A Probabilistic Approach to UCAV Engine Sizing

Abstract

This paper describes a probabilistic approach to aircraft engine thrust sizing which is intended to assist the designer in making decisions during the very early stages of the design process when the operational concept is still evolving and uncertainty abounds (in both mission requirements and technological capability). The focus of this paper is on analysis of mission uncertainty such as that due to ambiguity in payload, range, maneuver requirements, etc. and its impact on propulsion system sizing. Several analysis tools appropriate for probabilistic thrust sizing are discussed and one is applied to the probabilistic thrust sizing of an unmanned combat aerial vehicle designed for a deep-strike mission. The result is a distribution for thrust which can then be used in combination with the core engine design space to estimate the design? probability of successfully meeting the thrust requirements. Finally, a method for tracking mission uncertainty as the requirements develop is described and illustrated for the UCAV example.