11,110 research outputs found

    Aerodynamic Characteristics of Propeller-Driven VTOL Aircraft

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    This paper discusses the two major configurations that are usually considered for achieving VTOL while keeping the fuselage essentially horizontal - that is, the tilt-wing and the deflected-slipstream configurations. Because of the high turning losses incurred by deflected-slipstream configurations in hovering and because of the wing-stalling problem of the pure tilt-wing configurations during the transition, it appears that a combination of the two principles should be used. This tilt-wing and flap configuration should make use of a programmed extensible-chord slotted flap together with a leading-edge high-lift device in order to avoid the performance and handling qualities problems associated with wing stalling during the transition while keeping the wing area as low as possible for efficiency in cruising flight

    Flow and fracture of ice and ice mixtures

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    Frozen volatiles make up an important volume fraction of the low density moons of the outer solar system. Understanding the tectonic history of the surfaces of these moons, as well as the evolution of their interiors, requires knowledge of the mechanical strength of these icy materials under the appropriate planetary conditions (temperature, hydrostatic pressure, strain rate). Ongoing lab research is being conducted to measure mechanical properties of several different ices under conditions that faithfully reproduce condition both at the moons' surfaces (generally low temperature, to about 100 K, and low pressures) and in the deep interiors (warmer temperatures, pressures to thousands of atmospheres). Recent progress is reported in two different phases of the work: rheology of ices in the NH3-H2O system at temperatures and strain rates lower than ever before explored, with application to the ammonia-rich moons of Saturn and Uranus; and the water ice I yields II phase transformation, which not only applies directly to process deep in the interiors of Ganymede and Callisto, but holds implications for deep terrestrial earthquakes as well

    Study of passenger subjective response to ideal and real-vehicle vibration environments

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    The stimulus received by subjects tested on the passenger ride quality apparatus (PRQA) is defined. Additional analyses on the data collected from field tests using buses, were conducted to assess the relation between subjective ratings of ride quality and vibrations measured on the buses, and to better define the vibration stimulus measured in the field. The relation of subjective evaluation of simulations of bus rides produced by the DRQA to subjective evaluations of the actual bus rides is discussed. The relative contribution of the seat and floor vibration to human comfort in a simulated aircraft ride environment is discussed along with the determination of equal comfort curves through magnitude estimation

    The effectiveness of an oculometer training tape on pilot and copilot trainees in a commercial flight training program

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    A study was designed to evaluate the effectiveness of a video tape detailing the various aspects of instrument scanning by experienced pilots on performance by pilots and copilots undergoing flight training in a Boeing 737 flight simulator. The performance ratings by instructor pilots (IP's) and self-reported instrument scan behavior by trainees were compared with those of a control group. The results indicated that the training tape had little or no effect on performance by trainees in the experimental group. Feedback from the IP's and trainees suggested that a feedback strategy providing each trainee's individual instrument scan behavior might be more beneficial in flight training than the general instructional strategy of the oculometer training tape. Flight training personnel and trainees' reports of performance decrements on or around the third day of flight simulator training were investigated. The IP's performance ratings of 27 pilot and copilot trainees failed to reveal a systematic performance decrement; however, feedback from the trainees revealed that their own attribution of performance decrements was associated with the order in which their training occurred within a session. Further research was suggested

    The effectiveness of incorporating a real-time oculometer system in a commercial flight training program

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    The effectiveness of incroporating a real-time oculometer system into a Boeing 737 commercial flight training program was studied. The study combined a specialized oculometer system with sophisticated video equipment that would allow instructor pilots (IPs) to monitor pilot and copilot trainees' instrument scan behavior in real-time, and provide each trainee with video tapes of his/her instrument scanning behavior for each training session. The IPs' performance ratings and trainees' self-ratings were compared to the performance ratings by IPs and trainees in a control group. The results indicate no difference in IP ratings or trainees' self-ratings for the control and experimental groups. The results indicated that the major beneficial role of a real-time oculometer system for pilots and copilots having a significant amount of flight experience would be for problem solving or refinement of instrument scanning behavior rather than a general instructional scheme. It is suggested that this line of research be continued with the incorporation of objective data (e.g., state of the aircraft data), measures of cost effectiveness and with trainees having less flight experience

    Creep of ice: Further studies

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    Detailed studies have been done of ice creep as related to the icy satellites, Ganymede and Callisto. Included were: (1) the flow of high-pressure water ices II, III, and V, and (2) frictional sliding of ice I sub h. Work was also begun on the study of the effects of impurities on the flow of ice. Test results are summarized

    The effectiveness of incorporating a real-time oculometer system in a commercial flight training program

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    The effectiveness on pilot and trainee performance and scanning behavior of incorporating a real time oculometer system in a commerical flight training program was assessed. Trainees received simulator training in pairs requiring the trainees to alternate the order of training within a session. The 'third day phenomenon' of performance decrement was investigated, including the role of order of training on performance

    ELF: The electronic learning facilitator

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    As the world‐wide computer network becomes ubiquitous, new tools have been developed, such as the World Wide Web (WWW), for the delivery of multimedia hypertext‐based documents. Similarly, there has been an explosion in the amount of email, bulletin boards, and Usenet News available. This has led to a major problem of information overload: we are slowly but surely being overwhelmed by the amount of information available to us
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