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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Small transport aircraft technology. A report for the committee on commerce, science, and transportation, United States Senate

A preliminary assessment of the research and technology that NASA could undertake to improve small transport aircraft is presented. The advanced technologies currently under study for potential application to the small transport aircraft of the future are outlined. Background information on the commuter and shorthaul local service air carriers, the regulations pertaining to their aircraft and operations, and the overall airline system interface is included.

Source record↗
NASA NTRS1979

Study of advanced electric propulsion system concept using a flywheel for electric vehicles

Advanced electric propulsion system concepts with flywheels for electric vehicles are evaluated and it is predicted that advanced systems can provide considerable performance improvement over existing electric propulsion systems with little or no cost penalty. Using components specifically designed for an integrated electric propulsion system avoids the compromises that frequently lead to a loss of efficiency and to inefficient utilization of space and weight. A propulsion system using a flywheel power energy storage device can provide excellent acceleration under adverse conditions of battery degradation due either to very low temperatures or high degrees of discharge. Both electrical and mechanical means of transfer of energy to and from the flywheel appear attractive; however, development work is required to establish the safe limits of speed and energy storage for advanced flywheel designs and to achieve the optimum efficiency of energy transfer. Brushless traction motor designs using either electronic commutation schemes or dc-to-ac inverters appear to provide a practical approach to a mass producible motor, with excellent efficiency and light weight. No comparisons were made with advanced system concepts which do not incorporate a flywheel.

Younger, F. C.↗
NASA NTRS1980

Outlook for advanced concepts in transport aircraft

Air transportation demand trends, air transportation system goals, and air transportation system trends well into the 21st century were examined in detail. The outlook is for continued growth in both air passenger travel and air freight movements. The present system, with some improvements, is expected to continue to the turn of the century and to utilize technologically upgraded, derivative versions of today's aircraft, plus possibly some new aircraft for supersonic long haul, short haul, and high density commuter service. Severe constraints of the system, expected by early in the 21st century, should lead to innovations at the airport, away from the airport, and in the air. The innovations are illustrated by descriptions of three candidate systems involving advanced aircraft concepts. Advanced technologies and vehicles expected to impact the airport are illustrated by descriptions of laminar flow control aircraft, very large air freighters and cryogenically fueled transports.

Conner, D. W.↗
NASA NTRS1979

Near hybrid passenger vehicle development program, phase 1. Appendices A and B. Mission analysis and performance specification studies report, volume 1

The three most promising vehicle use patterns (missions) for the near term electric hybrid vehicle were found to be all-purpose city driving, commuting, and family and civic business. The mission selection process was based principally on an analysis of the travel patterns found in the Nationwide Transportation Survey and on the Los Angeles and Washington, D.C. origin-destination studies data. Travel patterns in turn were converted to fuel requirements for 1985 conventional and hybrid cars. By this means, the potential fuel savings for each mission were estimated, and preliminary design requirements for hybrid vehicles were derived.

Source record↗
NASA NTRS1979

Concepts for reference frames in geodesy and geodynamics - The reference directions

The paper discusses a study that establishes a reference frame, moving with the earth (in some average sense), in which the geometric and dynamical behavior of the earth can be monitored, and whose motion with respect to inertial space can also be determined. Emphasis is placed on the fact that the reference directions at an observation point on the earth surface, are defined by fundamental vectors for both space and time. The interrelationships between this space- and time-variant angular parameter are illustrated in a commutative diagram and tower of triads. Although the model tower is also space- and time-variant, its variations are described by adopted parameters using our current knowledge of the earth.

Grafarend, E. W.↗
NASA NTRS1980

A remarkable operator version of the Navier-Stokes equation

The Navier-Stokes equation is transformed into a closed nonlinear equation for the convected curl operator. It is shown how Lie algebraic methods can be employed to solve the obtained double-commutator equation. The proposed operator equation provides a way to the further development of the Navier-Stokes fluid flow theory.

Rosen, G.↗
NASA NTRS1980

Pilot-aircraft system response to wind shear

The nonlinear aircraft motion and automatic control computer model of Frost and Reddy has been expanded to incorporate the human pilot into simulations of aircraft response to wind shear. Fixed-stick, autopilot, and manned computer simulations are made with an aircraft having characteristics of a Queen Air (small commuter-type aircraft) flown through longitudinal winds measured by a Doppler radar beamed along the glide slope during the SESAME '79 experiments in Oklahoma. Simulations are also made flying a model Boeing 727 through sinusoidal head wind to tail wind shears at the phugoid frequency to evaluate the response of manned aircraft in thunderstorm wind environments.

Turkel, B. S.↗
NASA NTRS1980

An SCR inverter for electric vehicles

An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

Latos, T.↗
NASA NTRS1980

The future of short-haul transport aircraft

Owing to recent economic and regulatory changes and escalating fuel costs, major airlines have begun to shift their short-haul service to longer, more profitable routes, leaving short-haul operations to rapidly growing commuter airlines. The short-haul routes are currently serviced by small turboprop-powered aircraft. The results of some recent design studies aimed at replacing the turboprops with specialized propeller- and rotor-driven aircraft are discussed. Some potential future designs are illustrated and discussed.

Williams, L. J.↗
NASA NTRS1980

An acoustic sensitivity study of general aviation propellers

This paper describes the results of a study in which a systematic approach has been taken in studying the effect of selected propeller parameters on the character and magnitude of propeller noise. Four general aviation aircraft were chosen, i.e., a Cessna 172, Cessna 210, Cessna 441, and a 19 passenger commuter concept, to provide a range in flight velocity, engine horsepower, and gross weight. The propeller parameters selected for examination consisted of number of blades, rpm reduction, thickness/chord reduction, activity factor reduction, proplets, airfoil improvement, sweep, position of maximum blade loading, and diameter reduction.

Korkan, K. D.↗
NASA NTRS1980

Pilot-aircraft system reponse to wind shear

The nonlinear aircraft motion and automatic control model is expanded to incorporate the human pilot into simulations of aircraft response to wind to wind shear. The human pilot is described by a constant gains lag filter. Two runs are carried out using pilot transfer functions. Fixed-stick, autopilot, and manned computer simulations are made with an aircraft having characteristics of a small commuter type aircraft flown through longitudinal winds measured by a Doppler radar beamed along the glide slope. Simulations are also made flying an aircraft through sinusoidal head wind and tail wind shears at the phugoid frequency to evaluate the response of manned aircraft in thunderstorm wind environments.

Turkel, B. S.↗
NASA NTRS1980

Cost/benefit analysis of advanced materials technology candidates for the 1980's, part 2

Cost/benefit analyses to evaluate advanced material technologies projects considered for general aviation and turboprop commuter aircraft through estimated life-cycle costs, direct operating costs, and development costs are discussed. Specifically addressed is the selection of technologies to be evaluated; development of property goals; assessment of candidate technologies on typical engines and aircraft; sensitivity analysis of the changes in property goals on performance and economics, cost, and risk analysis for each technology; and ranking of each technology by relative value. The cost/benefit analysis was applied to a domestic, nonrevenue producing, business-type jet aircraft configured with two TFE731-3 turbofan engines, and to a domestic, nonrevenue producing, business type turboprop aircraft configured with two TPE331-10 turboprop engines. In addition, a cost/benefit analysis was applied to a commercial turboprop aircraft configured with a growth version of the TPE331-10.

Dennis, R. E.↗
NASA NTRS1981

NASA Research in aeropropulsion

Selected examples of recent accomplishments and current activities that are relevant to the principal classes of civil and military vehicles: subsonic transports, commuters, supersonic transports, general aviation, rotorcraft, V/STOL, and high performance. Some instances of emerging technologies with potential high impact on further progress are discussed.

Stewart, W. L.↗
NASA NTRS1980

Advanced propulsion system concept for hybrid vehicles

A series hybrid system, utilizing a free piston Stirling engine with a linear alternator, and a parallel hybrid system, incorporating a kinematic Stirling engine, are analyzed for various specified reference missions/vehicles ranging from a small two passenger commuter vehicle to a van. Parametric studies for each configuration, detail tradeoff studies to determine engine, battery and system definition, short term energy storage evaluation, and detail life cycle cost studies were performed. Results indicate that the selection of a parallel Stirling engine/electric, hybrid propulsion system can significantly reduce petroleum consumption by 70 percent over present conventional vehicles.

Bhate, S.↗
NASA NTRS1981

Microcomputer processing for Loran-C

Schematic diagrams are presented for the microcomputer processing for Loran-C. Diagrams are included for the following: microcomputer Loran-C loop improvements; Loran-C receiver commutated AGC; and DC-DC power supply.

Lilley, R. W.↗
NASA NTRS1981

Propulsion system study for Small Transport Aircraft Technology (STAT)

Propulsion system technologies applicable to the generation of commuter airline aircraft expected to enter service in the 1990's are identified and evaluated in terms of their impact on aircraft operating economics and fuel consumption. The most promising technologies in the areas of engine, propeller, gearbox, and nacelle design are recommended for future research. Each item under consideration is evaluated relative to a modern baseline engine, the General Electric CT7-5, in a current technology aircraft flying a fixed range and payload. The analysis is presented for two aircraft sizes (30 and 50 passenger), over a range of mission lengths (100 to 1100 km) and fuel costs ($264 to $396 per cu m).

Smith, C. E.↗
NASA NTRS1981

NASA research in aeropropulsion

NASA research activities in the development of civilian and military aircraft are discussed. The advances made in subsonic and supersonic transports, commuter aircraft, rotorcraft, V/STOL, and high-performance engines are reviewed, and the problems facing general aviation are considered. Comments on some new areas of technology are also presented.

Stewart, W. L.↗
NASA NTRS1980

Small Transport Aircraft Technology /STAT/ Propulsion Study

The NASA Small Transport Aircraft Technology (STAT) Propulsion Study was established to identify technology requirements and define the research and development required for new commuter aircraft. Interim results of the studies defined mission and design characteristics for 30- and 50-passenger aircraft. Sensitivities were defined that relate changes in engine specific fuel consumption (SFC), weight, and cost (including maintenance) to changes in the aircraft direct operating cost (DOC), takeoff gross weight, and empty weight. A comparison of performance and economic characteristics is presented between aircraft powered by 1980 production engines and those powered by a 1990 advanced technology baseline engine.

Heldenbrand, R. W.↗