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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Design, building and test of one prototype and four final position sensor assemblies: Hall effect position sensors

This report covers the development of a three channel Hall effect position sensing system for the commutation of a three phase dc torquer motor. The effort consisted of the evaluation, modification and re-packaging of a commercial position sensor and the design of a target configuration unique to this application. The resulting design meets the contract requirements and, furthermore, the test results indicate not only the practicality and versatility of the design, but also that there may be higher limits of resolution and accuracy achievable.

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NASA NTRS1975

Coordinate transformation and truncation for rotating spacecraft with flexible appendages

The analytical structures of alternative coordinate transformations for the variables that characterize the deformations of finite element models of flexible appendages on rotating spacecraft are examined. Particular emphasis is given to the truncation operations that are essential for efficient numerical simulations of flexible spacecraft, due to the necessarily large number of coordinates employed in a finite element description. A theorem is developed which establishes necessary conditions for the commutativity of the required truncation and inversion operations. The recommended alternative for the rotating elastic appendage is a complex transformation with previously published orthogonality properties, which permit the derivation in this paper of a relatively simple explicit set of transformed and truncated equations of modal vibration in real variables.

Likins, P.↗
NASA NTRS1976

Construction and verification of a model of passenger response to STOL aircraft characteristics

A technique for evaluating passenger acceptance of a transportation system's environment has been developed. This includes a model of passenger reaction to the vehicle, as well as the relative satisfaction compared to other system attributes. The technique is applied to two commercial airline operations - a U.S. commuter, and the Canadian Airtransit STOL system. It is demonstrated that system convenience and aircraft interior seating can play a large role in satisfying the passenger.

Jacobson, I. D.↗
NASA NTRS1977

Low-loss energy storage flywheel

Magnetically-levitated, ironless-armature spokeless rotor is used. Ironless armature construction eliminates core losses due to hysteresis and eddy currents. Device combines features of homopolar salient poles and stationary ironless electronically commutated armature.

Evans, H. E.↗
NASA NTRS1976

A study of the remote neighborhood office center concept

The substitution of communications for commuting to work is examined from several aspects. Attention is focused on the possibility of certain groups of white collar workers conducting their business affairs through a network of Remote Neighborhood Office Centers (RNOC's) located near their homes. Typically, employees would communicate with their headquarters organizations by means of voice and digital circuits. Although current technology is readily able to support such an RNOC network, the main problems confronting would-be implementers center around the need for demonstrating that a sufficient number of business operations can be carried out in such a decentralized configuration as efficiently as they are under more conventional circumstances. The description of a pilot program is presented which is intended to identify pacing issues that must be settled before firm conclusions can be reached on whether the concept is operationally viable.

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NASA NTRS1977

Development of a drive system for a sequential space camera contract modification 4(S)

The brush type dc motor and clutch were eliminated from the design of the 16 mm space sequential camera design and replaced by an electronically commutated motor. The new drive system reduces the current consumption at 24 fps to 220 mA. The drive can be programmed and controlled externally from the multipurpose programmable timer/intervalometer, as well as being controlled locally from the camera.

Sharpsteen, J. T.↗
NASA NTRS1976

Aircraft concepts for service to small communities

Small communities are served by trunk, local-service, and commuter carriers having a wide variety in route structure, type of service, and economic character, operating over stage lengths less than 400 statute miles. NASA studies have investigated various aircraft concepts for short-haul that have potential in this market area. Aircraft concepts for this market require a careful balancing of performance, technology, and design-to-cost considerations. This paper summarizes some results of recent NASA sponsored air transportation system studies applicable to small community arenas.

Galloway, T. L.↗
NASA NTRS1977

Flywheel energy storage. II - Magnetically suspended superflywheel

This article, the second of a two part paper, describes the general design requirements for a flywheel energy storage system. A new superflywheel energy storage system, using a spokeless, magnetically suspended, composite material pierced disk rotor is proposed. The new system is configured around a permanent magnet ('flux biased') magnetic suspension system with active control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of stationary armature coils is proposed. There is no mechanical contact with the rotating ring and long life and low run down losses are projected. A discussion of major components for a 10 kwh system is presented.

Kirk, J. A.↗
NASA NTRS1978

Energy storage apparatus

A high efficiency, flywheel type energy storage device which comprises an electronically commutated d.c. motor/generator unit having a massive flywheel rotor magnetically suspended around a ring shaped stator is presented. During periods of low energy demand, the storage devices were operated as a motor, and the flywheel motor was brought up to operating speed. Energy was drawn from the device functioning as a generator as the flywheel rotor rotated during high energy demand periods.

Studer, P. A.↗
NASA NTRS1978

Tread drum for animals

A device for exercising animals such as primates is described, which includes a cylindrical housing mounted for rotation about a horizontal axis of revolution and has a cylindrical treadway portion on which the animal treads while the drum is rotated by means of a motorized drive. The treadway portion of the drum includes an electrode structure with sectors being independently energizable by means of a commutator and source of potential so that an electrical shock station is created behind a running-in-place station on the moving treadway. In this manner, if the animal should fall behind its running-in-place station, it may be shocked by treading on the energized electrode structure. One end of the tread drum comprises a transparent wall for unobstructed viewing of the animal being exercised.

Howard, W. H.↗
NASA NTRS1978

Improved methods for calculating the thickness noise

Advanced methods to compute the rotor thickness noise which is predominant in the case of high speed rotor were developed. These methods were deduced from a previous method by transforming the integral coordinate, commuting the order of integration and differential, and/or performing chordwise integration analytically with some adequate assumption. The necessary computational times and waveforms obtained by the previous and three advanced methods were compared. It was then concluded that the advanced methods could save the computational time compared with the previous method with the same accuracy.

Nakamura, Y.↗
NASA NTRS1977

Ride quality assessment. III - Questionnaire results of a second flight programme

A questionnaire was completed by 861 passengers on regularly-scheduled flights of four commuter airlines. Four types of aircraft were involved. Questions assessed major demographic variables, attitudes toward flying, frequency of flying, experience of airsickness, and passenger perceptions of detailed aspects of the physical environment. Passengers also rated their overall comfort level and their willingness to fly again. Passengers perceive motion, noise, and seat factors as the primary determinants of their comfort. Rated comfort is strongly related to willingness to fly again. Incidence of airsickness was low. Sex differences in reactions to aspects of the environment were found.

Richards, L. G.↗
NASA NTRS1977

Continuous 30-day measurements utilizing the monkey metabolism pod

A fiberglass system was previously described, using which quantitative physiological measurements could be made to study the effects of weightlessness on 10 to 14 kg adult monkeys maintained in comfortable restraint under space flight conditions. Recent improvements in the system have made it possible to obtain continuous measurements of respiratory gas exchange, cardiovascular function, and mineral balance for periods of up to 30 days on pig-tailed monkeys. It has also been possible to operate two pods which share one set of instrumentation, thereby permitting simultaneous measurements to be made on two animals by commutating signal outputs from the pods. In principle, more than two pods could be operated in this fashion. The system is compatible with Spacelab design. Representative physiological data from ground tests of the system are presented.

Pace, N.↗
NASA NTRS1978

Photovoltaic tests and applications project

The activities and accomplishments of the Photovoltaic Tests and Applications Project during the period April 1976 through June 1977 are summarized. Results of efforts to identify potential near-term photovoltaic applications and users are discussed, including the outcome of an extensive survey of Federal government agencies. The status of application experiments is presented. Various general engineering efforts are reported, including the design and construction of a photovoltaic Systems Test Facility. Efforts to develop a high efficiency 10 kVA self-commutated inverter and controller specifically designed for photovoltaic systems are also discussed. The results of a wide variety of activities in the area of photovoltaic measurements and standards are related. Documents generated by the Project during the reporting period are listed in an Appendix.

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NASA NTRS1978

A distributed microcomputer telemetry system for spacecraft applications

Distributed microcomputer telemetry system design difficulties are examined and solutions to these difficulties are discussed. In the telemetry system being considered, the data gathering is actually distributed among a number of computers, each with its own commutation cycle, data storage buffers, and specified set of measurements to be sampled. A computer based high level module controls the formation of the final telemetry stream by accessing individual computer's data storage buffers at the appropriate time and inserting them into the telemetry stream. Attention is given to the precise time tagging of data samples, the interconnection of several computers, the autonomous operation of science instruments, and reliability considerations.

Lord, D. D.↗
NASA NTRS1978

A programmable power processor for a 25 kW power module

The paper presents the concept and major design problems of a programmable power processor for the 25 kW electrical power system for the Shuttle Orbiter. The load will be handled by three parallel power stages operated in phase sequence with each power transistor having its own commutating diode and filter inductor. The power stages will be run at a fixed frequency of 10 kHz with the 'on'-time variable up to 100%. The input filter bank in the breadboard programmable power processor is planned to be a series-parallel combination of tantalum cased tantalum wet-slug capacitors.

Kapustka, R. E.↗
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.

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