An overview of propulsion systems for flying vehicles

This report presents an overview of propulsion systems for flying vehicles, based on literature studies on current and future technologies. This effort is motivated by the need of this kind of information for the studies of vehicle concepts, being pursued in order to evaluate their performance merits. General information on inlets and outlets are also presented, as these influence the geometry and performance of the vehicles. The overview of inlet types is given with respect to the requirements at various Mach number regimes that govern the design. The stealth aspects are also viewed. In the report the available propulsion principles are presented category-wise, where most are based on combustion according to the Brayton cycle (heat addition under constant-pressure) and the other are based on combustion according to the Humphrey cycle (heat addition under constant-volume). The choice of propulsion system is mainly dictated by the requirements on the vehicle in terms of flight mission and maximum Mach number. Each propulsion system is described more or less in detail, depending on the applicability interests for the vehicle studies. Some information to be of help for judging performance is also given. The main focus is given to the following propulsion areas: turbojet/turbofan, turboramjet, air turbo ramjet, and pulse detonation engine.