Propulsion System Optimization for the ATT

Supercritical airfoil technology offers the potential of efficient commercial flight at or near the speed of sound. This paper reviews a recent internal study by Pratt & Whitney to define the optimum propulsion system characteristics for a commercial transport designed to fly at Mach 0.95. The impact on aircraft gross weight of propulsion cycle characteristics such as bypass ratio, overall pressure ratio, turbine temperature, nacelle weight, and drag as well as the important criteria of noise is reviewed. In addition, the implications of flying at very high initial cruise altitudes above the majority of current traffic is discussed.