Comparison of turbojet-engine altitude performance characteristics and ignition limits with MIL-F-5624A fuel, grades JP-3 and JP-4

The performance of MIL-F-5624A fuels, grades JP-3 and JP-4, was investigated in an axial-flow turbojet engine over a range of altitude conditions of 10,000 to 55,000 feet. Examination of the fuel flow, combustion efficiency, and net thrust specific fuel consumption showed the grade JP-4 fuel to be slightly inferior to the grade JP-3 fuel, although the altitude ignition limits were essentially equal for the two fuels over a range of flight Mach numbers and fuel-inlet temperatures.