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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A method for increasing thrust reverser utilization on STOL aircraft.

A technique for increasing the utilization of thrust reversers on STOL aircraft is described. The technique involves asymmetric orientation of the reversed exhaust in such a manner as to avoid the problems of self-ingestion, even in the presence of a cross wind, and cross ingestion between adjacent engines. Experimental results of ingestion in a single nacelle inlet are discussed and flow visualization pictures are presented. An analytical model of ingestion is described and sample results are shown.

Tatom, J. W.↗
NASA NTRS1973

STOL aircraft flight and landing area considerations.

One proposed solution to the total short-haul transportation system problem is to use existing low-wing-loading turbopropeller STOL aircraft. Deflected slipstream turboprop aircraft have also been considered for early STOL service. Aspects of current aircraft research are discussed together with the NASA research aircraft, field length and aircraft performance considerations, crosswind landings, crosswind reducing fences, elevated STOL ports, a guaranteed friction STOL runway, and problems of runway containment.

Riebe, J. M.↗
NASA NTRS1974

A simulator investigation of engine failure compensation for powered-lift STOL aircraft

A piloted simulator investigation of various engine failure compensation concepts for powered-lift STOL aircraft was carried out at the Ames Research Center. The purpose of this investigation was to determine the influence of engine failure compensation on recovery from an engine failure during the landing approach and on the precision of the STOL landing. The various concepts include: (1) cockpit warning lights to cue the pilot of an engine failure, (2) programmed thrust and roll trim compensation, (3) thrust command and (4) flight-path stabilization. The aircraft simulated was a 150 passenger four-engine, externally blown flap civil STOL transport having a 90 psf wing loading and a .56 thrust to weight ratio. Results of the simulation indicate that the combination of thrust command and flight-path stabilization offered the best engine-out landing performance in turbulence and did so over the entire range of altitudes for which engine failures occurred.

Nieuwenhuijse, A. W.↗
NASA NTRS1981

A method for determining landing runway length for a STOL aircraft

Based on data obtained from flight tests of the augmentor wing jet STOL research aircraft, a method is proposed for determining the length of the landing runway for powered-lift STOL aircraft. The suggested method determines runway landing length by summing three segments: the touchdown-dispersion distance, the transition distance from touchdown to application of brakes, and the stopping distance after brakes are applied. It is shown how the landing field length can be reduced either through improved autoland system design or by providing the pilot with appropriate information to allow him to identify a "low probability" long or short landing and to execute a go-around. The proposed method appears to determine a safe runway landing length for the STOL application and offers the potential for reducing runway length if great emphasis is placed on a short-runway capability. FAR Parts 25 and 121 appear conservative and suitable for the situation where no great emphasis is placed on reducing the runway length requirement.

Watson, D. M.↗
NASA NTRS1987

The ground effects of a powered-lift STOL aircraft during landing approach

The effects of ground proximity on a powered lift STOL aircraft are presented. The data are from NASA's Quiet Short Haul Research Aircraft (QSRA) flown at landing approach airspeeds of less than 60 knots with an 80 lb/sq ft wing loading. These results show that the ground effect change in lift is positive and does significantly reduce the touchdown sink rate. These results are compared to those of the YC-14 and YC-15. The change in drag and pitching moment caused by ground effects is also presented.

Stevens, Victor C.↗
NASA NTRS1962

Tables of Interference Factors for Use in Wind-tunnel and Ground-effect Calculations for VTOL-STOL Aircraft. Part III- Wind Tunnels Having Width-height Ratio of 1.0

Tables of interference factors for use in wind-tunnel and ground-effect calculations for VTOL-STOL aircraft are presented for wind tunnels having a width-height ratio of 1.0. These tables were machine-calculated and are intended for use with the procedures of NASA Technical Report R-124. These tables are presented without comment.

STOL aircraft↗
NASA NTRS1962

Tables of Interference Factors for Use in Wind-tunnel and Ground-effect Calculations for VTOL-STOL Aircraft. Part IV- Wind Tunnels Having Width-height Ratio of 0.5

Tables of interference factors for use in wind-tunnel and ground-effect calculations for VTOL-STOL aircraft are presented for wind tunnels having a width-height ratio of 0.5. These tables were machine-calculated and are intended for use with the procedures of NASA Technical Report R-124. These tables are presented without comment.

Wind tunnel↗
NASA NTRS1973

Study of quiet turbofan STOL aircraft for short-haul transportation. Volume 5: Economics

The economic aspects of the STOL aircraft for short-haul air transportation are discussed. The study emphasized the potential market, the preferred operational concepts, the design characteristics, and the economic viability. Three central issues governing economic viability are as follows: (1) operator economics given the market, (2) the required transportation facilities, and (3) the external economic effects of a set of regional STOL transportation systems.

Source record↗
NASA NTRS1965

Operating Problems Peculiar to V/STOL and STOL Aircraft

This paper covers the unique features and different modes of operation of V/STOL and STOL aircraft which result in new operating problems and serves to introduce the papers which deal in more detail with some of the more important V/STOL and STOL operating problems.

Campbell, John P.↗
NASA NTRS1972

Program plan to develop airworthiness standards for STOL aircraft

A program plan to develop criteria for airworthiness standards for STOL transport aircraft is presented. Initially, three different STOL concepts are to be examined with a goal to arrive at a generalized set of standards. The Breguet 941 deflected-slipstream STOL has been initially evaluated on a piloted motion simulator and in flight. Confidence in establishing criteria for airworthiness standards for STOL transport aircraft has been obtained from these studies.

Cayot, J. E.↗
NASA NTRS1976

Optimal control of a low wing-loading STOL aircraft

Linear optimal quadratic control theory is applied to a low wing-loading STOL aircraft for ride quality and flight path following. Design criteria include minimum rms response to wind turbulence and desired transient response characteristics. Design techniques include proper choosing of design versus evaluation models, choosing appropriate performance index responses, and use of classical evaluation techniques. Results are obtained through a combination of frequency response shaping and gust observation. Effects of control rate and authority saturation are examined with a new rapid calculation of random input describing functions. Parameter sensitivity is also evaluated using a Liapunov type matrix equation.

Cunningham, T. B.↗
NASA NTRS1983

Flight directors for STOl aircraft

Flight director logic for flight path and airspeed control of a powered-lift STOL aircraft in the approach, transition, and landing configurations are developed. The methods for flight director design are investigated. The first method is based on the Optimal Control Model (OCM) of the pilot. The second method, proposed here, uses a fixed dynamic model of the pilot in a state space formulation similar to that of the OCM, and includes a pilot work-load metric. Several design examples are presented with various aircraft, sensor, and control configurations. These examples show the strong impact of throttle effectiveness on the performance and pilot work-load associated with manual control of powered-lift aircraft during approach. Improved performed and reduced pilot work-load can be achieved by using direct-lift-control to increase throttle effectiveness.

Rabin, U. H.↗
NASA NTRS1985

The ground effects of a powered-lift STOL aircraft during landing approach

Attention is given to the ground proximity effects of a powered lift STOL aircraft, NASA's Quiet Short Haul Research Aircraft (QSRA); these effects have a profound influence on a landing's touchdown dispersion and sink rates, and must be determined with the greatest possible accuracy. The QSRA flight parameter values obtained by means of a small perturbation model for the trim flight condition out of ground effect, during a landing approach, are compared with flight test values, on the premise that any discrepancies between the two sets of values will be due to ground effect.

Stevens, V. C.↗
NASA NTRS1986

Recommendations for ground effects research for V/STOL and STOL aircraft and associated equipment for large scale testing

The current understanding of the effects of ground proximity on V/STOL and STOL aircraft is reviewd. Areas covered include (1) single jet suckdown in hover, (2) fountain effects on multijet configurations, (3) STOL ground effects including the effect of the ground vortex flow field, (4) downwash at the tail, and (5) hot gas ingestion in both hover and STOL operation. The equipment needed for large scale testing to extend the state of the art is reviewed and developments in three areas are recommended as follows: (1) improve methods for simulating the engine exhaust and inlet flows; (2) develop a model support system that can simulate realistic rates of climb and descent as well as steady height operation; and (3) develop a blowing BLC ground board as an alternative to a moving belt ground board to properly simulate the flow on the ground.

Kuhn, Richard E.↗
NASA NTRS1974

A compilation and analysis of typical approach and landing data for a simulator study of an externally blown flap STOL aircraft

A piloted simulation study has been made of typical landing approaches with an externally blown flap STOL aircraft to ascertain a realistic dispersion of parameter values at both the flare window and touchdown. The study was performed on a fixed-base simulator using standard cockpit instrumentation. Six levels of stability and control augmentation were tested during a total of 60 approaches (10 at each level). A detached supplement containing computer printouts of the flare-window and touchdown conditions for all 60 runs has been prepared.

Middleton, D. B.↗
NASA NTRS1981

Development and evaluation of automatic landing control laws for light wing loading STOL aircraft

Automatic flare and decrab control laws were developed for NASA's experimental Twin Otter. This light wing loading STOL aircraft was equipped with direct lift control (DLC) wing spoilers to enhance flight path control. Automatic landing control laws that made use of the spoilers were developed, evaluated in a simulation and the results compared with these obtained for configurations that did not use DLC. The spoilers produced a significant improvement in performance. A simulation that could be operated faster than real time in order to provide statistical landing data for a large number of landings over a wide spectrum of disturbances in a short time was constructed and used in the evaluation and refinement of control law configurations. A longitudinal control law that had been previously developed and evaluated in flight was also simulated and its performance compared with that of the control laws developed. Runway alignment control laws were also defined, evaluated, and refined to result in a final recommended configuration. Good landing performance, compatible with Category 3 operation into STOL runways, was obtained.

Feinreich, B.↗
NASA NTRS1982

A technique for determining powered-lift STOL aircraft performance at sea level from flight data taken at altitude

State-of-the-technology powered-lift STOL aircraft can develop very high lift coefficients. The determination of how this high lift capability can be utilized for landing approaches is accomplished by evaluating aircraft velocity versus flightpath performance. This paper briefly discusses upper-surface-blowing power-lift technology and some of the significant features of the velocity versus flightpath plot that are used in evaluating the performance of powered-lift aircraft. A procedure for deriving the velocity versus flightpath plot for a powered-lift aircraft at any specified weight at sea level, based on flight-test data obtained at various weights and altitudes, is discussed in detail. Actual flight-test data obtained with NASA's Quiet Short-Haul Research Aircraft (QSRA) are used to illustrate this procedure and to evaluate the results.

Stevens, V. C.↗