A variable cycle jet engine for ASTOVL aircraft

Abstract

Describes a novel concept in aircraft propulsion: investigates a variable cycle jet engine for a supersonic advanced short take‐off vertical landing (ASTOVL) aircraft. The engine is the selective bleed turbofan. The selective bleed turbofan is a two shaft, three compressor, variable cycle gas turbine. At subsonic flight speeds it operates as a medium bypass turbofan. It becomes a low bypass turbofan when flying faster and is capable of supersonic cruise in the dry mode. A preliminary design of an ASTOVL aircraft from Cranfield, the S‐95, was used as the vehicle. Outlines the performance of the engine and its integration with the aircraft. Explains off‐design engine performance characteristics and describes variable geometry requirements. The major advantage of this engine is that all the components are employed all the time, for all operating modes, thus incurring low weight penalties. Predicts that the aircraft/ engine combination will perform in a satisfactory way, meeting most performance targets provided that some improvements are carried out.