Development of a surplus value parameter for use in initial aircraft conceptual design

Simple constraints analysis, as taught to most aerospace engineering students gives little guidance as to exactly which design point should be selected. There is a recent body of work that attempts to solve this for initial designs, without having to fully size the new aircraft concept. The best of these focuses on maximizing a ‘Range Parameter’ which leads to minimizing gross weight for transport aircraft. However, this is not guaranteed to maximize the value of the new design. This paper presents a corresponding surplus value parameter which is designed to provide just that capability. Furthermore, it shows that in at least some cases the resulting optimum design point will shift from that suggested by the range parameter