Airframe-Propulsion Integration for Future Aircraft Systems 680288

This paper discusses the impact of mixed mission requirements for future tactical and strategic aircraft on inlet design and inlet engine interaction. These mixed missions may include subsonic high altitude, transonic low altitude, and supersonic high altitude flight conditions. Trade-off trends are presented which relate inlet, airframe, and engine design characteristics to desirable mission features. Specific airframe-propulsion integration problems for mixed mission aircraft are discussed, such as the wide variation in airflow matching between the conditions of transonic low altitude flight and supersonic high altitude flight. For tactical and strategic aircraft the critical flight and maneuvering regimes are outlined; the origin of steady state and dynamic distortion in the vehicle integrated inlets of future aircraft systems is presented and the effect on engine compressor stall margin is discussed. The influence of vehicle-inlet flow field interactions, maneuvering conditions, and off-design inlet conditions on inlet-engine stability and performance are also discussed. For V/STOL tactical aircraft, the inlet requirements for take-off, transition and high speed flight are pointed out and the effect of hot gas reingestion on inlet-engine compatibility is presented. Test requirements and simulation techniques required for future aircraft to assure proper airframe-propulsion integration are outlined. Recommendations are made as to the type of research and test programs which should be pursued during the various phases of the development of a multimission aircraft to assure proper airframe-propulsion integration.