircraft design. New configurations, including small multi-rotor uncrewed aerial systems, fixed- and tilt-wing distributed electric propulsion aircraft, high-speed rotorcraft, hybrid-electric commercial transports, and low-boom supersonic transports, are being made possible through a host of propulsion and airframe technology developments. The resulting noise signatures may be radically different, both spectrally and temporally, than those of the current fleet. Noise certification metrics currently used in aircraft design do not necessarily reflect these characteristics and therefore may not correlate well with human response. Further, as operations and missions become less airport-centric, e.g., those associated with on-demand mobility or package delivery, vehicles may operate in closer proximity to the population than ever before. Fortunately, a new set of tools are available for assessing human perception during the design process in order to affect the final design in a positive manner. The tool chain utilizes system noise prediction methods coupled with auralization and psychoacoustic testing, making possible the inclusion of human response to noise, along with performance criteria and certification requirements, into the aircraft design process. Several case studies are considered to illustrate how this approach could be used to influence the design of future aircraft.

  20. Development and experimental characterization of a fuel cell powered aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Thomas H.; Moffitt, Blake A.; Mavris, Dimitri N.; Parekh, David E. [Georgia Institute of Technology, Atlanta, GA 30332-0405 (United States)


    This paper describes the characteristics and performance of a fuel cell powered unmanned aircraft. The aircraft is novel as it is the largest compressed hydrogen fuel cell powered airplane built to date and is currently the only fuel cell aircraft whose design and test results are in the public domain. The aircraft features a 500 W polymer electrolyte membrane fuel cell with full balance of plant and compressed hydrogen storage incorporated into a custom airframe. Details regarding the design requirements, implementation and control of the aircraft are presented for each major aircraft system. The performances of the aircraft and powerplant are analyzed using data from flights and laboratory tests. The efficiency and component power consumption of the fuel cell propulsion system are measured at a variety of flight conditions. The performance of the aircraft powerplant is compared to other 0.5-1 kW-scale fuel cell powerplants in the literature and means of performance improvement for this aircraft are proposed. This work represents one of the first studies of fuel cell powered aircraft to result in a demonstration aircraft. As such, the results of this study are of practical interest to fuel cell powerplant and aircraft designers. (author)

  1. Skylon Aerodynamics and SABRE Plumes (United States)

    Mehta, Unmeel; Afosmis, Michael; Bowles, Jeffrey; Pandya, Shishir


    An independent partial assessment is provided of the technical viability of the Skylon aerospace plane concept, developed by Reaction Engines Limited (REL). The objectives are to verify REL's engineering estimates of airframe aerodynamics during powered flight and to assess the impact of Synergetic Air-Breathing Rocket Engine (SABRE) plumes on the aft fuselage. Pressure lift and drag coefficients derived from simulations conducted with Euler equations for unpowered flight compare very well with those REL computed with engineering methods. The REL coefficients for powered flight are increasingly less acceptable as the freestream Mach number is increased beyond 8.5, because the engineering estimates did not account for the increasing favorable (in terms of drag and lift coefficients) effect of underexpanded rocket engine plumes on the aft fuselage. At Mach numbers greater than 8.5, the thermal environment around the aft fuselage is a known unknown-a potential design and/or performance risk issue. The adverse effects of shock waves on the aft fuselage and plumeinduced flow separation are other potential risks. The development of an operational reusable launcher from the Skylon concept necessitates the judicious use of a combination of engineering methods, advanced methods based on required physics or analytical fidelity, test data, and independent assessments.

  2. Hybrid-Wing-Body Vehicle Composite Fuselage Analysis and Case Study (United States)

    Mukhopadhyay, Vivek


    Recent progress in the structural analysis of a Hybrid Wing-Body (HWB) fuselage concept is presented with the objective of structural weight reduction under a set of critical design loads. This pressurized efficient HWB fuselage design is presently being investigated by the NASA Environmentally Responsible Aviation (ERA) project in collaboration with the Boeing Company, Huntington Beach. The Pultruded Rod-Stiffened Efficient Unitized Structure (PRSEUS) composite concept, developed at the Boeing Company, is approximately modeled for an analytical study and finite element analysis. Stiffened plate linear theories are employed for a parametric case study. Maximum deflection and stress levels are obtained with appropriate assumptions for a set of feasible stiffened panel configurations. An analytical parametric case study is presented to examine the effects of discrete stiffener spacing and skin thickness on structural weight, deflection and stress. A finite-element model (FEM) of an integrated fuselage section with bulkhead is developed for an independent assessment. Stress analysis and scenario based case studies are conducted for design improvement. The FEM model specific weight of the improved fuselage concept is computed and compared to previous studies, in order to assess the relative weight/strength advantages of this advanced composite airframe technology

  3. Resin transfer molding of textile preforms for aircraft structural applications (United States)

    Hasko, Gregory H.; Dexter, H. Benson; Weideman, Mark H.


    The NASA LaRC is conducting and supporting research to develop cost-effective fabrication methods that are applicable to primary composite aircraft structures. One of the most promising fabrication methods that has evolved is resin transfer molding (RTM) of dry textile material forms. RTM has been used for many years for secondary structures, but has received increased emphasis because it is an excellent method for applying resin to damage-tolerant textile preforms at low cost. Textile preforms based on processes such as weaving, braiding, knitting, stitching, and combinations of these have been shown to offer significant improvements in damage tolerance compared to laminated tape composites. The use of low-cost resins combined with textile preforms could provide a major breakthrough in achieving cost-effective composite aircraft structures. RTM uses resin in its lowest cost form, and storage and spoilage costs are minimal. Near net shape textile preforms are expected to be cost-effective because automated machines can be used to produce the preforms, post-cure operations such as machining and fastening are minimized, and material scrap rate may be reduced in comparison with traditional prepreg molding. The purpose of this paper is to discuss experimental and analytical techniques that are under development at NASA Langley to aid the engineer in developing RTM processes for airframe structural elements. Included are experimental techniques to characterize preform and resin behavior and analytical methods that were developed to predict resin flow and cure kinetics.

  4. On the design of flight-deck procedures (United States)

    Degani, Asaf; Wiener, Earl L.


    In complex human-machine systems, operations, training, and standardization depend on a elaborate set of procedures which are specified and mandated by the operational management of the organization. The intent is to provide guidance to the pilots, to ensure a logical, efficient, safe, and predictable means of carrying out the mission objectives. In this report the authors examine the issue of procedure use and design from a broad viewpoint. The authors recommend a process which we call 'The Four P's:' philosophy, policies, procedures, and practices. We believe that if an organization commits to this process, it can create a set of procedures that are more internally consistent, less confusing, better respected by the flight crews, and that will lead to greater conformity. The 'Four-P' model, and the guidelines for procedural development in appendix 1, resulted from cockpit observations, extensive interviews with airline management and pilots, interviews and discussion at one major airframe manufacturer, and an examination of accident and incident reports. Although this report is based on airline operations, we believe that the principles may be applicable to other complex, high-risk systems, such as nuclear power production, manufacturing process control, space flight, and military operations.

  5. Development and Short-Range Testing of a 100 kW Side-Illuminated Millimeter-Wave Thermal Rocket (United States)

    Bruccoleri, Alexander; Eilers, James A.; Lambot, Thomas; Parkin, Kevin


    The objective of the phase described here of the Millimeter-Wave Thermal Launch System (MTLS) Project was to launch a small thermal rocket into the air using millimeter waves. The preliminary results of the first MTLS flight vehicle launches are presented in this work. The design and construction of a small thermal rocket with a planar ceramic heat exchanger mounted along the axis of the rocket is described. The heat exchanger was illuminated from the side by a millimeter-wave beam and fed propellant from above via a small tank containing high pressure argon or nitrogen. Short-range tests where the rocket was launched, tracked, and heated with the beam are described. The rockets were approximately 1.5 meters in length and 65 millimeters in diameter, with a liftoff mass of 1.8 kilograms. The rocket airframes were coated in aluminum and had a parachute recovery system activated via a timer and Pyrodex. At the rocket heat exchanger, the beam distance was 40 meters with a peak power intensity of 77 watts per square centimeter. and a total power of 32 kilowatts in a 30 centimeter diameter circle. An altitude of approximately 10 meters was achieved. Recommendations for improvements are discussed.

  6. Fielding a structural health monitoring system on legacy military aircraft: A business perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bos, Marcel J. [Dept. of Gas Turbines and Structural Integrity, National Aerospace Laboratory NLR, Amsterdam (Netherlands)


    An important trend in the sustainment of military aircraft is the transition from preventative maintenance to condition based maintenance (CBM). For CBM, it is essential that the actual system condition can be measured and the measured condition can be reliably extrapolated to a convenient moment in the future in order to facilitate the planning process while maintaining flight safety. Much research effort is currently being made for the development of technologies that enable CBM, including structural health monitoring (SHM) systems. Great progress has already been made in sensors, sensor networks, data acquisition, models and algorithms, data fusion/mining techniques, etc. However, the transition of these technologies into service is very slow. This is because business cases are difficult to define and the certification of the SHM systems is very challenging. This paper describes a possibility for fielding a SHM system on legacy military aircraft with a minimum amount of certification issues and with a good prospect of a positive return on investment. For appropriate areas in the airframe the application of SHM will reconcile the fail-safety and slow crack growth damage tolerance approaches that can be used for safeguarding the continuing airworthiness of these areas, combining the benefits of both approaches and eliminating the drawbacks.

  7. Identification of Material Parameters for the Simulation of Acoustic Absorption of Fouled Sintered Fiber Felts

    Directory of Open Access Journals (Sweden)

    Nicolas Lippitz


    Full Text Available As a reaction to the increasing noise pollution, caused by the expansion of airports close to residential areas, porous trailing edges are investigated to reduce the aeroacoustic noise produced by flow around the airframe. Besides mechanical and acoustical investigations of porous materials, the fouling behavior of promising materials is an important aspect to estimate the performance in long-term use. For this study, two sintered fiber felts were selected for a long-term fouling experiment where the development of the flow resistivity and accumulation of dirt was observed. Based on 3D structural characterizations obtained from X-ray tomography of the initial materials, acoustic models (Biot and Johnson–Champoux–Allard in the frame of the transfer matrix method were applied to the sintered fiber felts. Flow resistivity measurements and the measurements of the absorption coefficient in an impedance tube are the basis for a fouling model for sintered fiber felts. The contribution will conclude with recommendations concerning the modeling of pollution processes of porous materials.

  8. Advanced Aerodynamic Technologies for Future Green Regional Aircraft

    Directory of Open Access Journals (Sweden)

    Catalin NAE


    Full Text Available Future Green Regional Aircraft (GRA will operate over airports located in the neighborhood of densely populated areas, with high frequency of takeoff/ landing events and, hence, strongly contribute to community noise and gaseous emissions. These issues currently limit further growth of traffic operated by regional airliners which, in the next future, will have to face even more stringent environmental normative worldwide and therefore re-designed to incorporate advanced active aerodynamic technologies. The new concept behind GRA is based on several mainstream technologies: airframe low-noise (LN, aerodynamic load control (LC and load alleviation (LA. These technologies integrate relevant concepts for hybrid and natural laminar flow (HLC/NLF wing, active control of wing movables and aeroelastic tailoring for LC/LA functions, passive means (micro-riblets for turbulent flow drag reduction, innovative gapless architectures (droop nose, morphing flap beside conventional high-lift devices (HLDs, active flow control through synthetic jets, low-noise solutions applied to HLDs (liners, fences, and to fuselage-mounted main and nose landing gears (bay/doors acoustic treatments, fairings, wheels hub cap. The paper deals with the technological readiness level (TRL assessment of the most promising technologies and overall integration in the new generation of GRA, as a highly optimized configuration able to meet requirements for FlighPath 2050.

  9. Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer (United States)

    Kolappan Geetha, Ganesh; Roy Mahapatra, D.; Srinivasan, Gopalakrishnan


    Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

  10. An economic model of the manufacturers' aircraft production and airline earnings potential, volume 3 (United States)

    Kneafsey, J. T.; Hill, R. M.


    A behavioral explanation of the process of technological change in the U. S. aircraft manufacturing and airline industries is presented. The model indicates the principal factors which influence the aircraft (airframe) manufacturers in researching, developing, constructing and promoting new aircraft technology; and the financial requirements which determine the delivery of new aircraft to the domestic trunk airlines. Following specification and calibration of the model, the types and numbers of new aircraft were estimated historically for each airline's fleet. Examples of possible applications of the model to forecasting an individual airline's future fleet also are provided. The functional form of the model is a composite which was derived from several preceding econometric models developed on the foundations of the economics of innovation, acquisition, and technological change and represents an important contribution to the improved understanding of the economic and financial requirements for aircraft selection and production. The model's primary application will be to forecast the future types and numbers of new aircraft required for each domestic airline's fleet.

  11. Aircraft recognition and pose estimation (United States)

    Hmam, Hatem; Kim, Jijoong


    This work presents a geometry based vision system for aircraft recognition and pose estimation using single images. Pose estimation improves the tracking performance of guided weapons with imaging seekers, and is useful in estimating target manoeuvres and aim-point selection required in the terminal phase of missile engagements. After edge detection and straight-line extraction, a hierarchy of geometric reasoning algorithms is applied to form line clusters (or groupings) for image interpretation. Assuming a scaled orthographic projection and coplanar wings, lateral symmetry inherent in the airframe provides additional constraints to further reject spurious line clusters. Clusters that accidentally pass all previous tests are checked against the original image and are discarded. Valid line clusters are then used to deduce aircraft viewing angles. By observing that the leading edges of wings of a number of aircraft of interest are within 45 to 65 degrees from the symmetry axis, a bounded range of aircraft viewing angles can be found. This generic property offers the advantage of not requiring the storage of complete aircraft models viewed from all aspects, and can handle aircraft with flexible wings (e.g. F111). Several aircraft images associated with various spectral bands (i.e. visible and infra-red) are finally used to evaluate the system's performance.

  12. Laser hazard analysis for airborne AURA (Big Sky variant) Proteus platform.

    Energy Technology Data Exchange (ETDEWEB)

    Augustoni, Arnold L.


    A laser safety and hazard analysis was performed for the airborne AURA (Big Sky Laser Technology) lidar system based on the 2000 version of the American National Standard Institute's (ANSI) Standard Z136.1, for the Safe Use of Lasers and the 2000 version of the ANSI Standard Z136.6, for the Safe Use of Lasers Outdoors. The AURA lidar system is installed in the instrument pod of a Proteus airframe and is used to perform laser interaction experiments and tests at various national test sites. The targets are located at various distances or ranges from the airborne platform. In order to protect personnel, who may be in the target area and may be subjected to exposures, it was necessary to determine the Maximum Permissible Exposure (MPE) for each laser wavelength, calculate the Nominal Ocular Hazard Distance (NOHD), and determine the maximum 'eye-safe' dwell times for various operational altitudes and conditions. It was also necessary to calculate the appropriate minimum Optical Density (ODmin) of the laser safety eyewear used by authorized personnel who may receive hazardous exposures during ground base operations of the airborne AURA laser system (system alignment and calibration).

  13. Alpha-1 adrenergic antagonists in aircrew for the treatment of benign prostatic hypertrophy. (United States)

    Matthies, Andrew K; Tachikawa, Nina J


    Benign prostatic hypertrophy (BPH) affects the majority of men later in life. Other than surgery, finasteride (Proscar) is currently the only pharmacologic option available for U.S. Air Force (USAF) aircrew. This article will evaluate the current literature regarding the treatment of benign prostatic hypertrophy with FDA approved tamsulosin (Flomax) and alfuzosin (Uroxatrol), third-generation alpha-1 adrenergic antagonists. Current literature supports the fact that some third-generation alpha blockers limit the side effects of hypotension when compared to other alpha blockers as a result of the specificity of subtype binding of the receptors and the sustained release formulation. Alpha blockers are currently used almost universally for the treatment of BPH; however, they are currently not approved for USAF aircrew. This article will review the aeromedical implications of the side effects of alpha-1 adrenergic antagonists (alfuzosin, tamsulosin), which affect aircrew while performing aeronautical duties, and examine whether alpha-1 adrenergic antagonists should be acceptable medications in certain situations depending on airframe and aeronautical duties.

  14. Design and Performance of the NASA SCEPTOR Distributed Electric Propulsion Flight Demonstrator (United States)

    Borer, Nicholas K.; Patterson, Michael D.; Viken, Jeffrey K.; Moore, Mark D.; Clarke, Sean; Redifer, Matthew E.; Christie, Robert J.; Stoll, Alex M.; Dubois, Arthur; Bevirt, JoeBen; Gibson, Andrew R.; Foster, Trevor J.; Osterkamp, Philip G.


    Distributed Electric Propulsion (DEP) technology uses multiple propulsors driven by electric motors distributed about the airframe to yield beneficial aerodynamic-propulsion interaction. The NASA SCEPTOR flight demonstration project will retrofit an existing internal combustion engine-powered light aircraft with two types of DEP: small "high-lift" propellers distributed along the leading edge of the wing which accelerate the flow over the wing at low speeds, and larger cruise propellers co-located with each wingtip for primary propulsive power. The updated high-lift system enables a 2.5x reduction in wing area as compared to the original aircraft, reducing drag at cruise and shifting the velocity for maximum lift-to-drag ratio to a higher speed, while maintaining low-speed performance. The wingtip-mounted cruise propellers interact with the wingtip vortex, enabling a further efficiency increase that can reduce propulsive power by 10%. A tradespace exploration approach is developed that enables rapid identification of salient trades, and subsequent creation of SCEPTOR demonstrator geometries. These candidates were scrutinized by subject matter experts to identify design preferences that were not modeled during configuration exploration. This exploration and design approach is used to create an aircraft that consumes an estimated 4.8x less energy at the selected cruise point when compared to the original aircraft.

  15. Framework for Small-Scale Experiments in Software Engineering: Guidance and Control Software Project: Software Engineering Case Study (United States)

    Hayhurst, Kelly J.


    Software is becoming increasingly significant in today's critical avionics systems. To achieve safe, reliable software, government regulatory agencies such as the Federal Aviation Administration (FAA) and the Department of Defense mandate the use of certain software development methods. However, little scientific evidence exists to show a correlation between software development methods and product quality. Given this lack of evidence, a series of experiments has been conducted to understand why and how software fails. The Guidance and Control Software (GCS) project is the latest in this series. The GCS project is a case study of the Requirements and Technical Concepts for Aviation RTCA/DO-178B guidelines, Software Considerations in Airborne Systems and Equipment Certification. All civil transport airframe and equipment vendors are expected to comply with these guidelines in building systems to be certified by the FAA for use in commercial aircraft. For the case study, two implementations of a guidance and control application were developed to comply with the DO-178B guidelines for Level A (critical) software. The development included the requirements, design, coding, verification, configuration management, and quality assurance processes. This paper discusses the details of the GCS project and presents the results of the case study.

  16. NO and NO2 emission ratios measured from in-use commercial aircraft during taxi and takeoff. (United States)

    Herndon, Scott C; Shorter, Joanne H; Zahniser, Mark S; Nelson, David D; Jayne, John; Brown, Robert C; Miake-Lye, Richard C; Waitz, Ian; Silva, Phillip; Lanni, Thomas; Demerjian, Ken; Kolb, Charles E


    In August 2001, the Aerodyne Mobile Laboratory simultaneously measured NO, NO2, and CO2 within 350 m of a taxiway and 550 m of a runway at John F. Kennedy Airport. The meteorological conditions were such that taxi and takeoff plumes from individual aircraft were clearly resolved against background levels. NO and NO2 concentrations were measured with 1 s time resolution using a dual tunable infrared laser differential absorption spectroscopy instrument, utilizing an astigmatic multipass Herriott cell. The CO2 measurements were also obtained at 1 s time resolution using a commercial non-dispersive infrared absorption instrument. Plumes were measured from over 30 individual planes, ranging from turbo props to jumbo jets. NOx emission indices were determined by examining the correlation between NOx (NO + NO2) and CO2 during the plume measurements. Several aircraft tail numbers were unambiguously identified, allowing those specific airframe/engine combinations to be determined. The resulting NOx emission indices from positively identified in-service operating airplanes are compared with the published International Civil Aviation Organization engine certification test database collected on new engines in certification test cells.

  17. Investigation of Inner Loop Flight Control Strategies for High-Speed Research (United States)

    Newman, Brett; Kassem, Ayman


    This report describes the activities and findings conducted under contract NAS1-19858 with NASA Langley Research Center. Subject matter is the investigation of suitable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Techniques considered in this body of work are primarily conventional-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include 1) current aeroelastic vehicle modeling procedures require further emphasis and refinement, 2) traditional and nontraditional inner loop flight control strategies employing a single feedback loop do not appear sufficient for highly flexible HSCT class vehicles, 3) inner loop flight control systems will, in all likelihood, require multiple interacting feedback loops, and 4) Ref. H HSCT configuration presents major challenges to designing acceptable closed-loop flight dynamics.

  18. 弹载共形遥测天线的设计%Design of conformal telemetry antenna on missiles

    Institute of Scientific and Technical Information of China (English)

    周旭冉; 高宝建; 伍捍东; 任宇辉


    In this paper, a microstrip antenna on missiles is proposed. The antenna is conformal with the curved surface of missile, and the convex height of radome is less than 8 mm. This proposal will not have any influence on both dynamic characteristics of the missile body and mechanical strength of the airframe. The antenna can obtain the high gain of 8.4dBi, its simulation pattern is almost consistent with the measured pattern results, and the antenna has the stable radiation characteristics in operating frequency range. Therefore it is very suitable to be fuze, telemetry antennas on missiles.%设计了一种弹载微带天线,该天线与弹体曲面共形,加上天线罩所凸出的曲面高度不超过8 mm,不仅不影响弹体的动力学特性,而且也不损伤弹体的机械强度.该天线具有较高的增益(8.4 dBi),仿真方向图与实测方向图吻合良好,且在整个工作频段内辐射特性稳定,非常适合作为弹载引信、遥测天线.

  19. Development of a Technique and Method of Testing Aircraft Models with Turboprop Engine Simulators in a Small-scale Wind Tunnel - Results of Tests

    Directory of Open Access Journals (Sweden)

    A. V. Petrov


    Full Text Available This report presents the results of experimental investigations into the interaction between the propellers (Ps and the airframe of a twin-engine, twin-boom light transport aircraft with a Π-shaped tail. An analysis was performed of the forces and moments acting on the aircraft with rotating Ps. The main features of the methodology for windtunnel testing of an aircraft model with running Ps in TsAGI’s T-102 wind tunnel are outlined.The effect of 6-blade Ps slipstreams on the longitudinal and lateral aerodynamic characteristics as well as the effectiveness of the control surfaces was studied on the aircraft model in cruise and takeoff/landing configurations. The tests were conducted at flow velocities of V∞ = 20 to 50 m/s in the ranges of angles of attack α =  -6 to 20 deg, sideslip angles of β = -16 to 16 deg and blade loading coefficient of B 0 to 2.8. For the aircraft of unusual layout studied, an increase in blowing intensity is shown to result in decreasing longitudinal static stability and significant asymmetry of the directional stability characteristics associated with the interaction between the Ps slipstreams of the same (left-hand rotation and the empennage.

  20. Active Structural Acoustic Control in an Original A400M Aircraft Structure (United States)

    Koehne, C.; Sachau, D.; Renger, K.


    Low frequency noise has always been a challenge in propeller driven aircraft. At low frequencies passive noise treatments are not as efficient as active noise reduction systems. The Helmut-Schmidt-University has built up a full-scale test rig with an original A400M aircraft structure. This provides a good opportunity to develop and test active noise reduction systems in a realistic environment. The currently installed system consists of mechanical actuators and acoustical sensors. The actuators are called TVAs (Tuneable Vibration Absorber) and contain two spring-mass systems whose natural frequencies are adjusted to the BPFs (Blade Passage Frequency) of the propellers. The TVAs are mounted to the frames and the force direction is normal to the skin. The sensors are condenser microphones which are attached to the primary structure of the airframe. The TVAs are equipped with signal processing devices. These components carry out Fourier transforms and signal amplification for the sensor data and actuator signals. The communication between the TVAs and the central control unit is implemented by the CAN Bus protocol and mainly consists of complex coefficients for the sensor and actuator data. This paper describes the basic structure of the system, the hardware set-up and function tests of the controller.

  1. Small transport aircraft technology propeller study (United States)

    Black, B. M.; Magliozzi, B.; Rohrbach, C.


    A study to define potential benefits of advanced technology propeller for 1985-1990 STAT commuter airplanes was completed. Two baselines, a Convair, 30 passenger, 0.47 Mach number airplane and a Lockheed, 50 passenger, 0.70 Mach number airplane, were selected from NASA-Ames sponsored airframe contracts. Parametric performance, noise level, weight and cost trends for propellers with varying number of blades, activity factor, camber and diameter incorporating blade sweep, tip proplets, advanced composite materials, advanced airfoils, advanced prevision synchrophasing and counter-rotation are presented. The resulting DOC, fuel burned, empty weight and acquisition cost benefits are presented for resizings of the two baseline airplanes. Six-bladed propeller having advanced composite blades, advanced airfoils, tip proplets and advanced prevision synchrophasers provided the maximum DOC improvements for both airplanes. DOC and fuel burned were reduced by 8.3% and 17.0% respectively for the Convair airplane and by 24.9% and 41.2% respectively for the Lockheed airplane. The larger reductions arose from a baseline definition with very heavy fuselage acoustic treatment. An alternate baseline, with a cabin noise 13dB in excess of the objective, was also studied.

  2. Aircraft noise prediction (United States)

    Filippone, Antonio


    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

  3. Enhancing pulsed eddy current for inspection of P-3 Orion lap-joint structures (United States)

    Butt, D. M.; Underhill, P. R.; Krause, T. W.


    During flight, aircraft are subjected to cyclic loading. In the Lockheed P-3 Orion airframe, this cyclic loading can lead to development of fatigue cracks at steel fastener locations in the top and second layers of aluminum wing skin lap-joints. An inspection method that is capable of detecting these cracks, without fastener removal, is desirable as this can minimize aircraft downtime, while subsequently reducing the risk of collateral damage. The ability to detect second layer cracks has been demonstrated using a Pulsed Eddy Current (PEC) probe design that utilizes the ferrous fastener as a flux conduit. This allows for deeper penetration of flux into the lap-joint second layer and consequently, sensitivity to the presence of cracks. Differential pick-up coil pairs are used to sense the eddy current response due to the presence of a crack. The differential signal obtained from pick-up coils on opposing sides of the fastener is analyzed using a Modified Principal Components Analysis (MPCA). This is followed by a cluster analysis of the resulting MPCA scores to separate fastener locations with cracks from those without. Probe design features, data acquisition system parameters and signal post-processing can each have a strong impact on crack detection. Physical probe configurations and signal analysis processes, used to enhance the PEC system for detection of cracks in P-3 Orion lap-joint structures, are investigated and an enhanced probe design is identified.

  4. Concept development of a Mach 4 high-speed civil transport (United States)

    Domack, Christopher S.; Dollyhigh, Samuel M.; Beissner, Fred L., Jr.; Geiselhart, Karl A.; Mcgraw, Marvin E., Jr.; Shields, Elwood W.; Swanson, Edward E.


    A study was conducted to configure and analyze a 250 passenger, Mach 4 High Speed Civil Transport with a design range of 6500 n.mi. The design mission assumed an all-supersonic cruise segment and no community noise or sonic boom constraints. The study airplane was developed in order to examine the technology requirements for such a vehicle and to provide an unconstrained baseline from which to assess changes in technology levels, sonic boom limits, or community noise constraints in future studies. The propulsion, structure, and materials technologies utilized in the sizing of the study aircraft were assumed to represent a technology availability date of 2015. The study airplane was a derivative of a previously developed Mach 3 concept and utilized advanced afterburning turbojet engines and passive airframe thermal protection. Details of the configuration development, aerodynamic design, propulsion system, mass properties, and mission performance are presented. The study airplane was estimated to weigh approx. 866,000 lbs. Although an aircraft of this size is a marginally acceptable candidate to fit into the world airport infrastructure, it was concluded that the inclusion of community noise or sonic boom constraints would quickly cause the aircraft to grow beyond acceptable limits using the assumed technology levels.

  5. Analysis of technological innovation and environmental performance improvement in aviation sector. (United States)

    Lee, Joosung; Mo, Jeonghoon


    The past oil crises have caused dramatic improvements in fuel efficiency in all industrial sectors. The aviation sector-aircraft manufacturers and airlines-has also made significant efforts to improve the fuel efficiency through more advanced jet engines, high-lift wing designs, and lighter airframe materials. However, the innovations in energy-saving aircraft technologies do not coincide with the oil crisis periods. The largest improvement in aircraft fuel efficiency took place in the 1960s while the high oil prices in the 1970s and on did not induce manufacturers or airlines to achieve a faster rate of innovation. In this paper, we employ a historical analysis to examine the socio-economic reasons behind the relatively slow technological innovation in aircraft fuel efficiency over the last 40 years. Based on the industry and passenger behaviors studied and prospects for alternative fuel options, this paper offers insights for the aviation sector to shift toward more sustainable technological options in the medium term. Second-generation biofuels could be the feasible option with a meaningful reduction in aviation's lifecycle environmental impact if they can achieve sufficient economies of scale.

  6. VLM Tool for IDS Integration

    Directory of Open Access Journals (Sweden)

    Cǎtǎlin NAE


    Full Text Available This paper is dedicated to a very specific type of analysis tool (VLM - Vortex Lattice Method to be integrated in a IDS - Integrated Design System, tailored for the usage of small aircraft industry. The major interest is to have the possibility to simulate at very low computational costs a preliminary set of aerodynamic characteristics for basic aerodynamic global characteristics (Lift, Drag, Pitching Moment and aerodynamic derivatives for longitudinal and lateral-directional stability analysis. This work enables fast investigations of the influence of configuration changes in a very efficient computational environment. Using experimental data and/or CFD information for a specific calibration of VLM method, reliability of the analysis may me increased so that a first type (iteration zero aerodynamic evaluation of the preliminary 3D configuration is possible. The output of this tool is basic state aerodynamic and associated stability and control derivatives, as well as a complete set of information on specific loads on major airframe components.The major interest in using and validating this type of methods is coming from the possibility to integrate it as a tool in an IDS system for conceptual design phase, as considered for development for CESAR project (IP, UE FP6.

  7. Open Circuit Resonant (SansEC) Sensor for Composite Damage Detection and Diagnosis in Aircraft Lightning Environments (United States)

    Wang, Chuantong; Dudley, Kenneth L.; Szatkowski, George N.


    Composite materials are increasingly used in modern aircraft for reducing weight, improving fuel efficiency, and enhancing the overall design, performance, and manufacturability of airborne vehicles. Materials such as fiberglass reinforced composites (FRC) and carbon-fiber-reinforced polymers (CFRP) are being used to great advantage in airframes, wings, engine nacelles, turbine blades, fairings, fuselage and empennage structures, control surfaces and coverings. However, the potential damage from the direct and indirect effects of lightning strikes is of increased concern to aircraft designers and operators. When a lightning strike occurs, the points of attachment and detachment on the aircraft surface must be found by visual inspection, and then assessed for damage by maintenance personnel to ensure continued safe flight operations. In this paper, a new method and system for aircraft in-situ damage detection and diagnosis are presented. The method and system are based on open circuit (SansEC) sensor technology developed at NASA Langley Research Center. SansEC (Sans Electric Connection) sensor technology is a new technical framework for designing, powering, and interrogating sensors to detect damage in composite materials. Damage in composite material is generally associated with a localized change in material permittivity and/or conductivity. These changes are sensed using SansEC. Unique electrical signatures are used for damage detection and diagnosis. NASA LaRC has both experimentally and theoretically demonstrated that SansEC sensors can be effectively used for in-situ composite damage detection.

  8. Analysis Regarding the Effects of Atmospheric Turbulence on Aircraft Dynamics

    Directory of Open Access Journals (Sweden)

    Gabriela STROE


    Full Text Available This paper will analyze the Gust Load Alleviation (GLA systems which can be used to reduce the effects of atmospheric turbulences generated by wind gusts on vertical acceleration of aircraft. Their purpose is to reduce airframe loads and to improve passenger comfort. The dynamic model of the aircraft is more realistic than a rigid-body model, since it includes the structural flexibility; due to its complexity, such model can make feedback control design for gust load alleviation more challenging. The gust is generated with the Dryden power spectral density model. This kind of model lends itself well to frequency-domain performance specifications in the form of the weighting functions. Two classical analytical representations for the power spectral density (PSD function of atmospheric turbulence as given by Von Kármán and Dryden, were used. The analysis is performed for a set of specified values for flight velocity and altitude (as test cases, with different gust signals that must be generated with the required intensity, scale lengths and PSD functions.

  9. Micro- and Nano-Air Vehicles: State of the Art

    Directory of Open Access Journals (Sweden)

    Luca Petricca


    Full Text Available Micro- and nano air vehicles are defined as “extremely small and ultra-lightweight air vehicle systems” with a maximum wingspan length of 15 cm and a weight less than 20 grams. Here, we provide a review of the current state of the art and identify the challenges of design and fabrication. Different configurations are evaluated, such as fixed wings, rotary wings, and flapping wings. The main advantages and drawbacks for each typology are identified and discussed. Special attention is given to rotary-wing vehicles (helicopter concept; including a review of their main structures, such as the airframe, energy storage, controls, and communications systems. In addition, a review of relevant sensors is also included. Examples of existing and future systems are also included. Micro- and nano-vehicles with rotary wings and rechargeable batteries are dominating. The flight times of current systems are typically around 1 hour or less due to the limited energy storage capabilities of the used rechargeable batteries. Fuel cells and ultra capacitors are promising alternative energy supply technologies for the future. Technology improvements, mainly based on micro- and nanotechnologies, are expected to continue in an evolutionary way to improve the capabilities of future micro- and nano air vehicles, giving improved flight times and payload capabilities.

  10. A Cool Tool for Deicing Planes (United States)


    Nicknamed the "ice zapper," the Electro Expulsive Separation System (EESS) is an aircraft ice removal system that "pulverizes ice and removes layers of ice as thin as frost or as thick as an inch of glaze," according to the principle inventor of the technology. Patented by NASA's Ames Research Center, the EESS consists of layers of conductors encased in materials that are bonded directly to the airframe structure. When ice accumulates on the aircraft, an electric current is sent through the conductors, causing them to pulse. Even though the conductors move less than a twenty-thousandth of an inch in just a millisecond, the movement is sufficient to pulverize the ice. It is this highly accelerated motion that shatters the ice into particles the size of table salt; too small to be harmful to the aircraft. When compared with other systems in use, such as thermal deicers and pneumatic boots, the ice zapper does very well. Thermal deicers are fairly common, although they use an enormous amount of energy and present the possibility of ice refreezing. Pneumatic boots are not always effective because they require an inflation device that is unable to work until a quarter inch of ice has accumulated. With both systems, the ice that is loosened may still be large enough to cause problems for the plane once dislodged.

  11. Worthy test programmes and developments of smart electromechanical actuators (United States)

    Annaz, Fawaz Yahya


    Early aircraft flight control systems were totally manually operated, that is, the force required to move flight control surfaces was generated by the pilot and transmitted by cables and rods. As aerodynamics and airframe technology developed and speeds increased, the forces required to move control surfaces increased, as did the number of surfaces. In order to provide the extra power required, hydraulic technology was introduced. To date, the common element in the development of flight control systems has been, mainly, restricted to this type of technology. This is because of its proven reliability and the lack of alternative technologies. However, the technology to build electromechanically actuated primary flight control systems is now available. Motors developing the required power at the required frequencies are now possible (with the use of high energy permanent magnetic materials and compact high speed electronic circuits). It is this particular development which may make the concept of an 'all electric aircraft' realizable in the near future. The purpose of the all electric aircraft concept is the consolidation of all secondary power systems into electric power. The elimination of hydraulic and pneumatic secondary power systems will improve maintainability, flight readiness and use of energy. This paper will present the development of multi-lane smart electric actuators and offer an insight into other subsequent fields of study. The key areas of study may be categorized as follows. State of the art hydraulic actuators. Electromechanical actuator system test programmes. Development of electromechanical actuators. Modelling of electromechanical actuators.

  12. Computational structures technology at Grumman: Current practice/future needs (United States)

    Pifko, Allan B.; Eidinoff, Harvey


    The current practice for the design analysis of new airframe structural systems is to construct a master finite element model of the vehicle in order to develop internal load distributions. The inputs to this model include the geometry which is taken directly from CADAM and CATIA structural layout and aerodynamic loads and mass distribution computer models. This master model is sufficiently detailed to define major load paths and for the computation of dynamic mode shapes and structural frequencies, but not detailed enough to define local stress gradients and notch stresses. This master model is then used to perform structural optimization studies that will provide minimum weights for major structural members. The post-processed output from the master model, load, stress, and strain analysis is then used by structural analysts to perform detailed stress analysis of local regions in order to design local structure with all its required details. This local analysis consists of hand stress analysis and life prediction analysis with the assistance of manuals, design charts, computer stress and structural life analysis and sometimes finite element or boundary element analysis. The resulting design is verified by fatigue tests.

  13. Detailed design of a lattice composite fuselage structure by a mixed optimization method (United States)

    Liu, D.; Lohse-Busch, H.; Toropov, V.; Hühne, C.; Armani, U.


    In this article, a procedure for designing a lattice fuselage barrel is developed. It comprises three stages: first, topology optimization of an aircraft fuselage barrel is performed with respect to weight and structural performance to obtain the conceptual design. The interpretation of the optimal result is given to demonstrate the development of this new lattice airframe concept for the fuselage barrel. Subsequently, parametric optimization of the lattice aircraft fuselage barrel is carried out using genetic algorithms on metamodels generated with genetic programming from a 101-point optimal Latin hypercube design of experiments. The optimal design is achieved in terms of weight savings subject to stability, global stiffness and strain requirements, and then verified by the fine mesh finite element simulation of the lattice fuselage barrel. Finally, a practical design of the composite skin complying with the aircraft industry lay-up rules is presented. It is concluded that the mixed optimization method, combining topology optimization with the global metamodel-based approach, allows the problem to be solved with sufficient accuracy and provides the designers with a wealth of information on the structural behaviour of the novel anisogrid composite fuselage design.

  14. Using Virtual Testing for Characterization of Composite Materials (United States)

    Harrington, Joseph

    Composite materials are finally providing uses hitherto reserved for metals in structural systems applications -- airframes and engine containment systems, wraps for repair and rehabilitation, and ballistic/blast mitigation systems. They have high strength-to-weight ratios, are durable and resistant to environmental effects, have high impact strength, and can be manufactured in a variety of shapes. Generalized constitutive models are being developed to accurately model composite systems so they can be used in implicit and explicit finite element analysis. These models require extensive characterization of the composite material as input. The particular constitutive model of interest for this research is a three-dimensional orthotropic elasto-plastic composite material model that requires a total of 12 experimental stress-strain curves, yield stresses, and Young's Modulus and Poisson's ratio in the material directions as input. Sometimes it is not possible to carry out reliable experimental tests needed to characterize the composite material. One solution is using virtual testing to fill the gaps in available experimental data. A Virtual Testing Software System (VTSS) has been developed to address the need for a less restrictive method to characterize a three-dimensional orthotropic composite material. The system takes in the material properties of the constituents and completes all 12 of the necessary characterization tests using finite element (FE) models. Verification and validation test cases demonstrate the capabilities of the VTSS.

  15. Can Water-Injected Turbomachines Provide Cost-Effective Emissions and Maintenance Reductions? (United States)

    Hendricks, Robert C.; Daggett, David L.; Shouse, Dale T.; Roquemore, William M.; Brankovic, Andreja; Ryder, Robert C., Jr.


    An investigation has been performed to evaluate the effect of water injection on the performance of the Air Force Research Laboratory (AFRL, Wright-Patterson Air Force Base (WPAFB)) experimental trapped vortex combustor (TVC) over a range of fuel-to-air and water-to-fuel ratios. Performance is characterized by combustor exit quantities: temperature and emissions measurements using rakes, and overall pressure drop, from upstream plenum to combustor exit. Combustor visualization is performed using gray-scale and color still photographs and high-frame-rate videos. A parallel investigation evaluated the performance of a computational fluid dynamics (CFD) tool for the prediction of the reacting flow in a liquid fueled combustor (e.g., TVC) that uses water injection for control of pollutant emissions and turbine inlet temperature. Generally, reasonable agreement is found between data and NO(x) computations. Based on a study assessing the feasibility and performance impact of using water injection on a Boeing 747-400 aircraft to reduce NO(x) emissions during takeoff, retrofitting does not appear to be cost effective; however, an operator of a newly designed engine and airframe might be able to save up to 1.0 percent in operating costs. Other challenges of water injection will be discussed.

  16. Measurement of the effect of manufacturing deviations on natural laminar flow for a single engine general aviation airplane (United States)


    Renewed interest in natural laminar flow (NLF) had rekindled designer concern that manufacuring deviations may destroy the effectiveness of NLF for an operational aircraft. Experiments are summarized that attemtped to measure total drag changes associated with three different wing surface conditions on an aircraft typical of current general aviation high performance singles. The speed power technique was first used in an attempt to quantify the changes in total drag. Predicted and measured boundary layer transition locations for three different wing surface conditions were also compared, using two different forms of flow visualization. The three flight test phases included: assessment of an unpainted airframe, flight tests of the same aircraft after painstakingly filling and sanding the wings to design contours, and similar measurement after this aricraft was painted. In each flight phase, transition locations were monitored using with sublimating chemicals or pigmented oil. Two-dimensional drag coefficients were estimated using the Eppler-Somers code and measured with a wake rake in a method very similar to Jones' pitot traverse method. The net change in two-dimensional drag coefficient was approximately 20 counts between the unpainted aircraft and the hand-smoothed aircraft for typical cruise flight conditions.

  17. Overview: Applications of numerical optimization methods to helicopter design problems (United States)

    Miura, H.


    There are a number of helicopter design problems that are well suited to applications of numerical design optimization techniques. Adequate implementation of this technology will provide high pay-offs. There are a number of numerical optimization programs available, and there are many excellent response/performance analysis programs developed or being developed. But integration of these programs in a form that is usable in the design phase should be recognized as important. It is also necessary to attract the attention of engineers engaged in the development of analysis capabilities and to make them aware that analysis capabilities are much more powerful if integrated into design oriented codes. Frequently, the shortcoming of analysis capabilities are revealed by coupling them with an optimization code. Most of the published work has addressed problems in preliminary system design, rotor system/blade design or airframe design. Very few published results were found in acoustics, aerodynamics and control system design. Currently major efforts are focused on vibration reduction, and aerodynamics/acoustics applications appear to be growing fast. The development of a computer program system to integrate the multiple disciplines required in helicopter design with numerical optimization technique is needed. Activities in Britain, Germany and Poland are identified, but no published results from France, Italy, the USSR or Japan were found.

  18. Patient Litter System Response in a Full-Scale CH-46 Crash Test. (United States)

    Weisenbach, Charles A; Rooks, Tyler; Bowman, Troy; Fralish, Vince; McEntire, B Joseph


    U.S. Military aeromedical patient litter systems are currently required to meet minimal static strength performance requirements at the component level. Operationally, these components must function as a system and are subjected to the dynamics of turbulent flight and potentially crash events. The first of two full-scale CH-46 crash tests was conducted at NASA's Langley Research Center and included an experiment to assess patient and litter system response during a severe but survivable crash event. A three-tiered strap and pole litter system was mounted into the airframe and occupied by three anthropomorphic test devices (ATDs). During the crash event, the litter system failed to maintain structural integrity and collapsed. Component structural failures were recorded from the litter support system and the litters. The upper ATD was displaced laterally into the cabin, while the middle ATD was displaced longitudinally into the cabin. Acceleration, force, and bending moment data from the instrumented middle ATD were analyzed using available injury criteria. Results indicated that a patient might sustain a neck injury. The current test illustrates that a litter system, with components designed and tested to static requirements only, experiences multiple component structural failures during a dynamic crash event and does not maintain restraint control of its patients. It is unknown if a modern litter system, with components tested to the same static criteria, would perform differently. A systems level dynamic performance requirement needs to be developed so that patients can be provided with protection levels equivalent to that provided to seated aircraft occupants.

  19. Automated metrology and NDE measurements for increased throughput in aerospace component manufacture (United States)

    MacLeod, Charles N.; Pierce, S. Gareth; Morozov, Maxim; Summan, Rahul; Dobie, Gordon; McCubbin, Paul; McCubbin, Coreen; Dearie, Scott; Munro, Gavin


    Composite materials, particularly Carbon-Fibre-Reinforced Polymer (CFRP), find extensive use in construction of modern airframe structures. Quality and conformance checks can be a serious limitation on production throughput in aerospace manufacturing. Traditionally Non-Destructive Evaluation (NDE) and metrology measurements are undertaken at different stages of a product manufacture cycle using specific dedicated equipment and personnel. However, since both processes involve direct interaction with the component's surface, an opportunity exists to combine these to potentially reduce overall cycle time. In addition when considering moves towards automation of both inspection processes, it is clear that measured metrology data is an essential input parameter to the automated NDE workflow. The authors present the findings of a proof of concept combined sub-scale NDE and Metrology demonstrator cell for aerospace components. Permitting a maximum part area size of 3 × 1 m2, KUKA KR5 6 degree of freedom robotic manipulators were utilised to deploy two inspection payloads. Firstly automated non-contact photogrammetric metrology measurement was employed to inspect the structure for conformance of dimension in relation to reference designs (available from CAD). Secondly automated phased array technology was deployed to inspect and produce ultrasonic thickness mapping of components of nominal 20mm thickness. Parameters such as overall cycle time, part dimensional accuracy, robotic path accuracy and data registration are assessed in the paper to highlight both the current state of the art performance available and the future direction of required research focus.

  20. Formation Flight of Multiple UAVs via Onboard Sensor Information Sharing

    Directory of Open Access Journals (Sweden)

    Chulwoo Park


    Full Text Available To monitor large areas or simultaneously measure multiple points, multiple unmanned aerial vehicles (UAVs must be flown in formation. To perform such flights, sensor information generated by each UAV should be shared via communications. Although a variety of studies have focused on the algorithms for formation flight, these studies have mainly demonstrated the performance of formation flight using numerical simulations or ground robots, which do not reflect the dynamic characteristics of UAVs. In this study, an onboard sensor information sharing system and formation flight algorithms for multiple UAVs are proposed. The communication delays of radiofrequency (RF telemetry are analyzed to enable the implementation of the onboard sensor information sharing system. Using the sensor information sharing, the formation guidance law for multiple UAVs, which includes both a circular and close formation, is designed. The hardware system, which includes avionics and an airframe, is constructed for the proposed multi-UAV platform. A numerical simulation is performed to demonstrate the performance of the formation flight guidance and control system for multiple UAVs. Finally, a flight test is conducted to verify the proposed algorithm for the multi-UAV system.

  1. High Altitude Long Endurance UAV Analysis of Alternatives and Technology Requirements Development (United States)

    Nickol, Craig L.; Guynn, Mark D.; Kohout, Lisa L.; Ozoroski, Thomas A.


    An Analysis of Alternatives and a Technology Requirements Study were conducted for two mission areas utilizing various types of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicles (UAV). A hurricane science mission and a communications relay mission provided air vehicle requirements which were used to derive sixteen potential HALE UAV configurations, including heavier-than-air (HTA) and lighter-than-air (LTA) concepts with both consumable fuel and solar regenerative propulsion systems. A HTA diesel-fueled wing-body-tail configuration emerged as the preferred concept given near-term technology constraints. The cost effectiveness analysis showed that simply maximizing vehicle endurance can be a sub-optimum system solution. In addition, the HTA solar regenerative configuration was utilized to perform both a mission requirements study and a technology development study. Given near-term technology constraints, the solar regenerative powered vehicle was limited to operations during the long days and short nights at higher latitudes during the summer months. Technology improvements are required in energy storage system specific energy and solar cell efficiency, along with airframe drag and mass reductions to enable the solar regenerative vehicle to meet the full mission requirements.

  2. 基于无人机的安防监控系统在智慧城市中的应用前景与实现%Application Prospect and Implementation of Security Surveillance System Based on Unmanned Aerial Vehicle in Smart City

    Institute of Scientific and Technical Information of China (English)



    本文阐述了无人机在安防监控领域的优势与背景。无人机安防监控系统的构建主要为三个模块:首先介绍了无人机的机体设计与内部系统设计;接着阐述了安防监控后台系统的主要功能,以及无人机如何与后台系统进行无线通信;最后总结了无人机安防监控系统的优势,并提出了该系统目前存在的缺陷与改进方法。%This paper elaborates the advantage and the background of unmanned aerial vehicle in security surveillance system. The construction of security surveillance system mainly includes three parts. We first intro-duce the design of airframe and inner system of UAV;later we present the major function of its background sys-tem, and put forward the wireless communication of UAV and the background system. In conclusion we show the advantage of unmanned aerial vehicle security surveillance system, and we put forward an improvement aiming at the defect.

  3. Formation Flight of Multiple UAVs via Onboard Sensor Information Sharing. (United States)

    Park, Chulwoo; Cho, Namhoon; Lee, Kyunghyun; Kim, Youdan


    To monitor large areas or simultaneously measure multiple points, multiple unmanned aerial vehicles (UAVs) must be flown in formation. To perform such flights, sensor information generated by each UAV should be shared via communications. Although a variety of studies have focused on the algorithms for formation flight, these studies have mainly demonstrated the performance of formation flight using numerical simulations or ground robots, which do not reflect the dynamic characteristics of UAVs. In this study, an onboard sensor information sharing system and formation flight algorithms for multiple UAVs are proposed. The communication delays of radiofrequency (RF) telemetry are analyzed to enable the implementation of the onboard sensor information sharing system. Using the sensor information sharing, the formation guidance law for multiple UAVs, which includes both a circular and close formation, is designed. The hardware system, which includes avionics and an airframe, is constructed for the proposed multi-UAV platform. A numerical simulation is performed to demonstrate the performance of the formation flight guidance and control system for multiple UAVs. Finally, a flight test is conducted to verify the proposed algorithm for the multi-UAV system.

  4. Early aerospaceplane propulsion research: Marquardt Corporation: ca 1956-1963 (United States)

    Lindley, Charles A.


    A brief summary is presented of the very early days of aerospaceplane propulsion and concept research, from a viewpoint based in the Astro Division of Marquardt Aircraft Co. in the years listed, with some view into later times that were on Bill Escher's watch and others. Other groups who were pursuing the same goals by various routes are discussed by some following speakers. The chief purpose is to bring out background information that may be of value to members of the workshop and future workers in the field. The state of engine and airframe technology at those times must be understood to make sense of the effort. Operational kerosene fueled ramjets were routinely flying Mach 2 to 3 in the Bomarc and Talos interceptors. One Marquardt ramjet had accelerated a Lockheed X-7 test vehicle to about Mach 4.7 in an all-out test, holding it at nearly 1 'G' until the fuel ran out. Development of further research at Marquardt is outlined.

  5. Fundamental Aeronautics Program: Overview of Propulsion Work in the Supersonic Cruise Efficiency Technical Challenge (United States)

    Castner, Ray


    The Supersonics Project, part of NASA's Fundamental Aeronautics Program, contains a number of technical challenge areas which include sonic boom community response, airport noise, high altitude emissions, cruise efficiency, light weight durable engines/airframes, and integrated multi-discipline system design. This presentation provides an overview of the current (2012) activities in the supersonic cruise efficiency technical challenge, and is focused specifically on propulsion technologies. The intent is to develop and validate high-performance supersonic inlet and nozzle technologies. Additional work is planned for design and analysis tools for highly-integrated low-noise, low-boom applications. If successful, the payoffs include improved technologies and tools for optimized propulsion systems, propulsion technologies for a minimized sonic boom signature, and a balanced approach to meeting efficiency and community noise goals. In this propulsion area, the work is divided into advanced supersonic inlet concepts, advanced supersonic nozzle concepts, low fidelity computational tool development, high fidelity computational tools, and improved sensors and measurement capability. The current work in each area is summarized.

  6. Fundamental Aeronautics Program: Overview of Project Work in Supersonic Cruise Efficiency (United States)

    Castner, Raymond


    The Supersonics Project, part of NASA?s Fundamental Aeronautics Program, contains a number of technical challenge areas which include sonic boom community response, airport noise, high altitude emissions, cruise efficiency, light weight durable engines/airframes, and integrated multi-discipline system design. This presentation provides an overview of the current (2011) activities in the supersonic cruise efficiency technical challenge, and is focused specifically on propulsion technologies. The intent is to develop and validate high-performance supersonic inlet and nozzle technologies. Additional work is planned for design and analysis tools for highly-integrated low-noise, low-boom applications. If successful, the payoffs include improved technologies and tools for optimized propulsion systems, propulsion technologies for a minimized sonic boom signature, and a balanced approach to meeting efficiency and community noise goals. In this propulsion area, the work is divided into advanced supersonic inlet concepts, advanced supersonic nozzle concepts, low fidelity computational tool development, high fidelity computational tools, and improved sensors and measurement capability. The current work in each area is summarized.

  7. NDARC - NASA Design and Analysis of Rotorcraft Validation and Demonstration (United States)

    Johnson, Wayne


    Validation and demonstration results from the development of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are presented. The principal tasks of NDARC are to design a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft chosen as NDARC development test cases are the UH-60A single main-rotor and tail-rotor helicopter, the CH-47D tandem helicopter, the XH-59A coaxial lift-offset helicopter, and the XV-15 tiltrotor. These aircraft were selected because flight performance data, a weight statement, detailed geometry information, and a correlated comprehensive analysis model are available for each. Validation consists of developing the NDARC models for these aircraft by using geometry and weight information, airframe wind tunnel test data, engine decks, rotor performance tests, and comprehensive analysis results; and then comparing the NDARC results for aircraft and component performance with flight test data. Based on the calibrated models, the capability of the code to size rotorcraft is explored.

  8. Intelligent Unmanned Vehicle Systems Suitable For Individual or Cooperative Missions

    Energy Technology Data Exchange (ETDEWEB)

    Matthew O. Anderson; Mark D. McKay; Derek C. Wadsworth


    The Department of Energy’s Idaho National Laboratory (INL) has been researching autonomous unmanned vehicle systems for the past several years. Areas of research have included unmanned ground and aerial vehicles used for hazardous and remote operations as well as teamed together for advanced payloads and mission execution. Areas of application include aerial particulate sampling, cooperative remote radiological sampling, and persistent surveillance including real-time mosaic and geo-referenced imagery in addition to high resolution still imagery. Both fixed-wing and rotary airframes are used possessing capabilities spanning remote control to fully autonomous operation. Patented INL-developed auto steering technology is taken advantage of to provide autonomous parallel path swathing with either manned or unmanned ground vehicles. Aerial look-ahead imagery is utilized to provide a common operating picture for the ground and air vehicle during cooperative missions. This paper will discuss the various robotic vehicles, including sensor integration, used to achieve these missions and anticipated cost and labor savings.

  9. An analysis of aircraft accidents involving fires (United States)

    Lucha, G. V.; Robertson, M. A.; Schooley, F. A.


    All U. S. Air Carrier accidents between 1963 and 1974 were studied to assess the extent of total personnel and aircraft damage which occurred in accidents and in accidents involving fire. Published accident reports and NTSB investigators' factual backup files were the primary sources of data. Although it was frequently not possible to assess the relative extent of fire-caused damage versus impact damage using the available data, the study established upper and lower bounds for deaths and damage due specifically to fire. In 12 years there were 122 accidents which involved airframe fires. Eighty-seven percent of the fires occurred after impact, and fuel leakage from ruptured tanks or severed lines was the most frequently cited cause. A cost analysis was performed for 300 serious accidents, including 92 serious accidents which involved fire. Personal injury costs were outside the scope of the cost analysis, but data on personnel injury judgements as well as settlements received from the CAB are included for reference.

  10. Development, Implementation, and Pilot Evaluation of a Model-Driven Envelope Protection System to Mitigate the Hazard of In-Flight Ice Contamination on a Twin-Engine Commuter Aircraft (United States)

    Martos, Borja; Ranaudo, Richard; Norton, Billy; Gingras, David; Barnhart, Billy


    Fatal loss-of-control accidents have been directly related to in-flight airframe icing. The prototype system presented in this report directly addresses the need for real-time onboard envelope protection in icing conditions. The combination of prior information and real-time aerodynamic parameter estimations are shown to provide sufficient information for determining safe limits of the flight envelope during inflight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system was designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. The utility of the ICEPro system for mitigating a potentially hazardous icing condition was evaluated by 29 pilots using the NASA Ice Contamination Effects Flight Training Device. Results showed that real time assessment cues were effective in reducing the number of potentially hazardous upset events and in lessening exposure to loss of control following an incipient upset condition. Pilot workload with the added ICEPro displays was not measurably affected, but pilot opinion surveys showed that real time cueing greatly improved their awareness of a hazardous aircraft state. The performance of ICEPro system was further evaluated by various levels of sensor noise and atmospheric turbulence.

  11. Looking ever so much like an alien spacecraft, the Altus II remotely piloted aircraft shows off some (United States)


    Looking ever so much like an alien spacecraft, the Altus II remotely piloted aircraft shows off some of the instruments and camera lenses mounted in its nose for a lightning study over Florida flown during the summer of 2002. The Altus Cumulus Electrification Study (ACES), led by Dr. Richard Blakeslee of NASA Marshall Space Flight center, focused on the collection of electrical, magnetic and optical measurements of thunderstorms. Data collected will help scientists understand the development and life cycles of thunderstorms, which in turn may allow meteorologists to more accurately predict when destructive storms may hit. The Altus II, built by General Atomics Aeronautical Systems, Inc., is one of several remotely operated aircraft developed and matured under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. The program focused on developing airframe, propulsion, control system and communications technologies to allow unmanned aerial vehicles (UAVs) to operate at very high altitudes for long durations while carrying a variety of sensors, cameras or other instruments for science experiments, surveillance or telecommunications relay missions.

  12. Fin Buffeting Features of an Early F-22 Model (United States)

    Moses, Robert W.; Huttsell, Lawrence


    Fin buffeting is an aeroelastic phenomenon encountered by high performance aircraft, especially those with twin vertical tails that must operate at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. To date, the buffet (unsteady pressures) and buffeting (structural response) characteristics of the F-15 and F/A-18 fins have been studied extensively using flow visualization, flow velocity measurements, pressure transducers, and response gages. By means of windtunnel and flight tests of the F-15 and F/A-18, this phenomenon is well studied to the point that buffet loads can be estimated and fatigue life can he increased by structural enhancements to these airframes. However, prior to the present research, data was not available outside the F-22 program regarding fin buffeting on the F-22 configuration. During a test in the Langley Transonic Dynamics Tunnel, flow visualization and unsteady fin surface pressures were recorded for a 13.3%-scale F-22 model at high angles of attack for the purpose of comparing with results available for similar aircraft configurations. Details of this test and fin buffeting are presented herein.

  13. Aeroacoustics research in Europe: The CEAS-ASC report on 2014 highlights (United States)

    Detandt, Yves


    The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on an European scale and European aeronautics activities internationally. Each year the committee highlights some of the research and development projects in Europe. This paper is the 2014 issue of this collection of Aeroacoustic Highlights, compiled from informations submitted to the CEAS-ASC. The contributions are classified in different topics; the first categories being related to specific aeroacoustic challenges (airframe noise, fan and jet noise, helicopter noise, aircraft interior noise) and two last sections are respectively devoted to recent improvements and emerging techniques and to general advances in aeroacoustics. For each section, the present paper focus on accomplished projects, providing the state of the art in each research category in 2014. A number of research programmes involving aeroacoustics were funded by the European Commission. Some of the highlights from these programmes are summarised in this paper, as well as highlights funded by national programmes or by industry.

  14. Creep-age forming of AA7475 aluminum panels for aircraft lower wing skin application

    Directory of Open Access Journals (Sweden)

    Diego José Inforzato


    Full Text Available Creep-age forming (CAF is an interesting process for the airframe industry, as it is able to form or shape panels into smooth, but complex, curvatures. In the CAF process, the ageing cycle of the alloy is used to relax external loads imposed to the part, through creep mechanisms. Those relaxed stresses impose a new curvature to the part. At the end of the process, significant spring back (sometimes about 70% is observed and the success in achieving the desired form depends on how the spring back can be predicted in order to compensate it by tooling changes. Most of the applications relate to simple (non stiffened panels. The present work deals with the CAF of aluminum panels for aircraft wing skin application. CAF was performed using vacuum-bagging autoclave technique in small scale complex shape stiffened panels, machined from an AA7475 alloy plate. An analytical reference model from the literature was employed estimate the spring back effect in such panel geometry. This model that deals with simple plates was adapted to stiffened panels using a geometric simplification, resulting in a semi-empirical model. The results demonstrate that CAF is a promising process to form stiffened panels, and the spring back can be roughly estimated through a simple model and few experiments.

  15. High-resolution LCD projector for extra-wide-field-of-view head-up display (United States)

    Brown, Robert D.; Modro, David H.; Quast, Gerhardt A.; Wood, Robert B.


    LCD projection-based cockpit displays are beginning to make entry into military and commercial aircraft. Customers for commercial Head-Up Displays (HUDs)(including airframe manufacturers) are now interested in the adaptation of the technology into existing and future HUD optical systems. LCD projection can improve mean-time-between-failure rates because the LCDs are very robust and the light sources can be replaced with scheduled maintenance by the customer without the need for re-calibration. LCD projectors promise to lower the cost of the HUD because the cost of these displays continues to drop while the cost of CRTs remain stable. LCD projectors provide the potential for multi-colors, higher brightness raster, and all-digital communication between the flight computer and display unit. Another potential benefit of LCD projection is the ability to increase field of view and viewing eyebox without exceeding existing power budgets or reducing display lifetime and reliability compared to the capabilities provided by CRTs today. This paper describes the performance requirements and improved performance of a third-generation LCD projection image source for use in a wide field of view head-up display (HUD) optical system. This paper will focus on new HUD requirements and the application of various technologies such as LCOS microdisplays, arc lamps, and rear-projection screens. Measured performance results are compared to the design requirements.

  16. Re-Educating Jet-Engine-Researchers to Stay Relevant (United States)

    Gal-Or, Benjamin


    To stay relevantly supported, jet-engine researchers, designers and operators should follow changing uses of small and large jet engines, especially those anticipated to be used by/in the next generation, JET-ENGINE-STEERED ("JES") fleets of jet drones but fewer, JES-Stealth-Fighter/Strike Aircraft. In addition, some diminishing returns from isolated, non-integrating, jet-engine component studies, vs. relevant, supersonic, shock waves control in fluidic-JES-side-effects on compressor stall dynamics within Integrated Propulsion Flight Control ("IPFC"), and/or mechanical JES, constitute key relevant methods that currently move to China, India, South Korea and Japan. The central roles of the jet engine as primary or backup flight controller also constitute key relevant issues, especially under post stall conditions involving induced engine-stress while participating in crash prevention or minimal path-time maneuvers to target. And when proper instructors are absent, self-study of the JES-STVS REVOLUTION is an updating must, where STVS stands for wing-engine-airframe-integrated, embedded stealthy-jet-engine-inlets, restructured engines inside Stealth, Tailless, canard-less, Thrust Vectoring IFPC Systems. Anti-terror and Airliners Super-Flight-Safety are anticipated to overcome US legislation red-tape that obstructs JES-add-on-emergency-kits-use.

  17. Finite Element Simulation of Three Full-Scale Crash Tests for Cessna 172 Aircraft (United States)

    Mason, Brian H.; Warren, Jerry E., Jr.


    The NASA Emergency Locator Transmitter Survivability and Reliability (ELT-SAR) project was initiated in 2013 to assess the crash performance standards for the next generation of emergency locator transmitter (ELT) systems. Three Cessna 172 aircraft were acquired to perform crash testing at NASA Langley Research Center's Landing and Impact Research Facility. Full-scale crash tests were conducted in the summer of 2015 and each test article was subjected to severe, but survivable, impact conditions including a flare-to-stall during emergency landing, and two controlled-flight-into-terrain scenarios. Full-scale finite element analyses were performed using a commercial explicit solver, ABAQUS. The first test simulated impacting a concrete surface represented analytically by a rigid plane. Tests 2 and 3 simulated impacting a dirt surface represented analytically by an Eulerian grid of brick elements using a Mohr-Coulomb material model. The objective of this paper is to summarize the test and analysis results for the three full-scale crash tests. Simulation models of the airframe which correlate well with the tests are needed for future studies of alternate ELT mounting configurations.

  18. Modeling and Prediction of Krueger Device Noise (United States)

    Guo, Yueping; Burley, Casey L.; Thomas, Russell H.


    This paper presents the development of a noise prediction model for aircraft Krueger flap devices that are considered as alternatives to leading edge slotted slats. The prediction model decomposes the total Krueger noise into four components, generated by the unsteady flows, respectively, in the cove under the pressure side surface of the Krueger, in the gap between the Krueger trailing edge and the main wing, around the brackets supporting the Krueger device, and around the cavity on the lower side of the main wing. For each noise component, the modeling follows a physics-based approach that aims at capturing the dominant noise-generating features in the flow and developing correlations between the noise and the flow parameters that control the noise generation processes. The far field noise is modeled using each of the four noise component's respective spectral functions, far field directivities, Mach number dependencies, component amplitudes, and other parametric trends. Preliminary validations are carried out by using small scale experimental data, and two applications are discussed; one for conventional aircraft and the other for advanced configurations. The former focuses on the parametric trends of Krueger noise on design parameters, while the latter reveals its importance in relation to other airframe noise components.

  19. Delivering better power: the role of simulation in reducing the environmental impact of aircraft engines. (United States)

    Menzies, Kevin


    The growth in simulation capability over the past 20 years has led to remarkable changes in the design process for gas turbines. The availability of relatively cheap computational power coupled to improvements in numerical methods and physical modelling in simulation codes have enabled the development of aircraft propulsion systems that are more powerful and yet more efficient than ever before. However, the design challenges are correspondingly greater, especially to reduce environmental impact. The simulation requirements to achieve a reduced environmental impact are described along with the implications of continued growth in available computational power. It is concluded that achieving the environmental goals will demand large-scale multi-disciplinary simulations requiring significantly increased computational power, to enable optimization of the airframe and propulsion system over the entire operational envelope. However even with massive parallelization, the limits imposed by communications latency will constrain the time required to achieve a solution, and therefore the position of such large-scale calculations in the industrial design process.

  20. A plume capture technique for the remote characterization of aircraft engine emissions. (United States)

    Johnson, G R; Mazaheri, M; Ristovski, Z D; Morawska, L


    A technique for capturing and analyzing plumes from unmodified aircraft or other combustion sources under real world conditions is described and applied to the task of characterizing plumes from commercial aircraft during the taxiing phase of the Landing/Take-Off (LTO) cycle. The method utilizes a Plume Capture and Analysis System (PCAS) mounted in a four-wheel drive vehicle which is positioned in the airfield 60 to 180 m downwind of aircraft operations. The approach offers low test turnaround times with the ability to complete careful measurements of particle and gaseous emission factors and sequentially scanned particle size distributions without distortion due to plume concentration fluctuations. These measurements can be performed for individual aircraft movements at five minute intervals. A Plume Capture Device (PCD) collected samples of the naturally diluted plume in a 200 L conductive membrane conforming to a defined shape. Samples from over 60 aircraft movements were collected and analyzed in situ for particulate and gaseous concentrations and for particle size distribution using a Scanning Particle Mobility Sizer (SMPS). Emission factors are derived for particle number, NO(x), and PM2.5 for a widely used commercial aircraft type, Boeing 737 airframes with predominantly CFM56 class engines, during taxiing. The practical advantages of the PCAS include the capacity to perform well targeted and controlled emission factor and size distribution measurements using instrumentation with varying response times within an airport facility, in close proximity to aircraft during their normal operations.