Correlated optimum lift coefficient and thrust-vector angle for longitudinal performance

Abstract

This note explores the optimization of thrust-vector angle for the cruise and initial climb phases of an airliner. For each performance, the lift coefficient and thrust-vector angle have been optimized simultaneously leading to a global optimum. However, the gain offered on the longitudinal performance by an ad-hoc inclination is limited. Finally, analytical expressions of the optimum thrust-vector angle have been derived for each performance, in complement to the expressions already provided by former studies on this subject.