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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 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Design and piloted simulation evaluation of integrated flight/propulsion controls for STOVL aircraft

Integrated flight/propulsion control systems have been designed for operation of STOVL aircraft over the low speed powered-lift flight envelope. The control system employs command modes for attitude, flightpath angle and flightpath acceleration during transition, and translational velocity command for hover and vertical landing. The command modes and feedback control are implemented in the form of a state-rate feedback implicit model follower to achieve the desired flying qualities and to suppress the effects of external disturbances and variations in the aircraft characteristics over the low speed envelope. A nonlinear inverse system was used to translate the output from these commands and feedback control into commands for the various aerodynamic and propulsion control effectors that are employed in powered-lift flight. Piloted evaluations of these STOVL integrated control designs have been conducted on Ames Research Center's Vertical Motion Simulator to assess flying qualities over the low-speed flight envelope. Results indicate that Level 1 flying qualities are achieved with this control system concept for each of these low-speed operations over a wide range of wind, atmospheric turbulence, and visibility conditions.

Franklin, James A.↗
NASA NTRS1972

Low voltage 30cm ion thruster

The construction of an ion thruster module (including thruster, power conditioning, and control system) capable of operating for 10,000 hours over a five to one range at an effective specific impulse of approximately 2800 seconds is discussed. The several interrelated tasks involved in the construction of the engine are described. Performance tests of the engine and the effects of various modifications are reported. It was demonstrated that thruster performance and stability were not materially affected by reasonable changes from the nominal operating point.

Source record↗
NASA NTRS1973

Performance of electrical subsystem of 2- to 15-kilowatt Brayton power conversion system

The electrical subsystem of the 2-to 15-kilowatt Brayton power conversion system was evaluated under various operating and off-design temperature conditions in a vacuum environment. Overall operation was satisfactory. Speed controller operation is a major cause of distortion in the system ac voltage and current waveforms. This distortion has a small, but potentially significant effect on the performance of individual subsystem components.

Secunde, R. R.↗
NASA NTRS1974

Load insensitive electrical device

A class of power converters is described for supplying direct current at one voltage from a source at another voltage. It includes a simple passive circuit arrangement of solid-state switches, inductors, and capacitors by which the output voltage of the converter tends to remain constant in spite of changes in load. The switches are sensitive to the current flowing in the circuit and are employed to permit the charging of capacitance devices in accordance with the load requirements. Because solid-state switches (such as SCR's) may be used with relatively high voltage and because of the inherent efficiency of the invention that permits relatively high switching frequencies, power supplies built in accordance with the invention, together with their associated cabling, can be substantially lighter in weight for a given output power level and efficiency of operation than systems of the prior art.

Schwarz, F. C.↗
NASA NTRS1974

Nuclear Science Symposium, 20th, and Nuclear Power Systems Symposium, 5th, San Francisco, Calif., November 14-16, 1973, Proceedings

Subjects considered are in the areas of position sensitive detectors, semiconductor detector materials, semiconductor detector technology, biomedical instrumentation, reactor instrumentation, nuclear instrumentation, and data acquisition and processing. Topics related to photon detection are discussed together with methods for environmental radiation measurement, aspects of environmental gamma-ray analysis, and nuclear techniques for elemental analysis. Attention is also given to operation and design experience with systems at nuclear power plants. Individual items are announced in this issue.

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NASA NTRS1974

Review of hydrogen accidents and incidents in NASA operations

Safety, as a major factor in the development of a power economy based on hydrogen produced by nuclear- or solar-energy operated water electrolysis, is considered in terms of the safety problems involved in the production, handling, transportation, and use of liquid and gaseous hydrogen. These problems are reviewed through the records of accidents and incidents that have occurred in the development and operation of NASA's propulsion and power systems. Areas of research and development are suggested for increased safety and for the development of techniques to reduce the consequences of any mishaps.

Ordin, P. M.↗
NASA NTRS1975

Summary of results indicating the beneficial effects of rotor vortex modification

The possibility of reducing blade-slap noise and high-frequency air loads and of increasing performance by tip air mass injection (TAMI) is investigated. The discussion is limited to two types of TAMI: chordwise injection with air injected at the blade tip in a chordwise direction and spanwise injection with air injected in a spanwise direction. Experimental and analytical results indicate that a properly designed TAMI system can restructure the near field characteristics of a concentrated vortex that trails off the tip of a lifting surface, that the tip vortex is spread by the application of chordwise TAMI, that mixing exists between the injected air mass and the vortex flow which enhances vortex decay, that the net power requirements to implement the system on operational helicopters are within acceptable levels, that maximum drop of noise level reductions of about 25 dB can be achieved, and that a decrease in the drag induced by the tip vortex in a spanwise TAMI system can be obtained by restructuring the vortex as it forms along the airfoil chord and by moving the vortex farther outboard of the tip.

White, R. P., Jr.↗
NASA NTRS1975

Interactive computer aided technology, evolution in the design/manufacturing process

A powerful computer-operated three dimensional graphic system and associated auxiliary computer equipment used in advanced design, production design, and manufacturing was described. This system has made these activities more productive than when using older and more conventional methods to design and build aerospace vehicles. With the use of this graphic system, designers are now able to define parts using a wide variety of geometric entities, define parts as fully surface 3-dimensional models as well as "wire-frame" models. Once geometrically defined, the designer is able to take section cuts of the surfaced model and automatically determine all of the section properties of the planar cut, lightpen detect all of the surface patches and automatically determine the volume and weight of the part. Further, his designs are defined mathematically at a degree of accuracy never before achievable.

English, C. H.↗
NASA NTRS1975

The assembly of large structures in space

Techniques developed for orbital assembly of the support structure for a 1000 meter diameter microwave power transmission system antenna are described. The operation is performed in two phases using the shuttle remote manipulator system in low earth orbit, and a mobile assembler in geosynchronous orbit.

Smith, G. W.↗
NASA NTRS1979

Phase 1 of the First Solar Small Power System Experiment (experimental System No. 1). Volume 3: Appendix E - N

The design of a solar electric power plant for a small community is reported. Topics covered include: (1) control configurations and interface requirements for the baseline power system; (2) annual small power system output; (3) energy requirements for operation of the collectors and control building; (4) life cycle costs and reliability predictions; (5) thermal conductivities and costs of receiver insulation materials; (6) transient thermal modelling for the baseline receiver/thermal transport system under normal and inclement operating conditions; (7) high temperature use of sodium; (8) shading in a field of parabolic collectors; and (9) buffer storage materials.

Clark, T. B.↗
NASA NTRS1981

Low cost high temperature, duplex coating for superalloys

Duplex silicon-slurry/aluminide coating substantially improves high temperature resistance to oxidation and corrosion of nickel base alloys. Coating used in critical sections of power systems like turbojet engines extends their operating capabilities.

Young, S. G.↗
NASA NTRS1981

Application of Nonlinear Systems Inverses to Automatic Flight Control Design: System Concepts and Flight Evaluations

A practical method for the design of automatic flight control systems for aircraft with complex characteristics and operational requirements, such as the powered lift STOL and V/STOL configurations, is presented. The method is effective for a large class of dynamic systems requiring multi-axis control which have highly coupled nonlinearities, redundant controls, and complex multidimensional operational envelopes. It exploits the concept of inverse dynamic systems, and an algorithm for the construction of inverse is given. A hierarchic structure for the total control logic with inverses is presented. The method is illustrated with an application to the Augmentor Wing Jet STOL Research Aircraft equipped with a digital flight control system. Results of flight evaluation of the control concept on this aircraft are presented.

Meyer, G.↗
NASA NTRS1980

Nonmicrowave health and ecological effects: Overview

The potential environmental impacts due to the operation and construction of the Satellite Power System are discussed. The nonmicrowave health and ecological effects encompass impacts on the public, the terrestrial worker, the space worker, the ecology, and agriculture.

White, M. R.↗