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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1967

Temperature-stabilized, triggerable microelectronic astable multivibrator starts reliably

Multiple chip custom block, MIC construction is used to fabricate an ultracompact, low-power astable multivibrator. The design provides a multivibrator that free runs, eliminating lockup, is triggerable, pulling into synchronization with an external signal source, and permits design flexibility for controlling the frequency variations with temperature.

Stebbins, W. J.↗
NASA NTRS1968

Adaptive control circuit prevents amplifier saturation

Adaptive control circuit prevents saturation of push-pull output amplifiers used in low-power, low-torque suspension system. The adaptive control circuit senses how near the output amplifiers are to saturation and sets the B voltage in such a way as to keep them just clear of saturation.

Nondsieck, A. J.↗
NASA NTRS1968

Small, low power analog-to-digital converter

A small, low-power, high-speed, 8-bit analog-to-digital converter using silicon chip integrated circuits is suitable for use in airborne test data systems. The successive approximation method of analog-to-digital conversion is used to generate the digital output.

Dunn, R. D.↗
NASA NTRS1968

Fluidic-thermochromic display device

Fluidic decoder and display device has low-power requirements for temperature control of thermochromic materials. An electro-to-fluid converter translates incoming electrical signals into pneumatics signal of sufficient power to operate the fluidic logic elements.

Grafstein, D.↗
NASA NTRS1968

A rapid stress-corrosion test for aluminum alloys

Stressed alloy specimens are immersed in a salt-dichromate solution at 60 degrees C. Because of the minimal general corrosion of these alloys in this solution, stress corrosion failures are detected by low-power microscopic examination.

Helfrich, W. J.↗
NASA NTRS1971

A compact and low power coherent optical system for on-board spacecraft data processing.

Discussion of the design and performance of a compact low-power coherent optical data processing system suitable for spacecraft onboard applications. The system is a modification of the conventional optical data processing system in which a much more efficient solid state GaAs laser is substituted for the bulky and inferior He-Ne laser and paraboloidal mirror segments are substituted for the axially symmetric optical system of the conventional data processing system. Theoretical considerations are given to substantiate the improvement of performance aimed at in the modified system. Preliminary tests of the modified design being in progress indicate that a low power, rugged, small size optical system, capable of onboard spacecraft data processing, can be constructed by using off-axis paraboloidal mirror segments.-

Husain-Abidi, A. S.↗
NASA NTRS1991

Resistor Extends Life Of Battery In Clocked CMOS Circuit

Addition of fixed resistor between battery and clocked complementary metal oxide/semiconductor (CMOS) circuit reduces current drawn from battery. Basic idea to minimize current drawn from battery by operating CMOS circuit at lowest possible current consistent with use of simple, fixed off-the-shelf components. Prolongs lives of batteries in such low-power CMOS circuits as watches and calculators.

Wells, George H., Jr.↗
NASA NTRS1993

Ampere-Hour Meter For Rechargeable Battery

Low-power analog/digital electronic circuit meters discharge of storage battery in ampere-hours. By metering discharge, one obtains indication of state of charge of battery and avoids unnecessary recharging, maintaining capacity of battery and prolonging life. Because of its small size and low power consumption, useful in such applications as portable video cameras, communication equipment on boats, portable audio equipment, and portable medical equipment.

Tripp, John S.↗
NASA NTRS1924

Comparing the performance of geometrically similar airplanes

This note has been prepared for the National Advisory Committee for Aeronautics. It deals with the model rules relating to aeronautical problems, and shows how the characteristics of one airplane can be determined from those of another airplane of different weight or size, and of similar type. If certain rules for the ratios of the dimensions, the weights and the horsepower are followed, a small low-powered airplane can be used for obtaining information as to performance, stability, controllability and maneuverability of a larger prototype, and contrariwise.

Munk, Max M↗
NASA NTRS1938

Engines and propellers for powered gliders and light airplanes

The object of the present paper is to consider the interaction of engine, propeller, and airplane for the low-power range. The discussion is presented in a form so as to provide the engine builder with a basis in his selection in the type of engine required, a suitable selection being possible only in connection with considerations on the best possible propeller.

Gropp, H↗
NASA NTRS1954

An Investigation in the Ames 40- by 80-Foot Wind Tunnel of a YT-56A Turboprop Engine Incorporating a Decoupler and a Controlled-Feathering Device

An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph. It was found that with neither device free to operate, the drag levels realized after power failures at airspeeds above 170 mph would impose vertical tail loads higher than those allowable for the YC-130, the airplane for which the test power package was designed. These levels were reached in approximately one second. The maximum drag realized after power failure was not appreciably altered by the use of the decoupler although the decoupler did put a limit on the duration of the peak drag. The controlled-feathering device maintained a level of essentially zero drag after power failure. The use of the decoupler in the YT-56A engine complicates windmilling air-starting procedures and makes it necessary to place operating restrictions on the engine to assure safe flight at low-power conditions,

Rogallo, Vernon L.↗
NASA NTRSDate not supplied

Investigating Laser Beam Welding as an In-Space Joining Technique via Thermal Vacuum and Microgravity and Vacuum Experiments

In-space joining technologies are crucial for stimulating an in-space economy and for enabling sustained space exploration by in-space manufacturing and repair of metallic structures. Compared to brazing or soldering, in-space welding (ISW) can provide highly hermetic, strong, and complex joints, potentially without introducing additional material. However, the influence of extreme temperatures, reduced pressure, and reduced gravity on ISW is not yet fully elucidated. Several efforts at NASA are investigating laser beam welding (LBW) as a joining and repair method in both thermal vacuum (TVAC) and combined vacuum & reduced gravity environments. NASA Marshall Space Flight Center (MSFC) shepherded several ISW projects in its past, including the 1973 electron beam welding on Skylab, the 1989 low-power LBW on parabolic flights, and the unflown 1990s-era In-Space Welding Experiment. Recent parabolic flights and 3 degree-of-freedom ground testing build upon this heritage. A collaboration with the Ohio State University using NASA Langley Research Center (LaRC) hardware retrofitted for LBW achieved the first high-powered laser welds under vacuum and low gravity and developed a workforce capable developing such experimental hardware. A ground testing campaign at the MSFC Flat Floor simulated fit-up and welding representative of ISW in 3 degrees of freedom to emulate microgravity effects on inertial systems. One ongoing effort is a NASA Early Career Initiative project – Lunar Assembly and Servicing by Autonomous Robotics (LASAR). Ruggedized LBW components were developed by an external partner for use in TVAC. A TVAC-rated robotic arm was procured by MSFC and used in the first known robotic laser weld where all components save the laser generator were under vacuum. NASA Johnson Space Center (JSC) is advancing supervised autonomy of ISW. NASA LaRC continues to adapt their unique snowflake joint geometry, suitable for connecting segments in trusses and other structures, to LBW. Upcoming TVAC campaigns will focus on testing extreme temperatures, proving out autonomous operations, and demonstrating weld repair. Weld inspection will occur via a non-contact nondestructive evaluation (NDE) technique – electromagnetic acoustic transduction (EMAT). Another ongoing effort based at MSFC is the DISCMAN -- DIsk-Shaped Configurable and Modular vAcuum uNit – which seeks to development a compact, modular payload that can provide a vacuum environment while in a reduced gravity condition. This payload could support multiple in-space manufacturing developmental efforts, with the first demonstration technology being LBW. Currently, the design is targeting operations in the pressurized volume of a space station, but the payload could readily be adapted to other flight platforms such as parabolic or even suborbital vehicles. LASAR elucidates the effects of temperature and vacuum on LBW while DISCMAN probes those of vacuum and gravity. Through these complementary efforts, NASA is addressing the primary challenges of ISW across the space environment while simultaneously developing and maturing technologies including robotic systems and inspection methodologies for future practical implementation on the Moon and beyond. This approach is timely, as upcoming missions requiring sustained human presence in space will depend on reliable ISW capabilities to create robust metallic joints currently unproven in the space environment and to perform repairs in situ .

hypogravity↗
NASA NTRS1925

Light aeroplane engine development

It has frequently been stated and written that in order to popularize light aircraft the first essential is the production of a reliable engine capable of being easily maintained and having a long life, at the same time selling at a low figure. It is desired to point out the difficulties in the way of realizing this ideal before remarking on the claims of the various types for adoption.

ENGINES - DES↗