PROPULSION TECHNOLOGY ADVANCES NEEDED FOR A QUIET SUPERSONIC TRANSPORT

Operation of a U.S. developed supersonic transport must and will meet community noise standards. This paper examines the airport noise problems of large transport aircraft, highlights critical considerations, and then studies possible solutions available from advanced propulsion technology. Engine sizing requirements to meet SST payload-range and airport performance criteria are reviewed first, and the impact of noise on the engine size and aircraft performance is then identified. Relief offered by noise suppressor development and technology advances that can be foreseen in the next decade for turbojet and turbofan engines are described. The advantages offered by a duct heating turbofan engine cycle are discussed. The potential offered by variable cycle engines to provide low noise characteristics with minimum penalty on performance are shown, and the practical restraints imposed on this potential by airframe aerodynamic noise is illustrated. The importance of supporting engine technology advances with corresponding improvements in aerodynamic technology so as to enhance both airplane performance and noise relief is discussed to show the benefits on noise footprint exposure and flight operation procedures.