Cost-Effective Multipoint Design of a Blended High-Speed Civil Transport

Abstract

The multipoint design of a high-speed civil transport (HSCT) is considered. Low computational costs are maintained by parameterizing the HSCT using a novel method of surface generation known as the partial differential equation method. This method enables a reduction in the computational costs because of its ability to describe complex surfaces using a small number of parameters. The two design points that are considered are the subsonic and supersonic (Mach 2) flight regimes with design criteria of maximized lift and minimized wave drag, respectively. Subsonic lift is estimated using Panel Method Ames Research Center, whereas supersonic wave drag is estimated using the Harris wave-drag code (which is based upon linearized potential flow theory and the supersonic area rule). An efficient quasi-Newton method of optimization is used to optimize a weighted combination of subsonic lift and supersonic wave drag subject to the constraints of a fixed wing plan area and fixed fuselage and wing volumes. A variety of test problems are considered in which the weightings of the two design criteria are varied