Optimal takeoff of a helicopter for category A V/STOL operations

Two applications of a nonlinear optimal control theory are used to calculate the optimal control procedures for a helicopter following one engine failure during takeoff. One application is concerning the problem of optimization of the takeoff procedure for category A short-takeoff-and-Ianding (STOL) operation so that the required heliport size is minimized. The results show that the required takeoff distance using the normal takeoff procedure can be reduced by 30-60% if the takeoff path and the critical decision point are specifically optimized for a given set of the operating conditions, e.g., takeoff weight, ambient conditions, and heliport configuration. The second application concerns the problem of evaluation of the takeoff performance for category A verticaltakeoff-and-landing (VTOL) operation. The calculated maximum weight for the normal takeoff path shows good agreement with the certificated takeoff weight. Additionally, optimization of the takeoff path is shown to allow increasing the payload by 10%.