Air Forces

As the fleet of military aircraft and support equipment ages, the damage caused by corrosion becomes an increasing concern. The aircraft spend a longer time in depots for maintenance and repair, which leads to a decrease in readiness and an increase in cost to maintain the aircraft. Moreover, a possible loss of integrity of the structure is possible if the corrosion goes undetected and becomes severe. 

The total cost of direct corrosion maintenance to the US Air Force for fiscal year 1997 was estimated at approximately 800 million (48 Table 3.19). 

The table clearly indicates that the major portion of the cost can be attributed to aircraft repair and paint. Significant amounts are also spent on washing and vehicle maintenance. In addition to the total cost findings, it was found that maintenance in the depot accounted for 80% of the total cost of corrosion maintenance. While the total number of aircraft in the fleet decreased by 20%, the costs decreased by only 10%, and the maintenance costs have increased. 

The data presented in Table 3.20 show the effect of aging on weapon system costs. The difference in age and size has an effect on the cost of aircraft. 

Office of the Civil Engineer, Washington, DC 20330 Environmental Restoration Division, (703) 697-3445 Environmental Compliance Division, (703) 697-3341. 

Air Force Center for Environmental Excellence, Brooks Air Force Base, TX, (210) 536-1110. 

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Another application of laser-based profilometry is the inspection of rocket and missile components. The U.S. Air Force has funded work to develop a non-contact laser-based profilometer for the inside surface of solid rocket motors. Over time, these devices are subject to slumping and cracking, which could potentially render the rocket motor ineffective and hazardous. When fully implemented, this system will provide a meaningful screening method for evaluating the condition of aging rocket motors. 

Bogner, F. K., Fox, F. L. and Scliinit, L. A., 1965. The generation of interelemenl-coinpatible stiffness and mass matrices by the use of interpolation formulae. Proc. Conf. on Matrix Methods in Structural Mechanics, Air Force Institute of Technology, Wright-Patterson AF Base, OH. 

Furfural reacts with ketones to form strong, crosslinked resins of technical interest in the former Soviet Union the U.S. Air Force has also shown some interest (42,43). The so-called furfurylidene acetone monomer, a mixture of 2-furfurylidene methyl ketone [623-15-4] (1 )> bis-(2-furfurylidene) ketone [886-77-1] (14), mesityl oxide, and other oligomers, is obtained by condensation of furfural and acetone under basic conditions (44,45). Treatment of the "monomer" with an acidic catalyst leads initially to polymer of low molecular weight and ultimately to cross-linked, black, insoluble, heat-resistant resin (46). 

S. ColHs, The Development and Evaluation of Paint Remover Used bj the US. AirTorce Air Force Technical Report 5714, Suppl. 1, Jan. 1955. 

Y. O. Dova, The Chemistry and Technology of High Explosives, Wright Patterson Air force Base Translation, Dayton, Ohio, 1961. 

The Annual Proceedings of the Joiat Army-Navy-Air Force (JANNAF) Propulsion Meetings, the reports of the special committees, and the periodic hterature surveys pubHshed by the Chemical Propulsion Information Agency including the aimual Chemical Propulsion Abstracts are iuvaluable sources of information on all aspects of Hquid and soHd gun and rocket propellants. They maybe classified. 

H. Shaw, C. D. Kalfadehs, and C. E. Jahnig, Evaluation of Methods to Produce Aviation Turbine Fuels From Synthetic Crude Oils-Phase I, Technical Report AFAPL-TR-75-10, Vol. 1, Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio, Mar. 1975. 

U.S. Dept, of the Air Force, Specification MIE-F-25017dforFuelSoluble Corrosion Inhibitor, Wright Patterson AFB, Dayton, Ohio, May 1981. 

W. L. Haskin, Cyogenic Heat Pipe, Report AFFDT-TR-023, Flight Dynamics Lab., Wright Patterson Air Force Base, Ohio, 1967. 

PBO andPBZT. PBZ, a family of/ -phenylene-heterocycHc rigid-rod and extended chain polymers includes poly(/)-phenylene-2,6-benzobisthiazole) [69794-31-6] trans-V 27V) and poly(/)-phenylene-2,6-benzobisoxazole) [60871-72-9] (ot-PBO). PBZT and PBO were initially prepared at the Air Force Materials Laboratory at Wright-Patterson Air Force Base, Dayton, Ohio. PBZT was prepared by the reaction of... 

PBI is being marketed as a replacement for asbestos and as a high temperature filtration fabric with exceUent textile apparel properties. The synthesis of whoUy aromatic polybenzimidazoles with improved thermal stabUities was reported in 1961 (12). The Non-MetaUic Materials and Manufacturing Technology Division of the U.S. Air Force Materials Laboratory, Wright-Patterson Air Force Base, awarded a contract to the Narmco Research and Development Division of the Whittaker Corp. for development of these materials into high temperature adhesives and laminates. 

J. B. Gisclard, ReportMFFDE-TR-75-116, Air Eorce Flight Dynamics Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio, June 1975. 

C. H. Dumey and co-workers, Kadiofrequemy Kadiation Dosimetg Handbook, 4th ed.. Report SAM-TR-85-73, USAF, Brooks Air Force Base, Tex., Oct. 1986. 

Aircraft Reactors. As early as World War II, the U.S. Army Air Force considered the use of a nuclear reactor for the propulsion of aircraft (62—64). In 1946 the nuclear energy for propulsion of aircraft (NEPA) program was set up at Oak Ridge, under Fairchild Engine and Airplane Corporation. Basic theoretical and experimental studies were carried out. The emphasis was on materials. A high temperature reactor was built and operated successfiiUy. 

K. P. Gant2, ed.. Nuclear Flight The United States Air Force Programs for Atomic Jets, Missiles, and Rockets, DueU, Sloan and Pearce, New York. 

During the 1930s gradual improvements in the product and processing overcame some of the drawbacks of this material. Nonetheless, the apphcations were limited and Thiokol Corp. stmggled to remain solvent. The first year Thiokol reported a profit was in 1941, 13 years after its foundation. This was realized when the U.S. Air Force discovered that the aUphatic polysulftdes were usehil as a fuel-resistant sealant for aircraft tanks and hoses. Polysulftdes also began to be used as sealants for boat hulls and decks. 

Joiat Army—Navy—Air Force (fANAF), Thermochemical Tables, 2nd ed., NSRDS— NBS 37,1971. 

A minimum volatihty is frequently specified to assure adequate vaporization under low temperature conditions. It can be defined either by a vapor pressure measurement or by initial distillation temperature limits. Vaporization promotes engine start-up. Fuel vapor pressure assumes an important role particularly at low temperature. For example, if fuel has cooled to —40°C, as at arctic bases, the amount of vapor produced is well below the lean flammabihty limit. In this case a spark igniter must vaporize enough fuel droplets to initiate combustion. Start-up under the extreme temperature conditions of the arctic is a major constraint in converting the Air Force from volatile JP-4 to kerosene-type JP-8, the military counterpart of commercial Jet Al. 

The lower volatihty of JP-8 is a significant factor in the U.S. Air Force conversion from JP-4, since fires and explosions under both combat and ordinary handling conditions have been attributed to the use of JP-4. In examining the safety aspects of fuel usage in aircraft, a definitive study (15) of the accident record of commercial and military jet transports concluded that kerosene-type fuel is safer than wide-cut fuel with respect to survival in crashes, in-flight fires, and ground fueling accidents. However, the difference in the overall accident record is small because most accidents are not fuel-related. 

Worldwide demand for the jet fuels specified in Table 3 amounted to about 477,000 m /d (3 million barrels per day) in 1990. About one-half of this demand was kerosene Jet A sold in the United States. One-third represented kerosene Jet A1 for dehvery to international airlines outside the United States the balance comprised various military fuels used by air forces around the world. 

Elemental Boron, Technical Report AFAPL-TR-65-88, U.S. Air Force Contract No. AF33(615)2258 CaUery Chemical, CaUery, Pa., 1988. 

J. M. Ctiscione and co-workers, U.S. Air Force Materials Laboratory ML-TDR64-173, Parts I through IV, 1964—1966. 

A. M. Rajendran and W. H. Cook, "A Comprehensive Review of Modeling of Impact Damage in Ceramics," Joint report between the University of Dayton Research and the Air Force Armament Eaboratory, AFATL-TR-88-143 SBI-AD-E801 843, 99 pp., Dec. 1988. 

Military Chemistry and Chemical Compounds. U.S. Army Field Manual 3-9/U.S. Air Forces Field Manual 355-7, U.S. Government Printing Office, Washington, D.C., Oct. 1975. 

Mihtary interest in the development of fuel and thermal resistant elastomers for low temperature service created a need for fluorinated elastomers. In the early 1950s, the M. W. Kellogg Co. in a joint project with the U.S. Army Quartermaster Corps, and 3M in a joint project with the U.S. Air Force, developed two commercial fluorocarbon elastomers. The copolymers of vinyUdene fluoride, CF2=CH2, and chlorotrifluoroethylene, CF2=CFC1, became available from Kellogg in 1955 under the trademark of Kel-F (1-3) (see Fluorine compounds, ORGANic-POLYcm.OROTRiFLUOROETHYLENE Poly(vinylidene) fluoride). In 1956, 3M introduced a polymer based on poly(l,l-dihydroperfluorobutyl acrylate) trademarked 3M Brand Fluorombber 1F4 (4). The poor balance of acid, steam, and heat resistance of the latter elastomer limited its commercial use. 

Extracted from U.S. Standard Atmosphere, 1976, National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration and tte U.S. Air Force, Washington, 1976. Z = geometric altitude, T = temperature, P = pressure, g = acceleration of gravity, M = molecular weight, a = velocity of sound, i = viscosity, k = thermal conductivity, X = mean free path, p = density, and H = geopotential altitude. The notation 1.79.—5 signifies 1.79 X 10 . ... 

Seaman, L., SRIPUFF 3 Computer Code for Stress Wave Propagation, Air Force Weapons Laboratory Technical Report No. AFWL-TR-70-51, Kirtland AFB, NM, 370 pp., September 1970. 

Anonymous, Impact Physics Publications, Air Force Materials Laboratory Report, Wright-Patterson AFB, OH, 34 pp., August 1970. 

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