Inlet and Fan Aerodynamics

Current trends in military combat aircraft are clearly toward increased emphasis on multimission capability. This requires an engine that is considerably oversized when compared with the subsonic cruise or dash requirements of the aircraft. With oversized engines, engine performance is no longer an isolated element. A new approach is needed. This paper analyzes the inlet portion of the installed propulsion system. An assessment is made of the magnitude of the inlet drag associated with oversized engines for typical multimission aircraft. Some thoughts are presented on inclusion of inlet drag considerations into the engine cycle optimization process.