A Method of Sizing Multi-Cycle Engines for Hypersonic Aircraft

A method of sizing multi-cycle engines for integration with hypersonic vehicles has been developed. The new procedure independently sizes the inlet, each engine cycle, and the nozzle during the vehicle sizing loop to optimize propulsion/aircraft integration. Using uninstalled engine performance for each cycle of a multi-cycle engine along with inlet and nozzle performance and an estimate of aircraft drag, an iterative procedure is utilized to size each component simultaneously. A propulsion system is defined that meets the aircraft thrust requirements at all mission points. The inlet is sized to provide airflow such that the maximum Mach cruise and/or combat thrust conditions are met. Each cycle is sized independently to meet all thrust requirements while minimizing either inlet drag or engine size. Nozzle sizing must trade off thrust, drag and nozzle weight. This methodology has been incorporated into a computer code entitled “Multi-Cycle Engine Sizing Program,” MCESP.