Propulsion System Concepts and Technology Requirements for Quiet Supersonic Transports

The requirements of a viable SST place conflicting requirements on the design and configuration of the propulsion system. In particular, optimisation of propulsion systems for supersonic cruise performance is compromised by the requirement to meet stringent targets on takeoff noise. Rolls-Royce has studied numerous engine concepts aimed at minimising the compromise on installed performance imposed by noise constraints. The different concepts are discussed, and the preferred Variable Cycle Turbofan configuration is described with relation to associated challenges in the aeroacoustic design of corresponding intakes and nozzles. Alternative nozzle configurations are considered, along with further technologies which could indirectly improve acoustic performance.