Propulsion cycle effects for a two-fan V/STOL aircraft

This paper discusses the results of an in-depth study investigating the impacts of variable pitch, geared turbofan cycle parameters on a two-fan, subsonic, V/STOL aircraft. Variations in fan pressure ratio, compressor pressure ratio and combustor exit temperature are presented as they affect critical mission legs, aircraft performance, engine thrust-to-weight ratio and as a total systems impact in terms of aircraft takeoff gross weight. Several parameters have counter acting components which, when combined, synergistically result in an optimum value for that parameter. Careful attention has been paid to the changes in aircraft installation penalties associated with each cycle parameter.