Isomer Energy Source in Hybrid Jet Engines for High Altitude Reconnaissance Flight

Abstract

An investigation was performed on the possibility of employing a triggered isomer heat exchanger (TIHE) as part of a hybrid heat source in an otherwise conventional turbojet engine. Reported is the application of such a long duration engine in a high-altitude long endurance surveillance and reconnaissance mission. Two-phase operation would include a switchover point, that is, an altitude and Mach number at which conventional combustion is replaced by the TIHE. A comparison of conventional and hybrid engines indicates a hybrid mixed-stream turbofan engine flying a part conventional and part TIHE mission, with a switchover at a Mach number of 0.4 at 40,000 ft, could provide weeks of endurance. Takeoff weight would be reduced by 20% due to lower fuel requirements.