Orientador: Jose Geraldo Trani Brandão / Banca: José Elias Tomazini / Banca: Valdeci Donizete Gonçalves / Resumo: No desempenho de suas atividades aéreas, os pilotos de helicópteros são submetidos a posturas que impõem tensões contínuas em determinados grupos musculares, ao mesmo tempo em que deixam outras musculaturas em desuso. Diante disso, observam-se inúmeros casos de lombalgia que acometem pilotos de helicópteros Esquilo, principalmente nas Forças Armadas, sendo prováveis causas a ergonomia do assento e a vibração que o corpo sofre. Diante de tal fato, este estudo teve os seguintes objetivos: (1) mensurar os níveis de aceleração (vibração), na direção longitudinal (eixo z) da coluna lombar a que os pilotos de helicópteros As-350 L1 Esquilo estão expostos durante o voo; (2) verificar a atividade muscular dos eretores da espinha dos pilotos de helicópteros As-350 L1 Esquilo, com um aparelho de eletromiografia, durante a exposição à vibração em voo; (3) analisar os dados dos pilotos, da aceleração, os sinais de eletromiografia dos músculos eretores da espinha e a sua correlação. A fim de atingir esses objetivos, foram distribuídos 60 questionários para os pilotos de Esquilo do Complexo de Aviação do Exército em Taubaté-SP. Posteriormente, foram selecionados dois pilotos do sexo masculino, de estatura média e acima da média, na faixa etária de 30 a 35 anos de idade, com mais de 300 horas de voo e com classificações morfológicas corporais diferentes, de acordo com a tabela IMC. Após a coleta dos dados, os resultados foram analisados através da norma ISO 2631: 1997 e tratados estatisticamente. No estudo, observou-se que esses pilotos estão expostos a uma vibração de corpo inteiro que requer cautela em relação ao risco à saúde, pois os valores de aceleração encontrados no estudo encontraram-se compreendidos na... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The helicopter pilot's posture while operating an aircraft can cause continuing strain on certain muscle groups while leaving others unused. Many Esquilo helicopter pilots, especially in the military, are reported to suffer from low back pain, the probable causes being seat ergonomics and the effect of aircraft vibration on the body. With this in mind, this study proposed the following objectives: (1) measure the levels of acceleration (vibration) in the longitudinal direction (z axis) to which the L1-350 Esquilo pilot lumbar spine is exposed during flight, (2) check the L1-350 Esquilo pilot spinal erector muscle activity while exposed to vibration during flight, using electromyography and (3) analyze the data pertaining to the pilot and acceleration, the spinal erector muscle electromyography signals and the correlation between them. In order to achieve these goals, 60 questionnaires were distributed to Esquilo pilots from the Army Aviation Compound of Taubaté (Complexo de Aviação do Exército de Taubaté) in São Paulo. Then, two male pilots were selected, between the ages of 30 and 35, each with more than 300 flight hours, with different body morphological classifications according to the BMI table, one of average height and the other above average height. The collected data was analyzed according to ISO 2631:1997 and statistically studied. It was observed that the pilots' whole-body vibration levels are such that caution is required to avoid health problems, especially considering those pilots who are members of the military whose exposure is higher due to the number of operational flights. The electromyogram also showed that pilot muscle activity was insignificant due to the small variation in the activity potential of the analyzed muscle. It was... (Complete abstract click electronic access below) / Mestre

In this study the dynamic induced velocity field of a model helicopter rotor - excited in collective and cyclic pitch at frequencies extending to 1.5 times the nominal shaft speed - is investigated using mainly hot-wire and laser Doppler anemometry. The dynamic induced velocities are found to vary significantly with radial station and frequency. For cyclic excitations, azimuthal variations are also observed. The results point to the dynamic induced flow being influenced by the distribution of shed vorticity in the wake and cannot be explained using simple momentum theory. Vertical variations of the measured inflow response are also observed, with phase changes possibly partly due to transmission type delays. At frequencies above shaft speed a change in character of the induced flow is seen and around shaft speed an increase in the general level of turbulence is found. The available data on the dynamic induced velocity field of a rotor under controlled excitation, are substantially extended. The measured induced flow response was compared to that predicted using the Pitt and Peters dynamic inflow model. In the 'collective' case good agreement was found, suggesting that the primary inflow model parameters such as the inflow gain and apparent mass are correct with some evidence that a higher order inflow representation might be desirable. A novel method is used to infer the aerodynamic hub loading, which could not be directly measured, from the blade flapping data. This is used to isolate the inflow response using the Pitt and Peters dynamic inflow model and the results are compared with experimental measurements. The method shows the Pitt and Peters dynamic inflow representation to be adequate in the 'collective' case. In the 'cyclic' case, the inferred hub loads were very sensitive to the blade model and hence conclusions for this case are limited. A literature survey and review of the Pitt and Peters dynamic inflow model are also given

The objective of this thesis is to determine whether a scheduled helicopter service is feasible in the Vancouver area. The helicopter can provide the major advantage of transportation directly to the center of any area, be it downtown or an airport terminal building, at speeds in excess of those attainable by most surface modes of travel. This potential for time savings makes a helicopter service commonly desirable. However, cost and revenue considerations are critical to the implementation of a helicopter service. Cost and revenue estimates have been proposed, developed and tested for applicability in the Vancouver area. Consideration of cost and revenue data allowed conclusions regarding commercial feasibility. Study of benefits and costs external to the helicopter operation itself then permitted examination of the economic feasibility of a scheduled helicopter service in the Vancouver area. The subject of this thesis is recognized as being both broad and complex. This study is but a brief investigation of the subject and only some of the major forces have been considered. In fact, any one major section of this thesis could warrant a significantly large study in itself. It was deemed worthwhile to embark on the entire study while recognizing that only the major factors could be considered as the value of the entire project would almost certainly be of greater value than any one of the parts. Restricting the thesis to the study of either costs, revenues or benefits would not allow conclusions regarding commercial or economic feasibility. Conclusions to the broader problem were deemed desirable. The annual operating cost for a fleet of three S-61-N helicopters has been estimated at $3.2 million. The forecast revenues for a route serving Victoria, Vancouver Airport, Vancouver downtown, Comox, Powell River and Campbell River are $1.48 million, $1.58 million and $1.69 million for 1968, 1969 and 1970 respectively. Resulting losses which exclude any capital cost allowance are $1.72 million in 1968, $1.62 million in 1969 and $1.51 million in 1970. A sensitivity analysis indicates that even if revenues were doubled (a highly unlikely possibility) from twice the forecast number of passengers with fares constant or visa versa, service would still incur a $0.24 million loss in 1968. A study of the indirect benefits that could accrue from this hypothetical service indicates little justification for government subsidization. Airline financial assistance, particularly for the significant amount required does not appear warranted. Lack of forecast commercial feasibility and insufficient justification for government subsidization or airline assistance to compensate for the difference leads to the conclusion that a scheduled helicopter service in the Vancouver area is not feasible although it is operationally possible. / Business, Sauder School of / Graduate

No description available.

Experiments were performed to document the turbulent flowfield produced downstream of an airfoil encountering an intense streamwise vortex. This type of perpendicular airfoil--vortex interaction commonly occurs in helicopter rotor flows. The experiments presented here thus provide useful information for the prediction of helicopter noise, particularly BWI noise. Three-component velocity and turbulence measurements were made in unprecedented detail using a computerized miniature four-sensor hot-wire probe system; revealing much about the structure and behavior of this flow over a range of conditions. The interaction between the vortex and the airfoil wake leaves the vortex surrounded by a large region of intense turbulence unlike the turbulence surrounding an isolated vortex. Even for close separations, the vortex core passes the airfoil virtually unchanged. However, vorticity of opposite sign is shed by the airfoil in response to the angle of attack distribution induced by the vortex resulting in an unstable circulation distribution according to Rayleigh's criterion. Simple theoretical models adequately describe the shed vorticity distribution of the airfoil and the unstable circulation distribution it imparts on the vortex. As the flow develops, the vortex continuously distorts the airfoil wake. The strain rates imparted by the vortex on the spanwise vorticity contained in the airfoil wake result in an anisotropic, turbulence producing stress field. For several chord lengths downstream, the vortex core remains laminar and little change is seen in the unstable circulation distribution. While the vortex core is laminar, turbulent fluctuations measured in the core are the result of inactive wandering motions and the characteristic length and velocity scales of the flat portion of the vortex wake appear to be appropriate scales for the fluctuations. Eventually, the vortex core becomes turbulent as indicated by an increase in high frequency velocity fluctuation levels of more than an order of magnitude. Subsequently, the circulation distribution reorganizes to a stable distribution. A loss in core circulation occurs due to a decrease in the peak tangential velocity which is proportionately larger than the increase in the vortex core radius. The peak tangential velocity decreases to the point where it is exceeded by the axial velocity deficit---another unstable situation. These effects increase with decreased separation between the vortex and the airfoil, but appear to be largely independent of airfoil angle of attack an only weakly dependent upon vortex strength. / Ph. D.

The initial forecasting of logistical support for new types of military aircraft is a perplexing problem. The objective of this research was to investigate the feasibility of using data generated by the accelerated flight tests as a basis for forecasting the logistical field requirements. The data used in the study were obtained from the U.S. Army Aviation Board, Fort Rucker, Alabama, where performance tests are conducted on all new aircraft to determine their suitability for Army use. It was statistically shown that the use of these data could provide more realistic logistical forecasts earlier in the introductory phase of the aircraft. This concept would increase the operational availability of the aircraft and reduce the cost of maintaining the aircraft during its introductory phase.

Helicopters have been used in applications where they need to carry a slung load for years. More recently, unmanned (UAV) helicopters are being used to deliver supplies to military units on the ground in theaters of war. This thesis presents a helicopter slung vehicle used to carry the payload and furthermore, provide a means of actuation for the payload. This provides more control authority to the system and may ultimately allow a helicopter to fly higher with a longer tether. The vehicle designed in this thesis was designed for use with 100kg class helicopters, such as the Yamaha RMAX operated by the Virginia Tech Unmanned Systems Lab. Each system on the vehicle was custom designed — including the propulsion system, wall detection / localization system, and controller. Three shrouded propellers provided thruster actuation. A scanning laser range finder and inertial measurement unit (IMU) were used to provide localization. A first attempt at a linear full state feedback controller with a complementary filter was used to control the vehicle. All of the systems were tested individually for functionality. The shrouded propellers met their design goals and were capable of producing .7lbf of thrust each. The wall detection system was able to detect walls and windows reliably and with repeatability. Results from the controller however were less than ideal, as it was only able to control yaw in an oscillatory motion, most likely due to model deficiencies. A reaction wheel was used to control yaw of the vehicle with more success. / Master of Science

The feasibility of intercity helicopter service has been demonstrated at several locations in North America. To study the feasibility of a helicopter service in the Phoenix-Tucson corridor, the travel time and cost characteristics of a proposed helicopter service were compared to the characteristics of existing travel modes in the corridor. Helicopter service travel times were developed using current helicopter performance data and an assumption that heliports would be located in the central business districts of each city. Helicopter service travel cost (fare) was developed using the break-even analysis relating operating cost to demand revenue. From the comparative analysis, significant travel time savings would result with a helicopter service if demand exists between the heliport locations and heliport access times are negligible. However, any travel time savings were offset by significant higher travel costs for the helicopter service when compared with the travel costs of existing modes.

Miniature Unmanned Aerial Vehicles (UAVs) are currently being researched for a wide range of tasks, including search and rescue, surveillance, reconnaissance, traffic monitoring, fire detection, pipe and electrical line inspection, and border patrol to name only a few of the application domains. Although small / miniature UAVs, including both Vertical Takeoff and Landing (VTOL) vehicles and small helicopters, have shown great potential in both civilian and military domains, including research and development, integration, prototyping, and field testing, these unmanned systems / vehicles are limited to only a handful of university labs. For VTOL type aircraft the number is less than fifteen worldwide! This lack of development is due to both the extensive time and cost required to design, integrate and test a fully operational prototype as well as the shortcomings of published materials to fully describe how to design and build a "complete" and "operational" prototype system. This dissertation overcomes existing barriers and limitations by describing and presenting in great detail every technical aspect of designing and integrating a small UAV helicopter including the on-board navigation controller, capable of fully autonomous takeoff, waypoint navigation, and landing. The presented research goes beyond previous works by designing the system as a testbed vehicle. This design aims to provide a general framework that will not only allow researchers the ability to supplement the system with new technologies but will also allow researchers to add innovation to the vehicle itself. Examples include modification or replacement of controllers, updated filtering and fusion techniques, addition or replacement of sensors, vision algorithms, Operating Systems (OS) changes or replacements, and platform modification or replacement. This is supported by the testbed's design to not only adhere to the technology it currently utilizes but to be general enough to adhere to a multitude of technology that have yet to be tested. This research will allow labs without the proper expertise to build a safe and reliable vehicle that can provide them access to real world data thus increasing the effectiveness and validity of their research. It will also allow researchers working in simulation to quickly enter into UAV development without utilizing thousands of man hours to create an unmanned vehicle. The presented research is designed to benefit the entire UAV researching community by allowing in depth access to an area of research that has been typically classified as too expensive and too time consuming to enter.

The problem of this study was to compare two methods of instruction in helicopter pilot ground training in terms of cost of training and support services and customer satisfaction upon completion of training. The purpose of the study was the evaluation of a specialized program of instruction taught on videotape by comparison with conventional instruction. The significance of the study was related to savings in costs of instruction per trainee. Research questions for the study sought significant differences between mean scores achieved by students receiving the two treatments. Data providing information on specific characteristics of the learners were gathered as a preliminary step to establish similarity of the students in the two groups compared. A table of random numbers was used to select subjects from the population of student pilots entering training for the Bell model 206B helicopter during the months of March, April and May 1981. Upon completion of the course, all students were asked to complete an evaluation opinionaire relating to satisfaction with selected aspects of the instructional program.