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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Pilot usage of decoupled flight path and pitch controls

Data from decoupled flight maneuvers have been collected and analyzed for four AFTI-F-16 pilots operating this aircraft's highly augmented fly-by-wire control system, in order to obtain spectral density, cross spectra, and Bode amplitude data, as well as coherences and phase angles for the two longitudinal axis control functions of each of 50 20-sec epochs. The analysis of each epoch yielded five distinct plotted parameters for the left hand twist grip and right hand sidestick controller output time series. These two control devices allow the left hand to generate vertical translation, direct lift, or pitch-pointing commands that are decoupled from those of the right hand. Attention is given to the control patterns obtained for decoupled normal flight, air-to-air gun engagement decoupled maneuvering, and decoupled air-to-surface bombing run maneuvering.

Berkhout, J.↗
NASA NTRS1986

Flight test of a decoupler pylon for wing/store flutter suppression

The decoupler pylon is a NASA concept of passive wing-store flutter suppression achieved by providing a low store-pylon pitch frequency. Flight tests where performed on an F-16 airplane carrying on each wing an AIM-9J wingtip missile, a GBU-8 bomb near midspan, and an external fuel tank. Baseline flights with the GBU-8 mounted on a standard pylon established that this configuration is characterized by an antisymmetric limited amplitude flutter oscillation within the operational envelope. The airplane was then flown with the GBU-8 mounted on the decoupler pylon. The decoupler pylon successfully suppressed wing-store flutter thoughout the flight envelope. A 37-percent increase in flutter velocity over the standard pylon was demonstrated. Maneuvers with load factors to 4g were performed. Although the static store displacements during maneuvers were not sufficiently large to be of concern, a store pitch alignment system was tested and performed successfully. One GBU-8 was ejected demonstrating that weapon separation from the decoupler pylon is normal. Experience with the present decoupler pylon design indicated that friction in the pivoting mechanism could affect its proper functioning as a flutter suppressor.

Cazier, F. W., Jr.↗
NASA NTRS1987

Gas exchange on Mono Lake and Crowley Lake, California

Gas exchange coefficients (k) have been determined for freshwater Crowley Lake and saline Mono Lake through the use of a man-made purposefully injected gas, SF6. The concentration decreased from an initial value of 40 to 4 pmol/L for Mono Lake and from 20 to 1 pmol/L for Crowley lake over a period of 6 wks. Wind-speed (u) records from anemometers on the shore of each lake made it possible to determine the relationship between k and u. The average u and k values for the experiment were identical for the two lakes, despite the large chemical differences. It is estimated that, for the u values observed over Mono Lake from July to December 1984, the exchange of CO2 occurred 2.5 times faster than without chemical enhancement. This is a factor of 4 lower than needed to explain the high invasion rate of C-14 produced by nuclear bomb tests.

Wanninkhof, Rik↗
NASA NTRS1989

Cockpit resource management skills enhance combat mission performance in a B-52 simulator

A cockpit resource management (CRM) program for mission-ready B-52 aircrew is developed. The relationship between CRM performance and combat mission performance is studied. The performances of six crew members flying a simulated high workload mission in a B-52 weapon system trainer are evaluated. The data reveal that CRM performance enhances tactical maneuvers and bombing accuracy.

Povenmire, H. Kingsley↗
NASA NTRS1992

Blast-Absorbing Bag

Proposed expandable bag contains debris from explosion. Permanently surrounds vessel or devices prone to explosive disintegration or slipped around small bomb. Finned cells shaped like outward-opening cups. Cells built up from overlapped sheets of fabric and stitched together to form expandable polyhedral bag. Cells pentagonal, triangular or square.

Kahn, Jon B.↗
NASA NTRS1991

Lunar and Hawaiian lava tubes: Analogs and uses based on terrestrial field data

Presented here is an analysis of the data collected for a large number of Hawaiian lava tubes on the islands of Oahu, Molokai, and Hawaii. The results are extrapolated to lunar conditions. It is argued that lava tubes that formed on the Earth and the Moon are relatively stable over time, as illustrated by the ridigity of the Hawaiian prehistoric lava tubes as well as the historic tubes located in the bombing range near Mauna Loa. These natural structures should be considered for use in planning for the expansion and advanced stages of the future manned lunar base.

Coombs, Cassandra R.↗
NASA NTRS1991

Cyclone: A close air support aircraft for tomorrow

To meet the threat of the battlefield of the future, the U.S. ground forces will require reliable air support. To provide this support, future aircrews demand a versatile close air support aircraft capable of delivering ordinance during the day, night, or in adverse weather with pin-point accuracy. The Cyclone aircraft meets these requirements, packing the 'punch' necessary to clear the way for effective ground operations. Possessing anti-armor, missile, and precision bombing capability, the Cyclone will counter the threat into the 21st Century. Here, it is shown that the Cyclone is a realistic, economical answer to the demand for a capable close air support aircraft.

Cox, George↗
NASA NTRS1991

The Eliminator: A design of a close air support aircraft

The Eliminator is the answer to the need for an affordable, maintainable, survivable, high performance close air support aircraft primarily for the United States, but with possible export sales to foreign customers. The Eliminator is twin turbofan, fixed wing aircraft with high mounted canards and low mounted wings. It is designed for high subsonic cruise and an attack radius of 250 nautical miles. Primarily it would carry 20 500 pound bombs as its main ordnance , but is versatile enough to carry a variety of weapons configurations to perform several different types of missions. It carries state of the art navigation and targeting systems to deliver its payload with pinpoint precision and is designed for maximum survivability of the crew and aircraft for a safe return and quick turnaround. It can operate from fields as short as 1800 ft. with easy maintenance for dispersed operation during hostile situations. It is designed for exceptional maneuverability and could be used in a variety of roles from air-to-air operations to anti-submarine warfare and maritime patrol duties.

Hendrix, Mandy↗
NASA NTRS1991

Applications of the Strategic Defense Initiative's compact accelerators

The Strategic Defense Initiative's (SDI) investment in particle accelerator technology for its directed energy weapons program has produced breakthroughs in the size and power of new accelerators. These accelerators, in turn, have produced spinoffs in several areas: the radio frequency quadrupole linear accelerator (RFQ linac) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI-sponsored compact induction linear accelerator may replace Cobalt-60 radiation and hazardous ethylene-oxide as a method for sterilizing medical products, and other SDIO-funded accelerators may be used to produce the radioactive isotopes oxygen-15, nitrogen-13, carbon-11, and fluorine-18 for positron emission tomography (PET). Other applications of these accelerators include bomb detection, non-destructive inspection, decomposing toxic substances in contaminated ground water, and eliminating nuclear waste.

Montanarelli, Nick↗
NASA NTRS1991

Nuclear winter - Physics and physical mechanisms

The basic physics of the environmental perturbations caused by multiple nuclear detonations is explored, summarizing current knowledge of the possible physical, chemical, and biological impacts of nuclear war. Emphasis is given to the impact of the bomb-generated smoke (soot) particles. General classes of models that have been used to simulate nuclear winter are examined, using specific models as examples.

Turco, R. P.↗
NASA NTRS1992

Relationship between wind speed and gas exchange over the ocean

A quadratic dependence of gas exchange on wind speed is employed to analyze the relationship between gas transfer and wind speed with particular emphasizing variable and/or low wind speeds. The quadratic dependence is fit through gas-transfer velocities over the ocean determined by methods based on the natural C-14 disequilibrium and the bomb C-14 inventory. The variation in the CO2 levels is related to these mechanisms, but the results show that other causes play significant roles. A weaker dependence of gas transfer on wind is suggested for steady winds, and long-term averaged winds demonstrate a stronger dependence in the present model. The chemical enhancement of CO2 exchange is also shown to play a role by increasing CO2 fluxes at low wind speeds.

Wanninkhof, Rik↗
NASA NTRS1992

Impactite and pseudotachylite from Roter Kamm Crater, Namibia

Pseudotachylite is known to occur in a variety of geologic settings including thrust belts (e.g., the Alps and the Himalayas) and impact craters such as Roter Kamm, Namibia. Controversy exists, however, as to whether pseudotachylite can be produced by shock brecciation as well as by tectonic frictional melting. Also open to debate is the question of whether pseudotachylites form by frictional fusion or by cataclasis. It was speculated that the pseudotachylite at Roter Kamm was formed by extensional settling and adjustment of basement blocks during 'late modification stage' of impact. The occurrence of pseudotachylite in association with rocks resembling quenched glass bombs and melt breccias in a relatively young crater of known impact origin offers a rare opportunity to compare features of these materials. Petrographic, x-ray diffraction, and electron microprobe analyses of the impactites and pseudotachylites are being employed to determine the modes of deformation and to assess the role of frictional melting and comminution of adjacent target rocks.

Degenhardt, J. J., Jr.↗
NASA NTRS1993

Precision linear shaped charge severance of graphite-epoxy materials

This paper presents Precision Linear Shaped Charge (PLSC) components designed to sever a variety of target materials. Recent data for the severance of graphite-epoxy panels or targets with PLSC's are presented. A brief history of the requirement to originate the development of PLSC's for weapon components at Sandia National Laboratories is presented. The Department of Energy's (DOE) nuclear weapon systems have continually decreased in size. Today's relatively small weapons require the design of much more efficient, lighter, and smaller explosive components because fragments, air shocks, and pyro-shocks associated with the function of these components can damage electrical and other sensitive components located nearby. The DOE requirements for PLSC's are listed. Therefore, linear shaped charge (LSC) components for weapon systems can no longer be empirically or experimentally designed for a given application. Many of today's designs require severing concentric cylinders, for example, where the LSC jet is designed to sever only one of the two cylinders as was the case for the B90/Nuclear Depth Strike Bomb. Therefore, code modeling and simulation technology must be utilized to obtain a better understanding of the LSC jet hydrodynamic penetration, fracture, shear, and spall mechanisms associated with the severance of metallic as well as composite targets.

Vigil, Manuel G.↗
NASA NTRS1993

Radiological assessment for Space Station Freedom

Circumstances have made it necessary to reassess the risks to Space Station Freedom crewmembers that arise from exposure to the space radiation environment. An option is being considered to place it in an orbit similar to that of the Russian Mir space station. This means it would be in a 51.6 deg inclination orbit instead of the previously planned 28.5 deg inclination orbit. A broad range of altitudes is still being considered, although the baseline is a 407 km orbit. In addition, recent data from the Japanese A-bomb survivors has made it necessary for NASA to have the exposure limits reviewed. Preliminary findings of the National Council on Radiation Protection and Measurements indicate that the limits must be significantly reduced. Finally, the Space Station will be a laboratory where effects of long-term zero gravity on human physiology will be studied in detail. It is possible that a few crewmembers will be assigned to as many as three 1-year missions. Thus, their accumulated exposure will exceed 1,000 days. Results of this radiation risk assessment for Space Station Freedom crewmembers finds that females less than 35 years old will be confined to mission assignments where the altitude is less than about 400 km. Slight restrictions may also need to be made for male crewmembers less than 35 years old.

Badhwar, Gautam D.↗
NASA NTRS1991

Project summary

California Polytechnic State University's design project for the 1990-91 school year was the design of a close air support aircraft. There were eight design groups that participated and were given requests for proposals. These proposals contained mission specifications, particular performance and payload requirements, as well as the main design drivers. The mission specifications called for a single pilot weighing 225 lb with equipment. The design mission profile consisted of the following: (1) warm-up, taxi, take off, and accelerate to cruise speed; (2) dash at sea level at 500 knots to a point 250 nmi from take off; (3) combat phase, requiring two combat passes at 450 knots that each consist of a 360 deg turn and an energy increase of 4000 ft. - at each pass, half of air-to-surface ordnance is released; (4) dash at sea level at 500 knots 250 nmi back to base; and (5) land with 20 min of reserve fuel. The request for proposal also specified the following performance requirements with 50 percent internal fuel and standard stores: (1) the aircraft must be able to accelerate from Mach 0.3 to 0.5 at sea level in less than 20 sec; (2) required turn rates are 4.5 sustained g at 450 knots at sea level; (3) the aircraft must have a reattack time of 25 sec or less (reattack time was defined as the time between the first and second weapon drops); (4) the aircraft is allowed a maximum take off and landing ground roll of 2000 ft. The payload requirements were 20 Mk 82 general-purpose free-fall bombs and racks; 1 GAU-8A 30-mm cannon with 1350 rounds; and 2 AIM-9L Sidewinder missiles and racks. The main design drivers expressed in the request for proposal were that the aircraft should be survivable and maintainable. It must be able to operate in remote areas with little or no maintenance. Simplicity was considered the most important factor in achieving the former goal. In addition, the aircraft must be low cost both in acquisition and operation. The summaries of the aircraft configurations developed by the eight groups are presented.

Source record↗
NASA NTRS1992

A NASA study of the impact of technology on future sea based attack aircraft

A conceptual aircraft design study was recently completed evaluating carrier-based, subsonic attack aircraft using contemporary and future technology assumptions. The study examined a configuration matrix that was made up of light and medium bomb loads, one and two man crews, internal and external weapons carriage, as well as conventional and flying wing planforms. Use of common technology assumptions, engine cycle simulation code, design mission, and consistent application of methods allow for direct comparison of the aircraft. This paper describes the design study ground rules and the aircraft designed. The aircraft descriptions include weights, dimensions, layout, design mission, design constraints, maneuver performance, and fallout mission performance. The strengths, and weaknesses of each aircraft are highlighted.

Hahn, Andrew S.↗
NASA NTRS1992

The GBU-28 - Concept to combat

The story of the development and use of the GBU-28, the weapon used to destroy the main Iraqi command and control bunker during Operation Desert Storm, is told. The construction of the bombs, flight testing, and penetration testing are described. Emphasis is given to the choice between the F-111 and the F-15E as delivery system.

Polansky, Mark↗
NASA NTRS1926

NACA Flight-Path Angle and Air-Speed Recorder

A new trailing bomb-type instrument for photographically recording the flight-path angle and air speed of aircraft in unaccelerated flight is described. The instrument consists essentially of an inclinometer, air-speed meter and a film-drum case. The inclinometer carries an oil-damped pendulum which records optically the flight-path angle upon a rotating motor-driven film drum. The air-speed meter consists of a taut metal diaphragm of high natural frequency which is acted upon by the pressure difference of a Prandtl type Pitot-static tube. The inclinometer record and air-speed record are made optically on the same sensitive film. Two records taken by this instrument are shown.

Coleman, Donald G↗