Robert F. Salmon

Three types of gelled Jet A-1 fuels were tested to determine the capability of the thickened fuels with typical turbojet engines. The three fuels were: (1) Gel A, a 2 percent concentration of a styrene polymer additive in Jet A-1, (2) Gel B, a 2 percent concentration of a sodium free styrene polymer in Jet A-1, and (3) Gel C, an aluminum octoate gel in Jet A-1, concentration ranging from 0.2 to 1.0 percent. The two polymer gels had a 13,000 centiposie reading on the Brookfield Viscometer, RVT model, and the aluminum octoate ranged from 2,800 to 13,000 centipoises. Spray pattern tests were run with the fuels and a 1-hour engine test was conducted on a J47 engine. Comparison of engine performance when using regular Jp-4 and polymer gelled Jet A-1 fuels indicated that the gel did not markedly affect the engine performance in the power range from 70 to 95 percent of rated engine. The polymer gels, however, could not be used from engine light-off to idle power in the J47 engine since they required higher fuel manifold pressures for vaporization than the engine could produce during the starting sequence. A 15-minute test using Gel A was conducted on a J57 engine. When operating the J57 engine, the Gel A was used from light-off to maximum power, and no difficulty was experienced in running the unmodified engine with this fuel. Gel C would not be used successfully in the J47 engine even when providing fuel manifold pressures of 250 psi, corresponding with 82 percent of rated rotor speed. Combustion could not be maintained and a relight could not be effected when switching back to JP-4 fuel. Preliminary chemical analysis of a combustion can, after 1 hour of engine operation using the sodium free polymer, Gel B, indicated no corrosive effects or excessive carbon buildup in the combustion chamber.

Warren K. Smith, James B. King

Surface temperatures of nine organic combustible materials heated to flaming ignition by quartz lamp radiant heating equipment were measured without interference from reflected energy by means of a long wavelength infrared pyrometer. Temperature vs. time curves for irradiances from 0.125 to 2.5 cal/cm2-sec are presented along with summary plots of surface temperatures at ignition for piloted and unpiloted ignition conditions. The factors influencing the shape of the curves and the initiation of ignition are discussed.

A.T. Peacock, R.F. Hazelton, L.S. Gresko, L.D. Christensen

The rheological and physical properties of four gelled and three emulsified turbine fuels were evaluated. One gelled and one emulsified fuel were selected for further test and analysis in a compatibility study with a four engine commercial jet transport aircraft fuel system. Full scale testing of system components was performed. Penalties and problem areas associated with using the fuels were identified by an analysis of the fuel system. A full-scale ground test program to evaluate an aircraft fuel system's performance on thickened fuels was outlined. Results show signjficant decreases in available fuel and large increases in system weights are associated with the use of the thickened fuels described. Substantial fuel development is indicated before application to commercial aircraft.

A.T. Peacock

The investigation described in this paper were primarily funded by the Federal Aviation Administration (FAA). Contributions from independent studies by the Douglas Aircraft Co. have been offered to enhance the final results of the continuing FAA investigations into the use of gelled and emulsified fuels for reducing the hazards of fuel fires caused by aircraft crashes.

C.P. Sarkos

To experimentally determine if fuselage sections backed with rigid foams will increase the burn-through time from an external fuel fire to the cabin interior. Also, to determine what effect the foam’s decomposition products will have on the ambient conditions within the cabin.