| Preliminary Burn and Impact Tests of Hybrid Polymeric Composites |
JUL 78 |
27 pages |
| Authors:
Stephen S. Tompkins; william d. brewer; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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 | Recent studies have shown that free graphite fibers released into the environment from resin matrix composite components, as a result of fire and/or explosion, pose a potential hazard to electrical equipment. An approach to prevent the fibers from becoming airborne is to use hybrid composite materials which retain the fibers at the burn site. Test results are presented for three hybrid composites that were exposed to a simulation of an ... |
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| Graphite and Ablative Material Response to CO2-Laser, Carbon-Arc, and Xenon-Arc Radiation |
SEP 76 |
38 pages |
| Authors:
william d. brewer; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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| This study investigated the behavior of graphite and several charring ablators in a variety of high-radiative heat-flux environments. A commercial- grade graphite and nine state-of-the-art charring ablators were subjected to various radiative environments produced by a CO2 laser and a carbon arc. Graphite was also tested in xenon-arc radiation. Heat-flux levels ranged from 10 to 47 Mw/m2. Tests were conducted in air, nitrogen, helium, and a CO2-N2 mixture which simulated ... |
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| Effect of the Chemical State of Pyrolysis Gases on Heat-Shield Mass |
DEC 68 |
28 pages |
| Authors:
william d. brewer; C. W. Stroud; Ronald K. Clark; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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| Results are presented from an analytical investigation to determine the effect of the chemical state of the pyrolysis gases on the heat-shield mass required for a reentry vehicle in a given environment. Mass per unit area of ablative material required is calculated for a number of constant-heating-rate environments and the total mass is calculated for a lifting-body vehicle in a typical reentry trajectory. The required mass of ablative material is ... |
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| Effect of Composition, Density, and Environment on the Ablative Performance of Phenolic Nylon |
APR 67 |
31 pages |
| Authors:
Robert T. Swann; william d. brewer; Ronald K. Clark; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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| Ablative materials are commonly used to protect spacecraft from the thermal environment which is encountered when entering planetary atmospheres. Materials which char when heated provide the best protection in many cases. Many char-forming materials have been formulated and tested; a mixture of phenolic resin and nylon is representative of the best performing of these ablative materials. Good thermal-protection performance has been demonstrated for a mixture of 25 percent powdered phenolic ... |
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| Analytical Determination of the Effect of Thermal Property Variations on the Performance of a Charring Ablator |
JUL 66 |
31 pages |
| Authors:
Claud M. Pittman; william d. brewer; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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| An analytical investigation of the effects of varying certain material properties on the performance of a charring ablator material has been made. The quantities which are varied are char conductivity, conductivity and specific heat of the uncharred material, heat of pyrolysis, temperature of pyrolysis, and the specific heat of the gases of pyrolysis. The effects of these variations on surface recession, charred-uncharred interface recession, and internal temperature histories are shown. ... |
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| Performance of Several Ablation Materials Exposed to Low Convective Heating Rates in an ARC-Jet Stream |
JAN 65 |
51 pages |
| Authors:
Marvin B. Dow; william d. brewer; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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| An investigation was made of the performance of eleven different types of ablation materials bonded to beryllium or aluminum backup plates. Thirty-four specimens fabricated as flat square sections with a nominal side dimension of 5 inches (12.70 cm) were exposed to convective heating rates of less than 10 Btu/(sq ft)(sec) (0.ll4 MW/m2) for exposure times in excess of 200 seconds in the 2500-kilowatt arc jet at the Langley Research Center. ... |
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| flash x-ray technique for investigating ablative material response tosimulated re-entry environments |
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| Authors:
william d. brewer; philip c. kassel jr.
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 | a flash x-ray technique is used to investigate ablative material behavior during testing in an arc-jet facility. the technique was developed primarily to measure surface and interface recessions in charring ablators, but is capable of yielding additional informatin such as density changes within a material. use is made of a system with which several radiographs of a specimen can be made during a single test. the flash x-ray ... |
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