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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 577 records · Page 32

All sources NASA NTRS DOE OSTI

NASA NTRS1975

Rotary-wing aircraft systems for the short-haul market

This paper describes preliminary designs of tilt-rotor and tandem-rotor helicopter V/STOL aircraft for the 1958 short-haul market. These designs include a tilt-rotor aircraft designed for STOL-only operation. The baseline designs are presented with technological and cost data. The impact of noise and ride qualities on aircraft size and cost, and on passenger acceptance are discussed. The results of the study are compared against competitive alternatives in air transportation.

Magee, J. P.↗

NASA NTRS1975

Advanced concept considerations for STOL short-haul systems

Design, performance, and economic tradeoffs for STOL short-haul systems are presented. The analyses showed that quiet, short-field aircraft can be economically viable and provide benefits to airport congestion and to community noise relief. The objective of the studies was to compare and evaluate propulsive-lift systems and low-wing-loading aircraft provided with ride quality control and gust load alleviation, and to determine fuel consumption and cost tradeoffs, along with recommendations for development of technology, noise criteria, and airport planning. In the low density arena, the optimum aircraft sized for less than 50 passengers have active controls for ride quality and gust alleviation; turboprop propulsion offers significant cost and fuel saving with no appreciable block time penalty for the short typical stage lengths (on the order of 150 miles). In the high density arena, high bypass-ratio fan-powered aircraft, with design cruise speed of 0.7 to 0.75M and range capability to 1500 miles, are considered to be optimum. Field performance of 3000 feet or better can be achieved by the hybrid over-the-wing/internally blown flap concept with viable economics and low fuel consumption. Mechanical flap aircraft with high bypass-ratio engines are indicated to be superior for field lengths of 3500 feet or more. Technology development of propulsive lift is required, and further definition of the best fan-powered engine for low noise and low fuel consumption is needed.

Sweet, H. S.↗

NASA NTRS1975

Air transportation energy consumption - Yesterday, today, and tomorrow

The energy consumption by aviation is reviewed and projections of its growth are discussed. Forecasts of domestic passenger demand are presented, and the effect of restricted fuel supply and increased fuel prices is considered. The most promising sources for aircraft fuels, their availability and cost, and possible alternative fuels are reviewed. The energy consumption by various air and surface transportation modes is identified and compared on typical portal-to-portal trips. A measure of the indirect energy consumed by ground and air modes is defined. Historical trends in aircraft energy intensities are presented and the potential fuel savings with new technologies are discussed.

Mascy, A. C.↗

NASA NTRS1975

Diagnostic calculations of airframe-radiated noise

Methods of calculating airframe noise due to the following components are presented: wings and stabilizers, flaps, landing gear 'self-noise', landing gear bay (wheel well) oscillations, separated flow interaction with edges of cavities, and doors associated with gear deployment. The predominant source mechanisms were dipole-like in nature, being related to the local fluctuating aerodynamic forces on struts, airfoil edges, cavity edges, etc. Available data are converted into semiempirical prediction methods to enable a tentative rank ordering of noise sources. A sample application of these prediction procedures is carried out for a typical CTOL passenger jet using actual aircraft parameters, where available.

Hayden, R. E.↗

NASA NTRS1975

Ride-quality testing under controlled flight conditions

As part of a NASA program to develop the technology of ride quality, a flight-test program has been conducted to obtain subjective reactions of a significant number of test passengers to a variety of controlled and repeatable flight conditions. For these experiments, the computer of a variable-stability research aircraft was programmed to precisely control the aircraft's in-flight motions as specified by motion command signals prerecorded on magnetic tape. Problems initially encountered derived primarily from the quality of the motion command signals and tape playback device, plus the aircraft motion response in degrees of freedom other than that desired. Problem solutions were obtained through the use of filtering and compensating networks. The variable-stability-system modifications, problems encountered, and their solutions are described. The test procedure is described and sample results are presented which illustrate the usefulness of this technique for ride-quality research.

Schoonover, W. E., Jr.↗

NASA NTRS1975

Challenges of short-haul air transportation

Short-haul transportation systems are characterized by low average utilization, high peak but low average passenger demand, severe competition from other transportation modes, high fixed costs and high operating costs. Studies were conducted to analyze the operational requirements and market size for medium-density air transportation. The determination of the aircraft that will most efficiently meet the requirements of this market requires the careful evaluation of variable parameters such as engine cycles, payload, field length range and type of high-lift system. Low noise, low cost and thrust reversing capability are the basic criteria for the propulsion system. It is concluded that aircraft of less than 50-seat capacity cannot generate satisfactory profits operating in the medium-density market.

Galloway, T. L.↗

NASA NTRS1975

The shuttle orbiter cabin atmospheric revitalization systems

The Orbiter Atmospheric Revitalization Subsystem (ARS) and Pressure Control Subsystem (ARPCS) are designed to provide the flight crew and passengers with a pressurized environment that is both life-supporting and within crew comfort limitations. The ARPCS is a two-gas (oxygen-nitrogen) system that obtains oxygen from the Power Reactant Supply and Distribution (PRSD) subsystem and nitrogen from the nitrogen storage tanks. The ARS includes the water coolant loop; cabin CO2, odor, humidity and temperature control; and avionics cooling. Baseline ARPCS and ARS changes since 1973 include removal of the sublimator from the water coolant loop, an increase in flowrates to accommodate increased loads, elimination of the avionics bay isolation from the cabin, a decision to have an inert vehicle during ferry flight, elimination of coldwall tubing around windows and hatches, and deletion of the cabin heater.

Ward, C. F.↗

NASA NTRS1975

Interior noise considerations for powered-lift STOL aircraft

Powered-lift configurations which are currently under development for future use on STOL aircraft involve impingement of the jet engine exhaust onto wing and flap surfaces. Previous studies have suggested that 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 (USB) and an externally blown flap (EBF) configuration. This paper describes the procedure used to estimate the interior noise levels and compares these levels 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

An economic study of an advanced technology supersonic cruise vehicle

A description is given of the methods used and the results of an economic study of an advanced technology supersonic cruise vehicle. This vehicle was designed for a maximum range of 4000 n.mi. at a cruise speed of Mach 2.7 and carrying 292 passengers. The economic study includes the estimation of aircraft unit cost, operating cost, and idealized cash flow and discounted cash flow return on investment. In addition, it includes a sensitivity study on the effects of unit cost, manufacturing cost, production quantity, average trip length, fuel cost, load factor, and fare on the aircraft's economic feasibility.

Smith, C. L.↗

NASA NTRS1975

Fire-resistant aircraft materials development and evaluation program

An aircraft flammability program was undertaken to utilize spacecraft developed fire-resistant materials to improve passenger safety and decrease losses from unattended fires in commercial aircraft. Five full-scale aircraft flammability tests were performed to evaluate the effectiveness of improved fire-resistant materials by comparing their burning characteristics with those of pre-1968 aircraft materials.

Bricker, R. W.↗

NASA NTRS1975

A method for the determination of potentially profitable service patterns for commuter air carriers

A methodology for estimating market conception was developed as a part of the short-haul air transportation program. It is based upon an analysis of actual documents which provide a record of known travel history. Applying this methodology a forecast was made of the demand for an air feeder service between Charlottesville, Virginia and Dulles International Airport. Local business travel vouchers and local travel agent records were selected to provide the documentation. The market was determined to be profitable for an 8-passenger Cessna 402B aircraft flying a 2-hour daily service pattern designed to mesh to the best extent possible with the connecting schedules at Dulles. The Charlottesville - Dulles air feeder service market conception forecast and its methodology are documented.

Ransone, R. K.↗

NASA NTRS1975

Application of active controls technology to aircraft bide smoothing systems

A critical review of past efforts in the design and testing of ride smoothing and gust alleviation systems is presented. Design trade offs involving sensor types, choice of feedback loops, human comfort, and aircraft handling-qualities criteria are discussed. Synthesis of a system designed to employ direct-lift and side-force producing surfaces is reported. Two STOL aircraft and an executive transport are considered. Theoretically predicted system performance is compared with hybrid simulation and flight test data. Pilot opinion rating, pilot workload, and passenger comfort rating data for the basic and augmented aircraft are included.

Lapins, M.↗

NASA NTRS1975

Some aspects of hybrid-zeppelins

To increase an airship's maneuverability and payload capacity as well as to save bouyant gas it is proposed to outfit it with a slender delta-wing, which carries about one half of the total take-off weight of the vehicle. An optimization calculation based on the data of LZ 129 (the last airship, which saw passenger-service) leads to a Hybrid-Zeppelin with a wing of aspect-ratio 1.5 and 105 m span. The vehicle carries a payload of 40% of it's total take-off weight and consumes 0.8 t fuel per ton payload over a distance of 10000 km.

Mackrodt, P. A.↗

NASA NTRS1975

Thermal area effectiveness for future aircraft

Problem areas in airport planning, design, and operations identified by a decision matrix developed to display various airport functions interfaced with facilities and an extensive literature survey were investigated. Areas considered include: site selection and growth potential; emissions and noise control/containment for airports; financial and legal aspects of airport planning, contruction, and operation; intra-airport transportation and other passenger flow facilitators; simulation and modeling for airports; guidelines for airport multimodal access planning. Results are summarized and a bibliography is included.

Happ, W. W.↗

NASA NTRS1975

The 1975 Ride Quality Symposium

A compilation is presented of papers reported at the 1975 Ride Quality Symposium held in Williamsburg, Virginia, August 11-12, 1975. The symposium, jointly sponsored by NASA and the United States Department of Transportation, was held to provide a forum for determining the current state of the art relative to the technology base of ride quality information applicable to current and proposed transportation systems. Emphasis focused on passenger reactions to ride environment and on implications of these reactions to the design and operation of air, land, and water transportation systems acceptable to the traveling public. Papers are grouped in the following five categories: needs and uses for ride quality technology, vehicle environments and dynamics, investigative approaches and testing procedures, experimental ride quality studies, and ride quality modeling and criteria.

Source record↗

NASA NTRS1975

Review of ride quality technology needs of industry and user groups

A broad survey of ride quality technology state-of-the-art and a review of user evaluation of this technology were conducted. During the study 17 users of ride quality technology in 10 organizations representing land, marine and air passenger transportation modes were interviewed. Interim results and conclusions of this effort are reported.

Mckenzie, J. R.↗

NASA NTRS1975

Nonmotion factors which can affect ride quality

Data pertaining to nonmotion factors affecting ride quality of transport aircraft were obtained as part of NASA in-house and sponsored research studies carried out onboard commuter-airline and research aircraft. From these data, quantitative effects on passenger discomfort of seat width, seat legroom, change in cabin pressure, and cabin noise are presented. Visual cue effects are also discussed.

Conner, D. W.↗

NASA NTRS1975

Vehicle for civil helicopter ride quality research

A research aircraft for investigating the factors involved in civil helicopter operations was developed for NASA Langley Research Center. The aircraft is a reconfigured 17000 kg (36000 lb) military transport helicopter. The basic aircraft was reconfigured with advanced acoustic treatment, air-conditioning, and a 16-seat airline cabin. During the spring of 1975, the aircraft was flight tested to measure interior environment characteristics - noise and vibration - and was flown on 60 subjective flight missions with over 600 different subjects. Data flights established noise levels somewhat higher than expected, with a pure tone at 1400 Hz and vertical vibration levels between 0.07g and 0.17g. The noise and vibration levels were documented during subjective flight evaluations as being the primary source of discomfort. The aircraft will be utilized to document in detail the impact of various noise and vibration levels on passenger comfort during typical short-haul missions.

Snyder, W. J.↗