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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Conceptual design study of improved 1985 remote lift-fan V/STOL commercial transports

A design study was conducted for a remote lift-fan commercial V/STOL transport for the 1985 time period. The investigation centered on the commercial short haul transportation application to carry 100 passengers over trip distances of 400 nautical miles from a vertical takeoff and landing, and 800 nautical miles after a 1600 foot STOL takeoff. The study included investigation of alternate numbers and arrangements of lift fans and gas generators, fan control margins, and structural concepts. The sensitivity of direct operating costs to major airframe parameters, airframe costs, propulsion costs, yearly aircraft utilization rate, and trip distances are evaluated.

Cavage, R. L.↗
NASA NTRS1975

Evaluation of advanced lift concepts and potential fuel conservation for short-haul aircraft

The effect of different field lengths, cruise requirements, noise level, and engine cycle characteristics on minimizing fuel consumption and minimizing operating cost at high fuel prices were evaluated for some advanced short-haul aircraft. The conceptual aircraft were designed for 148 passengers using the upper surface-internally blown jet flap, the augmentor wing, and the mechanical flap lift systems. Advanced conceptual STOL engines were evaluated as well as a near-term turbofan and turboprop engine. Emphasis was given to designs meeting noise levels equivalent to 95-100 EPNdB at 152 m (500 ft) sideline.

Sweet, H. S.↗
NASA NTRS1974

Evaluation of routing and scheduling considerations for possible future commercial hypersonic transport aircraft

Travel markets which would be served by high speed commercial transport aircraft and the ability of the airlines to schedule and route the aircraft in a way that would achieve good daily utilization and productivity are examined. The following areas are considered: (1) identification of the major long-haul city pairs that would most likely demand nonstop service; (2) selection of flight tracks observing alternative sonic boom restrictions; (3) estimation of flight times for all city pairs for the various sonic boom constraints; (4) impact of airport curfews on possible departure and arrival schedules; (5) projection of passenger traffic volumes on the selected city pairs; and (6) potential daily utilization and aircraft productivity.

Feir, J. B.↗
NASA NTRS1975

Preliminary study of advanced turbofans for low energy consumption

This analysis determines the effect of higher overall engine pressure ratios (OPR's), bypass ratios (BPR's), and turbine rotor-inlet temperature on a Mach-0.85 transport having a range of 5556 km (3000 nmi) and carrying a payload of 18144 kg (40,000 lbs-200 passengers). Sideline noises (jet plus fan) of between 91 and 106 EPNdB (FAR36) are considered. Takeoff gross weight (TOGW), fuel consumption (kg/pass. km) and direct operating cost (DOC) are used at the figures of merit. Based on predicted 1985 levels of engine technology and a noise goal of 96 EPNdB, the higher-OPR engine results in an airplane that is 18 percent lighter in terms of TOGW, uses 22.3 percent less fuel, and has a 14.7 percent lower DOC than a comparable airplane powered by a current turbofan. Cooling the compressor bleed air and lowering the cruise Mach number appear attractive in terms of further improving the figures of merit.

Knip, G.↗
NASA NTRS1975

Preliminary evaluation of turbofan cycle parameters and acoustical suppression on the noise and direct operating cost of a commercial Mach 0.85 transport

A study was made of the effects of turbofan cycle parameters and the use of acoustic noise suppression material to quiet 200 passenger, Mach 0.85 trijets having design ranges of 2778, 4630, and 9260 kilometers (1500, 2500, and 5000 n. mi). Aircraft gross weight and direct operating cost, which varied with amount of suppression and cycle selection, are presented as functions of both EPNdB traded and 90 EPNdB contour footprint area. Noise levels 10.9 EPNdB below FAR 36 requirements result in a 5 percent increase in DOC for an aircraft designed for a range of 9260 kilometers (5000 n. mi.). An aircraft designed for a 2778 kilometer (1500 n. mi.) range would have an EPNdB level 14 below FAR 36 for this same economic penalty. In this range of noise level, fan-machinery noise is the principal source.

Eisenberg, J. D.↗
NASA NTRS1975

Interior noise considerations for powered-lift STOL aircraft

Powered-jet configuration which are under development for use on STOL aircraft involve impingement of the jet engine exhaust onto wing and flap surfaces. The impinging jet produces higher noise levels at lower frequencies than does the jet alone. These higher levels, together with the close proximity of the engine and flap noise sources to the fuselage sidewall, suggest that the noise levels in these aircraft may be high enough to interfere with passenger comfort. To investigate this possibility, interior noise levels were estimated for both an upper surface blown and an externally blown flap configuration. This paper describes the procedure used to estimate the interior noise levels is described these levels are compared with levels on existing jet aircraft and on ground transportation vehicles. These estimates indicate high levels in the STOL aircraft; therefore, areas of possible improvements in technology for control of STOL interior noise are also discussed.

Barton, C. K.↗
NASA NTRS1975

Terminal area considerations for an advanced CTOL transport aircraft

Projected future conditions at large urban airports were used to identify design objectives for a long-haul, advanced transport airplane introduced for operation in the mid-1980s. Operating constraints associated with airport congestion and aircraft noise and emissions were of central interest. In addition, some of the interaction of these constraints with aircraft fuel usage were identified. The study allowed for advanced aircraft design features consistent with the future operating period. A baseline 200 passenger airplane design was modified to comply with design requirements imposed by terminal area constraints. Specific design changes included: (1) modification of engine arrangement; wing planform; (2) drag and spoiler surfaces; (3) secondary power systems; (4) brake and landing gear characteristics; and (5) the aircraft avionics. These changes, based on exploratory design estimates and allowing for technology advance, were judged to enable the airplane to: reduce wake turbulence; handle steeper descent paths with fewer limitation due to engine characteristics; reduce runway occupancy times; improve community noise contours; and reduce the total engine emittants deposited in the terminal area. The penalties to airplane performance and operating cost associated with improving the terminal area characteristics of the airplane were assessed. Finally, key research problems requiring solution in order to validate the assumed advanced airplane technology were identified.

Sussman, M. B.↗
NASA NTRS1975

Analysis of operational requirements for medium density air transportation. Volume 1: Summary

The medium density air travel market was studied to determine the aircraft design and operational requirements. The impact of operational characteristics on the air travel system and the economic viability of the study aircraft were also evaluated. Medium density is defined in terms of numbers of people transported (20 to 500 passengers per day on round trip routes), and frequency of service ( a minumium of two and maximum of eight round trips per day) for 10 regional carriers. The operational characteristics of aircraft best suited to serve the medium density air transportation market are determined and a basepoint aircraft is designed from which tradeoff studies and parametric variations could be conducted. The impact of selected aircraft on the medium density market, economics, and operations is ascertained. Research and technology objectives for future programs in medium density air transportation are identified and ranked.

Source record↗
NASA NTRS1975

The effects of aircraft design on STOL ride quality

Effects of aircraft dynamic characteristics on passenger ride quality are investigated to determine ride-quality isocontours similar to aircraft handling-qualities contours. Measurements are made on a moving-base simulator while varying the aircraft short-period and Dutch Roll frequencies and dampings. Both pilot ratings and subjective ride-quality ratings are obtained during flight. Ride and handling qualities were found to be complementary for the Dutch Roll mode, but not for the short-period mode. Regions of optimal ride and handling qualities are defined for the short-period mode, and the effects of turbulence levels studied.

Jones, C. R.↗
NASA NTRS1975

An elementary psychophysical model to predict ride comfort in the combined stress of multiple degrees of freedom

The quality of airplane rides probably will become increasingly important to passengers, particularly in terminal area operations and on short haul trips. The development of models to predict ride comfort is considered. An elementary model concept is presented herein and compared with subjective ride comfort response ratings measured on actual scheduled airline flights and simulated flights.

Stone, R. W., Jr.↗
NASA NTRS1975

Conceptual design study of 1985 commercial VTOL transports that utilize rotors

Conceptual design studies of pure and compound helicopter commercial short-haul transport aircraft for initial fabrication in 1980 were performed to determine their technical and economic feasibility. One-hundred-passenger configurations were optimized for minimum direct operating cost consistent with producibility and marketability, with emphasis on proper account of mass properties, performance and handling qualities adequacy, and suppression of internal and external noise. The effect of external noise constraints was assessed, in terms of gross weight and direct operating cost, for each aircraft.

Kefford, N. F. K.↗
NASA NTRS1975

The next forty years in aviation

A prediction of the status of various types of aviation activities which may be expected in twenty years is presented. The basic assumptions are that the population of the nation will continue to grow at more than 7 percent and that the need for air transportation of passengers and cargo will increase accordingly. Various predictions are also made for the developments in vertical takeoff aircraft, short haul airline operations, general aviation, and military aircraft. Areas of improvement are indicated for air navigation, air traffic control, night vision, quiet aircraft, and the use of hydrogen as a fuel.

Hawkins, W. M.↗
NASA NTRS1974

Conceptual design studies of 1985 commercial VTOL transports that utilized rotors, Volume 1

Results of conceptual design studies of commercial rotary wing transport aircraft for the 1985 time period are presented. Two aircraft configurations, a tandem helicopter and a tilt rotor, were designed for a 200 nautical mile short haul mission with an upper limit of 100 passengers. In addition to the baseline aircraft two further designs of each configuration are included to assess the impact of external noise design criteria on the aircraft size, weight, and cost.

Magee, J. P.↗
NASA NTRS1975

Study of the application of hydrogen fuel to long-range subsonic transport aircraft, volume 2

The feasibility, practicability, and potential advantages/disadvantages of using liquid hydrogen as fuel in long range, subsonic transport aircraft of advanced design were studied. Both passenger and cargo-type aircraft were investigated. To provide a valid basis for comparison, conventional hydrocarbon (Jet A) fueled aircraft were designed to perform identical missions using the same advanced technology and meeting the same operational constraints. The liquid hydrogen and Jet A fueled aircraft were compared on the basis of weight, size, energy utilization, cost, noise, emissions, safety, and operational characteristics. A program of technology development was formulated.

Brewer, G. D.↗
NASA NTRS1975

NASTRAN modeling and analysis of rigid and flexible walled acoustic cavities

The acoustic slot elements, CSLOTi, are applied to analyze two-dimensional enclosures with fixed or moving boundaries. The capability utilized to compute (a) the acoustic natural modes and frequencies of a rigid walled enclosure and (b) the sound pressure at any point inside an enclosure when the surrounding walls are forced to vibrate. Applications to an automobile passenger compartment illustrate the technique. The axisymmetric fluid elements, CFLUIDi, are used in conjunction with a suitable choice of symmetry planes and a model of the surrounding structure to approximate a two-dimensional enclosure with flexible walls. The enclosure walls are modeled using finite elements or structural modes. Illustrative examples include a comparison of rectangular cavity modes with those calculated using the acoustic slot element and the free vibration modes of two enclosures coupled through a flexible rectangular panel.

Wolf, J. A., Jr.↗
NASA NTRS1975

Test procedures and performance measures sensitive to automobile steering dynamics

A maneuver complex and related performance measures used to evaluate driver/vehicle system responses as effected by variations in the directional response characteristics of passenger cars are described. The complex consists of normal and emergency maneuvers (including random and discrete disturbances) which, taken as a whole, represent all classes of steering functions and all modes of driver response behavior. Measures of driver/vehicle system response and performance in regulation tasks included direct describing function measurements and rms yaw velocity. In transient maneuvers, measures such as steering activity and cone strikes were used.

Klein, R. H.↗
NASA NTRS1974

Rating aircraft on energy

Questions concerning the energy efficiency of aircraft compared to ground transport are considered, taking into account as energy intensity the energy consumed per passenger statute mile. It is found that today's transport aircraft have an energy intensity potential comparable to that of ground modes. Possibilities for improving the energy density are also much better in the case of aircraft than in the case of ground transportation. Approaches for potential reductions in aircraft energy consumption are examined, giving attention to steps for increasing the efficiency of present aircraft and to reductions in energy intensity obtainable by the introduction of new aircraft utilizing an advanced technology. The use of supercritical aerodynamics is discussed along with the employment of composite structures, advances in propulsion systems, and the introduction of very large aircraft. Other improvements in fuel economy can be obtained by a reduction of skin-friction drag and a use of hydrogen fuel.

Maddalon, D. V.↗