WorldWideScience

Sample records for airspeed

  1. Diagnosis of airspeed measurement faults for unmanned aerial vehicles

    DEFF Research Database (Denmark)

    Hansen, Søren; Blanke, Mogens

    2014-01-01

    Airspeed sensor faults are common causes for incidents with unmanned aerial vehicles with pitot tube clogging or icing being the most common causes. Timely diagnosis of such faults or other artifacts in signals from airspeed sensing systems could potentially prevent crashes. This paper employs pa...

  2. Flow-Angle and Airspeed Sensor System (FASS) Using Flush-Mounted Hot-Films Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Micron-thin surface hot-film signatures will be used to simultaneously obtain airspeed and flow direction. The flow-angle and airspeed sensor system (FASS) will...

  3. Low-speed airspeed calibration data for a single-engine research-support aircraft

    Science.gov (United States)

    Holmes, B. J.

    1980-01-01

    A standard service airspeed system on a single engine research support airplane was calibrated by the trailing anemometer method. The effects of flaps, power, sideslip, and lag were evaluated. The factory supplied airspeed calibrations were not sufficiently accurate for high accuracy flight research applications. The trailing anemometer airspeed calibration was conducted to provide the capability to use the research support airplane to perform pace aircraft airspeed calibrations.

  4. Airspeed adjustment and lipid reserves in migratory Neotropical butterflies

    Science.gov (United States)

    Aerodynamic theory predicts that migrant fliers should reduce their speed of flight as endogenous energy reserves are gradually consumed. This prediction was tested for butterfly species that engage in annual rainy season migrations through central Panama. Direct airspeed measurements together wit...

  5. Directed flight and optimal airspeeds: homeward-bound gulls react flexibly to wind yet fly slower than predicted

    NARCIS (Netherlands)

    J.D. McLaren; J. Shamoun; C.J. Camphuysen; W. Bouten

    2016-01-01

    Birds in flight are proposed to adjust their body orientation (heading) and airspeed to wind conditions adaptively according to time and energy constraints. Airspeeds in goal-directed flight are predicted to approach or exceed maximum-range airspeeds, which minimize transport costs (energy expenditu

  6. Flow-Angle and Airspeed Sensor System (FASS) Using Flush-Mounted Hot-Films Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Micron-thin surface hot-film gages are used to develop flow-angle and airspeed sensor system (FASS). Unlike Pitot-static and other pressure-based devices, which...

  7. Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor

    Directory of Open Access Journals (Sweden)

    W. A. Cooper

    2014-09-01

    Full Text Available A new laser air-motion sensor measures the true airspeed with a standard uncertainty of less than 0.1 m s−1 and so reduces uncertainty in the measured component of the relative wind along the longitudinal axis of the aircraft to about the same level. The calculated pressure expected from that airspeed at the inlet of a pitot tube then provides a basis for calibrating the measurements of dynamic and static pressure, reducing standard uncertainty in those measurements to less than 0.3 hPa and the precision applicable to steady flight conditions to about 0.1 hPa. These improved measurements of pressure, combined with high-resolution measurements of geometric altitude from the global positioning system, then indicate (via integrations of the hydrostatic equation during climbs and descents that the offset and uncertainty in temperature measurement for one research aircraft are +0.3 ± 0.3 °C. For airspeed, pressure and temperature, these are significant reductions in uncertainty vs. those obtained from calibrations using standard techniques. Finally, it is shown that although the initial calibration of the measured static and dynamic pressures requires a measured temperature, once calibrated these measured pressures and the measurement of airspeed from the new laser air-motion sensor provide a measurement of temperature that does not depend on any other temperature sensor.

  8. The effects of angle-of-attack indication on aircraft control in the event of an airspeed indicator malfunction

    Science.gov (United States)

    Boesser, Claas Tido

    Analysis of accident data by the Federal Aviation Administration, the National Transportation Safety Board, and other sources show that loss of control is the leading cause of aircraft accidents. Further evaluation of the data indicates that the majority of loss of control accidents are caused by the aircraft stalling. In response to these data, the Federal Aviation Administration and the General Aviation Joint Steering Committee emphasize the importance of stall and angle-of-attack awareness during flight. The high-profile crash of Air France Flight 447, in which pilots failed to recover from a self-induced stall, reinforced concerns over the need for improved stall and angle-of-attack awareness and reinvigorated interest in the debate over the effectiveness of angle-of-attack information displays. Further support for aerodynamic information in the form of an angle-of-attack indicator comes from core cognitive engineering principles. These principles argue for the provision of information about system functioning and dynamics as a means to ensure a human is always in position to recover a system when technology is unable. The purpose of this research was to empirically evaluate the importance of providing pilots with feedback about fundamental aircraft aerodynamics, especially during non-standard situations and unexpected disturbances. An experiment was conducted using a flight simulator to test the effects of in-cockpit angle-of-attack indication on aircraft control following an airspeed indicator malfunction on final approach. Participants flew a final approach with a target airspeed range of 60 to 65 knots. Once participants slowed the aircraft for final approach, the airspeed indicator needle would be stuck at an indication of 70 knots. One group of participants flew the final approach with an angle-of-attack indicator while the other group lacked such an instrument. Examination of aircraft performance data along the final approach showed that, when confronted

  9. A hybrid system approach to airspeed, angle of attack and sideslip estimation in Unmanned Aerial Vehicles

    KAUST Repository

    Shaqura, Mohammad

    2015-06-01

    Fixed wing Unmanned Aerial Vehicles (UAVs) are an increasingly common sensing platform, owing to their key advantages: speed, endurance and ability to explore remote areas. While these platforms are highly efficient, they cannot easily be equipped with air data sensors commonly found on their larger scale manned counterparts. Indeed, such sensors are bulky, expensive and severely reduce the payload capability of the UAVs. In consequence, UAV controllers (humans or autopilots) have little information on the actual mode of operation of the wing (normal, stalled, spin) which can cause catastrophic losses of control when flying in turbulent weather conditions. In this article, we propose a real-time air parameter estimation scheme that can run on commercial, low power autopilots in real-time. The computational method is based on a hybrid decomposition of the modes of operation of the UAV. A Bayesian approach is considered for estimation, in which the estimated airspeed, angle of attack and sideslip are described statistically. An implementation on a UAV is presented, and the performance and computational efficiency of this method are validated using hardware in the loop (HIL) simulation and experimental flight data and compared with classical Extended Kalman Filter estimation. Our benchmark tests shows that this method is faster than EKF by up to two orders of magnitude. © 2015 IEEE.

  10. Design methodology for composite structures: A small low air-speed wind turbine blade case study

    International Nuclear Information System (INIS)

    Highlights: ► Case study demonstrates application of graphical selection methodology for preliminary design. ► Small wind turbine blade example used to challenge method. ► Many designs considered, varying composite material and layup. ► Structural finite element analysis used to assess performance. ► Graphical stages used to interrogate database of solutions to select appropriate designs. -- Abstract: A small low air-speed wind turbine blade case study is used to demonstrate the effectiveness of a materials and design selection methodology described by Monroy Aceves et al. (2008) for composite structures. The blade structure comprises a shell of uniform thickness and a unidirectional reinforcement. The shell outer geometry is fixed by aerodynamic considerations. A wide range of lay-ups are considered for the shell and reinforcement. Structural analysis is undertaken using the finite element method. Results are incorporated into a database for analysis using material selection software. A graphical selection stage is used to identify the lightest blade meeting appropriate design constraints. The proposed solution satisfies the design requirements and improves on the prototype benchmark by reducing the mass by almost 50%. The flexibility of the selection software in allowing identification of trends in the results and modifications to the selection criteria is demonstrated. Introducing a safety factor of two on the material failure stresses increases the mass by only 11%. The case study demonstrates that the proposed design methodology is useful in preliminary design where a very wide range of cases should be considered using relatively simple analysis.

  11. Evaluation of Naval Aviation Enterprise airspeed's generation of measurable cost savings and reinvestiment for recapitalization of the future Navy and Marine Corps

    OpenAIRE

    Williams, Robert J.

    2007-01-01

    Naval Aviation, faced with budgetary pressures, decreasing buying power and increasing costs of aircraft and equipment, realized it had to change the way it did business in order to recapitalize. The Naval Aviation Enterprise (NAE) was formed to implement the aviation components of Sea Power 21 and Sea Enterprise, including modernization and recapitalization. Through the implementation of AIRSpeed, the NAE strives to provide the right amount of readiness at the right cost, so that money can b...

  12. Trajectory Identification Method Based on Airspeed Sensor%基于空速传感器的弹道辨识方法

    Institute of Scientific and Technical Information of China (English)

    李亚楠; 王金柱

    2014-01-01

    In order to improve the identification accuracy of mortar trajectory,on the basis of the mortar shell centroid motion differential equation,a trajectory identification method is proposed based on air-speed sensor.By measuring velocity of projectile and changes of dynamic and static pressure,muzzle ve-locity and firing angle are identified separately,thus solving the problem of prolonging calculating time with usual method which reduces interval identification velocity and firing angle through continual itera-tion.Through analysis of ballistic simulation data,the feasibility of the algorithm is proved theoretically. Simulation result shows that trajectory identification accuracy of the algorithm is high;it is suitable for mortar projectile trajectory identification.%为提高迫击炮弹弹道辨识精度,在迫击炮弹质心运动微分方程的基础上,提出了基于空速传感器的弹道辨识方法。通过测量弹丸速度及所受动压和静压的变化,来相互独立进行初速和射角的辨识,从而解决了以往方法中通过不断迭代来缩小辨识初速和射角的区间而延长了解算时间的问题。通过对弹道仿真数据的分析,从理论上证明了该算法的可行性。仿真结果表明:该方法对弹道的识别精度较高,适合于迫击炮弹的弹道辨识。

  13. 14 CFR 25.335 - Design airspeeds.

    Science.gov (United States)

    2010-01-01

    ... under consideration. ER09FE96.017 ρ=density of air (slugs/ft3); c=mean geometric chord of the wing (feet... gusts, and penetration of jet streams and cold fronts) and for instrument errors and airframe...

  14. A Monte Carlo approach to competition strategy. [for maximum lift and airspeed

    Science.gov (United States)

    Teter, M. P.

    1979-01-01

    Variables taken into account in glider flight strategy decisions are modeled. These include height of clouds, distance between thermals, time of day, water ballast, present altitude, weather changes, lift organization, and distance to goal, as well as the strength of the next thermal. Results of the Monte Carlo atmospheric model are discussed.

  15. Measuring droplet size of agriuclutral spray nozzles - Measurement distance and airspeed effects

    Science.gov (United States)

    With a number of new spray testing laboratories going into operation within the U.S. and each gearing up to measure spray atomization from agricultural spray nozzles using laser diffraction, establishing and following a set of scientific standard procedures is crucial to long term data generation an...

  16. CO Airspeed Performance of Vehicle Catalytic Converter%车用催化转化器的CO空速特性

    Institute of Scientific and Technical Information of China (English)

    方瑞华; 雷雨成

    2002-01-01

    根据三元催化转化器的CO空速特性试验,得出了CO空速特性试验曲线.应用流体附面层理论和质量传输的基本原理分析了三元催化转化器蜂窝孔内的CO气体流动和质量传输的过程,解释了三元催化转化器CO空速特性的内在机理.认为随着空速的增加,开始时CO的体积分数附面层厚度直线降低,CO传质系数k1直线上升,加快了CO向催化剂表面的传质速度,有更多的CO被输送到催化剂表面,增加了CO反应物的体积分数,加快了CO的转化率,而与此同时气体流过三元催化转化器所需的时间在直线减小,CO参加化学反应的时间在直线减小,空速对CO传质系数的正面影响和对化学反应时间的负面影响都呈线性变化,二者作用相互抵消,总体表现为CO的转化率没有什么变化.而随空速的进一步增加,CO的体积分数附面层厚度降低变得缓慢,并趋向于稳定,同时CO传质系数kf的上升速度也开始变得缓慢,并趋于稳定,也就是说CO向催化剂表面的传质速度趋于稳定,在催化剂表面的CO的体积分数不再随着空速的增加而增加,CO的化学反应速度基本维持不变,而与此同时CO参加化学反应的时间还是在直线减小,所以CO的催化转化率表现为下降趋势.

  17. The Static-Pressure Error of a Wing Airspeed Installation of the McDonnell XF-88 Airplane in Dives to Transonic Speeds

    Science.gov (United States)

    Goodman, Harold R.

    1949-01-01

    Measurements were made, in dives to transonic speeds, of the static-pressure position error at a distance of one chord ahead of the McDonnell XF-88 airplane. The airplane incorporates a wing which is swept back 35 deg along the 0.22 chord line and utilizes a 65-series airfoil with a 9-percent-thick section perpendicular to the 0.25-chord line. The section in the stream direction is approximately 8-percent thick. Data up to a Mach number of about 0.97 were obtained within an airplane normal-force-coefficient range from about 0.05 to about 0.68. Data at Mach numbers above about 0.97 were obtained within an airplane normal-force-coefficient range from about 0.05 to about 0.68. Results of the measurements indicate that the static-pressure error, within the accuracy of measurement, is negligible from a Mach number of 0.65 to a Mach number of about 0.97. With a further increase in Mach number, the static-pressure error increases rapidly; at the highest Mach number attained in these tests (about M = 1.038), the error increases to about 8 percent of the impact pressure. Above a Mach number of about 0.975, the recorded Mach number remains substantially constant with increasing true Mach number; the installation is of no value between a Mach number of about 0.975 and at least 1.038, as the true Mach number cannot be obtained from the recorded Mach number in this range. Previously published data have shown that at 0.96 chord ahead of the wing tip of the straight-wing X-l airplanes, a rapid rise of position error started at a Mach number of about 0.8. In the case of the XF-88 airplane, this rise of position error was delayed, presumably by the sweep of the wing, to a Mach number of about 0.97.

  18. Best-range flight conditions for cruise-climb flight of a jet aircraft

    Science.gov (United States)

    Hale, F. J.

    1976-01-01

    The Breguet range equation was developed for cruise climb flight of a jet aircraft to include the climb angle and is then maximized with respect to the no wind true airspeed. The expression for the best range airspeed is a function of the specific fuel consumption and minimum drag airspeed and indicates that an operational airspeed equal to the fourth root of three times the minimum-drag airspeed introduces range penalties of the order of one percent.

  19. 14 CFR 1.1 - General definitions.

    Science.gov (United States)

    2010-01-01

    ... output) of an aircraft engine. Calibrated airspeed means the indicated airspeed of an aircraft, corrected... primary means of navigation, and has at least one source of navigational input, such as inertial... the FAA that contains minimum configuration, operating, and maintenance requirements, hardware...

  20. Acoustic Reduction of Flow Separation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Airfoils produce more lift and less drag when the boundary layer is attached to the airfoil. With most aircraft there are combinations of airspeed and angle of...

  1. The NASA radar entomology program at Wallops Flight Center

    Science.gov (United States)

    Vaughn, C. R.

    1979-01-01

    NASA contribution to radar entomology is presented. Wallops Flight Center is described in terms of its radar systems. Radar tracking of birds and insects was recorded from helicopters for airspeed and vertical speed.

  2. Evaluation of organizational self-assessment tools and methodologies to measure continuous process improvement for the Naval Aviation Enterprise

    OpenAIRE

    Kaehler. Theodore J.

    2006-01-01

    The Naval Aviation Enterprise (NAE) has created a program called AIRSpeed to deliver the efficiency gains of continuous process improvement (CPI). NAE leadership seeks a self-assessment tool to measure how well AIRSpeed has been implemented, including possible areas for improvement. This thesis studies the origins of continuous process improvement, the value of assessment, and current assessment methodologies. Key concepts are cited for the use of organizational assessment tools. The objectiv...

  3. Naval Aviation Maintenance: A Case Study for Process Improvement

    OpenAIRE

    Eric Jafar; Terence Noel C. Mejos; Chieh Yang

    2006-01-01

    This case is divided into two parts: Part A describes the J52-P408 engine repair process prior to the implementation of AIRspeed at the AIMD Naval Air Station, Whidbey Island (NASWI) J52 engine repair shop. Part B discusses the post-implementation of AIRSpeed and the use of Value Stream Mapping (VSM) to eliminate non-value-added processes; the use of which resulted in increased productivity.

  4. Ecology of tern flight in relation to wind, topography and aerodynamic theory.

    Science.gov (United States)

    Hedenström, Anders; Åkesson, Susanne

    2016-09-26

    Flight is an economical mode of locomotion, because it is both fast and relatively cheap per unit of distance, enabling birds to migrate long distances and obtain food over large areas. The power required to fly follows a U-shaped function in relation to airspeed, from which context dependent 'optimal' flight speeds can be derived. Crosswinds will displace birds away from their intended track unless they make compensatory adjustments of heading and airspeed. We report on flight track measurements in five geometrically similar tern species ranging one magnitude in body mass, from both migration and the breeding season at the island of Öland in the Baltic Sea. When leaving the southern point of Öland, migrating Arctic and common terns made a 60° shift in track direction, probably guided by a distant landmark. Terns adjusted both airspeed and heading in relation to tail and side wind, where coastlines facilitated compensation. Airspeed also depended on ecological context (searching versus not searching for food), and it increased with flock size. Species-specific maximum range speed agreed with predicted speeds from a new aerodynamic theory. Our study shows that the selection of airspeed is a behavioural trait that depended on a complex blend of internal and external factors.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528786

  5. Preliminary test results of a flight management algorithm for fuel conservative descents in a time based metered traffic environment. [flight tests of an algorithm to minimize fuel consumption of aircraft based on flight time

    Science.gov (United States)

    Knox, C. E.; Cannon, D. G.

    1979-01-01

    A flight management algorithm designed to improve the accuracy of delivering the airplane fuel efficiently to a metering fix at a time designated by air traffic control is discussed. The algorithm provides a 3-D path with time control (4-D) for a test B 737 airplane to make an idle thrust, clean configured descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithms and the results of the flight tests are discussed.

  6. Expansion of the USDA ARS Aerial Application spray atomization models

    Science.gov (United States)

    An effort is underway to update the USDA ARS aerial spray nozzle models using new droplet sizing instrumen-tation and measurement techniques. As part of this effort, the applicable maximum airspeed is being increased from 72 to 80 m/s to provide guidance to applicators when using new high speed air...

  7. 14 CFR 25.103 - Stall speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Stall speed. 25.103 Section 25.103... STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Performance § 25.103 Stall speed. (a) The reference stall speed, VSR, is a calibrated airspeed defined by the applicant. VSR may not be less than a 1-g...

  8. 14 CFR 25.1505 - Maximum operating limit speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  9. 14 CFR 23.149 - Minimum control speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 23.149 Section 23... Maneuverability § 23.149 Minimum control speed. (a) VMC is the calibrated airspeed at which, when the critical... still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank...

  10. 14 CFR 121.303 - Airplane instruments and equipment.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplane instruments and equipment. 121.303... Airplane instruments and equipment. (a) Unless otherwise specified, the instrument and equipment... airspeed limitation and item of related information in the Airplane Flight Manual and pertinent...

  11. 76 FR 2607 - Airworthiness Directives; MD Helicopters, Inc. (MDHI) Model MD900 Helicopters

    Science.gov (United States)

    2011-01-14

    ... position. (ii) Pull the following AP circuit breakers located on the A601 Essential Bus Circuit Breaker... YSAS switches instead of pulling the circuit breakers and installing placards that limit airspeed to... the helicopter to its normal configuration by returning the switches and circuit breakers to...

  12. 76 FR 69123 - Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters

    Science.gov (United States)

    2011-11-08

    .... (ii) Pull the following AP circuit breakers located on the A601 Essential Bus Circuit Breaker Panel... breakers; installing a placard near the AP/SAS master switch; installing an airspeed limitation placard on... breakers to their normal operating position, operationally testing the auto-pilot system, removing the...

  13. 77 FR 64439 - Airworthiness Directives; Bell Helicopter Textron Canada (Bell) Model Helicopters

    Science.gov (United States)

    2012-10-22

    ... and copilot airspeed indicators; (ii) Leak test the pilot pitot static system; and (iii) Operationally test the overspeed warning system. (2) For helicopters with a Single or Dual Automatic Flight Control... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in...

  14. 76 FR 17062 - Special Conditions: Bombardier Model BD-700-1A10 and BD-700-1A11 Airplanes, Head-Up Display (HUD...

    Science.gov (United States)

    2011-03-28

    ..., individual, stroke-written symbols on the HUD, the pilot may not be able to see around or through the image..., such ] as alerts, airspeed, attitude, altitude and direction, approach guidance, windshear guidance... conditions encountered during a time-critical, high-workload phase of flight (e.g., low-visibility...

  15. 76 FR 17582 - Special Conditions: Bombardier Model BD-700-1A10 and BD-700-1A11 Airplanes, Head-Up Display (HUD...

    Science.gov (United States)

    2011-03-30

    ..., individual, stroke-written symbols on the HUD, the pilot may not be able to see around or through the image... information displayed on the HUD, such as alerts, airspeed, attitude, altitude and direction, approach... range of lighting conditions encountered during a time-critical, high-workload phase of flight...

  16. Update to the USDA-ARS fixed-wing spray nozzle models

    Science.gov (United States)

    The current USDA ARS Aerial Spray Nozzle Models were updated to reflect both new standardized measurement methods and systems, as well as, to increase operational spray pressure, aircraft airspeed and nozzle orientation angle limits. The new models were developed using both Central Composite Design...

  17. 78 FR 67799 - Qualification, Service, and Use of Crewmembers and Aircraft Dispatchers

    Science.gov (United States)

    2013-11-12

    ... Indicated Airspeed ICAO International Civil Aviation Organization ICATEE International Committee for.... 106(f), which vests final authority in the Administrator for carrying out all functions, powers, and... proposed rulemaking (NPRM) published in the Federal Register on January 12, 2009 (74 FR 1280). List...

  18. Atomization from agricultural spray nozzles: Effects of air shear and tank mix adjuvants

    Science.gov (United States)

    Spray adjuvants can have a substantial impact on spray atomization from agricultural nozzles; however, this process is also affected by the nozzle type, operating pressure and, for aerial application, the airspeed of application. Different types of ground spray nozzle can dramatically affect the im...

  19. Investigation of Slipstream Velocity

    Science.gov (United States)

    Crowley, J W , Jr

    1925-01-01

    These experiments were made at the request of the Bureau of Aeronautics, Navy Department, to investigate the velocity of the air in the slipstream in horizontal and climbing flight to determine the form of expression giving the slipstream velocity in terms of the airspeed of the airplane. The method used consisted in flying the airplane both on a level course and in climb at full throttle and measuring the slipstream velocity at seven points in the slipstream for the whole speed range of the airplane in both conditions. In general the results show that for both condition, horizontal and climbing flights, the slipstream velocity v subscript 3 and airspeed v can be represented by straight lines and consequently the equations are of the form: v subscript s = mv+b where m and b are constant. (author)

  20. Airflow and optic flow mediate antennal positioning in flying honeybees

    Science.gov (United States)

    Roy Khurana, Taruni; Sane, Sanjay P

    2016-01-01

    To maintain their speeds during navigation, insects rely on feedback from their visual and mechanosensory modalities. Although optic flow plays an essential role in speed determination, it is less reliable under conditions of low light or sparse landmarks. Under such conditions, insects rely on feedback from antennal mechanosensors but it is not clear how these inputs combine to elicit flight-related antennal behaviours. We here show that antennal movements of the honeybee, Apis mellifera, are governed by combined visual and antennal mechanosensory inputs. Frontal airflow, as experienced during forward flight, causes antennae to actively move forward as a sigmoidal function of absolute airspeed values. However, corresponding front-to-back optic flow causes antennae to move backward, as a linear function of relative optic flow, opposite the airspeed response. When combined, these inputs maintain antennal position in a state of dynamic equilibrium. DOI: http://dx.doi.org/10.7554/eLife.14449.001 PMID:27097104

  1. Airflow and optic flow mediate antennal positioning in flying honeybees.

    Science.gov (United States)

    Roy Khurana, Taruni; Sane, Sanjay P

    2016-01-01

    To maintain their speeds during navigation, insects rely on feedback from their visual and mechanosensory modalities. Although optic flow plays an essential role in speed determination, it is less reliable under conditions of low light or sparse landmarks. Under such conditions, insects rely on feedback from antennal mechanosensors but it is not clear how these inputs combine to elicit flight-related antennal behaviours. We here show that antennal movements of the honeybee, Apis mellifera, are governed by combined visual and antennal mechanosensory inputs. Frontal airflow, as experienced during forward flight, causes antennae to actively move forward as a sigmoidal function of absolute airspeed values. However, corresponding front-to-back optic flow causes antennae to move backward, as a linear function of relative optic flow, opposite the airspeed response. When combined, these inputs maintain antennal position in a state of dynamic equilibrium. PMID:27097104

  2. Development and test results of a flight management algorithm for fuel conservative descents in a time-based metered traffic environment

    Science.gov (United States)

    Knox, C. E.; Cannon, D. G.

    1980-01-01

    A simple flight management descent algorithm designed to improve the accuracy of delivering an airplane in a fuel-conservative manner to a metering fix at a time designated by air traffic control was developed and flight tested. This algorithm provides a three dimensional path with terminal area time constraints (four dimensional) for an airplane to make an idle thrust, clean configured (landing gear up, flaps zero, and speed brakes retracted) descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithm is described. The results of the flight tests flown with the Terminal Configured Vehicle airplane are presented.

  3. The Effects of Ambient Conditions on Helicopter Rotor Source Noise Modeling

    Science.gov (United States)

    Schmitz, Frederic H.; Greenwood, Eric

    2011-01-01

    A new physics-based method called Fundamental Rotorcraft Acoustic Modeling from Experiments (FRAME) is used to demonstrate the change in rotor harmonic noise of a helicopter operating at different ambient conditions. FRAME is based upon a non-dimensional representation of the governing acoustic and performance equations of a single rotor helicopter. Measured external noise is used together with parameter identification techniques to develop a model of helicopter external noise that is a hybrid between theory and experiment. The FRAME method is used to evaluate the main rotor harmonic noise of a Bell 206B3 helicopter operating at different altitudes. The variation with altitude of Blade-Vortex Interaction (BVI) noise, known to be a strong function of the helicopter s advance ratio, is dependent upon which definition of airspeed is flown by the pilot. If normal flight procedures are followed and indicated airspeed (IAS) is held constant, the true airspeed (TAS) of the helicopter increases with altitude. This causes an increase in advance ratio and a decrease in the speed of sound which results in large changes to BVI noise levels. Results also show that thickness noise on this helicopter becomes more intense at high altitudes where advancing tip Mach number increases because the speed of sound is decreasing and advance ratio increasing for the same indicated airspeed. These results suggest that existing measurement-based empirically derived helicopter rotor noise source models may give incorrect noise estimates when they are used at conditions where data were not measured and may need to be corrected for mission land-use planning purposes.

  4. Investigating the use of wing sweep for pitch control of a small unmanned air vehicle

    OpenAIRE

    Wright, Kim

    2011-01-01

    Small Unmanned Air Vehicles (UAVs) are versatile tools with both civilian and military applications. Fixed wing UAVs require forward airspeed to remain airborne, usually resulting in constant energy expenditure to loiter over targets. A UAV capable of perching could reduce energy expenditure by settling on a site near the target, thus increasing mission duration. Avian perching techniques were observed to build a hypothesis for the biological control techniques employed during the landing man...

  5. Method and system for estimating and predicting airflow around air vehicles

    KAUST Repository

    Claudel, Christian G.

    2015-12-31

    A method, system, and sensor for air flow sensing. The system can include a cantilever, a transducer, and a processing module. The method can include measuring beam deflections of one or more cantilevers, extracting information about air flow, and determining one or more of an airspeed, an angle of attack, and a sideslip, based on extracted information. The system and method can exploit nonlinearities in the behavior of the cantilever in fluid flow.

  6. Fault Tolerant Control Design for the Longitudinal Aircraft Dynamics using Quantitative Feedback Theory

    OpenAIRE

    Ossmann, Daniel

    2015-01-01

    Flight control laws of modern aircraft are scheduled with respect to flight point parameters. The loss of the air data measurement system implies inevitably the loss of relevant scheduling information. A strategy to design a fault tolerant longitudinal flight control system is proposed which can accommodate the total loss of the angle of attack and the calibrated airspeed measurements. In this scenario the described robust longitudinal control law is employed ensuring a control performance ...

  7. Soaring energetics and glide performance in a moving atmosphere.

    Science.gov (United States)

    Taylor, Graham K; Reynolds, Kate V; Thomas, Adrian L R

    2016-09-26

    Here, we analyse the energetics, performance and optimization of flight in a moving atmosphere. We begin by deriving a succinct expression describing all of the mechanical energy flows associated with gliding, dynamic soaring and thermal soaring, which we use to explore the optimization of gliding in an arbitrary wind. We use this optimization to revisit the classical theory of the glide polar, which we expand upon in two significant ways. First, we compare the predictions of the glide polar for different species under the various published models. Second, we derive a glide optimization chart that maps every combination of headwind and updraft speed to the unique combination of airspeed and inertial sink rate at which the aerodynamic cost of transport is expected to be minimized. With these theoretical tools in hand, we test their predictions using empirical data collected from a captive steppe eagle (Aquila nipalensis) carrying an inertial measurement unit, global positioning system, barometer and pitot tube. We show that the bird adjusts airspeed in relation to headwind speed as expected if it were seeking to minimize its aerodynamic cost of transport, but find only weak evidence to suggest that it adjusts airspeed similarly in response to updrafts during straight and interthermal glides.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528788

  8. Operational experiences of a commercial helicopter flown in a large metropolitan area

    Science.gov (United States)

    Dicarlo, D. J.

    1975-01-01

    A survey of commercial helicopter-operating experiences was conducted using a helicopter flight recorder in order to provide a basis for extending helicopter design and service-life criteria. These data are representative of 182 flight hours accumulated during 1414 flights comprised of the separate legs of the total route structure employed. The operating experiences are presented in terms of the time spent within different airspeed brackets, within the classifiable flight conditions of climb, en route, and descent, at various rates of climb and descent, and at different rotor rotational speeds. The results indicated that the helicopter spent a majority of the flight time at airspeeds either below 40 knots or above 100 knots. Rates of climb and descent were concentrated at values below 5.1 m/s (1000 ft/min) particularly for higher airspeeds. Normal acceleration experiences were low, both in the total number and peak value realized; however, an extremely large number of pitch angular-velocity experiences were noted. Rotor rotational speeds were normal with no occurrences above the upper red-line limit.

  9. Hovering and forward flight energetics in Anna's and Allen's hummingbirds.

    Science.gov (United States)

    Clark, Christopher James; Dudley, Robert

    2010-01-01

    Aerodynamic theory predicts that the mechanical costs of flight are lowest at intermediate flight speeds; metabolic costs of flight should trend similarly if muscle efficiency is constant. We measured metabolic rates for nine Anna's hummingbirds (Calypte anna) and two male Allen's hummingbirds (Selasphorus sasin) feeding during flight from a free-standing mask over a range of airspeeds. Ten of 11 birds exhibited higher metabolic costs during hovering than during flight at intermediate airspeeds, whereas one individual exhibited comparable costs at hovering and during forward flight up to speeds of approximately 7 m s(-1). Flight costs of all hummingbirds increased at higher airspeeds. Relative to Anna's hummingbirds, Allen's hummingbirds exhibited deeper minima in the power curve, possibly due to higher wing loadings and greater associated costs of induced drag. Although feeding at a mask in an airstream may reduce body drag and, thus, the contributions of parasite power to overall metabolic expenditure, these results suggest that hummingbird power curves are characterized by energetic minima at intermediate speeds relative to hovering costs. PMID:20455711

  10. The impact of physical and mental tasks on pilot mental workoad

    Science.gov (United States)

    Berg, S. L.; Sheridan, T. B.

    1986-01-01

    Seven instrument-rated pilots with a wide range of backgrounds and experience levels flew four different scenarios on a fixed-base simulator. The Baseline scenario was the simplest of the four and had few mental and physical tasks. An activity scenario had many physical but few mental tasks. The Planning scenario had few physical and many mental taks. A Combined scenario had high mental and physical task loads. The magnitude of each pilot's altitude and airspeed deviations was measured, subjective workload ratings were recorded, and the degree of pilot compliance with assigned memory/planning tasks was noted. Mental and physical performance was a strong function of the manual activity level, but not influenced by the mental task load. High manual task loads resulted in a large percentage of mental errors even under low mental task loads. Although all the pilots gave similar subjective ratings when the manual task load was high, subjective ratings showed greater individual differences with high mental task loads. Altitude or airspeed deviations and subjective ratings were most correlated when the total task load was very high. Although airspeed deviations, altitude deviations, and subjective workload ratings were similar for both low experience and high experience pilots, at very high total task loads, mental performance was much lower for the low experience pilots.

  11. Backward flight in hummingbirds employs unique kinematic adjustments and entails low metabolic cost.

    Science.gov (United States)

    Sapir, Nir; Dudley, Robert

    2012-10-15

    Backward flight is a frequently used transient flight behavior among members of the species-rich hummingbird family (Trochilidae) when retreating from flowers, and is known from a variety of other avian and hexapod taxa, but the biomechanics of this intriguing locomotor mode have not been described. We measured rates of oxygen uptake (V(O2)) and flight kinematics of Anna's hummingbirds, Calypte anna (Lesson), within a wind tunnel using mask respirometry and high-speed videography, respectively, during backward, forward and hovering flight. We unexpectedly found that in sustained backward flight is similar to that in forward flight at equivalent airspeed, and is about 20% lower than hovering V(O2). For a bird that was measured throughout a range of backward airspeeds up to a speed of 4.5 m s(-1), the power curve resembled that of forward flight at equivalent airspeeds. Backward flight was facilitated by steep body angles coupled with substantial head flexion, and was also characterized by a higher wingbeat frequency, a flat stroke plane angle relative to horizontal, a high stroke plane angle relative to the longitudinal body axis, a high ratio of maximum:minimum wing positional angle, and a high upstroke:downstroke duration ratio. Because of the convergent evolution of hummingbird and some hexapod flight styles, flying insects may employ similar kinematics while engaged in backward flight, for example during station keeping or load lifting. We propose that backward flight behavior in retreat from flowers, together with other anatomical, physiological, morphological and behavioral adaptations, enables hummingbirds to maintain strictly aerial nectarivory. PMID:23014570

  12. Turbulent dispersion of the icing cloud from spray nozzles used in icing tunnels

    Science.gov (United States)

    Marek, C. J.; Olsen, W. A., Jr.

    1986-01-01

    To correctly simulate flight in natural icing conditions, the turbulence in an icing simulator must be as low as possible. But some turbulence is required to mix the droplets from the spray nozzles and achieve an icing cloud of uniform liquid water content. The goal for any spray system is to obtain the widest possible spray cloud with the lowest possible turbulence in the test section of a icing tunnel. This investigation reports the measurement of turbulence and the three-dimensional spread of the cloud from a single spray nozzle. The task was to determine how the air turbulence and cloud width are affected by spray bars of quite different drag coefficients, by changes in the turbulence upstream of the spray, the droplet size, and the atomizing air. An ice accretion grid, located 6.3 m downstream of the single spray nozzle, was used to measure cloud spread. Both the spray bar and the grid were located in the constant velocity test section. Three spray bar shapes were tested: the short blunt spray bar used in the NASA Lewis Icing Research Tunnel, a thin 14.6 cm chord airfoil, and a 53 cm chord NACA 0012 airfoil. At the low airspeed (56 km/hr) the ice accretion pattern was axisymmetric and was not affected by the shape of the spray bar. At the high airspeed (169 km/hr) the spread was 30 percent smaller than at the low airspeed. For the widest cloud the spray bars should be located as far upstream in the low velocity plenum of the icing tunnel. Good comparison is obtained between the cloud spread data and predicitons from a two-dimensional cloud mixing computer code using the two equation turbulence (k epsilon g) model.

  13. Effect of time span and task load on pilot mental workload

    Science.gov (United States)

    Berg, S. L.; Sheridan, T. B.

    1985-01-01

    Two sets of experiments were run to examine how the mental workload of a pilot might be measured. The effects of continuous manual control activity versus discrete assigned mental tasks (including the length of time between receiving an assignment and executing it) were examined. The first experiment evaluated the strengths and weaknesses of measuring mental workload with an objective perforamance (altitude deviations) and five subjective ratings (activity level, complexity, difficulty, stress, and workload). The second set of experiments built upon the first set by increasing workload intensities and adding another performance measure: airspeed deviation. The results are discussed for both low and high experience pilots.

  14. Sources of helicopter rotor hub inplane shears

    Science.gov (United States)

    Kottapalli, Sesi

    1993-01-01

    Sources of helicopter rotor hub inplane shears are identified using simplified equations and the full aeroelastic analysis code, CAMRAD/JA (Johnson, 1988). Analytical results are obtained for an articulated rotor operating at moderate thrust and high airspeed. It is found that the blade chordwise inplane shear, which includes the aerodynamic component, the Coriolis contribution, and the inertial component, and the hub inplane shears are strongly dependent on the out-of-plane response. The sources of helicopter rotor hub inplane shears lie not only in the inplane response but depend on the flap and elastic flatwise responses/modes.

  15. Requirements for Kalman filtering on the GE-701 whole word computer

    Science.gov (United States)

    Pines, S.; Schmidt, S. F.

    1978-01-01

    The results of a study to determine scaling, storage, and word length requirements for programming the Kalman filter on the GE-701 Whole Word Computer are reported. Simulation tests are presented which indicate that the Kalman filter, using a square root formulation with process noise added, utilizing MLS, radar altimeters, and airspeed as navigation aids, may be programmed for the GE-701 computer to successfully navigate and control the Boeing B737-100 during landing approach, landing rollout, and turnoff. The report contains flow charts, equations, computer storage, scaling, and word length recommendations for the Kalman filter on the GE-701 Whole Word computer.

  16. Local flow management/profile descent algorithm. Fuel-efficient, time-controlled profiles for the NASA TSRV airplane

    Science.gov (United States)

    Groce, J. L.; Izumi, K. H.; Markham, C. H.; Schwab, R. W.; Thompson, J. L.

    1986-01-01

    The Local Flow Management/Profile Descent (LFM/PD) algorithm designed for the NASA Transport System Research Vehicle program is described. The algorithm provides fuel-efficient altitude and airspeed profiles consistent with ATC restrictions in a time-based metering environment over a fixed ground track. The model design constraints include accommodation of both published profile descent procedures and unpublished profile descents, incorporation of fuel efficiency as a flight profile criterion, operation within the performance capabilities of the Boeing 737-100 airplane with JT8D-7 engines, and conformity to standard air traffic navigation and control procedures. Holding and path stretching capabilities are included for long delay situations.

  17. Micro-cantilever flow sensor for small aircraft

    KAUST Repository

    Ghommem, Mehdi

    2013-10-01

    We extend the use of cantilever beams as flow sensors for small aircraft. As such, we propose a novel method to measure the airspeed and the angle of attack at which the air travels across a small flying vehicle. We measure beam deflections and extract information about the surrounding flow. Thus, we couple a nonlinear beam model with a potential flow simulator through a fluid-structure interaction scheme. We use this numerical approach to generate calibration curves that exhibit the trend for the variations of the limit cycle oscillations amplitudes of flexural and torsional vibrations with the air speed and the angle of attack, respectively. © The Author(s) 2013.

  18. 一种获取飞机RAT带载能力的试飞方法%A Flight Test Method of Determining Airplane RAT's Load Capacity

    Institute of Scientific and Technical Information of China (English)

    刘超强; 马明

    2014-01-01

    The load capacity of airplane's ram air turbine ( RAT) depends not only on airplane airspeed, but al-so on the flight attitude. It is difficult to calculate by using theoretical equations. A flight test method is designed to determine the RAT's real-time load capacity by just analyzing some flight test data obtained. This method plans two test subjects:RAT load capacity test at level flight and RAT load capacity test at sideslip. The former test can obtain the variation of RAT airspeed with airplane airspeed for different weights, and the latter can bring us the re-lationship for different sideslip angles. The results of the two tests show that the RAT airspeed at any weight and flight attitude can be determined and further know its load capacity.%飞机RAT的实际带载能力不仅取决于飞机空度,而且受到飞行姿态的制约,很难用理论公式准确推算。提出了一种飞行试验方法,分析特定的试飞测试数据,可获得飞机RAT的实际带载能力。试验包括RAT平飞带载和RAT侧滑带载两部分试飞。通过RAT平飞带载试验,得到不同重量下的RAT空速与飞机空速的关系曲线;通过RAT侧滑带载试验,可得到不同侧滑角飞行下RAT空速与飞机空速的关系曲线。结合试验结果,可以确定飞机在任意重量和飞行姿态下的RAT空速,进而获知RAT实际带载能力。

  19. Oxides Catalysts of Rare Earth and Transient Metal for Catalytic Oxidation of Benzene

    Institute of Scientific and Technical Information of China (English)

    Liang Kun; Li Rong; Chen Jianjun; Ma Jiantai

    2004-01-01

    The catalysts of CeO2 and the mixture of CeO2 and CuO were prepared, and the activities of these catalysts for completely oxidizing benzene were studied.The results show that the optimal proportion of CeO2/CuO is 6: 4.The highest temperature at which benzene was completely oxidized on these catalysts at different airspeed was measured.Compared these catalysts with the noble metal used, our catalysts had superiority in the resources and the industrial cost besides good activities.

  20. Design study of technology requirements for high performance single-propeller-driven business airplanes

    Science.gov (United States)

    Kohlman, D. L.; Hammer, J.

    1985-01-01

    Developments in aerodyamic, structural and propulsion technologies which influence the potential for significant improvements in performance and fuel efficiency of general aviation business airplanes are discussed. The advancements include such technolgies as natural laminar flow, composite materials, and advanced intermittent combustion engines. The design goal for this parameter design study is a range of 1300 nm at 300 knots true airspeed with a payload of 1200lbs at 35,000 ft cruise altitude. The individual and synergistic effects of various advanced technologies on the optimization of this class of high performance, single engine, propeller driven business airplanes are identified.

  1. Rugged constant-temperature thermal anemometer

    CERN Document Server

    Palma, J

    2016-01-01

    Here we report a robust thermal anemometer which can be easily built. It was conceived to measure outdoor wind speeds, and for airspeed monitoring in wind tunnels and other indoor uses. It works at a constant, low temperature of approximately 90$^\\circ$C, so that an independent measurement of the air temperature is required to give a correct speed reading. Despite the size and high thermal inertia of the probe, the test results show that this anemometer is capable of measuring turbulent fluctuations up to ~100 Hz in winds of ~14 m/s, which corresponds to a scale similar to the length of the probe.

  2. LEWICE3D/GlennHT Particle Analysis of the Honeywell Al502 Low Pressure Compressor

    Science.gov (United States)

    Bidwell, Colin S.; Rigby, David L.

    2015-01-01

    A flow and ice particle trajectory analysis was performed for the booster of the Honeywell AL502 engine. The analysis focused on two closely related conditions one of which produced a rollback and another which did not rollback during testing in the Propulsion Systems Lab at NASA Glenn Research Center. The flow analysis was generated using the NASA Glenn GlennHT flow solver and the particle analysis was generated using the NASA Glenn LEWICE3D v3.56 ice accretion software. The flow and particle analysis used a 3D steady flow, mixing plane approach to model the transport of flow and particles through the engine. The inflow conditions for the rollback case were: airspeed, 145 ms; static pressure, 33,373 Pa; static temperature, 253.3 K. The inflow conditions for the non-roll-back case were: airspeed, 153 ms; static pressure, 34,252 Pa; static temperature, 260.1 K. Both cases were subjected to an ice particle cloud with a median volume diameter of 24 microns, an ice water content of 2.0 gm3 and a relative humidity of 100 percent. The most significant difference between the rollback and non-rollback conditions was the inflow static temperature which was 6.8 K higher for the non-rollback case.

  3. Experiment Description and Results for Arrival Operations Using Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR)

    Science.gov (United States)

    Baxley, Brian T.; Murdoch, Jennifer L.; Swieringa, Kurt A.; Barmore, Bryan E.; Capron, William R.; Hubbs, Clay E.; Shay, Richard F.; Abbott, Terence S.

    2013-01-01

    The predicted increase in the number of commercial aircraft operations creates a need for improved operational efficiency. Two areas believed to offer increases in aircraft efficiency are optimized profile descents and dependent parallel runway operations. Using Flight deck Interval Management (FIM) software and procedures during these operations, flight crews can achieve by the runway threshold an interval assigned by air traffic control (ATC) behind the preceding aircraft that maximizes runway throughput while minimizing additional fuel consumption and pilot workload. This document describes an experiment where 24 pilots flew arrivals into the Dallas Fort-Worth terminal environment using one of three simulators at NASA?s Langley Research Center. Results indicate that pilots delivered their aircraft to the runway threshold within +/- 3.5 seconds of their assigned time interval, and reported low workload levels. In general, pilots found the FIM concept, procedures, speeds, and interface acceptable. Analysis of the time error and FIM speed changes as a function of arrival stream position suggest the spacing algorithm generates stable behavior while in the presence of continuous (wind) or impulse (offset) error. Concerns reported included multiple speed changes within a short time period, and an airspeed increase followed shortly by an airspeed decrease.

  4. 1.5 μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

    Science.gov (United States)

    Augere, B.; Besson, B.; Fleury, D.; Goular, D.; Planchat, C.; Valla, M.

    2016-05-01

    Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains. In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification. This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms‑1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed.

  5. Fuzzy Logic Decoupled Longitudinal Control for General Aviation Airplanes

    Science.gov (United States)

    Duerksen, Noel

    1996-01-01

    It has been hypothesized that a human pilot uses the same set of generic skills to control a wide variety of aircraft. If this is true, then it should be possible to construct an electronic controller which embodies this generic skill set such that it can successfully control difference airplanes without being matched to a specific airplane. In an attempt to create such a system, a fuzzy logic controller was devised to control throttle position and another to control elevator position. These two controllers were used to control flight path angle and airspeed for both a piston powered single engine airplane simulation and a business jet simulation. Overspeed protection and stall protection were incorporated in the form of expert systems supervisors. It was found that by using the artificial intelligence techniques of fuzzy logic and expert systems, a generic longitudinal controller could be successfully used on two general aviation aircraft types that have very difference characteristics. These controllers worked for both airplanes over their entire flight envelopes including configuration changes. The controllers for both airplanes were identical except for airplane specific limits (maximum allowable airspeed, throttle lever travel, etc.). The controllers also handled configuration changes without mode switching or knowledge of the current configuration. This research validated the fact that the same fuzzy logic based controller can control two very different general aviation airplanes. It also developed the basic controller architecture and specific control parameters required for such a general controller.

  6. Evaluation of two cockpit display concepts for civil tiltrotor instrument operations on steep approaches

    Science.gov (United States)

    Decker, William A.; Bray, Richard S.; Simmons, Rickey C.; Tucker, George E.

    1993-01-01

    A piloted simulation experiment was conducted using the NASA Ames Research Center Vertical Motion Simulator to evaluate two cockpit display formats designed for manual control on steep instrument approaches for a civil transport tiltrotor aircraft. The first display included a four-cue (pitch, roll, power lever position, and nacelle angle movement prompt) flight director. The second display format provided instantaneous flight path angle information together with other symbols for terminal area guidance. Pilots evaluated these display formats for an instrument approach task which required a level flight conversion from airplane-mode flight to helicopter-mode flight while decelerating to the nominal approach airspeed. Pilots tracked glide slopes of 6, 9, 15 and 25 degrees, terminating in a hover for a vertical landing on a 150 feet square vertipad. Approaches were conducted with low visibility and ceilings and with crosswinds and turbulence, with all aircraft systems functioning normally and were carried through to a landing. Desired approach and tracking performance was achieved with generally satisfactory handling qualities using either display format on glide slopes up through 15 degrees. Evaluations with both display formats for a 25 degree glide slope revealed serious problems with glide slope tracking at low airspeeds in crosswinds and the loss of the intended landing spot from the cockpit field of view.

  7. Math modeling for helicopter simulation of low speed, low altitude and steeply descending flight

    Science.gov (United States)

    Sheridan, P. F.; Robinson, C.; Shaw, J.; White, F.

    1982-01-01

    A math model was formulated to represent some of the aerodynamic effects of low speed, low altitude, and steeply descending flight. The formulation is intended to be consistent with the single rotor real time simulation model at NASA Ames Research Center. The effect of low speed, low altitude flight on main rotor downwash was obtained by assuming a uniform plus first harmonic inflow model and then by using wind tunnel data in the form of hub loads to solve for the inflow coefficients. The result was a set of tables for steady and first harmonic inflow coefficients as functions of ground proximity, angle of attack, and airspeed. The aerodynamics associated with steep descending flight in the vortex ring state were modeled by replacing the steady induced downwash derived from momentum theory with an experimentally derived value and by including a thrust fluctuations effect due to vortex shedding. Tables of the induced downwash and the magnitude of the thrust fluctuations were created as functions of angle of attack and airspeed.

  8. Collision avoidance in commercial aircraft Free Flight via neural networks and non-linear programming.

    Science.gov (United States)

    Christodoulou, Manolis A; Kontogeorgou, Chrysa

    2008-10-01

    In recent years there has been a great effort to convert the existing Air Traffic Control system into a novel system known as Free Flight. Free Flight is based on the concept that increasing international airspace capacity will grant more freedom to individual pilots during the enroute flight phase, thereby giving them the opportunity to alter flight paths in real time. Under the current system, pilots must request, then receive permission from air traffic controllers to alter flight paths. Understandably the new system allows pilots to gain the upper hand in air traffic. At the same time, however, this freedom increase pilot responsibility. Pilots face a new challenge in avoiding the traffic shares congested air space. In order to ensure safety, an accurate system, able to predict and prevent conflict among aircraft is essential. There are certain flight maneuvers that exist in order to prevent flight disturbances or collision and these are graded in the following categories: vertical, lateral and airspeed. This work focuses on airspeed maneuvers and tries to introduce a new idea for the control of Free Flight, in three dimensions, using neural networks trained with examples prepared through non-linear programming. PMID:18991361

  9. A GPS-Based Pitot-Static Calibration Method Using Global Output-Error Optimization

    Science.gov (United States)

    Foster, John V.; Cunningham, Kevin

    2010-01-01

    Pressure-based airspeed and altitude measurements for aircraft typically require calibration of the installed system to account for pressure sensing errors such as those due to local flow field effects. In some cases, calibration is used to meet requirements such as those specified in Federal Aviation Regulation Part 25. Several methods are used for in-flight pitot-static calibration including tower fly-by, pacer aircraft, and trailing cone methods. In the 1990 s, the introduction of satellite-based positioning systems to the civilian market enabled new inflight calibration methods based on accurate ground speed measurements provided by Global Positioning Systems (GPS). Use of GPS for airspeed calibration has many advantages such as accuracy, ease of portability (e.g. hand-held) and the flexibility of operating in airspace without the limitations of test range boundaries or ground telemetry support. The current research was motivated by the need for a rapid and statistically accurate method for in-flight calibration of pitot-static systems for remotely piloted, dynamically-scaled research aircraft. Current calibration methods were deemed not practical for this application because of confined test range size and limited flight time available for each sortie. A method was developed that uses high data rate measurements of static and total pressure, and GPSbased ground speed measurements to compute the pressure errors over a range of airspeed. The novel application of this approach is the use of system identification methods that rapidly compute optimal pressure error models with defined confidence intervals in nearreal time. This method has been demonstrated in flight tests and has shown 2- bounds of approximately 0.2 kts with an order of magnitude reduction in test time over other methods. As part of this experiment, a unique database of wind measurements was acquired concurrently with the flight experiments, for the purpose of experimental validation of the

  10. Development of a flight data acquisition system for small unmanned aircraft

    Science.gov (United States)

    Hood, Scott

    Current developments surrounding the use of unmanned aerial vehicles have produced a need for a high quality data acquisition platform developed specifically a research environment. This work was undertaken to produce such a system that is low cost, extensible, and better supports fixed wing research through the inclusion of a custom vane based air data probe capable of measuring airspeed, angle of attack, and angle of sideslip. This was accomplished by starting with the open source Pixhawk system as the core and then modifying the device firmware and adding sensors to suit the needs of current aerospace research at OSU. An overview of each component of the system is presented, as well as a description of various firmware modifications to the stock Pixhawk system. Tests were then performed on all of the major sensors using bench testing, wind tunnel analysis, and flight maneuvers to determine the final performance of each part of the system. This research shows that all of the critical sensors on the data acquisition platform produce data acceptable for flight research. The accelerometer has been shown to have an overall tolerance of +/-0.0545 m/s², with +/-0.223 deg/s for the gyroscopic sensor, +/-1.32 hPa for the barometric sensor, +/-0.318 m/s for the airspeed sensor, +/-1.65 °C for the outside air temperature sensor, and +/-0.00115 V for the analog to digital converter. The stock calibration curve for the airspeed sensor was determined to be correct to within +/-0.5 in H2O through wind tunnel testing, and an experimental step input analysis on the flow direction vanes showed that worst case steady state error and time to damp are acceptable for the system. Power spectral density and spectral coherence analysis of flight data was used to show that the custom air data probe is capable of following the flight dynamics of a given aircraft to within a 10 percent tolerance across a range of frequencies. Finally, general performance of the system was proven using

  11. Results of the flight noise measurement program using a standard and modified SH-3A helicopter

    Science.gov (United States)

    Pegg, R. J.; Henderson, H. R.; Hilton, D. A.

    1973-01-01

    A field noise measurement program has been conducted using both a standard SH-3A helicopter and an SH-3A helicopter modified to reduce external noise levels. Modifications included reducing rotor speed, increasing the number of rotor blades, modifying the blade-tip shapes, and acoustically treating the engine air intakes and exhaust. The purpose of this study was to document the noise characteristics recorded on the ground of each helicopter during flyby, hover, landing, and take-off operations. Based on an analysis of the measured results, the average of the overhead, overall, ontrack noise levels was approximately 4 db lower for the modified helicopter than for the standard helicopter. The improved in-flight noise characteristics, and associated small footprint areas and time durations, were judged to be mainly due to tail-rotor noise reductions. The noise reductions were obtained at the expense of required power increases at airspeeds greater than 70 knots for the modified helicopter.

  12. Application of BP neural network for LRAD-based alpha contamination monitoring inside pipes

    International Nuclear Information System (INIS)

    Factors of airspeed, flux, activity, source position, pipe length and pipe diameter affect nonlinearly source activity readout of the Long Range Alpha Detection (LRAD). In this paper, multiparameter influence experiment is carried out using variable-control method, aiming at studying relationships between the readout and each of the factors. The back propagation (BP) neural network model is established to overcome the nonlinear effects of the factors on the readout, with the readout and the multiparameters being the input, and the source activity being the output. Experiment data of 948 groups are used for BP neural network forecasting, with an average relative error of 3.4218×10-4. And in a 100-group test, an average relative error of 2.217×10-2 is obtained. It shows that with this method source radioactivity in pipes can be simulated. (authors)

  13. Minimum Wind Dynamic Soaring Trajectories under Boundary Layer Thickness Limits

    Science.gov (United States)

    Bousquet, Gabriel; Triantafyllou, Michael; Slotine, Jean-Jacques

    2015-11-01

    Dynamic soaring is the flight technique where a glider, either avian or manmade, extracts its propulsive energy from the non-uniformity of horizontal winds. Albatrosses have been recorded to fly an impressive 5000 km/week at no energy cost of their own. In the sharp boundary layer limit, we show that the popular image, where the glider travels in a succession of half turns, is suboptimal for travel speed, airspeed, and soaring ability. Instead, we show that the strategy that maximizes the three criteria simultaneously is a succession of infinitely small arc-circles connecting transitions between the calm and windy layers. The model is consistent with the recordings of albatross flight patterns. This lowers the required wind speed for dynamic soaring by over 50% compared to previous beliefs. In the thick boundary layer limit, energetic considerations allow us to predict a minimum wind gradient necessary for sustained soaring consistent with numerical models.

  14. Radioactive source localization inside pipes using a long-range alpha detector

    Institute of Scientific and Technical Information of China (English)

    WU Xue-Mei; TUO Xian-Guo; LI Zhe; LIU Ming-Zhe; ZHANG Jin-Zhao; DONG Xiang-Long; LI Ping-Chuan

    2013-01-01

    Long-range alpha detectors (LRADs) are attracting much attention in the decommissioning of nuclear facilities because of some problems in obtaining source positions on an interior surface during pipe decommissioning.By utilizing the characteristic that LRAD detects alphas by collecting air-driving ions,this article applies a method to localize the radioactive source by ions' fluid property.By obtaining the ion travel time and the airspeed distribution in the pipe,the source position can be determined.Thus this method overcomes the ion's lack of periodic characteristics.Experimental results indicate that this method can approximately localize the source inside the pipe.The calculation results are in good agreement with the experimental results.

  15. Bifurcation and chaos analysis for aeroelastic airfoil with freeplay structural nonlinearity in pitch

    International Nuclear Information System (INIS)

    The dynamics character of a two degree-of-freedom aeroelastic airfoil with combined freeplay and cubic stiffness nonlinearities in pitch submitted to supersonic and hypersonic flow has been gaining significant attention. The Poincaré mapping method and Floquet theory are adopted to analyse the limit cycle oscillation flutter and chaotic motion of this system. The result shows that the limit cycle oscillation flutter can be accurately predicted by the Floquet multiplier. The phase trajectories of both the pitch and plunge motion are obtained and the results show that the plunge motion is much more complex than the pitch motion. It is also proved that initial conditions have important influences on the dynamics character of the airfoil system. In a certain range of airspeed and with the same system parameters, the stable limit cycle oscillation, chaotic and multi-periodic motions can be detected under different initial conditions. The figure of the Poincaré section also approves the previous conclusion

  16. Discrete optimal control approach to a four-dimensional guidance problem near terminal areas

    Science.gov (United States)

    Nagarajan, N.

    1974-01-01

    Description of a computer-oriented technique to generate the necessary control inputs to guide an aircraft in a given time from a given initial state to a prescribed final state subject to the constraints on airspeed, acceleration, and pitch and bank angles of the aircraft. A discrete-time mathematical model requiring five state variables and three control variables is obtained, assuming steady wind and zero sideslip. The guidance problem is posed as a discrete nonlinear optimal control problem with a cost functional of Bolza form. A solution technique for the control problem is investigated, and numerical examples are presented. It is believed that this approach should prove to be useful in automated air traffic control schemes near large terminal areas.

  17. Long-Duration Low-to Medium-Altitude Solar Electric Airship Concept

    Science.gov (United States)

    Bents, David J.

    2011-01-01

    This report presents the conceptual design for a solar electric lighter-than-air, unmanned aerial vehicle, based on existing technology already reduced to practice, that could carry a 600-kg (1322-lbm) payload to altitudes up to 30 kft (9000 m), continuously maintain an airspeed up to 40 kt (21 m/sec), and remain in flight for up to 100 days. The design is based on modern nonrigid airship technology, high-strength polymer fabrics and barrier films, and previously demonstrated aerospace electrical power technology, including lightweight photovoltaics and hydrogen-air polymer electrolyte membrane (PEM) fuel cells. The vehicle concept exploits the inherent synergy between the use of hydrogen as a lifting gas and the use of hydrogen-air PEM fuel-cell technology for onboard solar energy storage. In this report, the air vehicle concept is physically characterized and its estimated performance envelope is defined

  18. Control response measurements of the Skyship-500 airship

    Science.gov (United States)

    Jex, H. R.; Hogue, J. R.; Gelhausen, P.

    1985-01-01

    An examination is conducted of the Skyship 500's dynamic response to control inputs from elevators, rudders, and throttles at zero, 25, and 40 kts indicated airspeed. Input frequency sweeps were made with pitch and turn controls at 25 and 40 kts, ranging in frequency from about 0.03 to 1.5 Hz. FFT data analysis was then applied to compute describing functions for each run. Frequency responses are noted to be very smooth, and comparisons between repeat runs indicate excellent agreement. Summary plots of the faired describing functions from each run form the core of the data presented. These data constitute a comprehensive and reliable data base on which to predicate future dynamic simulation mathematical models of small airship dynamic response.

  19. Nonlinear Dynamic Modeling of a Fixed-Wing Unmanned Aerial Vehicle: a Case Study of Wulung

    Directory of Open Access Journals (Sweden)

    Fadjar Rahino Triputra

    2015-07-01

    Full Text Available Developing a nonlinear adaptive control system for a fixed-wing unmanned aerial vehicle (UAV requires a mathematical representation of the system dynamics analytically as a set of differential equations in the form of a strict-feedback systems. This paper presents a method for modeling a nonlinear flight dynamics of the fixed-wing UAV of BPPT Wulung in any conditions of the flight altitude and airspeed for the first step into designing a nonlinear adaptive controller. The model was formed into 10-DOF differential equations in the form of strict-feedback systems which separates the terms of elevator, aileron, rudder and throttle from the model. The model simulation results show the behavior of the flight dynamics of the Wulung UAV and also prove the compliance with the actual flight test results.

  20. Flight evaluation of configuration management system concepts during transition to the landing approach for a powered-lift STOL aircraft

    Science.gov (United States)

    Franklin, J. A.; Innis, R. C.

    1980-01-01

    Flight experiments were conducted to evaluate two control concepts for configuration management during the transition to landing approach for a powered-lift STOL aircraft. NASA Ames' augmentor wing research aircraft was used in the program. Transitions from nominal level-flight configurations at terminal area pattern speeds were conducted along straight and curved descending flightpaths. Stabilization and command augmentation for attitude and airspeed control were used in conjunction with a three-cue flight director that presented commands for pitch, roll, and throttle controls. A prototype microwave system provided landing guidance. Results of these flight experiments indicate that these configuration management concepts permit the successful performance of transitions and approaches along curved paths by powered-lift STOL aircraft. Flight director guidance was essential to accomplish the task.

  1. Experimental Methods for UAV Aerodynamic and Propulsion Performance Assessment

    Directory of Open Access Journals (Sweden)

    Stefan ANTON

    2015-06-01

    Full Text Available This paper presents an experimental method for assessing the performances and the propulsion power of a UAV in several points based on telemetry. The points in which we make the estimations are chosen based on several criteria and the fallowing parameters are measured: airspeed, time-to-climb, altitude and the horizontal distance. With the estimated propulsion power and knowing the shaft motor power, the propeller efficiency is determined at several speed values. The shaft motor power was measured in the lab using the propeller as a break. Many flights, using the same UAV configuration, were performed before extracting flight data, in order to reduce the instrumental or statistic errors. This paper highlights both the methodology of processing the data and the validation of theoretical results.

  2. Simulator study of stall/post-stall characteristics of a fighter airplane with relaxed longitudinal static stability. [F-16

    Science.gov (United States)

    Nguyen, L. T.; Ogburn, M. E.; Gilbert, W. P.; Kibler, K. S.; Brown, P. W.; Deal, P. L.

    1979-01-01

    A real-time piloted simulation was conducted to evaluate the high-angle-of-attack characteristics of a fighter configuration based on wind-tunnel testing of the F-16, with particular emphasis on the effects of various levels of relaxed longitudinal static stability. The aerodynamic data used in the simulation was conducted on the Langley differential maneuvering simulator, and the evaluation involved representative low-speed combat maneuvering. Results of the investigation show that the airplane with the basic control system was resistant to the classical yaw departure; however, it was susceptible to pitch departures induced by inertia coupling during rapid, large-amplitude rolls at low airspeed. The airplane also exhibited a deep-stall trim which could be flown into and from which it was difficult to recover. Control-system modifications were developed which greatly decreased the airplane susceptibility to the inertia-coupling departure and which provided a reliable means for recovering from the deep stall.

  3. Intensive probing of clear air convective fields by radar and instrumented drone aircraft.

    Science.gov (United States)

    Rowland, J. R.

    1972-01-01

    Clear air convective fields were probed in three summer experiments (1969, 1970, and 1971) on an S-band monopulse tracking radar at Wallops Island, Virginia, and a drone aircraft with a takeoff weight of 5.2 kg, wingspan of 2.5 m, and cruising glide speed of 10.3 m/sec. The drone was flown 23.2 km north of the radar and carried temperature, pressure/altitude, humidity, and vertical and airspeed velocity sensors. Extensive time-space convective field data were obtained by taking a large number of RHI and PPI pictures at short intervals of time. The rapidly changing overall convective field data obtained from the radar could be related to the meteorological information telemetered from the drone at a reasonably low cost by this combined technique.

  4. A head-up display for mid-air drone recovery

    Science.gov (United States)

    Augustine, W. L.; Heft, E. L.; Bowen, T. E.; Newman, R. L.

    1978-01-01

    During mid-air retrieval of parachute packages, the absence of a natural horizon creates serious difficulties for the pilot of the recovery helicopter. A head-up display (HUD) was tested in an attempt to solve this problem. Both a roll-stabilized HUD and a no-roll (pitch only) HUD were tested. The results show that fewer missed passes occurred with the roll-stabilized HUD when the horizon was obscured. The pilots also reported that the workload was greatly reduced. Roll-stabilization was required to prevent vertigo when flying in the absence of a natural horizon. Any HUD intended for mid-air retrieval should display pitch, roll, sideslip, airspeed, and vertical velocity.

  5. Flight Technical Error Analysis of the SATS Higher Volume Operations Simulation and Flight Experiments

    Science.gov (United States)

    Williams, Daniel M.; Consiglio, Maria C.; Murdoch, Jennifer L.; Adams, Catherine H.

    2005-01-01

    This paper provides an analysis of Flight Technical Error (FTE) from recent SATS experiments, called the Higher Volume Operations (HVO) Simulation and Flight experiments, which NASA conducted to determine pilot acceptability of the HVO concept for normal operating conditions. Reported are FTE results from simulation and flight experiment data indicating the SATS HVO concept is viable and acceptable to low-time instrument rated pilots when compared with today s system (baseline). Described is the comparative FTE analysis of lateral, vertical, and airspeed deviations from the baseline and SATS HVO experimental flight procedures. Based on FTE analysis, all evaluation subjects, low-time instrument-rated pilots, flew the HVO procedures safely and proficiently in comparison to today s system. In all cases, the results of the flight experiment validated the results of the simulation experiment and confirm the utility of the simulation platform for comparative Human in the Loop (HITL) studies of SATS HVO and Baseline operations.

  6. Collective Flow Enhancement by Tandem Flapping Wings

    Science.gov (United States)

    Gravish, Nick; Peters, Jacob M.; Combes, Stacey A.; Wood, Robert J.

    2015-10-01

    We examine the fluid-mechanical interactions that occur between arrays of flapping wings when operating in close proximity at a moderate Reynolds number (Re ≈100 - 1000 ). Pairs of flapping wings are oscillated sinusoidally at frequency f , amplitude θM, phase offset ϕ , and wing separation distance D*, and outflow speed v* is measured. At a fixed separation distance, v* is sensitive to both f and ϕ , and we observe both constructive and destructive interference in airspeed. v* is maximized at an optimum phase offset, ϕmax, which varies with wing separation distance, D*. We propose a model of collective flow interactions between flapping wings based on vortex advection, which reproduces our experimental data.

  7. Dynamic Tow Maneuver Orbital Launch Technique

    Science.gov (United States)

    Rutan, Elbert L. (Inventor)

    2014-01-01

    An orbital launch system and its method of operation use a maneuver to improve the launch condition of a booster rocket and payload. A towed launch aircraft, to which the booster rocket is mounted, is towed to a predetermined elevation and airspeed. The towed launch aircraft begins the maneuver by increasing its lift, thereby increasing the flight path angle, which increases the tension on the towline connecting the towed launch aircraft to a towing aircraft. The increased tension accelerates the towed launch aircraft and booster rocket, while decreasing the speed (and thus the kinetic energy) of the towing aircraft, while increasing kinetic energy of the towed launch aircraft and booster rocket by transferring energy from the towing aircraft. The potential energy of the towed launch aircraft and booster rocket is also increased, due to the increased lift. The booster rocket is released and ignited, completing the launch.

  8. Linear Parameter Varying Model Identification for Control of Rotorcraft-based UAV

    CERN Document Server

    Budiyono, Agus

    2008-01-01

    A rotorcraft-based unmanned aerial vehicle exhibits more complex properties compared to its full-size counterparts due to its increased sensitivity to control inputs and disturbances and higher bandwidth of its dynamics. As an aerial vehicle with vertical take-off and landing capability, the helicopter specifically poses a difficult problem of transition between forward flight and unstable hover and vice versa. The LPV control technique explicitly takes into account the change in performance due to the real-time parameter variations. The technique therefore theoretically guarantees the performance and robustness over the entire operating envelope. In this study, we investigate a new approach implementing model identification for use in the LPV control framework. The identification scheme employs recursive least square technique implemented on the LPV system represented by dynamics of helicopter during a transition. The airspeed as the scheduling of parameter trajectory is not assumed to vary slowly. The exclu...

  9. Performance Enhancement of a Full-Scale Vertical Tail Model Equipped with Active Flow Control

    Science.gov (United States)

    Whalen, Edward A.; Lacy, Douglas; Lin, John C.; Andino, Marlyn Y.; Washburn, Anthony E.; Graff, Emilio; Wygnanski, Israel J.

    2015-01-01

    This paper describes wind tunnel test results from a joint NASA/Boeing research effort to advance active flow control (AFC) technology to enhance aerodynamic efficiency. A full-scale Boeing 757 vertical tail model equipped with sweeping jet actuators was tested at the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The model was tested at a nominal airspeed of 100 knots and across rudder deflections and sideslip angles that covered the vertical tail flight envelope. A successful demonstration of AFC-enhanced vertical tail technology was achieved. A 31- actuator configuration significantly increased side force (by greater than 20%) at a maximum rudder deflection of 30deg. The successful demonstration of this application has cleared the way for a flight demonstration on the Boeing 757 ecoDemonstrator in 2015.

  10. Rotorcraft control system design for uncertain vehicle dynamics using quantitative feedback theory

    Science.gov (United States)

    Hess, R. A.

    1994-01-01

    Quantitative Feedback Theory describes a frequency-domain technique for the design of multi-input, multi-output control systems which must meet time or frequency domain performance criteria when specified uncertainty exists in the linear description of the vehicle dynamics. This theory is applied to the design of the longitudinal flight control system for a linear model of the BO-105C rotorcraft. Uncertainty in the vehicle model is due to the variation in the vehicle dynamics over a range of airspeeds from 0-100 kts. For purposes of exposition, the vehicle description contains no rotor or actuator dynamics. The design example indicates the manner in which significant uncertainty exists in the vehicle model. The advantage of using a sequential loop closure technique to reduce the cost of feedback is demonstrated by example.

  11. The Duke University Helicopter Observation Platform (HOP) for Environmental and Earth Science Studies

    Science.gov (United States)

    Avissar, R.; Holder, H. E.; Bolch, A.

    2006-12-01

    Duke University purchased a new Bell 206B3 ("JetRanger") helicopter to perform various atmospheric in situ and remotely-sensed environmental observations (referred to as the Helicopter Observation Platform HOP). As compared to other aircraft, the helicopter has the unequaled flexibility and maneuverability to fly slowly and close to the ground. Furthermore, it can land and refuel at station, which allows performing long-term observations during field campaigns. It can also operate from a ship at sea. This presents significant advantages especially for the observations of aerosols, fluxes of heat, water and other gases important for various environmental and Earth science studies. The Duke HOP is currently equipped with high-frequency sensors that can measure the 3D components of the wind, temperature, moisture and CO2. It is also equipped with an inlet to sample undisturbed air outside of the zone of influence of the main rotor wake and it is designed to support many other remote and in-situ sensors. A computational fluid dynamics (CFD) software was used to simulate the aerodynamical envelope of the HOP in flight at various airspeeds. Together with in- situ observations of turbulence in front of the helicopter nose where all the sensors are attached, the CFD results are used to demonstrate that the HOP can make high-quality observations of the above-mentioned environmental characteristics unaffected by the main-rotor wake at airspeeds as low as 15 m/s and as high as 60 m/s. This emphasizes the strong potential of this platform for environmental observations, especially of aerosols, which are sampled very inefficiently with other aircraft platforms. Flights conducted in the Neuse River Basin in North Carolina where atmospheric variables were collected simultaneously with a tethered sonde, a lidar, and on towers demonstrate the HOP capability and potential.

  12. Research on automatic landing control for high span-chord ratio UAV in crosswind%大展弦比无人机抗侧风着陆控制研究

    Institute of Scientific and Technical Information of China (English)

    宋辉; 陈欣; 李春涛

    2011-01-01

    As one of the most complex phases in whole flight process, a high span-chord UAV is extremely sensitive to crosswind because of its low airspeed during landing. Through analyzing the influence of crosswind on flight performance of the sample UAV during landing phase, this essay puts forward some methods to enhance the control performance during automatic landing by optimizing the landing trajectory, controlling the airspeed and improving the longitudinal and lateral control strategy. Finally, simulation results show that the landing trajectory is reasonable , the automatic landing control strategy is valid and the control law is correct, which satisfy the demands of the automatic landing control under the crosswind conditions.%大展弦比无人机进场着陆过程中速度较低,对侧风十分敏感,是飞行过程中控制最复杂的阶段之一.通过分析侧风条件对样例无人机着陆过程的影响,提出了通过优化设计着陆轨迹线、控制空速以及完善纵横向控制策略的方法来改善侧风条件下大展弦比无人机自动着陆的控制品质.仿真结果表明,所设计的自动着陆轨迹线合理,控制策略完备,控制律品质良好,满足样例无人机在侧风条件下自动着陆控制的设计要求.

  13. 1.5 μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

    International Nuclear Information System (INIS)

    Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains. In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification. This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms−1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed. (special issue article)

  14. A wing-assisted running robot and implications for avian flight evolution

    International Nuclear Information System (INIS)

    DASH+Wings is a small hexapedal winged robot that uses flapping wings to increase its locomotion capabilities. To examine the effects of flapping wings, multiple experimental controls for the same locomotor platform are provided by wing removal, by the use of inertially similar lateral spars, and by passive rather than actively flapping wings. We used accelerometers and high-speed cameras to measure the performance of this hybrid robot in both horizontal running and while ascending inclines. To examine consequences of wing flapping for aerial performance, we measured lift and drag forces on the robot at constant airspeeds and body orientations in a wind tunnel; we also determined equilibrium glide performance in free flight. The addition of flapping wings increased the maximum horizontal running speed from 0.68 to 1.29 m s−1, and also increased the maximum incline angle of ascent from 5.6° to 16.9°. Free flight measurements show a decrease of 10.3° in equilibrium glide slope between the flapping and gliding robot. In air, flapping improved the mean lift:drag ratio of the robot compared to gliding at all measured body orientations and airspeeds. Low-amplitude wing flapping thus provides advantages in both cursorial and aerial locomotion. We note that current support for the diverse theories of avian flight origins derive from limited fossil evidence, the adult behavior of extant flying birds, and developmental stages of already volant taxa. By contrast, addition of wings to a cursorial robot allows direct evaluation of the consequences of wing flapping for locomotor performance in both running and flying.

  15. Technical Findings, Lessons Learned, and Recommendations Resulting from the Helios Prototype Vehicle Mishap

    Science.gov (United States)

    Noll, Thomas E.; Ishmael, Stephen D.; Henwood, Bart; Perez-Davis, Marla E.; Tiffany, Geary C.; Madura, John; Gaier, Matthew; Brown, John M.; Wierzbanowski, Ted

    2007-01-01

    The Helios Prototype was originally planned to be two separate vehicles, but because of resource limitations only one vehicle was developed to demonstrate two missions. The vehicle consisted of two configurations, one for each mission. One configuration, designated HP01, was designed to operate at extremely high altitudes using batteries and high-efficiency solar cells spread across the upper surface of its 247-foot wingspan. On August 13, 2001, the HP01 configuration reached an altitude of 96,863 feet, a world record for sustained horizontal flight by a winged aircraft. The other configuration, designated HP03, was designed for long-duration flight. The plan was to use the solar cells to power the vehicle's electric motors and subsystems during the day and to use a modified commercial hydrogen-air fuel cell system for use during the night. The aircraft design used wing dihedral, engine power, elevator control surfaces, and a stability augmentation and control system to provide aerodynamic stability and control. At about 30 minutes into the second flight of HP03, the aircraft encountered a disturbance in the way of turbulence and morphed into an unexpected, persistent, high dihedral configuration. As a result of the persistent high dihedral, the aircraft became unstable in a very divergent pitch mode in which the airspeed excursions from the nominal flight speed about doubled every cycle of the oscillation. The aircraft s design airspeed was subsequently exceeded and the resulting high dynamic pressures caused the wing leading edge secondary structure on the outer wing panels to fail and the solar cells and skin on the upper surface of the wing to rip away. As a result, the vehicle lost its ability to maintain lift, fell into the Pacific Ocean within the confines of the U.S. Navy's Pacific Missile Range Facility, and was destroyed. This paper describes the mishap and its causes, and presents the technical recommendations and lessons learned for improving the design

  16. Dynamics of air temperature, velocity and ammonia emissions in enclosed and conventional pig housing systems.

    Science.gov (United States)

    Song, J I; Park, K-H; Jeon, J H; Choi, H L; Barroga, A J

    2013-03-01

    This study aimed to compare the dynamics of air temperature and velocity under two different ventilation and housing systems during summer and winter in Korea. The NH3 concentration of both housing systems was also investigated in relation to the pig's growth. The ventilation systems used were; negative pressure type for the enclosed pig house (EPH) and natural airflow for the conventional pig house (CPH). Against a highly fluctuating outdoor temperature, the EPH was able to maintain a stable temperature at 24.8 to 29.1°C during summer and 17.9 to 23.1°C during winter whilst the CPH had a wider temperature variance during summer at 24.7 to 32.3°C. However, the temperature fluctuation of the CPH during winter was almost the same with that of EPH at 14.5 to 18.2°C. The NH3 levels in the CPH ranged from 9.31 to 16.9 mg/L during summer and 5.1 to 19.7 mg/L during winter whilst that of the EPH pig house was 7.9 to 16.1 mg/L and 3.7 to 9.6 mg/L during summer and winter, respectively. These values were less than the critical ammonia level for pigs with the EPH maintaining a lower level than the CPH in both winter and summer. The air velocity at pig nose level in the EPH during summer was 0.23 m/s, enough to provide comfort because of the unique design of the inlet feature. However, no air movement was observed in almost all the lower portions of the CPH during winter because of the absence of an inlet feature. There was a significant improvement in weight gain and feed intake of pigs reared in the EPH compared to the CPH (phousing systems, a stable indoor temperature was necessary to minimize the impact of an avoidable and highly fluctuating outdoor temperature. The EPH consistently maintained an effective indoor airspeed irrespective of season; however the CPH had defective and stagnant air at pig nose level during winter. Characteristics of airflow direction and pattern were consistent relative to housing system during both summer and winter but not of airspeed. The

  17. A characterization of autumn nocturnal migration detected by weather surveillance radars in the northeastern USA.

    Science.gov (United States)

    Farnsworth, Andrew; Van DOREN, Benjamin M; Hochachka, Wesley M; Sheldon, Daniel; Winner, Kevin; Irvine, Jed; Geevarghese, Jeffrey; Kelling, Steve

    2016-04-01

    Billions of birds migrate at night over North America each year. However, few studies have described the phenology of these movements, such as magnitudes, directions, and speeds, for more than one migration season and at regional scales. In this study, we characterize density, direction, and speed of nocturnally migrating birds using data from 13 weather surveillance radars in the autumns of 2010 and 2011 in the northeastern USA. After screening radar data to remove precipitation, we applied a recently developed algorithm for characterizing velocity profiles with previously developed methods to document bird migration. Many hourly radar scans contained windborne "contamination," and these scans also exhibited generally low overall reflectivities. Hourly scans dominated by birds showed nightly and seasonal patterns that differed markedly from those of low reflectivity scans. Bird migration occurred during many nights, but a smaller number of nights with large movements of birds defined regional nocturnal migration. Densities varied by date, time, and location but peaked in the second and third deciles of night during the autumn period when the most birds were migrating. Migration track (the direction to which birds moved) shifted within nights from south-southwesterly to southwesterly during the seasonal migration peaks; this shift was not consistent with a similar shift in wind direction. Migration speeds varied within nights, although not closely with wind speed. Airspeeds increased during the night; groundspeeds were highest between the second and third deciles of night, when the greatest density of birds was migrating. Airspeeds and groundspeeds increased during the fall season, although groundspeeds fluctuated considerably with prevailing winds. Significant positive correlations characterized relationships among bird densities at southern coastal radar stations and northern inland radar stations. The quantitative descriptions of broadscale nocturnal migration

  18. A hybrid thermal management system for lithium ion batteries combining phase change materials with forced-air cooling

    International Nuclear Information System (INIS)

    Highlights: • Heat accumulation in PCM causes failures of passive thermal management systems. • The introduction of forced air convection improves the reliability of PCMs. • Temperature distribution in the hybrid system remains uniform. • Active cooling and PCMs play separate roles in battery thermal management. • Numerical results agree with experiment data and give theoretic insights. - Abstract: Passive thermal management systems using phase change materials (PCMs) provides an effective solution to the overheating of lithium ion batteries. But this study shows heat accumulation in PCMs caused by the inefficient cooling of air natural convection leads to thermal management system failures: The temperature in a battery pack operating continuously outranges the safety limit of 60 °C after two cycles with discharge rate of 1.5 C and 2 C. Here a hybrid system that integrates PCMs with forced air convection is presented. This combined system successfully prevents heat accumulation and maintains the maximum temperature under 50 °C in all cycles. Study on airspeed effects reveals that thermo-physical properties of PCMs dictate the maximum temperature rise and temperature uniformity in the battery pack, while forced air convection plays a critical role in recovering thermal energy storage capacity of PCMs. A numerical study is also carried out and validated with experiment data, which gives theoretic insights on thermo-physical changes in this hybrid battery thermal management system

  19. Turbulent dispersivity under conditions relevant to airborne disease transmission between laboratory animals

    Science.gov (United States)

    Halloran, Siobhan; Wexler, Anthony; Ristenpart, William

    2014-11-01

    Virologists and other researchers who test pathogens for airborne disease transmissibility often place a test animal downstream from an inoculated animal and later determine whether the test animal became infected. Despite the crucial role of the airflow in modulating the pathogen transmission, to date the infectious disease community has paid little attention to the effect of airspeed or turbulence intensity on the probability of transmission. Here we present measurements of the turbulent dispersivity under conditions relevant to experimental tests of airborne disease transmissibility between laboratory animals. We used time lapse photography to visualize the downstream transport and turbulent dispersion of smoke particulates released from a point source downstream of a standard axial fan, thus mimicking the release and transport of expiratory aerosols exhaled by an inoculated animal. We demonstrate that the fan speed counterintuitively has no effect on the downstream plume width, a result replicated with a variety of different fan types and configurations. The results point toward a useful simplification in modeling of airborne disease transmission via fan-generated flows.

  20. Experiments on the fluid dynamics of the human cough

    Science.gov (United States)

    Settles, Gary

    2011-11-01

    Human coughing is studied non-intrusively by high-speed schlieren videography, revealing a turbulent jet lasting up to 1 sec with a total expelled air volume of about 2 L. Velocimetry of eddy motion reveals a jet centerline airspeed of at least 8 m/sec. With Re roughly 18,000 the cough jet is inertia-driven and buoyancy is negligible. It shows typical round-turbulent-jet behavior, including a conical spreading angle of 24 deg, despite irregular initial conditions. The cough jet is projected several m into the surrounding air before it mixes out. It is well known that a cough can transmit infectious agents, and we are advised to cover our mouths in an apparent attempt to thwart the jet formation. Present experiments have shown that wearing a surgical mask or respirator designed to prevent the inhalation of infectious agents also interferes with the cough-jet formation, redirecting it into the person's rising thermal plume. (Tang et al., J. Royal. Soc. Interface 6, S727, 2009.)

  1. IN-FLIGHT ICING CHARACTERISTICS OF UNMANNED AERIAL VEHICLES DURING SPECIAL ATMOSPHERIC CONDITION OVER THE CARPATHIAN-BASIN

    Directory of Open Access Journals (Sweden)

    ZSOLT BOTTYÁN

    2013-01-01

    Full Text Available The in-flight aerial icing phenomena is very important for the Unmanned Aerial Vehicles (UAV because it causes some serious problems such as reduced lift and increased drag forces, significantly decreased angle of attack, increased weight, structural imbalances and improper radio communications. In order to increase flight safety of UAV’s we develop an integrated meteorological support system for the UAV pilots, mission controllers and decision makers, too. In our paper we show the in-flight structural icing estimation method as a part of this support system based on a simple 2D ice accretion model predictions. We point out the role of the ambient air temperature, cloud liquid water content, airfoil geometry and mainly the true airspeed in the icing process on the wings of UAVs. With the help of our model we made an estimation of geometry and amount of ice accretion on the wing of a short-range and a high-altitude and long-endurance UAVs during a hypothetical flight under a typical icy weather situation with St clouds over the Carpathian-basin (a cold-pool situation case study. Finally we point out that our icing estimation system can easily be adapted for supporting the missions of UAVs.

  2. Boeing Smart Rotor Full-scale Wind Tunnel Test Data Report

    Science.gov (United States)

    Kottapalli, Sesi; Hagerty, Brandon; Salazar, Denise

    2016-01-01

    A full-scale helicopter smart material actuated rotor technology (SMART) rotor test was conducted in the USAF National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel at NASA Ames. The SMART rotor system is a five-bladed MD 902 bearingless rotor with active trailing-edge flaps. The flaps are actuated using piezoelectric actuators. Rotor performance, structural loads, and acoustic data were obtained over a wide range of rotor shaft angles of attack, thrust, and airspeeds. The primary test objective was to acquire unique validation data for the high-performance computing analyses developed under the Defense Advanced Research Project Agency (DARPA) Helicopter Quieting Program (HQP). Other research objectives included quantifying the ability of the on-blade flaps to achieve vibration reduction, rotor smoothing, and performance improvements. This data set of rotor performance and structural loads can be used for analytical and experimental comparison studies with other full-scale rotor systems and for analytical validation of computer simulation models. The purpose of this final data report is to document a comprehensive, highquality data set that includes only data points where the flap was actively controlled and each of the five flaps behaved in a similar manner.

  3. Reduced In-Plane, Low Frequency Helicopter Noise of an Active Flap Rotor

    Science.gov (United States)

    Sim, Ben W.; Janakiram, Ram D.; Barbely, Natasha L.; Solis, Eduardo

    2009-01-01

    Results from a recent joint DARPA/Boeing/NASA/Army wind tunnel test demonstrated the ability to reduce in-plane, low frequency noise of the full-scale Boeing-SMART rotor using active flaps. Test data reported in this paper illustrated that acoustic energy in the first six blade-passing harmonics could be reduced by up to 6 decibels at a moderate airspeed, level flight condition corresponding to advance ratio of 0.30. Reduced noise levels were attributed to selective active flap schedules that modified in-plane blade airloads on the advancing side of the rotor, in a manner, which generated counteracting acoustic pulses that partially offset the negative pressure peaks associated with in-plane, steady thickness noise. These favorable reduced-noise operating states are a strong function of the active flap actuation amplitude, frequency and phase. The associated noise reductions resulted in reduced aural detection distance by up to 18%, but incurred significant vibratory load penalties due to increased hub shear forces. Small reductions in rotor lift-to-drag ratios, of no more than 3%, were also measured

  4. Measurement and Characterization of Helicopter Noise at Different Altitudes

    Science.gov (United States)

    Watts, Michael E.; Greenwood, Eric; Stephenson, James

    2016-01-01

    This paper presents an overview of a flight test campaign performed at different test sites whose altitudes ranged from 0 to 7000 feet above mean sea level (AMSL) between September 2014 and February 2015. The purposes of this campaign were to: investigate the effects of altitude variation on noise generation, investigate the effects of gross weight variation on noise generation, establish the statistical variability in acoustic flight testing of helicopters, and characterize the effects of transient maneuvers on radiated noise for a medium-lift utility helicopter. In addition to describing the test campaign, results of the acoustic effects of altitude variation for the AS350 SD1 and EH-60L aircraft are presented. Large changes in acoustic amplitudes were observed in response to changes in ambient conditions when the helicopter was flown at constant indicated airspeed and gross weight at the three test sites. However, acoustic amplitudes were found to scale with ambient pressure when flight conditions were defined in terms of the non-dimensional parameters, such as the weight coefficient and effective hover tip Mach number.

  5. Drag on Sessile Drops

    Science.gov (United States)

    Milne, Andrew J. B.; Fleck, Brian; Nobes, David; Sen, Debjyoti; Amirfazli, Alidad; University of Alberta Mechanical Engineering Collaboration

    2013-11-01

    We present the first ever direct measurements of the coefficient of drag on sessile drops at Reynolds numbers from the creeping flow regime up to the point of incipient motion, made using a newly developed floating element differential drag sensor. Surfaces of different wettabilities (PMMA, Teflon, and a superhydrophobic surface (SHS)), wet by water, hexadecane, and various silicone oils, are used to study the effects of drop shape, and fluid properties on drag. The relation between drag coefficient and Reynolds number (scaled by drop height) varies slightly with liquid-solid system and drop volume with results suggesting the drop experiences increased drag compared to similar shaped solid bodies due to drop oscillation influencing the otherwise laminar flow. Drops adopting more spherical shapes are seen to experience the greatest force at any given airspeed. This indicates that the relative exposed areas of drops is an important consideration in terms of force, with implications for the shedding of drops in applications such as airfoil icing and fuel cell flooding. The measurement technique used in this work can be adapted to measure drag force on other deformable, lightly adhered objects such as dust, sand, snow, vesicles, foams, and biofilms. The authours acknowledge NSERC, Alberta Innovates Technology Futures, and the Killam Trusts.

  6. TRAGEN: Computer program to simulate an aircraft steered to follow a specified verticle profile. User's guide

    Science.gov (United States)

    1983-01-01

    The longitudinal dynamics of a medium range twin-jet or tri-jet transport aircraft are simulated. For the climbing trajectory, the thrust is constrained to maximum value, and for descent, the thrust is set at idle. For cruise, the aircraft is held in the trim condition. For climb or descent, the aircraft is steered to follow either (a) a fixed profile which is input to the program or (b) a profile computed at the beginning of that segment of the run. For climb, the aircraft is steered to maintain the given airspeed as a function of altitude. For descent, the aircraft is steered to maintain the given altitude as a function of range-to-go. In both cases, the control variable is angle-of-attack. The given output trajectory is presented and compared with the input trajectory. Step climb is treated just as climb. For cruise, the Breguet equations are used to compute the fuel burned to achieve a given range and to connect given initial and final values of altitude and Mach number.

  7. Effects of Self-Instructional Methods and Above Real Time Training (ARTT) for Maneuvering Tasks on a Flight Simulator

    Science.gov (United States)

    Ali, Syed Firasat; Khan, Javed Khan; Rossi, Marcia J.; Crane, Peter; Heath, Bruce E.; Knighten, Tremaine; Culpepper, Christi

    2003-01-01

    Personal computer based flight simulators are expanding opportunities for providing low-cost pilot training. One advantage of these devices is the opportunity to incorporate instructional features into training scenarios that might not be cost effective with earlier systems. Research was conducted to evaluate the utility of different instructional features using a coordinated level turn as an aircraft maneuvering task. In study I, a comparison was made between automated computer grades of performance with certified flight instructors grades. Every one of the six student volunteers conducted a flight with level turns at two different bank angles. The automated computer grades were based on prescribed tolerances on bank angle, airspeed and altitude. Two certified flight instructors independently examined the video tapes of heads up and instrument displays of the flights and graded them. The comparison of automated grades with the instructors grades was based on correlations between them. In study II, a 2x2 between subjects factorial design was used to devise and conduct an experiment. Comparison was made between real time training and above real time training and between feedback and no feedback in training. The performance measure to monitor progress in training was based on deviations in bank angle and altitude. The performance measure was developed after completion of the experiment including the training and test flights. It was not envisaged before the experiment. The experiment did not include self- instructions as it was originally planned, although feedback by experimenter to the trainee was included in the study.

  8. The Effects of Ambient Conditions on Helicopter Harmonic Noise Radiation: Theory and Experiment

    Science.gov (United States)

    Greenwood, Eric; Sim, Ben W.; Boyd, D. Douglas, Jr.

    2016-01-01

    The effects of ambient atmospheric conditions, air temperature and density, on rotor harmonic noise radiation are characterized using theoretical models and experimental measurements of helicopter noise collected at three different test sites at elevations ranging from sea level to 7000 ft above sea level. Significant changes in the thickness, loading, and blade-vortex interaction noise levels and radiation directions are observed across the different test sites for an AS350 helicopter flying at the same indicated airspeed and gross weight. However, the radiated noise is shown to scale with ambient pressure when the flight condition of the helicopter is defined in nondimensional terms. Although the effective tip Mach number is identified as the primary governing parameter for thickness noise, the nondimensional weight coefficient also impacts lower harmonic loading noise levels, which contribute strongly to low frequency harmonic noise radiation both in and out of the plane of the horizon. Strategies for maintaining the same nondimensional rotor operating condition under different ambient conditions are developed using an analytical model of single main rotor helicopter trim and confirmed using a CAMRAD II model of the AS350 helicopter. The ability of the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique to generalize noise measurements made under one set of ambient conditions to make accurate noise predictions under other ambient conditions is also validated.

  9. Whiskers aid anemotaxis in rats

    Science.gov (United States)

    Yu, Yan S. W.; Graff, Matthew M.; Bresee, Chris S.; Man, Yan B.; Hartmann, Mitra J. Z.

    2016-01-01

    Observation of terrestrial mammals suggests that they can follow the wind (anemotaxis), but the sensory cues underlying this ability have not been studied. We identify a significant contribution to anemotaxis mediated by whiskers (vibrissae), a modality previously studied only in the context of direct tactile contact. Five rats trained on a five-alternative forced-choice airflow localization task exhibited significant performance decrements after vibrissal removal. In contrast, vibrissal removal did not disrupt the performance of control animals trained to localize a light source. The performance decrement of individual rats was related to their airspeed threshold for successful localization: animals that found the task more challenging relied more on the vibrissae for localization cues. Following vibrissal removal, the rats deviated more from the straight-line path to the air source, choosing sources farther from the correct location. Our results indicate that rats can perform anemotaxis and that whiskers greatly facilitate this ability. Because air currents carry information about both odor content and location, these findings are discussed in terms of the adaptive significance of the interaction between sniffing and whisking in rodents. PMID:27574705

  10. An inventory of aeronautical ground research facilities. Volume 2: Air breathing engine test facilities

    Science.gov (United States)

    Pirrello, C. J.; Hardin, R. D.; Heckart, M. V.; Brown, K. R.

    1971-01-01

    The inventory covers free jet and direct connect altitude cells, sea level static thrust stands, sea level test cells with ram air, and propulsion wind tunnels. Free jet altitude cells and propulsion wind tunnels are used for evaluation of complete inlet-engine-exhaust nozzle propulsion systems under simulated flight conditions. These facilities are similar in principal of operation and differ primarily in test section concept. The propulsion wind tunnel provides a closed test section and restrains the flow around the test specimen while the free jet is allowed to expand freely. A chamber of large diameter about the free jet is provided in which desired operating pressure levels may be maintained. Sea level test cells with ram air provide controlled, conditioned air directly to the engine face for performance evaluation at low altitude flight conditions. Direct connect altitude cells provide a means of performance evaluation at simulated conditions of Mach number and altitude with air supplied to the flight altitude conditions. Sea level static thrust stands simply provide an instrumented engine mounting for measuring thrust at zero airspeed. While all of these facilities are used for integrated engine testing, a few provide engine component test capability.

  11. Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

    Science.gov (United States)

    Reehorst, Andrew; Brinker, David

    2010-01-01

    The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

  12. Flight Management System Execution of Idle-Thrust Descents in Operations

    Science.gov (United States)

    Stell, Laurel L.

    2011-01-01

    To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the trajectory predictor and its error models, commercial flights executed idle-thrust descents, and the recorded data includes the target speed profile and FMS intent trajectories. The FMS computes the intended descent path assuming idle thrust after top of descent (TOD), and any intervention by the controllers that alters the FMS execution of the descent is recorded so that such flights are discarded from the analysis. The horizontal flight path, cruise and meter fix altitudes, and actual TOD location are extracted from the radar data. Using more than 60 descents in Boeing 777 aircraft, the actual speeds are compared to the intended descent speed profile. In addition, three aspects of the accuracy of the FMS intent trajectory are analyzed: the meter fix crossing time, the TOD location, and the altitude at the meter fix. The actual TOD location is within 5 nmi of the intent location for over 95% of the descents. Roughly 90% of the time, the airspeed is within 0.01 of the target Mach number and within 10 KCAS of the target descent CAS, but the meter fix crossing time is only within 50 sec of the time computed by the FMS. Overall, the aircraft seem to be executing the descents as intended by the designers of the onboard automation.

  13. Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

    Directory of Open Access Journals (Sweden)

    A. R. Rodi

    2012-05-01

    Full Text Available Geometric altitude data from a combined Global Navigation Satellite System (GNSS and inertial measurement unit (IMU system on the University of Wyoming King Air research aircraft are used to estimate acceleration effects on static pressure measurement. Using data collected during periods of accelerated flight, comparison of measured pressure with that derived from GNSS/IMU geometric altitude show that errors exceeding 150 Pa can occur which is significant in airspeed and atmospheric air motion determination. A method is developed to predict static pressure errors from analysis of differential pressure measurements from a Rosemount model 858 differential pressure air velocity probe. The method was evaluated with a carefully designed probe towed on connecting tubing behind the aircraft – a "trailing cone" – in steady flight, and shown to have a precision of about ±10 Pa over a wide range of conditions including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, compared to the GNSS/IMU data, this algorithm predicts corrections to a precision of better than ±20 Pa. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are examined.

  14. Flight Test Results of a GPS-Based Pitot-Static Calibration Method Using Output-Error Optimization for a Light Twin-Engine Airplane

    Science.gov (United States)

    Martos, Borja; Kiszely, Paul; Foster, John V.

    2011-01-01

    As part of the NASA Aviation Safety Program (AvSP), a novel pitot-static calibration method was developed to allow rapid in-flight calibration for subscale aircraft while flying within confined test areas. This approach uses Global Positioning System (GPS) technology coupled with modern system identification methods that rapidly computes optimal pressure error models over a range of airspeed with defined confidence bounds. This method has been demonstrated in subscale flight tests and has shown small 2- error bounds with significant reduction in test time compared to other methods. The current research was motivated by the desire to further evaluate and develop this method for full-scale aircraft. A goal of this research was to develop an accurate calibration method that enables reductions in test equipment and flight time, thus reducing costs. The approach involved analysis of data acquisition requirements, development of efficient flight patterns, and analysis of pressure error models based on system identification methods. Flight tests were conducted at The University of Tennessee Space Institute (UTSI) utilizing an instrumented Piper Navajo research aircraft. In addition, the UTSI engineering flight simulator was used to investigate test maneuver requirements and handling qualities issues associated with this technique. This paper provides a summary of piloted simulation and flight test results that illustrates the performance and capabilities of the NASA calibration method. Discussion of maneuver requirements and data analysis methods is included as well as recommendations for piloting technique.

  15. The effects of aeroelastic deformation on the unaugmented stopped-rotor dynamics of an X-Wing aircraft

    Science.gov (United States)

    Gilbert, Michael G.; Silva, Walter A.

    1987-01-01

    A new design concept in the development of VTOL aircraft with high forward flight speed capability is that of the X-Wing, a stiff, bearingless helicopter rotor system which can be stopped in flight and the blades used as two forward-swept and two aft-swept wings. Because of the usual configuration in the fixed-wing mode, there is a high potential for aeroelastic divergence or flutter and coupling of blade vibration modes with rigid-body modes. An aeroelastic stability analysis of an X-Wing configuration aircraft was undertaken to determine if these problems could exist. This paper reports on the results of dynamic stability analyses in the lateral and longitudinal directions including the vehicle rigid-body and flexible modes. A static aeroelastic analysis using the normal vibration mode equations of motion was performed to determine the cause of a loss of longitudinal static margin with increasing airspeed. This loss of static margin was found to be due to aeroelastic washin of the forward-swept blades and washout of the aft-swept blades moving the aircraft aerodynamic center forward of the center of gravity. This phenomenon is likely to be generic to X-Wing aircraft.

  16. Aeroelastic behavior of twist-coupled HAWT blades

    Energy Technology Data Exchange (ETDEWEB)

    Lobitz, D.W.; Veers, P.S.

    1998-12-31

    As the technology for horizontal axis wind turbines (HAWT) development matures, more novel techniques are required for the capture of additional amounts of energy, alleviation of loads and control of the rotor. One such technique employs the use of an adaptive blade that could sense the wind velocity or rotational speed in some fashion and accordingly modify its aerodynamic configuration to meet a desired objective. This could be achieved in either an active or passive manner, although the passive approach is much more attractive due to its simplicity and economy. As an example, a blade design might employ coupling between bending and/or extension, and twisting so that, as it bends and extends due to the action of the aerodynamic and inertial loads, it also twists modifying the aerodynamic performance in some way. These performance modifications also have associated aeroelastic effects, including effects on aeroelastic instability. To address the scope and magnitude of these effects a tool has been developed for investigating classical flutter and divergence of HAWT blades. As a starting point, an adaptive version of the uniform Combined Experiment Blade will be investigated. Flutter and divergence airspeeds will be reported as a function of the strength of the coupling and also be compared to those of generic blade counterparts.

  17. The feasibility of a high-altitude aircraft platform with consideration of technological and societal constraints. Thesis - Kansas Univ.

    Science.gov (United States)

    Graves, E. B.

    1982-01-01

    The feasibility of remotely piloted aircraft performing year around missions at an altitude of 70,000 feet is determined. Blimp and airplane type vehicles employing solar-voltaic, microwave, or nuclear propulsion systems were considered. A payload weighing 100 pounds and requiring 1000 watts of continuous power was assumed for analysis purposes. Results indicate that a solar powered aircraft requires more solar cell area than is available on conventional aircraft configurations if designed for the short days and high wind speeds associated with the winter season. A conventionally shaped blimp that uses solar power appears feasible if maximum airspeed is limited to about 100 ft/s. No viable airplane configuration that uses solar power and designed to withstand the winter environment was found. Both a conventionally shaped blimp and airplane appear feasible using microwave power. Nuclear powered aircraft of these type are also feasible. Societal attitudes toward the use of solar power in high altitude aircraft appear favorable. The use of microwave power for this purpose is controversial, even though the ground station required would transmit power at levels comparable to existing satellite communications stations.

  18. Post-buckled precompressed subsonic micro-flight control actuators and surfaces

    Science.gov (United States)

    Barrett, Ron; Vos, Roelof

    2008-10-01

    This paper describes a new class of flight control actuators using post-buckled precompressed (PBP) piezoelectric elements to provide much improved actuator performance. These PBP actuator elements are modeled using basic large deflection Euler-beam estimations accounting for laminated plate effects. The deflection estimations are then coupled to a high rotation kinematic model which translates PBP beam bending to stabilator deflections. A test article using PZT-5H piezoceramic sheets built into an active bender element was fitted with an elastic band which induced much improved deflection levels. Statically the bender element was capable of producing unloaded end rotations on the order of ± 2.6°. With axial compression, the end deflections were shown to increase nearly four-fold. The PBP element was then fitted with a graphite-epoxy aeroshell which was designed to pitch around a tubular stainless steel main spar. Quasi-static bench testing showed excellent correlation between theory and experiment through ± 25° of pitch deflection. Finally, wind tunnel testing was conducted at airspeeds up to 120 kts (62 m s-1, 202 ft s-1). Testing showed that deflections up to ± 20° could be maintained at even the highest flight speed. The stabilator showed no flutter or divergence tendencies at all flight speeds. At higher deflection levels, it was shown that a slight degradation deflection was induced by nose-down pitching moments generated by separated flow conditions induced by extremely high angles of attack.

  19. Post-buckled precompressed (PBP) subsonic micro flight control actuators and surfaces

    Science.gov (United States)

    Barrett, Ron; Vos, Roelof; De Breuker, Roeland

    2007-04-01

    This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements to provide much improved actuator performance. These PBP actuator elements are modeled using basic large deflection Euler-beam estimations accounting for laminated plate effects. The deflection estimations are then coupled to a high rotation kinematic model which translates PBP beam bending to stabilator deflections. A test article using PZT-5H piezoceramic sheets built into an active bender element was fitted with an elastic band which induced much improved deflection levels. Statically the bender element was capable of producing unloaded end rotations on the order of +/-2.6°. With axial compression, the end deflections were shown to increase nearly 4-fold. The PBP element was then fitted with a graphite-epoxy aeroshell which was designed to pitch around a tubular stainless steel main spar. Quasi-static bench testing showed excellent correlation between theory and experiment through +/-25° of pitch deflection. Finally, wind tunnel testing was conducted at airspeeds up to 120kts (62m/s, 202ft/s). Testing showed that deflections up through +/-20° could be maintained at even the highest flight speed. The stabilator showed no flutter or divergence tendencies at all flight speeds. At higher deflection levels, it was shown that a slight degradation deflection was induced by nose-down pitching moments generated by separated flow conditions induced by extremely high angles of attack.

  20. Airborne Detection and Dynamic Modeling of Carbon Dioxide and Methane Plumes

    Science.gov (United States)

    Jacob, Jamey; Mitchell, Taylor; Whyte, Seabrook

    2015-11-01

    To facilitate safe storage of greenhouse gases such as CO2 and CH4, airborne monitoring is investigated. Conventional soil gas monitoring has difficulty in distinguishing gas flux signals from leakage with those associated with meteorologically driven changes. A low-cost, lightweight sensor system has been developed and implemented onboard a small unmanned aircraft that measures gas concentration and is combined with other atmospheric diagnostics, including thermodynamic data and velocity from hot-wire and multi-hole probes. To characterize the system behavior and verify its effectiveness, field tests have been conducted over controlled rangeland burns and over simulated leaks. In the former case, since fire produces carbon dioxide over a large area, this was an opportunity to test in an environment that while only vaguely similar to a carbon sequestration leak source, also exhibits interesting plume behavior. In the simulated field tests, compressed gas tanks are used to mimic leaks and generate gaseous plumes. Since the sensor response time is a function of vehicle airspeed, dynamic calibration models are required to determine accurate location of gas concentration in (x , y , z , t) . Results are compared with simulations using combined flight and atmospheric dynamic models. Supported by Department of Energy Award DE-FE0012173.

  1. A flight management algorithm and guidance for fuel-conservative descents in a time-based metered air traffic environment: Development and flight test results

    Science.gov (United States)

    Knox, C. E.

    1984-01-01

    A simple airborne flight management descent algorithm designed to define a flight profile subject to the constraints of using idle thrust, a clean airplane configuration (landing gear up, flaps zero, and speed brakes retracted), and fixed-time end conditions was developed and flight tested in the NASA TSRV B-737 research airplane. The research test flights, conducted in the Denver ARTCC automated time-based metering LFM/PD ATC environment, demonstrated that time guidance and control in the cockpit was acceptable to the pilots and ATC controllers and resulted in arrival of the airplane over the metering fix with standard deviations in airspeed error of 6.5 knots, in altitude error of 23.7 m (77.8 ft), and in arrival time accuracy of 12 sec. These accuracies indicated a good representation of airplane performance and wind modeling. Fuel savings will be obtained on a fleet-wide basis through a reduction of the time error dispersions at the metering fix and on a single-airplane basis by presenting the pilot with guidance for a fuel-efficient descent.

  2. Cloud particle size distributions measured with an airborne digital in-line holographic instrument

    Directory of Open Access Journals (Sweden)

    J. P. Fugal

    2009-03-01

    Full Text Available Holographic data from the prototype airborne digital holographic instrument HOLODEC (Holographic Detector for Clouds, taken during test flights are digitally reconstructed to obtain the size (equivalent diameters in the range 23 to 1000 μm, three-dimensional position, and two-dimensional profile of ice particles and then ice particle size distributions and number densities are calculated using an automated algorithm with minimal user intervention. The holographic method offers the advantages of a well-defined sample volume size that is not dependent on particle size or airspeed, and offers a unique method of detecting shattered particles. The holographic method also allows the volume sample rate to be increased beyond that of the prototype HOLODEC instrument, limited solely by camera technology.

    HOLODEC size distributions taken in mixed-phase regions of cloud compare well to size distributions from a PMS FSSP probe also onboard the aircraft during the test flights. A conservative algorithm for detecting shattered particles utilizing the particles depth-position along the optical axis eliminates the obvious ice particle shattering events from the data set. In this particular case, the size distributions of non-shattered particles are reduced by approximately a factor of two for particles 15 to 70 μm in equivalent diameter, compared to size distributions of all particles.

  3. The effects of energy beverages in counteracting the symptoms of mild hypoxia at legal general aviation altitudes

    Science.gov (United States)

    Bull, Daniel Mark

    The purpose of this thesis was to conduct preliminary research, in the form of a pilot study, concerning the natural effects of hypoxia compared to the effects of hypoxia experienced after the consumption of an energy beverage. The study evaluated the effects of hypoxia on FAA certificated pilots at a simulated legal general aviation altitude, utilizing the normobaric High Altitude Lab (HAL) located at Embry Riddle Aeronautical University, Daytona Beach, Florida. The researcher tested 11 subjects, who completed three simulated flight tasks within the HAL using the Frasca International Mentor Advanced Aviation Training Device (AATD). The flight tasks were completed after consuming Red BullRTM, MonsterRTM , or a placebo beverage. The researcher derived three test variables from core outputs of the AATD: lateral deviations from the glide slope, vertical deviations from the localizer, and airspeed deviations from the target speed of 100 knots. A repeated-measures ANOVA was carried out to determine effects of the beverages on the test variables. While results were non-significant, the researcher concluded that further research should be conducted with a larger sample.

  4. Fuzzy Logic Decoupled Lateral Control for General Aviation Airplanes

    Science.gov (United States)

    Duerksen, Noel

    1997-01-01

    It has been hypothesized that a human pilot uses the same set of generic skills to control a wide variety of aircraft. If this is true, then it should be possible to construct an electronic controller which embodies this generic skill set such that it can successfully control different airplanes without being matched to a specific airplane. In an attempt to create such a system, a fuzzy logic controller was devised to control aileron or roll spoiler position. This controller was used to control bank angle for both a piston powered single engine aileron equipped airplane simulation and a business jet simulation which used spoilers for primary roll control. Overspeed, stall and overbank protection were incorporated in the form of expert systems supervisors and weighted fuzzy rules. It was found that by using the artificial intelligence techniques of fuzzy logic and expert systems, a generic lateral controller could be successfully used on two general aviation aircraft types that have very different characteristics. These controllers worked for both airplanes over their entire flight envelopes. The controllers for both airplanes were identical except for airplane specific limits (maximum allowable airspeed, throttle ]ever travel, etc.). This research validated the fact that the same fuzzy logic based controller can control two very different general aviation airplanes. It also developed the basic controller architecture and specific control parameters required for such a general controller.

  5. Correlation of Space Shuttle Landing Performance with Post-Flight Cardiovascular Dysfunction

    Science.gov (United States)

    McCluskey, R.

    2004-01-01

    Introduction: Microgravity induces cardiovascular adaptations resulting in orthostatic intolerance on re-exposure to normal gravity. Orthostasis could interfere with performance of complex tasks during the re-entry phase of Shuttle landings. This study correlated measures of Shuttle landing performance with post-flight indicators of orthostatic intolerance. Methods: Relevant Shuttle landing performance parameters routinely recorded at touchdown by NASA included downrange and crossrange distances, airspeed, and vertical speed. Measures of cardiovascular changes were calculated from operational stand tests performed in the immediate post-flight period on mission commanders from STS-41 to STS-66. Stand test data analyzed included maximum standing heart rate, mean increase in maximum heart rate, minimum standing systolic blood pressure, and mean decrease in standing systolic blood pressure. Pearson correlation coefficients were calculated with the null hypothesis that there was no statistically significant linear correlation between stand test results and Shuttle landing performance. A correlation coefficient? 0.5 with a pcorrelations between landing performance and measures of post-flight cardiovascular dysfunction. Discussion: There was no evidence that post-flight cardiovascular stand test data correlated with Shuttle landing performance. This implies that variations in landing performance were not due to space flight-induced orthostatic intolerance.

  6. Aero-Assisted Pre-Stage for Ballistic and Aero-Assisted Launch Vehicles

    Science.gov (United States)

    Ustinov, Eugene A.

    2012-01-01

    A concept of an aero-assisted pre-stage is proposed, which enables launch of both ballistic and aero-assisted launch vehicles from conventional runways. The pre-stage can be implemented as a delta-wing with a suitable undercarriage, which is mated with the launch vehicle, so that their flight directions are coaligned. The ample wing area of the pre-stage combined with the thrust of the launch vehicle ensure prompt roll-out and take-off of the stack at airspeeds typical for a conventional jet airliner. The launch vehicle is separated from the pre-stage as soon as safe altitude is achieved, and the desired ascent trajectory is reached. Nominally, the pre-stage is non-powered. As an option, to save the propellant of the launch vehicle, the pre-stage may have its own short-burn propulsion system, whereas the propulsion system of the launch vehicle is activated at the separation point. A general non-dimensional analysis of performance of the pre-stage from roll-out to separation is carried out and applications to existing ballistic launch vehicle and hypothetical aero-assisted vehicles (spaceplanes) are considered.

  7. Jet transport performance in thunderstorm wind shear conditions

    Science.gov (United States)

    Mccarthy, J.; Blick, E. F.; Bensch, R. R.

    1979-01-01

    Several hours of three dimensional wind data were collected in the thunderstorm approach-to-landing environment, using an instrumented Queen Air airplane. These data were used as input to a numerical simulation of aircraft response, concentrating on fixed-stick assumptions, while the aircraft simulated an instrument landing systems approach. Output included airspeed, vertical displacement, pitch angle, and a special approach deterioration parameter. Theory and the results of approximately 1000 simulations indicated that about 20 percent of the cases contained serious wind shear conditions capable of causing a critical deterioration of the approach. In particular, the presence of high energy at the airplane's phugoid frequency was found to have a deleterious effect on approach quality. Oscillations of the horizontal wind at the phugoid frequency were found to have a more serious effect than vertical wind. A simulation of Eastern flight 66, which crashed at JFK in 1975, served to illustrate the points of the research. A concept of a real-time wind shear detector was outlined utilizing these results.

  8. Unmanned airships for near earth remote sensing missions

    Energy Technology Data Exchange (ETDEWEB)

    Hochstetler, R.D. [Research Adventures,Inc., Kensington, MD (United States)

    1996-10-01

    In recent years the study of Earth processes has increased significantly. Conventional aircraft have been employed to a large extent in gathering much of this information. However, with this expansion of research has come the need to investigate and measure phenomena that occur beyond the performance capabilities of conventional aircraft. Where long dwell times or observations at very low attitudes are required there are few platforms that can operate safely, efficiently, and cost-effectively. One type of aircraft that meets all three parameters is the unmanned, autonomously operated airship. The UAV airship is smaller than manned airships but has similar performance characteristics. It`s low speed stability permits high resolution observations and provides a low vibration environment for motion sensitive instruments. Maximum airspeed is usually 30mph to 35mph and endurance can be as high as 36 hours. With scientific payload capacities of 100 kilos and more, the UAV airship offers a unique opportunity for carrying significant instrument loads for protracted periods at the air/surface interface. The US Army has operated UAV airships for several years conducting border surveillance and monitoring, environmental surveys, and detection and mapping of unexploded ordinance. The technical details of UAV airships, their performance, and the potential of such platforms for more advanced research roles will be presented. 3 refs., 5 figs.

  9. Inertial attitude control of a bat-like morphing-wing air vehicle

    International Nuclear Information System (INIS)

    This paper presents a novel bat-like unmanned aerial vehicle inspired by the morphing-wing mechanism of bats. The goal of this paper is twofold. Firstly, a modelling framework is introduced for analysing how the robot should manoeuvre by means of changing wing morphology. This allows the definition of requirements for achieving forward and turning flight according to the kinematics of the wing modulation. Secondly, an attitude controller named backstepping+DAF is proposed. Motivated by biological evidence about the influence of wing inertia on the production of body accelerations, the attitude control law incorporates wing inertia information to produce desired roll (φ) and pitch (θ) acceleration commands (desired angular acceleration function (DAF)). This novel control approach is aimed at incrementing net body forces (Fnet) that generate propulsion. Simulations and wind-tunnel experimental results have shown an increase of about 23% in net body force production during the wingbeat cycle when the wings are modulated using the DAF as a part of the backstepping control law. Results also confirm accurate attitude tracking in spite of high external disturbances generated by aerodynamic loads at airspeeds up to 5 ms−1. (paper)

  10. Vertical Navigation Control Laws and Logic for the Next Generation Air Transportation System

    Science.gov (United States)

    Hueschen, Richard M.; Khong, Thuan H.

    2013-01-01

    A vertical navigation (VNAV) outer-loop control system was developed to capture and track the vertical path segments of energy-efficient trajectories that are being developed for high-density operations in the evolving Next Generation Air Transportation System (NextGen). The VNAV control system has a speed-on-elevator control mode to pitch the aircraft for tracking a calibrated airspeed (CAS) or Mach number profile and a path control mode for tracking the VNAV altitude profile. Mode control logic was developed for engagement of either the speed or path control modes. The control system will level the aircraft to prevent it from flying through a constraint altitude. A stability analysis was performed that showed that the gain and phase margins of the VNAV control system significantly exceeded the design gain and phase margins. The system performance was assessed using a six-deg-of-freedom non-linear transport aircraft simulation and the performance is illustrated with time-history plots of recorded simulation data.

  11. Designing Zoning of Remote Sensing Drones for Urban Applications: a Review

    Science.gov (United States)

    Norzailawati, M. N.; Alias, A.; Akma, R. S.

    2016-06-01

    This paper discusses on-going research related to zoning regulation for the remote sensing drone in the urban applications. Timestamped maps are presented here follow a citation-based approach, where significant information is retrieved from the scientific literature. The emergence of drones in domestic air raises lots understandable issues on privacy, security and uncontrolled pervasive surveillance that require a careful and alternative solution. The effective solution is to adopt a privacy and property rights approach that create a drone zoning and clear drone legislatures. In providing a differential trend to other reviews, this paper is not limited to drones zoning and regulations, but also, discuss on trend remote sensing drones specification in designing a drone zones. Remote sensing drone will specific according to their features and performances; size and endurance, maximum airspeed and altitude level and particular references are made to the drones range. The implementation of laws zoning could lie with the urban planners whereby, a zoning for drone could become a new tactic used to specify areas, where drones could be used, will provide remedies for the harm that arise from drones, and act as a different against irresponsible behaviour. Finally, underlines the need for next regulations on guidelines and standards which can be used as a guidance for urban decision makers to control the drones' operating, thus ensuring a quality and sustainability of resilience cities simultaneously encouraging the revolution of technology.

  12. The noise environment of a school classroom due to the operation of utility helicopters. [acoustic measurements of helicopter noise during flight over building

    Science.gov (United States)

    Hilton, D. A.; Pegg, R. J.

    1974-01-01

    Noise measurements under controlled conditions have been made inside and outside of a school building during flyover operations of four different helicopters. The helicopters were operated at a condition considered typical for a police patrol mission. Flyovers were made at an altitude of 500 ft and an airspeed of 45 miles per hour. During these operations acoustic measurements were made inside and outside of the school building with the windows closed and then open. The outside noise measurements during helicopter flyovers indicate that the outside db(A) levels were approximately the same for all test helicopters. For the windows closed case, significant reductions for the inside measured db(A) values were noted for all overflights. These reductions were approximately 20 db(A); similar reductions were noted in other subjective measuring units. The measured internal db(A) levels with the windows open exceeded published classroom noise criteria values; however, for the windows-closed case they are in general agreement with the criteria values.

  13. Efficient Low-Speed Flight in a Wind Field

    Science.gov (United States)

    Feldman, Michael A.

    1996-01-01

    A new software tool was needed for flight planning of a high altitude, low speed unmanned aerial vehicle which would be flying in winds close to the actual airspeed of the vehicle. An energy modeled NLP (non-linear programming) formulation was used to obtain results for a variety of missions and wind profiles. The energy constraint derived included terms due to the wind field and the performance index was a weighted combination of the amount of fuel used and the final time. With no emphasis on time and with no winds the vehicle was found to fly at maximum lift to drag velocity, V(sub md). When flying in tail winds the velocity was less than V(sub md), while flying in head winds the velocity was higher than V(sub md). A family of solutions was found with varying times of flight and varying fuel amounts consumed which will aid the operator in choosing a flight plan depending on a desired landing time. At certain parts of the flight, the turning terms in the energy constraint equation were found to be significant. An analysis of a simpler vertical plane cruise optimal control problem was used to explain some of the characteristics of the vertical plane NLP results.

  14. Implementation of the Rauch-Tung-Striebel Smoother for Sensor Compatibility Correction of a Fixed-Wing Unmanned Air Vehicle

    Directory of Open Access Journals (Sweden)

    Fei-Bin Hsiao

    2011-03-01

    Full Text Available This paper presents a complete procedure for sensor compatibility correction of a fixed-wing Unmanned Air Vehicle (UAV. The sensors consist of a differential air pressure transducer for airspeed measurement, two airdata vanes installed on an airdata probe for angle of attack (AoA and angle of sideslip (AoS measurement, and an Attitude and Heading Reference System (AHRS that provides attitude angles, angular rates, and acceleration. The procedure is mainly based on a two pass algorithm called the Rauch-Tung-Striebel (RTS smoother, which consists of a forward pass Extended Kalman Filter (EKF and a backward recursion smoother. On top of that, this paper proposes the implementation of the Wiener Type Filter prior to the RTS in order to avoid the complicated process noise covariance matrix estimation. Furthermore, an easy to implement airdata measurement noise variance estimation method is introduced. The method estimates the airdata and subsequently the noise variances using the ground speed and ascent rate provided by the Global Positioning System (GPS. It incorporates the idea of data regionality by assuming that some sort of statistical relation exists between nearby data points. Root mean square deviation (RMSD is being employed to justify the sensor compatibility. The result shows that the presented procedure is easy to implement and it improves the UAV sensor data compatibility significantly.

  15. Stochastic global identification of a bio-inspired self-sensing composite UAV wing via wind tunnel experiments

    Science.gov (United States)

    Kopsaftopoulos, Fotios; Nardari, Raphael; Li, Yu-Hung; Wang, Pengchuan; Chang, Fu-Kuo

    2016-04-01

    In this work, the system design, integration, and wind tunnel experimental evaluation are presented for a bioinspired self-sensing intelligent composite unmanned aerial vehicle (UAV) wing. A total of 148 micro-sensors, including piezoelectric, strain, and temperature sensors, in the form of stretchable sensor networks are embedded in the layup of a composite wing in order to enable its self-sensing capabilities. Novel stochastic system identification techniques based on time series models and statistical parameter estimation are employed in order to accurately interpret the sensing data and extract real-time information on the coupled air flow-structural dynamics. Special emphasis is given to the wind tunnel experimental assessment under various flight conditions defined by multiple airspeeds and angles of attack. A novel modeling approach based on the recently introduced Vector-dependent Functionally Pooled (VFP) model structure is employed for the stochastic identification of the "global" coupled airflow-structural dynamics of the wing and their correlation with dynamic utter and stall. The obtained results demonstrate the successful system-level integration and effectiveness of the stochastic identification approach, thus opening new perspectives for the state sensing and awareness capabilities of the next generation of "fly-by-fee" UAVs.

  16. Design of a Data Acquisition System for a Flying Laboratory

    Directory of Open Access Journals (Sweden)

    M. Millar

    2000-01-01

    Full Text Available The University of Glasgow, Department of Aerospace Engineering has been in possession of a Czech manufactured Remotely Piloted Vehicle (RPV airframe 1 since 1996. Significant modifications have been made and will continue to be made in order to render the design functional and airworthy. The name ‘Condor’ was chosen as the moniker for the new aircraft. The latest phase of these modifications is the design and implementation of the Condor’s in-flight data acquisition (DAQ system. The paper will outline the various processes involved and decisions made in the design and implementation of a simple data acquisition system for a RPV. The requirements of the system were first identified, such as those quantities that were deemed essential to the effective operation of the RPV. For example, airspeed, angle of attack, angle of sideslip etc. and the necessary instrumentation for measuring such values chosen and the subsequent signal conditioning needed for the signals to be intelligible to the DAQ Card and computer.

  17. Effects of ice crystals on the FSSP measurements in mixed phase clouds

    Directory of Open Access Journals (Sweden)

    G. Febvre

    2012-03-01

    Full Text Available In this paper, we show that in mixed phase clouds FSSP-100 measurements may be contaminated by ice crystals, inducing wrong interpretation of particle size and subsequent bulk parameters. This contamination is generally revealed by a bimodal feature of the particle size distribution; in other words, in mixed phase clouds bimodal features could be an indication of the presence of ice particles. The combined measurements of the FSSP-100 and the Polar Nephelometer give a coherent description of the effect of the ice crystals on the FSSP-100 response. The FSSP-100 particle size distributions are characterized by a bimodal shape with a second mode peaked between 25 and 35 μm related to ice crystals. This feature is observed with the FSSP-100 at airspeed up to 200 m s−1 and with the FSSP-300 series. In order to assess the size calibration for clouds of ice crystals the response of the FSSP-100 probe has been numerically simulated using a light scattering model of randomly oriented hexagonal ice particles and assuming both smooth and rough crystal surfaces. The results suggest that the second mode measured between 25 μm and 35 μm, does not necessarily represent true size responses but likely corresponds to bigger aspherical ice particles. According to simulation results, the sizing understatement would be neglected in the rough case but would be major with the smooth case. Qualitatively, the Polar Nephelometer phase function suggests that the rough case is the more suitable to describe real crystals. Quantitatively, however, it is difficult to conclude. Previous cloud in situ measurements suggest that the FSSP-100 secondary mode, peaked in the range 25–35 μm, is likely to be due to the shattering of large ice crystals on the probe tips. This finding is supported by the rather good relationship between the concentration of particles larger than 20 μm (hypothesized to be ice shattered-fragments measured by the FSSP and the

  18. Determination of optimal trajectories for an aircraft returning to the runway following a complete loss of thrust after takeoff

    Science.gov (United States)

    Gordon, Craig A.

    This thesis examines the ability of a small, single-engine airplane to return to the runway following an engine failure shortly after takeoff. Two sets of trajectories are examined. One set of trajectories has the airplane fly a straight climb on the runway heading until engine failure. The other set of trajectories has the airplane perform a 90° turn at an altitude of 500 feet and continue until engine failure. Various combinations of wind speed, wind direction, and engine failure times are examined. The runway length required to complete the entire flight from the beginning of the takeoff roll to wheels stop following the return to the runway after engine failure is calculated for each case. The optimal trajectories following engine failure consist of three distinct segments: a turn back toward the runway using a large bank angle and angle of attack; a straight glide; and a reversal turn to align the airplane with the runway. The 90° turn results in much shorter required runway lengths at lower headwind speeds. At higher headwind speeds, both sets of trajectories are limited by the length of runway required for the landing rollout, but the straight climb cases generally require a lower angle of attack to complete the flight. The glide back to the runway is performed at an airspeed below the best glide speed of the airplane due to the need to conserve potential energy after the completion of the turn back toward the runway. The results are highly dependent on the rate of climb of the airplane during powered flight. The results of this study can aid the pilot in determining whether or not a return to the runway could be performed in the event of an engine failure given the specific wind conditions and runway length at the time of takeoff. The results can also guide the pilot in determining the takeoff profile that would offer the greatest advantage in returning to the runway.

  19. Instrument Display Visual Angles for Conventional Aircraft and the MQ-9 Ground Control Station

    Science.gov (United States)

    Bendrick, Gregg A.; Kamine, Tovy Haber

    2008-01-01

    Aircraft instrument panels should be designed such that primary displays are in optimal viewing location to minimize pilot perception and response time. Human Factors engineers define three zones (i.e. "cones") of visual location: 1) "Easy Eye Movement" (foveal vision); 2) "Maximum Eye Movement" (peripheral vision with saccades), and 3) "Head Movement" (head movement required). Instrument display visual angles were measured to determine how well conventional aircraft (T-34, T-38, F- 15B, F-16XL, F/A-18A, U-2D, ER-2, King Air, G-III, B-52H, DC-10, B747-SCA) and the MQ-9 ground control station (GCS) complied with these standards, and how they compared with each other. Methods: Selected instrument parameters included: attitude, pitch, bank, power, airspeed, altitude, vertical speed, heading, turn rate, slip/skid, AOA, flight path, latitude, longitude, course, bearing, range and time. Vertical and horizontal visual angles for each component were measured from the pilot s eye position in each system. Results: The vertical visual angles of displays in conventional aircraft lay within the cone of "Easy Eye Movement" for all but three of the parameters measured, and almost all of the horizontal visual angles fell within this range. All conventional vertical and horizontal visual angles lay within the cone of "Maximum Eye Movement". However, most instrument vertical visual angles of the MQ-9 GCS lay outside the cone of "Easy Eye Movement", though all were within the cone of "Maximum Eye Movement". All the horizontal visual angles for the MQ-9 GCS were within the cone of "Easy Eye Movement". Discussion: Most instrument displays in conventional aircraft lay within the cone of "Easy Eye Movement", though mission-critical instruments sometimes displaced less important instruments outside this area. Many of the MQ-9 GCS systems lay outside this area. Specific training for MQ-9 pilots may be needed to avoid increased response time and potential error during flight.

  20. Parameter sensitivities affecting the flutter speed of a MW-sized blade.

    Energy Technology Data Exchange (ETDEWEB)

    Lobitz, Donald Wayne, Jr.

    2005-08-01

    With the current trend toward larger and larger horizontal axis wind turbines, classical flutter is becoming a more critical issue. Recent studies have indicated that for a single blade turning in still air the flutter speed for a modern 35 m blade occurs at approximately twice its operating speed (2 per rev), whereas for smaller blades (5-9 m), both modern and early designs, the flutter speeds are in the range of 3.5-6 per rev. Scaling studies demonstrate that the per rev flutter speed should not change with scale. Thus, design requirements that change with increasing blade size are producing the concurrent reduction in per rev flutter speeds. In comparison with an early small blade design (5 m blade), flutter computations indicate that the non rotating modes which combine to create the flutter mode change as the blade becomes larger (i.e., for the larger blade the second flapwise mode, as opposed to the first flapwise mode for the smaller blade, combines with the first torsional mode to produce the flutter mode). For the more modern smaller blade design (9 m blade), results show that the non rotating modes that couple are similar to those of the larger blade. For the wings of fixed-wing aircraft, it is common knowledge that judicious selection of certain design parameters can increase the airspeed associated with the onset of flutter. Two parameters, the chordwise location of the center of mass and the ratio of the flapwise natural frequency to the torsional natural frequency, are especially significant. In this paper studies are performed to determine the sensitivity of the per rev flutter speed to these parameters for a 35 m wind turbine blade. Additional studies are performed to determine which structural characteristics of the blade are most significant in explaining the previously mentioned per rev flutter speed differences. As a point of interest, flutter results are also reported for two recently designed 9 m twist/coupled blades.

  1. Parameter sensitivities affecting the flutter speed of a MW-sized blade.

    Energy Technology Data Exchange (ETDEWEB)

    Lobitz, Donald Wayne, Jr.

    2004-10-01

    With the current trend toward larger and larger horizontal axis wind turbines, classical flutter is becoming a more critical issue. Recent studies have indicated that for a single blade turning in still air the flutter speed for a modern 35 m blade occurs at approximately twice its operating speed (2 per rev), whereas for smaller blades (5-9 m), both modern and early designs, the flutter speeds are in the range of 3.5-6 per rev. Scaling studies demonstrate that the per rev flutter speed should not change with scale. Thus, design requirements that change with increasing blade size are producing the concurrent reduction in per rev flutter speeds. In comparison with an early small blade design (5 m blade), flutter computations indicate that the non rotating modes which combine to create the flutter mode change as the blade becomes larger (i.e., for the larger blade the second flapwise mode, as opposed to the first flapwise mode for the smaller blade, combines with the first torsional mode to produce the flutter mode). For the more modern smaller blade design (9 m blade), results show that the non rotating modes that couple are similar to those of the larger blade. For the wings of fixed-wing aircraft, it is common knowledge that judicious selection of certain design parameters can increase the airspeed associated with the onset of flutter. Two parameters, the chordwise location of the center of mass and the ratio of the flapwise natural frequency to the torsional natural frequency, are especially significant. In this paper studies are performed to determine the sensitivity of the per rev flutter speed to these parameters for a 35 m wind turbine blade. Additional studies are performed to determine which structural characteristics of the blade are most significant in explaining the previously mentioned per rev flutter speed differences. As a point of interest, flutter results are also reported for two recently designed 9 m twist/coupled blades.

  2. Studying a new technique and implementing a pilot-line process for obtaining dextrins from cassava starch

    Directory of Open Access Journals (Sweden)

    Johanna Aristizábal Galvis

    2010-04-01

    Full Text Available This study proposes and develops a new technique for dry-route dextrin production consisting of converting cassava starch pellets on a fixed-bed dryer; this technique is more applicable to rural Colombian agro-business in technical, economic, social and environmental terms, particularly to so-called “rallanderías” compared to currently available dextrin production technology. The proposed process is practically clean, requires low investment, allows humid starch-cake to be directly used without the need for expensive pre-drying equipment, eliminates large quantities of dust being produced thereby leading to an easily-handled and packaged product being obtained. Different dex-trinisation technologies were compared; a pilot-line was implemented which included blending, granulation and drying units. The variables evaluated were cassava-starch variety, catalyst concentration and agglutinant type and concentration; pellet-size, bed-thickness and air-speed were also evaluated during blending, granulation and drying stages, respectively. It was determined that using 0.1-0.3% HCl on cassava starch, 1.5-3% cassava starch paste, L/D=1.25 pellets, a 55ºC pre -drying phase and 150ºC final conversion on 2 cm thickness fixed-bed dryer at 2-3 m/s air speed led to obtaining low friability (13%, high rupture force (1.3 kg-f, high solubility (90-100% and low fluidity (50-70 s dextrin pellets. An adhesive was then obtained from the dextrin resulting from the process described above for sealing cardboard-boxes and cartons having greater stickiness, tensile strength and stability compared to corn dextrin adhesive, suggesting that the proposed new cassava dextrin production technique constitutes a good technological option for adding value to Colombian cassava production at small “rallandería” level.

  3. Airframe noise prediction

    Science.gov (United States)

    1990-11-01

    This Data Item 90023, an addition to the Noise Sub-series, provides the FORTRAN listing of a computer program for a semi-empirical method that calculates the far-field airframe aerodynamic noise generated by turbo-fan powered transport aircraft or gliders in one-third octave bands over a frequency range specified by the user. The overall sound pressure level is also output. The results apply for a still, lossless atmosphere; other ESDU methods may be used to correct for atmospheric attenuation, ground reflection, lateral attenuation, and wind and temperature gradients. The position of the aircraft relative to the observer is input in terms of the height at minimum range, and the elevation and azimuthal angles to the aircraft; if desired the user may obtain results over a range of those angles in 10 degree intervals. The method sums the contributions made by various components, results for which can also be output individually. The components are: the wind (conventional or delta), tailplane, fin, flaps (single/double slotted or triple slotted), leading-edge slats, and undercarriage legs and wheels (one/two wheel or four wheel units). The program requires only geometric data for each component (area and span in the case of lifting elements, flap deflection angle, and leg length and wheel diameter for the undercarriage). The program was validated for aircraft with take-off masses from 42,000 to 390,000 kg (92,000 to 860,000 lb) at airspeeds from 70 to 145 m/s (135 to 280 kn). Comparisons with available experimental data suggest a prediction rms accuracy of 1 dB at minimum range, rising to between 2 and 3 dB at 60 degrees to either side.

  4. Photogrammetric mapping using unmanned aerial vehicle

    Science.gov (United States)

    Graça, N.; Mitishita, E.; Gonçalves, J.

    2014-11-01

    Nowadays Unmanned Aerial Vehicle (UAV) technology has attracted attention for aerial photogrammetric mapping. The low cost and the feasibility to automatic flight along commanded waypoints can be considered as the main advantages of this technology in photogrammetric applications. Using GNSS/INS technologies the images are taken at the planned position of the exposure station and the exterior orientation parameters (position Xo, Yo, Zo and attitude ω, φ, χ) of images can be direct determined. However, common UAVs (off-the-shelf) do not replace the traditional aircraft platform. Overall, the main shortcomings are related to: difficulties to obtain the authorization to perform the flight in urban and rural areas, platform stability, safety flight, stability of the image block configuration, high number of the images and inaccuracies of the direct determination of the exterior orientation parameters of the images. In this paper are shown the obtained results from the project photogrammetric mapping using aerial images from the SIMEPAR UAV system. The PIPER J3 UAV Hydro aircraft was used. It has a micro pilot MP2128g. The system is fully integrated with 3-axis gyros/accelerometers, GPS, pressure altimeter, pressure airspeed sensors. A Sony Cyber-shot DSC-W300 was calibrated and used to get the image block. The flight height was close to 400 m, resulting GSD near to 0.10 m. The state of the art of the used technology, methodologies and the obtained results are shown and discussed. Finally advantages/shortcomings found in the study and main conclusions are presented

  5. Reduction of structural loads using maneuver load control on the Advanced Fighter Technology Integration (AFTI)/F-111 mission adaptive wing

    Science.gov (United States)

    Thornton, Stephen V.

    1993-01-01

    A transonic fighter-bomber aircraft, having a swept supercritical wing with smooth variable-camber flaps was fitted with a maneuver load control (MLC) system that implements a technique to reduce the inboard bending moments in the wing by shifting the spanwise load distribution inboard as load factor increases. The technique modifies the spanwise camber distribution by automatically commanding flap position as a function of flap position, true airspeed, Mach number, dynamic pressure, normal acceleration, and wing sweep position. Flight test structural loads data were obtained for loads in both the wing box and the wing root. Data from uniformly deflected flaps were compared with data from flaps in the MLC configuration where the outboard segment of three flap segments was deflected downward less than the two inboard segments. The changes in the shear loads in the forward wing spar and at the roots of the stabilators also are presented. The camber control system automatically reconfigures the flaps through varied flight conditions. Configurations having both moderate and full trailing-edge flap deflection were tested. Flight test data were collected at Mach numbers of 0.6, 0.7, 0.8, and 0.9 and dynamic pressures of 300, 450, 600, and 800 lb/sq ft. The Reynolds numbers for these flight conditions ranged from 26 x 10(exp 6) to 54 x 10(exp 6) at the mean aerodynamic chord. Load factor increases of up to 1.0 g achieved with no increase in wing root bending moment with the MLC flap configuration.

  6. Computational Fluid Dynamic Simulation (CFD and Experimental Study on Wing-external Store Aerodynamic Interference

    Directory of Open Access Journals (Sweden)

    Tholudin Mat Lazim

    2004-01-01

    Full Text Available The main objective of the present work is to study the effect of an external store to a subsonic fighter aircraft. Generally most modern fighter aircraft is designed with an external store installation. In this project a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the external store aerodynamic interference on the flow around the aircraft wing. A computational fluid dynamic (CFD and wind tunnel testing experiments have been carried out to ensure the aerodynamic characteristic of the model then certified the aircraft will not facing any difficulties in stability and controllability. In the CFD experiment, commercial CFD code is used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with test section sized 0.45 m×0.45 m. Result in the two-dimensional pressure distribution obtained by both experiments are comparable. There is only 12% deviation in pressure distribution found in wind tunnel testing compared to the result predicted by the CFD. The result shows that the effect of the external storage is only significant at the lower surface of the wing and almost negligible at the upper surface of the wing. Aerodynamic interference is due to the external storage were mostly evidence on a lower surface of the wing and almost negligible on the upper surface at low angle of attack. In addition, the area of influence on the wing surface by store interference increased as the airspeed increase. 

  7. Visualizing Flutter Mechanism as Traveling Wave Through Animation of Simulation Results for the Semi-Span Super-Sonic Transport Wind-Tunnel Model

    Science.gov (United States)

    Christhilf, David M.

    2014-01-01

    It has long been recognized that frequency and phasing of structural modes in the presence of airflow play a fundamental role in the occurrence of flutter. Animation of simulation results for the long, slender Semi-Span Super-Sonic Transport (S4T) wind-tunnel model demonstrates that, for the case of mass-ballasted nacelles, the flutter mode can be described as a traveling wave propagating downstream. Such a characterization provides certain insights, such as (1) describing the means by which energy is transferred from the airflow to the structure, (2) identifying airspeed as an upper limit for speed of wave propagation, (3) providing an interpretation for a companion mode that coalesces in frequency with the flutter mode but becomes very well damped, (4) providing an explanation for bursts of response to uniform turbulence, and (5) providing an explanation for loss of low frequency (lead) phase margin with increases in dynamic pressure (at constant Mach number) for feedback systems that use sensors located upstream from active control surfaces. Results from simulation animation, simplified modeling, and wind-tunnel testing are presented for comparison. The simulation animation was generated using double time-integration in Simulink of vertical accelerometer signals distributed over wing and fuselage, along with time histories for actuated control surfaces. Crossing points for a zero-elevation reference plane were tracked along a network of lines connecting the accelerometer locations. Accelerometer signals were used in preference to modal displacement state variables in anticipation that the technique could be used to animate motion of the actual wind-tunnel model using data acquired during testing. Double integration of wind-tunnel accelerometer signals introduced severe drift even with removal of both position and rate biases such that the technique does not currently work. Using wind-tunnel data to drive a Kalman filter based upon fitting coefficients to

  8. Interval Management with Spacing to Parallel Dependent Runways (IMSPIDR) Experiment and Results

    Science.gov (United States)

    Baxley, Brian T.; Swieringa, Kurt A.; Capron, William R.

    2012-01-01

    An area in aviation operations that may offer an increase in efficiency is the use of continuous descent arrivals (CDA), especially during dependent parallel runway operations. However, variations in aircraft descent angle and speed can cause inaccuracies in estimated time of arrival calculations, requiring an increase in the size of the buffer between aircraft. This in turn reduces airport throughput and limits the use of CDAs during high-density operations, particularly to dependent parallel runways. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) concept uses a trajectory-based spacing tool onboard the aircraft to achieve by the runway an air traffic control assigned spacing interval behind the previous aircraft. This paper describes the first ever experiment and results of this concept at NASA Langley. Pilots flew CDAs to the Dallas Fort-Worth airport using airspeed calculations from the spacing tool to achieve either a Required Time of Arrival (RTA) or Interval Management (IM) spacing interval at the runway threshold. Results indicate flight crews were able to land aircraft on the runway with a mean of 2 seconds and less than 4 seconds standard deviation of the air traffic control assigned time, even in the presence of forecast wind error and large time delay. Statistically significant differences in delivery precision and number of speed changes as a function of stream position were observed, however, there was no trend to the difference and the error did not increase during the operation. Two areas the flight crew indicated as not acceptable included the additional number of speed changes required during the wind shear event, and issuing an IM clearance via data link while at low altitude. A number of refinements and future spacing algorithm capabilities were also identified.

  9. Corrigendum to "Measuring the 3-D wind vector with a weight-shift microlight aircraft" published in Atmos. Meas. Tech., 4, 1421–1444, 2011

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2011-07-01

    Full Text Available This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. We draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 % by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %, as well as changes in the aircraft lift (16 % are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s−1 at the extremes of a 95 % confidence interval. (b During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s−1. (c The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error of ≈0.4 m s−1 for the horizontal and ≈0.3 m s−1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s−1 or true airspeed (ranging from 23–30 m s−1 is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  10. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    Science.gov (United States)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-07-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore we draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 %) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %), as well as changes in the aircraft lift (16 %) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95 % confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error) of ≈0.4 m s-1 for the horizontal and ≈0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  11. Corrigendum to "Measuring the 3-D wind vector with a weight-shiftmicrolight aircraft" published in Atmos. Meas. Tech., 4, 1421-1444, 2011

    Science.gov (United States)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-07-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. We draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 %) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %), as well as changes in the aircraft lift (16 %) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95 % confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error) of ≈0.4 m s-1 for the horizontal and ≈0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  12. Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) from an Unmanned Aerial Vehicle (UAV): Results from the 2014 AROMAT campaign

    Science.gov (United States)

    Merlaud, Alexis; Tack, Frederik; Constantin, Daniel; Fayt, Caroline; Maes, Jeroen; Mingireanu, Florin; Mocanu, Ionut; Georgescu, Lucian; Van Roozendael, Michel

    2015-04-01

    The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) is an instrument dedicated to atmospheric trace gas retrieval from an Unmanned Aerial Vehicle (UAV). The payload is based on a compact visible spectrometer and a scanning mirror to collect scattered sunlight. Its weight, size, and power consumption are respectively 920 g, 27x12x12 cm3, and 6 W. The custom-built 2.5 m flying wing UAV is electrically powered, has a typical airspeed of 100 km/h, and can operate at a maximum altitude of 3 km. Both the payload and the UAV were developed in the framework of a collaboration between the Belgian Institute for Space Aeronomy (BIRA-IASB) and the Dunarea de Jos University of Galati, Romania. We present here SWING-UAV test flights dedicated to NO2 measurements and performed in Romania on 10 and 11 September 2014, during the Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign. The UAV performed 5 flights in the vicinity of the large thermal power station of Turceni (44.67° N, 23.4° E). The UAV was operated in visual range during the campaign, up to 900 m AGL , downwind of the plant and crossing its exhaust plume. The spectra recorded on flight are analyzed with the Differential Optical Absorption Spectroscopy (DOAS) method. The retrieved NO2 Differential Slant Column Densities (DSCDs) are up to 1.5e17 molec/cm2 and reveal the horizontal gradients around the plant. The DSCDs are converted to vertical columns and compared with coincident car-based DOAS measurements. We also present the near-future perspective of the SWING-UAV observation system, which includes flights in 2015 above the Black Sea to quantify ship emissions, the addition of SO2 as a target species, and autopilot flights at higher altitudes to cover a typical satellite pixel extent (10x10 km2).

  13. Flying with the wind: scale dependency of speed and direction measurements in modelling wind support in avian flight

    Science.gov (United States)

    Safi, Kamran; Kranstauber, Bart; Weinzierl, Rolf P.; Griffin, Larry; Reese, Eileen C.; Cabot, David; Cruz, Sebastian; Proaño, Carolina; Takekawa, John Y.; Newman, Scott H.; Waldenström, Jonas; Bengtsson, Daniel; Kays, Roland; Wikelski, Martin; Bohrer, Gil

    2013-01-01

    Background: Understanding how environmental conditions, especially wind, influence birds' flight speeds is a prerequisite for understanding many important aspects of bird flight, including optimal migration strategies, navigation, and compensation for wind drift. Recent developments in tracking technology and the increased availability of data on large-scale weather patterns have made it possible to use path annotation to link the location of animals to environmental conditions such as wind speed and direction. However, there are various measures available for describing not only wind conditions but also the bird's flight direction and ground speed, and it is unclear which is best for determining the amount of wind support (the length of the wind vector in a bird’s flight direction) and the influence of cross-winds (the length of the wind vector perpendicular to a bird’s direction) throughout a bird's journey. Results: We compared relationships between cross-wind, wind support and bird movements, using path annotation derived from two different global weather reanalysis datasets and three different measures of direction and speed calculation for 288 individuals of nine bird species. Wind was a strong predictor of bird ground speed, explaining 10-66% of the variance, depending on species. Models using data from different weather sources gave qualitatively similar results; however, determining flight direction and speed from successive locations, even at short (15 min intervals), was inferior to using instantaneous GPS-based measures of speed and direction. Use of successive location data significantly underestimated the birds' ground and airspeed, and also resulted in mistaken associations between cross-winds, wind support, and their interactive effects, in relation to the birds' onward flight. Conclusions: Wind has strong effects on bird flight, and combining GPS technology with path annotation of weather variables allows us to quantify these effects for

  14. Coherent Doppler Laser Radar: Technology Development and Applications

    Science.gov (United States)

    Kavaya, Michael J.; Arnold, James E. (Technical Monitor)

    2000-01-01

    NASA's Marshall Space Flight Center has been investigating, developing, and applying coherent Doppler laser radar technology for over 30 years. These efforts have included the first wind measurement in 1967, the first airborne flights in 1972, the first airborne wind field mapping in 1981, and the first measurement of hurricane eyewall winds in 1998. A parallel effort at MSFC since 1982 has been the study, modeling and technology development for a space-based global wind measurement system. These endeavors to date have resulted in compact, robust, eyesafe lidars at 2 micron wavelength based on solid-state laser technology; in a factor of 6 volume reduction in near diffraction limited, space-qualifiable telescopes; in sophisticated airborne scanners with full platform motion subtraction; in local oscillator lasers capable of rapid tuning of 25 GHz for removal of relative laser radar to target velocities over a 25 km/s range; in performance prediction theory and simulations that have been validated experimentally; and in extensive field campaign experience. We have also begun efforts to dramatically improve the fundamental photon efficiency of the laser radar, to demonstrate advanced lower mass laser radar telescopes and scanners; to develop laser and laser radar system alignment maintenance technologies; and to greatly improve the electrical efficiency, cooling technique, and robustness of the pulsed laser. This coherent Doppler laser radar technology is suitable for high resolution, high accuracy wind mapping; for aerosol and cloud measurement; for Differential Absorption Lidar (DIAL) measurements of atmospheric and trace gases; for hard target range and velocity measurement; and for hard target vibration spectra measurement. It is also suitable for a number of aircraft operations applications such as clear air turbulence (CAT) detection; dangerous wind shear (microburst) detection; airspeed, angle of attack, and sideslip measurement; and fuel savings through

  15. The Effect of Rotor Cruise Tip Speed, Engine Technology and Engine/Drive System RPM on the NASA Large Civil Tiltrotor (LCTR2) Size and Performance

    Science.gov (United States)

    Robuck, Mark; Wilkerson, Joseph; Maciolek, Robert; Vonderwell, Dan

    2012-01-01

    A multi-year study was conducted under NASA NNA06BC41C Task Order 10 and NASA NNA09DA56C task orders 2, 4, and 5 to identify the most promising propulsion system concepts that enable rotor cruise tip speeds down to 54% of the hover tip speed for a civil tiltrotor aircraft. Combinations of engine RPM reduction and 2-speed drive systems were evaluated. Three levels of engine and the drive system advanced technology were assessed; 2015, 2025 and 2035. Propulsion and drive system configurations that resulted in minimum vehicle gross weight were identified. Design variables included engine speed reduction, drive system speed reduction, technology, and rotor cruise propulsion efficiency. The NASA Large Civil Tiltrotor, LCTR, aircraft served as the base vehicle concept for this study and was resized for over thirty combinations of operating cruise RPM and technology level, quantifying LCTR2 Gross Weight, size, and mission fuel. Additional studies show design sensitivity to other mission ranges and design airspeeds, with corresponding relative estimated operational cost. The lightest vehicle gross weight solution consistently came from rotor cruise tip speeds between 422 fps and 500 fps. Nearly equivalent results were achieved with operating at reduced engine RPM with a single-speed drive system or with a two-speed drive system and 100% engine RPM. Projected performance for a 2025 engine technology provided improved fuel flow over a wide range of operating speeds relative to the 2015 technology, but increased engine weight nullified the improved fuel flow resulting in increased aircraft gross weights. The 2035 engine technology provided further fuel flow reduction and 25% lower engine weight, and the 2035 drive system technology provided a 12% reduction in drive system weight. In combination, the 2035 technologies reduced aircraft takeoff gross weight by 14% relative to the 2015 technologies.

  16. Small Unmanned Aircraft Systems Integration into the National Airspace System Visual-Line-of-Sight Human-in-the-Loop Experiment

    Science.gov (United States)

    Trujillo, Anna C.; Ghatas, Rania W.; Mcadaragh, Raymon; Burdette, Daniel W.; Comstock, James R.; Hempley, Lucas E.; Fan, Hui

    2015-01-01

    As part of the Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) project, research on integrating small UAS (sUAS) into the NAS was underway by a human-systems integration (HSI) team at the NASA Langley Research Center. Minimal to no research has been conducted on the safe, effective, and efficient manner in which to integrate these aircraft into the NAS. sUAS are defined as aircraft weighing 55 pounds or less. The objective of this human system integration team was to build a UAS Ground Control Station (GCS) and to develop a research test-bed and database that provides data, proof of concept, and human factors guidelines for GCS operations in the NAS. The objectives of this experiment were to evaluate the effectiveness and safety of flying sUAS in Class D and Class G airspace utilizing manual control inputs and voice radio communications between the pilot, mission control, and air traffic control. The design of the experiment included three sets of GCS display configurations, in addition to a hand-held control unit. The three different display configurations were VLOS, VLOS + Primary Flight Display (PFD), and VLOS + PFD + Moving Map (Map). Test subject pilots had better situation awareness of their vehicle position, altitude, airspeed, location over the ground, and mission track using the Map display configuration. This configuration allowed the pilots to complete the mission objectives with less workload, at the expense of having better situation awareness of other aircraft. The subjects were better able to see other aircraft when using the VLOS display configuration. However, their mission performance, as well as their ability to aviate and navigate, was reduced compared to runs that included the PFD and Map displays.

  17. Computational Fluid Dynamic Simulation (CFD and Experimental Study on Wing-external Store Aerodynamic Interference of a Subsonic Fighter Aircraft

    Directory of Open Access Journals (Sweden)

    Tholudin Mat Lazim

    2003-01-01

    Full Text Available The main objective of the present work is to study the effect of an external store on a subsonic fighter aircraft. Generally most modern fighter aircrafts are designed with an external store installation. In this study, a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the aerodynamic interference of the external store on the flow around the aircraft wing. A computational fluid dynamic (CFD simulation was also carried out on the same configuration. Both the CFD and the wind tunnel testing were carried out at a Reynolds number 1.86×105 to ensure that the aerodynamic characteristic can certify that the aircraft will not be face any difficulties in its stability and controllability. Both the experiments and the simulation were carried out at the same Reynolds number in order to verify each other. In the CFD simulation, a commercial CFD code was used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with a test section sized 0.45 m×0.45 m. Measured and computed results for the two-dimensional pressure distribution were satisfactorily comparable. There is only a 19% deviation between pressure distribution measured in wind tunnel testing and the result predicted by the CFD. The result shows that the effect of the external storage is only significant on the lower surface of the wing and almost negligible on the upper surface of the wing. Aerodynamic interference due to the external store was most evident on the lower surface of the wing and almost negligible on the upper surface at a low angle of attack. In addition, the area of influence on the wing surface by the store interference increased as the airspeed increased.

  18. Technologies Render Views of Earth for Virtual Navigation

    Science.gov (United States)

    2012-01-01

    On a December night in 1995, 159 passengers and crewmembers died when American Airlines Flight 965 flew into the side of a mountain while in route to Cali, Colombia. A key factor in the tragedy: The pilots had lost situational awareness in the dark, unfamiliar terrain. They had no idea the plane was approaching a mountain until the ground proximity warning system sounded an alarm only seconds before impact. The accident was of the kind most common at the time CFIT, or controlled flight into terrain says Trey Arthur, research aerospace engineer in the Crew Systems and Aviation Operations Branch at NASA s Langley Research Center. In situations such as bad weather, fog, or nighttime flights, pilots would rely on airspeed, altitude, and other readings to get an accurate sense of location. Miscalculations and rapidly changing conditions could contribute to a fully functioning, in-control airplane flying into the ground. To improve aviation safety by enhancing pilots situational awareness even in poor visibility, NASA began exploring the possibilities of synthetic vision creating a graphical display of the outside terrain on a screen inside the cockpit. How do you display a mountain in the cockpit? You have to have a graphics-powered computer, a terrain database you can render, and an accurate navigation solution, says Arthur. In the mid-1990s, developing GPS technology offered a means for determining an aircraft s position in space with high accuracy, Arthur explains. As the necessary technologies to enable synthetic vision emerged, NASA turned to an industry partner to develop the terrain graphical engine and database for creating the virtual rendering of the outside environment.

  19. On Use of Global Positioning Technology for Solution of Wake Vortex Problem

    Science.gov (United States)

    Rossow, Vernon J.; Olson, Lawerence E. (Technical Monitor)

    1997-01-01

    Improved precision of the flight paths used by aircraft to approach and depart airports is becoming available when the Global Positioning System (GPS) is implemented at airports. An overview will be given of published information on how GPS precision guidance at airports can be used to avoid encounters with the lift-generated vortices shed by preceding aircraft during landing. It is pointed out that GPS provides two needed services to bring about improved avoidance capability. Firstly, GPS pseudolites are being built and installed at airports so that, when coupled with autopilot systems currently available on subsonic transport aircraft, the aircraft can make precision approaches for zero visibility landings. The same equipment can also be used for precision approaches for wake-vortex avoidance. Secondly, regular monitoring of atmospheric motions along the approach corridor can be obtained by use of GPS equipment on board aircraft that are in the flight corridors. That is, wind velocity is determined by use of GPS equipment to measure the ground speed of the aircraft and then combined with onboard instrumentation to measure the airspeed of the aircraft. The difference between the two measurements yields the wind velocity. When the measured wind velocities are transmitted to an airport ground station they are used to monitor whether air motions adverse for safety in the flight corridor are present. If any parts of the corridor are unsafe, the spacing of the aircraft, or the location of the flight corridor being used, is modified. It is estimated that the spacings between any combination of aircraft can then be safely reduced to a uniform 3 n. mi. Information to be presented is contained in an article published in the AIAA Journal of Aircraft, May-June 1996.

  20. A robust rotorcraft flight control system design methodology utilizing quantitative feedback theory

    Science.gov (United States)

    Gorder, Peter James

    1993-01-01

    Rotorcraft flight control systems present design challenges which often exceed those associated with fixed-wing aircraft. First, large variations in the response characteristics of the rotorcraft result from the wide range of airspeeds of typical operation (hover to over 100 kts). Second, the assumption of vehicle rigidity often employed in the design of fixed-wing flight control systems is rarely justified in rotorcraft where rotor degrees of freedom can have a significant impact on the system performance and stability. This research was intended to develop a methodology for the design of robust rotorcraft flight control systems. Quantitative Feedback Theory (QFT) was chosen as the basis for the investigation. Quantitative Feedback Theory is a technique which accounts for variability in the dynamic response of the controlled element in the design robust control systems. It was developed to address a Multiple-Input Single-Output (MISO) design problem, and utilizes two degrees of freedom to satisfy the design criteria. Two techniques were examined for extending the QFT MISO technique to the design of a Multiple-Input-Multiple-Output (MIMO) flight control system (FCS) for a UH-60 Black Hawk Helicopter. In the first, a set of MISO systems, mathematically equivalent to the MIMO system, was determined. QFT was applied to each member of the set simultaneously. In the second, the same set of equivalent MISO systems were analyzed sequentially, with closed loop response information from each loop utilized in subsequent MISO designs. The results of each technique were compared, and the advantages of the second, termed Sequential Loop Closure, were clearly evident.

  1. 基于传声器阵列过顶测量结果的飞机起落架噪声研究%A study on landing gear noise based on the fly-over measurements with a planar microphone array

    Institute of Scientific and Technical Information of China (English)

    乔渭阳; Michel.,U

    2001-01-01

    A large planar microphone array,which consists of 111 microphones,was successfully applied to obtain a two-dimensional mapping of the sound sources on a landing aircraft.The focus of study in this paper is on the landing gear noise source.The spectra,directivities and sound pressure levels of flap side-edge noise of 7 narrow-board commercial aircraft and 7 wide-board commercial aircraft are presented.It is found that the landing gear noise spectrum is broadband with some single tones in some cases.The directivity of the total sound pressure level of a landing gear noise resembles that of a horizontal dipole.The level differences between the various aircraft landing gears are larger than those expected from the airspeed differences.It is thus expected that the louder noise emission of the landing gears can be reduced by redesigning.%应用由111个传声器组成的平面传声器阵列对当前流行的民用客机进场着陆过程中的机体噪声源进行了实验测量,本文对七架窄体客机和七架宽体客机的起落架噪声进行了分析,得到了起落架噪声的频谱特性、指向特性和声级变化.研究发现,起落架噪声的频谱是由宽频随机噪声与一些较为明显的单音噪声源组成,起落架噪声的指向性类似于一个水平放置的偶极子.不同飞机起落架噪声的声级相差较大,这说明可以通过重新结构设计降低起落架噪声。

  2. Pilot Designed Aircraft Displays in General Aviation: An Exploratory Study and Analysis

    Science.gov (United States)

    Conaway, Cody R.

    From 2001-2011, the General Aviation (GA) fatal accident rate remained unchanged (Duquette & Dorr, 2014) with an overall stagnant accident rate between 2004 and 2013. The leading cause, loss of control in flight (NTSB, 2015b & 2015c) due to pilot inability to recognize approach to stall/spin conditions (NTSB, 2015b & 2016b). In 2013, there were 1,224 GA accidents in the U.S., accounting for 94% of all U.S. aviation accidents and 90% of all U.S. aviation fatalities that year (NTSB, 2015c). Aviation entails multiple challenges for pilots related to task management, procedural errors, perceptual distortions, and cognitive discrepancies. While machine errors in airplanes have continued to decrease over the years, human error still has not (NTSB, 2013). A preliminary analysis of a PC-based, Garmin G1000 flight deck was conducted with 3 professional pilots. Analyses revealed increased task load, opportunities for distraction, confusing perceptual ques, and hindered cognitive performance. Complex usage problems were deeply ingrained in the functionality of the system, forcing pilots to use fallible work arounds, add unnecessary steps, and memorize knob turns or button pushes. Modern computing now has the potential to free GA cockpit designs from knobs, soft keys, or limited display options. Dynamic digital displays might include changes in instrumentation or menu structuring depending on the phase of flight. Airspeed indicators could increase in size to become more salient during landing, simultaneously highlighting pitch angle on Attitude Indicators and automatically decluttering unnecessary information for landing. Likewise, Angle-of-Attack indicators demonstrate a great safety and performance advantage for pilots (Duquette & Dorr, 2014; NTSB, 2015b & 2016b), an instrument typically found in military platforms and now the Icon A5, light-sport aircraft (Icon, 2016). How does the design of pilots' environment---the cockpit---further influence their efficiency and

  3. Atmospheric Turbulence Measurements With the Automatic Mini UAV 'M2AV Carolo'

    Science.gov (United States)

    Bange, J.; van den Kroonenberg, A. C.; Spieß, T.; Buschmann, M.; Krüger, L.; Heindorf, A.; Vörsmann, P.

    2007-05-01

    The limitations of manned airborne meteorological measurements led to the development of an autonomously operating mini aircraft, the Meteorological Mini-UAV (M2AV), at the Institute of Aerospace Systems, Technical University of Braunschweig, Germany. The task was to develop, test and verify a meteorological sensor package as payload for an already available automatic carrier aircraft, the UAV 'Carolo T200', which operates autonomously i.e. without remote control. The M2AV is a self constructed model aircraft with two electrically powered engines and a wingspan of two meters. The maximum take-off weight is 4.5~kg (the M2AV is therefore classified as an model plane which simplifies authority issues), including 1.5~kg of payload. It is hand-launched which makes operation of the aircraft easy. With an endurance of approximately 50 minutes, the range accounts for 60 km at a cruising speed of 20~m/s. The M2AV is capable of performing turbulence measurements (wind vector, temperature and humidity) within the troposphere and offers an economic component during meteorological campaigns. The meteorological sensors are mounted on a noseboom to minimise the aircraft's influence on the measurements and to position the sensors closely to each other. Wind is measured via a small five-hole probe, an inertia measurement unit and GPS. The flight mission (waypoints, altitudes, airspeed) is planned and assigned to the aircraft before the semi- automatic launch. The flight is only controlled by the on-board autopilot system which only communicates with a ground station (laptop PC) for the exchange of measured data and command updates like new waypoints etc. The talk gives details on the technical items, calibration and first missions. Results from first field experiments like the LAUNCH-2005 campaign near Berlin are used for data quality assessment by comparison with simultaneous lidar and sodar measurements. An in situ comparison with the highly accurate helicopter-borne turbulence

  4. Some effects of ice crystals on the FSSP measurements in mixed phase clouds

    Directory of Open Access Journals (Sweden)

    G. Febvre

    2012-10-01

    Full Text Available In this paper, we show that in mixed phase clouds, the presence of ice crystals may induce wrong FSSP 100 measurements interpretation especially in terms of particle size and subsequent bulk parameters. The presence of ice crystals is generally revealed by a bimodal feature of the particle size distribution (PSD. The combined measurements of the FSSP-100 and the Polar Nephelometer give a coherent description of the effect of the ice crystals on the FSSP-100 response. The FSSP-100 particle size distributions are characterized by a bimodal shape with a second mode peaked between 25 and 35 μm related to ice crystals. This feature is observed with the FSSP-100 at airspeed up to 200 m s−1 and with the FSSP-300 series. In order to assess the size calibration for clouds of ice crystals the response of the FSSP-100 probe has been numerically simulated using a light scattering model of randomly oriented hexagonal ice particles and assuming both smooth and rough crystal surfaces. The results suggest that the second mode, measured between 25 μm and 35 μm, does not necessarily represent true size responses but corresponds to bigger aspherical ice particles. According to simulation results, the sizing understatement would be neglected in the rough case but would be significant with the smooth case. Qualitatively, the Polar Nephelometer phase function suggests that the rough case is the more suitable to describe real crystals. Quantitatively, however, it is difficult to conclude. A review is made to explore different hypotheses explaining the occurrence of the second mode. However, previous cloud in situ measurements suggest that the FSSP-100 secondary mode, peaked in the range 25–35 μm, is likely to be due to the shattering of large ice crystals on the probe inlet. This finding is supported by the rather good relationship between the concentration of particles larger than 20 μm (hypothesized to be ice shattered-fragments measured by the

  5. An investigation of the accuracy of empirical aircraft design for the development of an unmanned aerial vehicle intended for liquid hydrogen fuel

    Science.gov (United States)

    Chaney, Christopher Scott

    A study was conducted to assess the accuracy of empirical techniques used for the calculation of flight performance for unmanned aerial vehicles. This was achieved by quantifying the error between a mathematical model developed with these techniques and experimental test data taken using an unmanned aircraft. The vehicle utilized for this study was developed at Washington State University for the purpose of flying using power derived from hydrogen stored as a cryogenic liquid. The vehicle has a mass of 32.8 kg loaded and performed a total of 14 flights under battery power for 3.58 total flight hours. Over these flights, the design proved it is capable of sustaining level flight from the power available from a PEM fuel cell propulsion system. The empirical techniques used by the model are explicitly outlined within. These yield several performance metrics that are compared to measurements taken during flight testing. Calculations of required thrust for steady flight over all airspeeds and rates of climb modeled are found to have a mean percent error of 3.2%+/-7.0% and a mean absolute percent error of 34.6%+/-5.1%. Comparison of the calculated and measured takeoff distance are made and the calculated thrust required to perform a level turn at a given rate is compared to flight test data. A section of a test flight is analyzed, over which the vehicle proves it can sustain level flight under 875 watts of electrical power. The aircraft's design is presented including the wing and tail, propulsion system, and build technique. The software and equipment used for the collection and analysis of flight data are given. Documentation and validation is provided of a unique test rig for the characterization of propeller performance using a car. The aircraft remains operational to assist with research of alternative energy propulsion systems and novel fuel storage techniques. The results from the comparison of the mathematical model and flight test data can be utilized to assist

  6. α-羟基-β,β-二甲基-γ-丁内酯绿色合成工艺研究%New Technology for Green Synthesis of α-Hydroxy-β,β-dimethyl-γ-butyrolactone

    Institute of Scientific and Technical Information of China (English)

    吴现印; 吕志果; 张伟伟

    2011-01-01

    The new synthesis process of DL-pantolactone was researched, which employed glyoxalic acid and iso-butyraldehyde (IBD) as raw materials. The process included aldol condensation,catalytic hydrogenation of aldol condensate and dehydration-cycli-zation under nano copper-based catalyst in the fixed bed reactor. The results showed that the conservation of IBD was more than 95% under the following conditions in aldol condensation: reaction temperature 60 ℃, n (glyoxalic acid) : n (IBD) : n (TEA) = 1 : 1: 1. 2 and reaction time 2 h. Under the conditions of reaction temperature 120 *C, n (H2) : n(IBD) = 80 : 1, H2pressure 8. 0 Mpa, liquid airspeed 0. 6 ~ 1. 0 h-1, and vacuum distillation (the vacuity was 0.096 Mpa), the yield of DL-pantolactone was 90% , meanwhile the purity of the product reached 99. 65%.%研究了乙醛酸和异丁醛(IBD)在胺类催化剂作用下羟醛缩合及其缩合产物在纳米铜基催化剂上一步加氢脱水环化制备α-羟基-β,β-二甲基-γ-丁内酯的绿色合成新工艺.结果表明:在物料配比n(乙醛酸):n(异丁醛)∶n(三乙胺)为1∶1∶1.2,缩合温度60℃、反应时间2h的条件下羟醛缩合,IBD的转化率大于95%;将缩合产物采用负载于硅胶上的纳米铜基催化剂在120℃、n(H2)∶n(IBD)=80:1,氢气压力8.0 MPa、液空速0.6~1.0 h-1的条件下连续固定床加氢、环化脱水,减压蒸馏(真空度0.096 MPa),收集110 ~120℃馏分,DL-泛内酯的收率大于90%,产品纯度达到99.65%.

  7. Modeling aerial refueling operations

    Science.gov (United States)

    McCoy, Allen B., III

    Aerial Refueling (AR) is the act of offloading fuel from one aircraft (the tanker) to another aircraft (the receiver) in mid flight. Meetings between tanker and receiver aircraft are referred to as AR events and are scheduled to: escort one or more receivers across a large body of water; refuel one or more receivers; or train receiver pilots, tanker pilots, and boom operators. In order to efficiently execute the Aerial Refueling Mission, the Air Mobility Command (AMC) of the United States Air Force (USAF) depends on computer models to help it make tanker basing decisions, plan tanker sorties, schedule aircraft, develop new organizational doctrines, and influence policy. We have worked on three projects that have helped AMC improve its modeling and decision making capabilities. Optimal Flight Planning. Currently Air Mobility simulation and optimization software packages depend on algorithms which iterate over three dimensional fuel flow tables to compute aircraft fuel consumption under changing flight conditions. When a high degree of fidelity is required, these algorithms use a large amount of memory and CPU time. We have modeled the rate of aircraft fuel consumption with respect to AC GrossWeight, Altitude and Airspeed. When implemented, this formula will decrease the amount of memory and CPU time needed to compute sortie fuel costs and cargo capacity values. We have also shown how this formula can be used in optimal control problems to find minimum costs flight plans. Tanker Basing Demand Mismatch Index. Since 1992, AMC has relied on a Tanker Basing/AR Demand Mismatch Index which aggregates tanker capacity and AR demand data into six regions. This index was criticized because there were large gradients along regional boundaries. Meanwhile tankers frequently cross regional boundaries to satisfy the demand for AR support. In response we developed continuous functions to score locations with respect to their proximity to demand for AR support as well as their

  8. Analysis of a Dynamic Multi-Track Airway Concept for Air Traffic Management

    Science.gov (United States)

    Wing, David J.; Smith, Jeremy C.; Ballin, Mark G.

    2008-01-01

    The Dynamic Multi-track Airways (DMA) Concept for Air Traffic Management (ATM) proposes a network of high-altitude airways constructed of multiple, closely spaced, parallel tracks designed to increase en-route capacity in high-demand airspace corridors. Segregated from non-airway operations, these multi-track airways establish high-priority traffic flow corridors along optimal routes between major terminal areas throughout the National Airspace System (NAS). Air traffic controllers transition aircraft equipped for DMA operations to DMA entry points, the aircraft use autonomous control of airspeed to fly the continuous-airspace airway and achieve an economic benefit, and controllers then transition the aircraft from the DMA exit to the terminal area. Aircraft authority within the DMA includes responsibility for spacing and/or separation from other DMA aircraft. The DMA controller is responsible for coordinating the entry and exit of traffic to and from the DMA and for traffic flow management (TFM), including adjusting DMA routing on a daily basis to account for predicted weather and wind patterns and re-routing DMAs in real time to accommodate unpredicted weather changes. However, the DMA controller is not responsible for monitoring the DMA for traffic separation. This report defines the mature state concept, explores its feasibility and performance, and identifies potential benefits. The report also discusses (a) an analysis of a single DMA, which was modeled within the NAS to assess capacity and determine the impact of a single DMA on regional sector loads and conflict potential; (b) a demand analysis, which was conducted to determine likely city-pair candidates for a nationwide DMA network and to determine the expected demand fraction; (c) two track configurations, which were modeled and analyzed for their operational characteristic; (d) software-prototype airborne capabilities developed for DMA operations research; (e) a feasibility analysis of key attributes in

  9. The 5 Million t/a Methanol to Propylene Device DME Reactor Process Control in Shenhua Ningxia Coal Industry Group%神宁50万t/a甲醇制丙烯装置DME反应器工艺控制

    Institute of Scientific and Technical Information of China (English)

    温辉

    2013-01-01

    神宁烯烃公司甲醇制丙烯装置,是目前世界上首套工业化甲醇制丙烯装置,甲醇首先经DME反应器转化成DME,之后进入甲醇制丙烯反应器转化为富含丙烯气的气烃化合物。DME反应器为绝热式固定床反应器,是目前国内最大的DME反应器,由于催化剂装填量大,床层为固定床,控温手段主要靠自身物料将反应热带走,在开车投料时极易发生飞温,造成催化剂失活。本文主要针对DME反应器在开车期间空速低,大量反应器热不能及时带走易造成飞温的情况提供操作指导。%Methanol to propylene device in Alkenes Company of Coal Chemical Industry Company Branch, Shenhua Ningxia Coal Indus-try Group is the first methanol to propylene device at present in the world. At first, methanol by DEM reactor into DME and then by methanol to propylene reactor into gas hydrocarbon compounds rich in propylene gas. DME reactor as the adiabatic fixed bed reactor is currently the largest DME reactor inland. Because of the large catalyst loading quantity and the fixed bed, as well as the means of tem-perature control mainly rely on their own materials to take away heat of reaction, the temperature runaway easily during their drive feed-ing leading to catalyst deactivation. This paper mainly for operating instructions to temperature runaway as DME reactor is low during driving airspeed and a lot of heat is not taken in time.

  10. A Remotely Piloted Aircraft (RPA) as a Measurement Tool for Wind-Energy Research

    Science.gov (United States)

    Wildmann, Norman; Bange, Jens

    2014-05-01

    In wind energy meteorology, RPA have the clear advantage compared to manned aircraft that they allow to fly very close to the ground and even in between individual wind turbines in a wind farm. Compared to meteorological towers and lidar systems, the advantage is the flexibility of the system, which makes it possible to measure at the desired site on short notice and not only in main wind direction. At the Center of Applied Geoscience at the University of Tübingen, the research RPA MASC (Multi-purpose Airborne Sensor Carrier) was developed. RPA of type MASC have a wingspan of about 3 m and a maximum take-off weight of 7.5 kg, including payload. The standard meteorological payload includes instruments for temperature, humidity, barometric pressure and wind measurement. It is possible to resolve turbulence fluctuations of wind and temperature up to 20 Hz. The autopilot ROCS (Research Onboard Computer System), which is developed at the Institute of Flight Mechanics and Control, University of Stuttgart, makes it possible to automatically follow predefined waypoints at constant altitude and airspeed. At a cruising speed of 24 m/s and a battery life of approx. one hour, a range of 80 km is feasible. The project 'Lidar Complex', funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, is part of the research network 'WindForS', based in Southern Germany. The goal of the project is to establish lidar technology for wind energy plant site evaluation in complex terrain. Additional goals are the comparison of different measurement techniques and the validation of wind-field models in not IEC 61400 conform terrain. It is planned to design a turbulent wind-field generator, fed by real measurement data, which can be used to analyse WEC behaviour. Two test sites were defined for the 'Lidar Complex' project, one in IEC-conform terrain about 15 km from the Baltic Sea, the other in the Swabian Alb, only 2 km downstream of a 100 m steep

  11. On-line identification, flutter testing and adaptive notching of structural parameters for V-22 tiltrotor aircraft

    Indian Academy of Sciences (India)

    R K Mehra; P O Arambel; A M Sampath; R K Prasanth; T C Parham

    2000-04-01

    New algorithms and results are presented for flutter testing and adaptive notching of structural modes in V-22 tiltrotor aircraft based on simulated and flight-test data from Bell Helicopter Textron, Inc. (BHTI). For flutter testing and the identification of structural mode frequencies, dampings and mode shapes, time domain state space techniques based on Deterministic Stochastic Realization Algorithms (DSRA) are used to accurately identify multiple modessimultaneously from sine sweep and other multifrequency data, resulting in great savings over the conventional Prony method. Two different techniques for adaptive notching are explored in order to design an Integrated Flight Structural Control (IFSC) system. The first technique is based on on-line identification of structural mode parameters using DSRA algorithm and tuning of a notch filter. The second technique is based on decoupling rigid-body and structural modes of the aircraft by means of a Kalman filter and using rigid-body estimates in the feedback control loop. The difference between the two approaches is that on-line identification and adaptive notching in the first approach are entirely based on the knowledge of structural modes, whereas the Kalman filter design in the second approach is based on the rigid-body dynamic model only.In the first IFSC design, on-line identification is necessary for flight envelope expansion and to adjust the notch filter frequencies and suppress aero-servoelastic instabilities due to changing flight conditionssuch as gross weight, sling loads, and airspeed. It isshown that by tuning the notch filterfrequency to the identified frequency, the phase lag is reduced and the corresponding structural mode is effectively suppressed and stability is maintained. In the second IFSC design using Kalman filter design, the structural modes are again effectively suppressed. Furthermore, the rigid-body estimates are found to be fairly insensitive to both natural frequency and damping factor

  12. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2011-07-01

    Full Text Available This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore we draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 % by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %, as well as changes in the aircraft lift (16 % are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s−1 at the extremes of a 95 % confidence interval. (b During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s−1. (c The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error of ≈0.4 m s−1 for the horizontal and ≈0.3 m s−1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s−1 or true airspeed (ranging from 23–30 m s−1 is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  13. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2011-02-01

    Full Text Available This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore we draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14%, relative to the initial uncertainty from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31% by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's aeroelastic wing (53%, as well as sudden changes in wing loading (16% are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s−1 at the extremes of a 95% confidence interval. (b During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s−1. (c The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square deviation of ≈0.4 m s−1 for the horizontal and ≈0.3 m s−1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s−1 or true airspeed (ranging from 23–30 m s−1 is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable eddy-covariance flux measurements.

  14. High Resolution Airborne Shallow Water Mapping

    Science.gov (United States)

    Steinbacher, F.; Pfennigbauer, M.; Aufleger, M.; Ullrich, A.

    2012-07-01

    In order to meet the requirements of the European Water Framework Directive (EU-WFD), authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim) a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length) of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river bed was achieved

  15. Simulation and control of a helicopter operating in a ship airwake

    Science.gov (United States)

    Lee, Dooyong

    This thesis describes a study in simulation and control of a helicopter operating in proximity to a ship. The helicopter/ship combination used in the study is a UH-60A helicopter operating off an LHA class ship. This represents the same aircraft ship combination used in the JSHIP program. The flight dynamics model is based on the GENHEL software and this flight dynamics model has been updated to include high-order dynamic inflow model and gust penetration effects of the ship airwake. To simulate the pilot control inputs for typical shipboard operations, an optimal control model of the human pilot is developed. The pilot model can be tuned to achieve different tracking performances based on a desired crossover frequency in each control axis and is designed to operate over a range of airspeeds using a simple gain scheduling algorithm. The pilot model is then used to predict pilot workload for shipboard operations in two different wind-over-deck conditions. Validation studies are conducted using both time and frequency domain analyses to understand the impact of a time-varying ship airwake on the pilot control activity for the approach and departure operations. The pilot control input autospectra predicted from the simulation model are compared to those of flight test data from the JSHIP program. It is found that the control activities are similar in low frequency range but underestimate in magnitude in the high frequency range (over 1.5 Hz). There is clear evidence that the human pilot is continually moving cyclic stick in the maneuver. At this stage of the study no attempt has been made to optimize the parameters of the human pilot model. The paper also discusses the application of a stochastic airwake model for more efficient simulation. This new airwake model is derived from the simulation with the full CFD airwake by extracting an equivalent six-dimensional gust vector. The spectral properties of the gust components are then analyzed, and shaping filters are

  16. Field campaigns of the autonomous, closed-path, airborne TDLAS Hygrometer SEALDH-II and traceability to the German Primary Humidity Standards.

    Science.gov (United States)

    Buchholz, Bernhard; Ebert, Volker

    2014-05-01

    Airborne hygrometry is often demanded in scientific flight campaigns to provide datasets for environmental modeling or to correct for water vapor dilution or cross sensitivity effects in other gas analytical techniques. Water vapor measurements, however, are quite challenging due to the large dynamic range in the atmosphere (between 2 and 40000 ppmv) and the high spatio-temporal variability. Airborne hygrometers therefore need to combine a large measurement range with high temporal resolution to resolve - at typical airspeeds of 500 to 900 km/h - atmospheric gradients of several 1000 ppmv/s. Especially during the ascent into the upper troposphere, hygrometers need to work at high gas exchange rates to minimize water vapor adsorption effects. On the other hand, water vapor sensors are difficult to calibrate due to the strong water adsorption and the lack of bottled reference gas standards, which requires pre- or/and post-flight field calibrations. Recently in-flight calibration using an airborne H2O generator was demonstrated, which minimizes calibration drift but still imposes a lot of additional work and hardware to the experiments, since these kind of calibrations just transfer the accuracy level issues to the in-flight calibration-source. To make things worse, the low gas flow (1-5 std l/min, compared with up to 100 std l/min in flight for fast response instruments) adheres critical questions of wall absorption/desorption of the source and instrument even during the calibration process. The national metrological institutes (NMIs) maintain a global metrological water vapor scale which is defined via national primary humidity generators. These provide for calibration purposes well-defined, accurate water vapor samples of excellent comparability and stability traced back to the SI-units. The humidity calibration chain is maintained via high accuracy (but rather slow) Dew-Point-Mirror-Hygrometers as transfer standards. These provide a traceable performance and

  17. Rotorcraft Aeromechanics Branch Home Page on the World Wide Web

    Science.gov (United States)

    Peterson, Randall L.; Warmbrodt, William (Technical Monitor)

    1996-01-01

    The tilt rotor aircraft holds great promise for improving air travel in the future. It's benefits include vertical take off and landing combined with airspeeds comparable to propeller driven aircraft. However, the noise from a tilt rotor during approach to a landing is potentially a significant barrier to widespread acceptance of these aircraft. This approach noise is primarily caused by Blade Vortex Interactions (BVI), which are created when the blade passes near or through the vortex trailed by preceding blades. The XV- 15 Aeroacoustic test will measure the noise from a tilt rotor during descent conditions and demonstrate several possible techniques to reduce the noise. The XV- 15 Aeroacoustic test at NASA Ames Research Center will measure acoustics and performance for a full-scale XV-15 rotor. A single XV-15 rotor will be mounted on the Ames Rotor Test Apparatus (RTA) in the 80- by 120-Foot Wind Tunnel. The test will be conducted in helicopter mode with forward flight speeds up to 100 knots and tip path plane angles up to +/- 15 degrees. These operating conditions correspond to a wide range of tilt rotor descent and transition to forward flight cases. Rotor performance measurements will be made with the RTA rotor balance, while acoustic measurements will be made using an acoustic traverse and four fixed microphones. The acoustic traverse will provide limited directionality measurements on the advancing side of the rotor, where BVI noise is expected to be the highest. Baseline acoustics and performance measurements for the three-bladed rotor will be obtained over the entire test envelope. Acoustic measurements will also be obtained for correlation with the XV-15 aircraft Inflight Rotor Aeroacoustic Program (IRAP) recently conducted by Ames. Several techniques will be studied in an attempt to reduce the highest measured BVI noise conditions. The first of these techniques will use sub-wings mounted on the blade tips. These subwings are expected to alter the size

  18. Delay Banking for Managing Air Traffic

    Science.gov (United States)

    Green, Steve

    2008-01-01

    Delay banking has been invented to enhance air-traffic management in a way that would increase the degree of fairness in assigning arrival, departure, and en-route delays and trajectory deviations to aircraft impacted by congestion in the national airspace system. In delay banking, an aircraft operator (airline, military, general aviation, etc.) would be assigned a numerical credit when any of their flights are delayed because of an air-traffic flow restriction. The operator could subsequently bid against other operators competing for access to congested airspace to utilize part or all of its accumulated credit. Operators utilize credits to obtain higher priority for the same flight, or other flights operating at the same time, or later, in the same airspace, or elsewhere. Operators could also trade delay credits, according to market rules that would be determined by stakeholders in the national airspace system. Delay banking would be administered by an independent third party who would use delay banking automation to continually monitor flights, allocate delay credits, maintain accounts of delay credits for participating airlines, mediate bidding and the consumption of credits of winning bidders, analyze potential transfers of credits within and between operators, implement accepted transfers, and ensure fair treatment of all participating operators. A flow restriction can manifest itself in the form of a delay in assigned takeoff time, a reduction in assigned airspeed, a change in the position for the aircraft in a queue of all aircraft in a common stream of traffic (e.g., similar route), a change in the planned altitude profile for an aircraft, or change in the planned route for the aircraft. Flow restrictions are typically imposed to mitigate traffic congestion at an airport or in a region of airspace, particularly congestion due to inclement weather, or the unavailability of a runway or region of airspace. A delay credit would be allocated to an operator of a

  19. Vertical and Horizontal Measurements of Ambient Ozone over a Gas and Oil Production Area using a UAV Platform

    Science.gov (United States)

    Jensen, A.; Gowing, I.; Martin, R. S.

    2013-12-01

    During the 2013 wintertime Uintah Basin Ozone Study (UBOS13), an autonomous unmanned aerial vehicle (UAV) platform, coupled with an on-board UV ozone monitor, flew several spatial profiles near the location (Horse Pool) of other concentrated measurements by other co-investigators. The airframe, part of the Utah Water Research Laboratory's (UWRL) AggieAir UAV program, consisted of a custom-built, battery-operated plane with and 2.4 m (8 ft) wing span and a 12.7 cm x 12.7 cm x 30.5 cm payload bay with a carrying capacity of approximately 2.0 kg. With the current power system, the fully-loaded AggieAir UAV can fly for approximately 45 minutes at a nominal airspeed of 13.4 m/s (30 mph). The system can be operated either in manual control or be flown autonomously following preprogrammed waypoints via a built in GPS system. The AggieAir UAV systems were primarily designed for photographic and telemetry tracking projects. For the UBOS13 flights, a 2B Technologies Model 205 Ozone (O3) monitor was modified for minimal weight optimization, wrapped with lightweight insulation and secured into the UAV payload bay. Additionally, HOBO Model H08-001-02 shielded temperature/datalogger was secured to the exterior of the UAV from parallel thermal profile determination. During the study period, three demonstration flight profiles were obtained on February 17 and 18, 2013: two vertical 'curtain' profiles and a pair of 'stacked' horizontal profiles. As recorded by numerous ground-based monitoring sites, the ozone during the UAV test periods was characterized by initial trends of daytime O3 maximums over 130 ppb, followed by a meteorological front partially ventilating the Basin on the evening of Feb. 17th leading to decreased O3 minimums around 40 ppb. However, the ground level O3 rebuilt quickly to ground level maximums approaching 100 ppb. The vertical 'curtain' flown on the evening of Feb. 17th only reached a maximum elevation of about 2160 m ASL (600 m AGL) due to encountering

  20. Commercial application of hydrocracking catalysts for Fiseher-Tropsch synthesis%F-T合成加氢裂化催化剂的工业应用

    Institute of Scientific and Technical Information of China (English)

    刘尚利; 陈大方

    2014-01-01

    F-T synthetic oil is mainly composed of n-paraffins of alkanes and alkenes,in which wax is accounted for 40%. The production maximization of the high quality middle distillates are one of the effec-tive ways to make full use of F-T synthetic wax. The development and application of the catalysts with high performance is the key of hydrocracking technology. The recent research progress in hydrocracking cata-lysts and their application status at home and abroad were reviewed. The commercial applications of FC-14 and SC-I catalysts in Inner Mongolia Yitai CTO Co. ,Ltd. were especially introduced. The running results showed that SC-I catalyst exhibited good activity and selectivity to middle distillate. Under the condition of total feedstock rate 20 t·h-1,hydrogen partial pressure of reactor inlet 7. 0 MPa,hydrogen/oil volume ratio 800 ,total volume airspeed( 2 . 0-15 . 0 )h-1 ,reactor outlet temperature about 340 ℃ and overall temperature rise 14 ℃,the catalyst exhibited high reaction activity,flexible temperature control perform-ance and high selectivity to medium oil,and diesel yield increased about 3 -4 percentage point at the same time.%F-T合成油低温工艺产物中有大于质量分数40%的石蜡生成,必须对其进行加氢裂化生产优质的中间馏分油。加氢裂化关键在于高性能催化剂的研究开发,概述了近年来加氢裂化催化剂在国内外的应用现状。FC-14及SC-I催化剂在内蒙古伊泰煤制油有限责任公司的运行结果表明,SC-I催化剂表现出良好的活性及较高的中间馏分油选择性,在总进料20 t·h-1、反应器入口氢分压7.0 MPa、氢油体积比800和总体积空速(2.0~15.0)h-1条件下,反应器出口温度约340℃,总温升14℃,表现出较高的反应活性及灵活的温度调控性,柴油收率上升约3~4个百分点,具有较高的中油选择性。

  1. Edward (Ed) T. Schneider in Front of SR-71 Blackbird

    Science.gov (United States)

    1995-01-01

    SR-71 research pilot Ed Schneider is pictured here in front of an SR-71 Blackbird on the ramp at the Dryden Flight Research Center, Edwards, California. Schneider became a NASA research pilot at Dryden in 1983. Data from the SR-71 program will be used to aid designers of future supersonic aircraft and propulsion systems. He retired as a NASA research pilot in September 2000. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or

  2. Fast, multi-phase H2O measurements on board of HALO: Results from the novel HAI instrument during the first field campaigns.

    Science.gov (United States)

    Buchholz, Bernhard; Afchine, Armin; Krämer, Martina; Ebert, Volker

    2014-05-01

    in a so called "closed-path" cell [6] for total water measurement via a forward facing inlet. The other part of the laser light is coupled to an "open-path" cell [7] placed outside of the aircraft fuselage to measure gas phase water without any possible artifacts from ice or liquid particles. The frequency of the measurements can be up to 240 Hz (4.2 msec) for all four channels. Altogether, the novel HAI instrument allows fast, accurate and precise dual-phase water measurements. The individual evaluation of the multi-channel raw-data is done afterwards, without any channel interdependencies, in a calibration-free mode. The water signals are combined with an extensive set of more than 100 housekeeping data to enable a holistic data quality management and a rigorous signal scrutiny to maximize the confidence level of the final H2O values. HAI therefore represents a new unique research tool for atmospheric hygrometry to address numerous open topics in atmospheric research. First scientific HAI campaigns have been successfully realized in 2012 onboard the German research plane HALO (High Altitude and Long Range Research Aircraft) during the TACTS and ESMVal missions. The first two HALO campaigns in clouds (MLCIRRUS and ACRIDICON) will be realized in 2014. In our contribution we present and discuss the performance of HAI and show detailed evaluations of typical inflight data. The results of the first two HAI campaigns on HALO resulted in more than 100 operation hours of continuous data and show nice agreement between the closed-path and open-path under clear sky conditions, despite the different sampling conditions of the sensor channels and airspeed of up to 900 km/h in the open path section. All mission data are and will be uploaded to the HALO database and are available for further scientific exploitation. Furthermore, the HAI principle can be adapted to other (airborne) platforms and be used for phase resolved science of the atmospheric water cycle. In parallel HAI

  3. SR-71 Mid-air Refueling with KC-135 Tanker

    Science.gov (United States)

    1995-01-01

    NASA Dryden Flight Research Center's SR-71B, tail number 831, is seen here receiving air refueling from a USAF tanker during a July, 1995 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward-looking ultraviolet video camera placed in

  4. SR-71B - in Flight with F-18 Chase Aircraft - View from Air Force Tanker

    Science.gov (United States)

    1996-01-01

    NASA 831, an SR-71B operated by the Dryden Flight Research Center, Edwards, California, cruises over the Mojave Desert with an F/A-18 Hornet flying safety chase. They were photographed on a 1996 mission from an Air Force refueling tanker The F/A-18 Hornet is used primarily as a safety chase and support aircraft at Dryden. As support aircraft, the F-18s are used for safety chase, pilot proficiency and aerial photography. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used

  5. SR-71A - in Flight over Southern Sierra Nevada Mountains

    Science.gov (United States)

    1997-01-01

    NASA Dryden Flight Research Center's SR-71A, tail number 844, banks away over the Sierra Nevada mountains after air refueling from a USAF tanker during a 1997 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward-looking ultraviolet

  6. SR-71A - in Flight View from Tanker during an Airborne Refueling

    Science.gov (United States)

    1997-01-01

    This photo shows a USAF tanker aircraft Boom Operator's or 'Boomer's' view of NASA Dryden Flight Research Center's SR-71A, tail number 844, following air refueling during a 1997 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  7. SR-71 - In-flight Close-up from Tanker

    Science.gov (United States)

    1994-01-01

    collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward-looking ultraviolet video camera placed in the SR-71's nosebay studied a variety of celestial objects in wavelengths that are blocked to ground-based astronomers. Earlier in its history, Dryden had a decade of past experience at sustained speeds above Mach 3. Two YF-12A aircraft and an SR-71 designated as a YF-12C were flown at the center between December 1969 and November 1979 in a joint NASA/USAF program to learn more about the capabilities and limitations of high-speed, high-altitude flight. The YF-12As were prototypes of a planned interceptor aircraft based on a design that later evolved into the SR-71 reconnaissance aircraft. Dave Lux was the NASA SR-71 project manger for much of the decade of the 1990s, followed by Steve Schmidt. Developed for the USAF as reconnaissance aircraft more than 30 years ago, SR-71s are still the world's fastest and highest-flying production aircraft. The aircraft can fly at speeds of more than 2,200 miles per hour (Mach 3+, or more than three times the speed of sound) and at altitudes of over 85,000 feet. The Lockheed Skunk Works (now Lockheed Martin) built the original SR-71 aircraft. Each aircraft is 107.4 feet long, has a wingspan of 55.6 feet, and is 18.5 feet high (from the ground to the top of the rudders, when parked). Gross takeoff weight is about 140,000 pounds, including a possible fuel weight of 80,280 pounds. The airframes are built almost entirely of titanium and titanium alloys to withstand heat generated by sustained Mach 3 flight

  8. SR-71 - In-flight from Tanker

    Science.gov (United States)

    1994-01-01

    Dryden's SR-71B, NASA 831, slices across the snow-covered southern Sierra Nevada Mountains of California after being refueled by an Air Force tanker during a 1994 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  9. SR-71B - in Flight - View from Air Force Tanker

    Science.gov (United States)

    1997-01-01

    This look-down view shows NASA 831, an SR-71B flown by Dryden Flight Research Center, Edwards, California, as it cruises over the Mojave Desert. The photo was from an Air Force refueling tanker taken on a 1997 mission. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in

  10. SR-71B - in flight over snow-capped mountains

    Science.gov (United States)

    1995-01-01

    used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward-looking ultraviolet video camera placed in the SR-71's nosebay studied a variety of celestial objects in wavelengths that are blocked to ground-based astronomers. Dryden has had a decade of past experience at sustained speeds above Mach 3. Two YF-12A aircraft and an SR-71 designated as a YF-12C were flown at the center between December 1969 and November 1979 in a joint NASA/USAF program to learn more about the capabilities and limitations of high-speed, high-altitude flight. The YF-12As were prototypes of a planned interceptor aircraft based on a design that later evolved into the SR-71 reconnaissance aircraft. Dave Lux was the NASA SR-71 project manger for much of the decade of the 1990s, followed by Steve Schmidt. Developed for the USAF as reconnaissance aircraft more than 30 years ago, SR-71s are still the world's fastest and highest-flying production aircraft. The aircraft can fly at speeds of more than 2,200 miles per hour (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 feet. The Lockheed Skunk Works (now Lockheed Martin) built the original SR-71 aircraft. Each aircraft is 107.4 feet long, has a wingspan of 55.6 feet, and is 18.5 feet high (from the ground to the top of the rudders, when parked). Gross takeoff weight is about 140,000 pounds, including a possible fuel weight of 80,280 pounds. The airframes are built almost entirely of titanium and titanium alloys to withstand heat generated by sustained Mach 3 flight. Aerodynamic control surfaces consist of all

  11. Taxi Arrival of Second SR-71 to Dryden

    Science.gov (United States)

    1990-01-01

    One of two initial U.S. Air Force SR-71A reconnaissance aircraft that was retired from operational service and loaned to NASA for high-speed research programs taxis in to the ramp on its arrival at NASA's Ames-Dryden Flight Research Facility (later Dryden Flight Research Center), Edwards, California in March 1990. Data from the SR-71 high speed research program will be used to aid designers of future supersonic/hypersonic aircraft and propulsion systems. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the

  12. SR-71 - Taxi on Ramp with Engines

    Science.gov (United States)

    1995-01-01

    This photo shows a head-on shot of NASA's SR-71A aircraft taxiing on the ramp at NASA's Dryden Flight Research Center, Edwards, California, heat waves from its engines blurring the hangars in the background. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena