Optimal aircraft take-off with thrust vectoring

Abstract

Abstract The short take-off capability is of paramount importance for a fighter airplane to enable its operation from short and damaged runways. This paper analyses the airplane take-off process from the viewpoint of reducing the ground roll/take-off distance with the use of thrust vectoring. The airplane take-off is modelled incorporating the ground reactions on the landing gear and the thrust vector forces and moments. The take-off problem is formulated as an optimal control problem with appropriate constraints. Though many researchers have applied optimal control techniques for designing airplane manoeuvres, its application to the airplane take-off problem is rarely available in the open literature. It is expedient to use such methodology to understand the use of thrust vectoring features of an aircraft to maximise the benefits in shortening the ground roll/take-off distance. An optimal control methodology has been applied in this paper with the objectives stated above to a twin-engine fighter nonlinear aircraft model popularly known as F-18/HARV. Computation of flight path and control schedules using optimal control has been carried out with and without the use of vector nozzles. A reduction of about 6% in take-off distance and about 29% in ground roll distance is obtained with the use of thrust vector for the configuration studied.