Lovesey, E J
In just over a decade the hovercraft has progressed from first prototype to a successful commercial form of transport which also has the ability to penetrate many environments hitherto virtually inaccessible to manned vehicles. Comparison with rival short range vehicles such as the helicopter and hydrofoil show that the hovercraft has become one of the most versatile forms of transport available. This versatility and ability to operate in unusual or extreme environments has been accompanied by the problems of control and of protection of the occupants of the hovercraft from the hazards associated with these environments. Several of these problems are discussed, together with their possible solutions. This article is based on a paper given to the Nederlands Vereniging Voor Ergonomie/Ergonomics Research Society joint conference at Noordwijk in Holland, 11-13 June, 1969.
Noor, S. H. Mohamed; Syam, K.; Jaafar, A. A.; Mohamad Sharif, M. F.; Ghazali, M. R.; Ibrahim, W. I.; Atan, M. F.
This paper presents the development process to fabricate a working hovercraft model. The purpose of this study is to design and investigate of a fully functional hovercraft, based on the studies that had been done. The different designs of hovercraft model had been made and tested but only one of the models is presented in this paper. In this thesis, the weight, the thrust, the lift and the drag force of the model had been measured and the electrical and mechanical parts are also presented. The processing unit of this model is Arduino Uno by using the PSP2 (Playstation 2) as the controller. Since our prototype should be functioning on all kind of earth surface, our model also had been tested in different floor condition. They include water, grass, cement and tile. The Speed of the model is measured in every case as the respond variable, Current (I) as the manipulated variable and Voltage (V) as the constant variable.
Dickens, D; Belore, R; Buist, I; Humphrey, B
A series of field trials were carried out in Vancouver, Canada in July and August 1986 to determine whether or not hovercraft should be considered for dispersant application. Questions are: the ability of the hovercraft to ''fly'' over an oil slick at high speed without displacing the oil out of the path, the potential for using the hovercraft to impart vertical mixing energy into the water column to aid in the dispersant process and, the ability to mount a suitable spray boom and obtain a uniform spray pattern across the swath width. The field trials and subsequent interpretation of results provide positive answers to the first and second question. The question of mixing energy requires some qualification. The hovercraft contributes considerable mixing energy to the immediate water surface through air entrainment but this effect is short lived and there does not appear to be significant long term vertical mixing in the hovercraft wake. Recommendations are made for operating procedures and boom mounting which should ensure a uniform drop size and dose rate across a swath up to 18 m. The cushion air escaping from around the craft perimeter is not an important factor in adversly affecting the dispersant spray pattern. Depending on the type of machine available, hovcercraft have the capability of treating up to a 1km/sup 2/ slick between loads, at average speeds in the 15 to 25 knot range. The inherent advantages of high transit speed to the site (up to 45 Knots), amphibious operation (i.e. not draft limited) and lack of ceiling or visibility restrictions provide hovercarft with unique capabilities in the dispersant application role. Two patents relating to the process have been abstracted. Appendix B gives the sprecifications of two different models of hovercrafts. 14 refs., 29 figs., 6 tabs.
Moran, D. D.
Hovercraft lift fans are subjected to varying back pressure due to wave action and craft motions when these vehicles are operating in a seaway. The oscillatory back pressure causes the fans to perform dynamically, exhibiting a hysteresis type of response and a corresponding degradation in mean performance. Since Hovercraft motions are influenced by variations in lift fan pressure and discharge, it is important to understand completely the nature of the dynamic performance of lift fans in order to completely solve the Hovercraft seakeeping problem. The present study was performed to determine and classify the instabilities encountered in a centrifugal fan operating against time-varying back pressure. A model-scale experiment was developed in which the fan discharge was directed into a flow-measuring device, terminating in a rotating valve which produced an oscillatory back pressure superimposed upon a mean aerodynamic resistance. Pressure and local velocity were measured as functions of time at several locations in the fan volute. The measurements permitted the identification of rotating (or propagating) stall in the impeller. One cell and two cell configurations were classified and the transient condition connecting these two configurations was observed. The mechanisms which lead to rotating stall in a centrifugal compressor are presented and discussed with specific reference to Hovercraft applications.
Hall, J. K.; Kristoffersen, Y.; Brekke, H.; Hope, G.
After four years of testing methods, craft reliability, and innovative equipment, the R/H SABVABAA has embarked on its first FRAM-201x expedition to the highest Arctic. Named after the Inupiaq word for 'flows swiftly over it', the 12m by 6m hovercraft has been home-based in Longyearbyen, Svalbard since June 2008. In this, its fifth summer of work on the ice pack north of 81N, the craft is supported by the Norwegian Petroleum Directorate (NPD) via the Nansen Environmental and Remote Sensing Center (NERSC) in Bergen, and the Norwegian Scientific Academy for Polar Research. FRAM-2012 represents renewed Norwegian interest in returning to the highest Arctic some 116 years after the 1893-96 drift of Fridtjof Nansen's ship FRAM, the first serious scientific investigation of the Arctic. When replenished by air or icebreaker, the hovercraft Sabvabaa offers a hospitable scientific platform with crew of two, capable of marine geophysical, geological and oceanographic observations over long periods with relative mobility on the ice pack. FRAM-2012 is the first step towards this goal, accompanying the Swedish icebreaker ODEN to the Lomonosov Ridge, north of Greenland, as part of the LOMROG III expedition. The science plan called for an initial drive from the ice edge to Gakkel Ridge at 85N where micro-earthquakes would be monitored, and then to continue north to a geological sampling area on the Lomonosov Ridge at about 88N, 65W. The micro-earthquake monitoring is part of Gaute Hope's MSc thesis and entails five hydrophones in a WiFi-connected hydrophone array deployed over the Gakkel Rift Valley, drifting with the ice at up to 0.4 knots. On August 3 the hovercraft was refueled from icebreaker ODEN at 84-21'N and both vessels proceeded north. The progress of the hovercraft was hampered by insufficient visibility for safe driving and time consuming maneuvering in and around larger fields of rubble ice impassable by the hovercraft, but of little concern to the icebreaker. It
Hall, J. K.; Kristoffersen, Y.
We have tested the feasibility of hovercraft travel through predominantly first year ice of the Transpolar Drift between 81°N - 85°N north of Svalbard. With 2-9 ridges per kilometer, our hovercraft (Griffon TD2000 Mark II), with an effective hover height of about 0.5 m, had to travel a distance 1.3 times the great circle distance between the point of origin and the final destination. Instantaneous speeds were mostly 5-7 knots. Two weeks later icebreaker Oden completed the same transit under conditions with no significant pressure in the ice at a speed mostly 1 knot higher than the hovercraft and travelled 1.2 times the great circle distance. The hovercraft spent 25 days monitoring micro-earthquake activity of the Arctic Mid-Ocean Ridge at a section of the spreading center where no seismicity has been recorded by the global seismograph network. More than ten small earthquake events per day were recorded. Visibility appears to be the most critical factor to hovercraft travel in polar pack ice. Improved control of hovercraft motion would substantially increase the potential usefulness of hovercraft in the sea ice environment. University of Bergen graduate student Gaute Hope emplacing one of the hydrophones in the triangular array used to locate small earthquakes over the Gakkel Ridge rift valley around 85N during FRAM-2012. The research hovercraft R/H SABVABAA is in the background.
Ioannis A. Raptis
Full Text Available This paper introduces a methodology for the design, testing and assessment of incipient failure detection techniques for failing components/systems of an autonomous vehicle masked or hidden by feedback control loops. It is recognized that the optimum operation of critical assets (aircraft, autonomous systems, etc. may be compromised by feedback control loops by masking severe fault modes while compensating for typical disturbances. Detrimental consequences of such occurrences include the inability to detect expeditiously and accurately incipient failures, loss of control and inefficient operation of assets in the form of fuel overconsumption and adverse environmental impact. We pursue a systems engineering process to design, construct and test an autonomous hovercraft instrumented appropriately for improved autonomy. Hidden fault modes are detected with performance guarantees by invoking a Bayesian estimation approach called particle filtering. Simulation and experimental studies are employed to demonstrate the efficacy of the proposed methods.
V. P. Morozov
Full Text Available The principle of "early matching" aircraft aerohydrodynamic layouts with air cushion landing gear is suggested. Application of this principle is considered as an example of adaptation to the ball screw base circuit of light transport aircraft. The principle, other than weight, aerodynamic, technological and operational requirements includes additional project activities related to the installation of ball screws.
Yu. Yu. Merzlikin
Full Text Available The features of the physical modeling in the experimental determination of aerodynamics-cal tubes (WT of low-velocity steady and unsteady aerodynamic characteristics at takeoff and landing of aircraft (LA with the chassis air-cushion (ball screw and in studies to determine the stability of equilibrium regimes of movement and shock-absorbing properties of ball screws. Are conscdered the requirements for the experimental facilities, model aircraft with ball screws and re-test of the latest zhimam on the free stream velocity, flow and pressure blowers VР, the frequencies and amplitudes of the oscillations are formulated.
... bench above the beach. A diesel bus would be used to transport passengers between the hovercraft and... marine mammal Marking, Tagging, and Reporting Program (MTRP) indicates that on average, less than one sea...
McCarthy, M.W.; McGrath, J.
On July 22, 1991, the Tuo Hai, a 46,500 ton Chinese grain carrier, collided with the Tenyo Maru, a 4,800 ton Japanese fish processing ship, off the coast of Washington State. The Tenyo Maru sank, creating an oil spill that cost upwards of $4 million (US) to clean up. The incident initiated a joint response from the US and Canadian governments. As part of this response, the Canadian Coast Guard mobilized an SRN-6 hovercraft. This air cushioned vehicle (ACV) provided logistical support to responders on both sides of the international boundary. The response operation along the Pacific Coast was extensive. Dense fog and the remote location of the impacted area provided formidable challenges to the cleanup effort. It was the mission scenario of the Canadian SRN-6 hovercraft to provide logistical support-as an experiment in ACV utility-to the organizations responding to this incident. Based on this experience, it can be argued that the hovercraft offers great potential value in responding to marine oil spills. Appropriate application of ACV technology can enhance oil spill response work, spill waste management, and incident surveillance. This paper discusses the contribution of the SRN-6 hovercraft to the Tenyo Maru response, briefly examines the use of another, very different hovercraft, during a response in the Gulf of St. Lawrence, and reviews a new hovercraft design and discusses its potential contributions
Full Text Available In our ongoing project on the autonomous guidance of Micro-Air Vehicles (MAVs in confined indoor and outdoor environments, we have developed a bio-inspired optic flow based autopilot enabling a hovercraft to travel safely, and avoid the walls of a corridor. The hovercraft is an air vehicle endowed with natural roll and pitch stabilization characteristics, in which planar flight control can be developed conveniently. It travels at a constant ground height (∼2mm and senses the environment by means of two lateral eyes that measure the right and left optic flows (OFs. The visuomotor feedback loop, which is called LORA(1 (Lateral Optic flow Regulation Autopilot, Mark 1, consists of a lateral OF regulator that adjusts the hovercraft's yaw velocity and keeps the lateral OF constant on one wall equal to an OF set-point. Simulations have shown that the hovercraft manages to navigate in a corridor at a “preset” groundspeed (1m/s without requiring a supervisor to make it switch abruptly between the control-laws corresponding to behaviours such as automatic wall-following, automatic centring, and automatically reacting to an opening encountered on a wall. The passive visual sensors and the simple control system used here are suitable for use on MAVs with an avionic payload of only a few grams.
Shaw, G. W.; And Others
Provides a reading list for A- and S-level biology. Contains several experiments and demonstrations with topics on: the intestine, bullock corneal cells, valences, the science of tea, automated hydrolysis, electronics characteristics, bromine diffusion, enthalpy of vaporization determination, thermometers, pendulums, hovercraft, Bernoulli fluid…
Five years ago, Leon Strecker's technology education class at Darien High School came up with the idea of building a fuel cell-powered go-kart. In previous years, the class had worked on other creations, such as electric cars that competed in a state-sponsored race and a full-size hovercraft. But students had not taken on anything anywhere near…
Provided are activities and demonstrations which can be used to teach infants about the nature of air, uses of air, and objects that fly in the air. The latter include airships, hot-air balloons, kites, parachutes, airplanes, and Hovercraft. (JN)
Full Text Available In our ongoing project on the autonomous guidance of Micro-Air Vehicles (MAVs in confined indoor and outdoor environments, we have developed a bio-inspired optic flow based autopilot enabling a hovercraft to travel safely, and avoid the walls of a corridor. The hovercraft is an air vehicle endowed with natural roll and pitch stabilization characteristics, in which planar flight control can be developed conveniently. It travels at a constant ground height (~2mm and senses the environment by means of two lateral eyes that measure the right and left optic flows (OFs. The visuomotor feedback loop, which is called LORA(1 (Lateral Optic flow Regulation Autopilot, Mark 1, consists of a lateral OF regulator that adjusts the hovercraft's yaw velocity and keeps the lateral OF constant on one wall equal to an OF set-point. Simulations have shown that the hovercraft manages to navigate in a corridor at a "pre-set" groundspeed (1m/s without requiring a supervisor to make it switch abruptly between the control-laws corresponding to behaviours such as automatic wall-following, automatic centring, and automatically reacting to an opening encountered on a wall. The passive visual sensors and the simple control system used here are suitable for use on MAVs with an avionic payload of only a few grams.
High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...
Sevostyanov Ruslan A.
Full Text Available Advanced marine surface crafts, such as SWATHs, catamarans or hovercrafts become more and more popular for a great range of various tasks. They usually operate at much higher speed than conventional ships. Moreover, in the open sea there are a lot of requirements and restrictions concerning the quality of such crafts’ dynamics, especially in case of the wind or waves. This paper considers application of the control law with a special multipurpose structure for autopilot design for amphibious air cushion vehicles. Such control law allows to decompose the autopilot task into simpler optimization subtasks. Efficiency of this approach is shown in the task of stabilizing yaw angle of the air cushion vehicle in the different weather conditions.
A discussion of the Arctic Marine Oil Spill Program organized in 1976 by the Canadian Federal Government includes: an Arctic Atlas compiled by Fenco Consultants Ltd. to give background information necessary for developing marine oil spill countermeasures for the Arctic north of 60/sup 0/ including the west Greenland coast and the Labrador shelf (geology, meteorology and oceanography, ice conditions, biology, and social factors); program in emergency transport of spill-combatting equipment; and the factors which influence the choice of conveyance, i.e., accessibility of the site, urgency for response, and quantity of material required; laboratory studies involving the release of oil under artificial sea ice in simulated ice formation and decay purposes to determine the interaction of crude oil and first-year sea ice; inability of companies and government to control a major spill in the Labrador Sea because of poor and inadequate transport facilities, communications, and navigational aids, severe environmental conditions, and logistics problems; and studies on the effects of oil-well blowouts in deep water, including formation of oil and gas hydrates, design of oil skimmers, the use of hovercraft, and specifications for an airborne multisensor system for oil detection in ice-infested waters.
Senus, Michael P.; Tenbus, Frederick J.
This report presents lithologic and ground-water-quality data collected during April and May 2000 in the remote areas of the tidal wetland of West Branch Canal Creek, Aberdeen Proving Ground, Maryland. Contamination of the Canal Creek aquifer with volatile organic compounds has been documented in previous investigations of the area. This study was conducted to investigate areas that were previously inaccessible because of deep mud and shallow water, and to support ongoing investigations of the fate and transport of volatile organic compounds in the Canal Creek aquifer. A unique vibracore drill rig mounted on a hovercraft was used for drilling and ground-water sampling. Continuous cores of the wetland sediment and of the Canal Creek aquifer were collected at five sites. Attempts to sample ground water were made by use of a continuous profiler at 12 sites, without well installation, at a total of 81 depths within the aquifer. Of those 81 attempts, only 34 sampling depths produced enough water to collect samples. Ground-water samples from two sites had the highest concentrations of volatile organic compounds?with total volatile organic compound concentrations in the upper part of the aquifer ranging from about 15,000 to 50,000 micrograms per liter. Ground-water samples from five sites had much lower total volatile organic compound concentrations (95 to 2,100 micrograms per liter), whereas two sites were essentially not contaminated, with total volatile organic compound concentrations less than or equal to 5 micrograms per liter.
Harashima, Fumio; Suzuki, Satoshi
This paper mentions circumstance of mechatronics that sustain our human society, and introduces HAM(Human Adaptive Mechatronics)-project as one of research projects to create new human-machine system. The key point of HAM is skill, and analysis of skill and establishment of assist method to enhance total performance of human-machine system are main research concerns. As study of skill is an elucidation of human itself, analyses of human higher function are significant. In this paper, after surveying researches of human brain functions, an experimental analysis of human characteristic in machine operation is shown as one example of our research activities. We used hovercraft simulator as verification system including observation, voluntary motion control and machine operation that are needed to general machine operation. Process and factors to become skilled were investigated by identification of human control characteristics with measurement of the operator's line-of sight. It was confirmed that early switching of sub-controllers / reference signals in human and enhancement of space perception are significant.
Full Text Available Resumen: En este trabajo se realiza un análisis de diferentes metodologías de control robusto basadas en la técnica denominada Teoría de la Realimentación Cuantitativa, QFT (Quantitative Feedback Theory para resolver diferentes problemáticas que surgen en los sistemas de control marinos. En concreto se estudia el posicionamiento dinámico de una plataforma marina fondeada, la estabilización de un buque de alta velocidad, y el seguimiento de referencia para un aerodeslizador. Estos problemas de control presentan grandes retos de diseño, dado que son sistemas no lineales, multivariables, subactuados y con grandes perturbaciones. Los diferentes tipos de diseño QFT obtenidos consiguen una implementación robusta con prevención de acoplamientos, reducción de perturbaciones ambientales, respuestas rápidas y precisión en el seguimiento, que demuestran finalmente que es una alternativa práctica y eficaz para la solución de problemas de control en vehículos navales Abstract: In this work an analysis of the application of the Quantitative Feedback Theory (QFT technique to different marine systems is presented. Specifically, the problems of dynamic positioning of a moored platform, stabilization of a fast ferry and the tracking control of a hovercraft are studied. This control problem presents interesting questions to deal with, since the plants are non-linear, multivariable, underactuated and subject to large disturbances due to waves.Three multivariable nonlinear problems are solved using different sequential procedures. It is shown that the QFT controllers synthesis achieve robust performance, decoupling, environment disturbance reduction, quick answers and tracking precision. Therefore, it is shown that robust techniques based on QFT methodologies result feasible and very suitable, constituting an attractive alternative for robust design of marine vehicles. Palabras clave: Control robusto, sistema no lineal, vehículo subactuado
to be relocated. Besides supporting TBMP, I also supported the Section 508 Policy Compliance Coordinator, R. Liang. Section 508 is a policy that requires employers to implement accessibility assurance of information and technology to disabled communities. On Thursday, July 19, 2012, I was able to go to Camp Boggy Creek-a camp for disabled children-for an education outreach, in collaboration with the Education Office. We shared with them information about how astronauts live and work in space, they were able to ride hovercrafts, build paper rockets, and then launch them outside. Although this outreach was quite fun with the kids at the camp, this was a learning opportunity to gain some insight to those with cognitive and physical disabilities, the problems they typically face, and in tum, how to accommodate those with disabilities in the work environment. In the process of implementing accessibility and Section 508 compliance, I attended various teleconferences, did field runs to supply closed-caption call phones to employees with limited hearing, and helped with the development of the charter ofthe Section 508 Compliance Working Group.