Optimization of Balanced Field Length Performance of Multi-Engine Helicopters

Abstract

The development is described of a balanced field length trajectory optimization approach for a multi-engine helicopter sustaining a single engine failure. Whereas most studies typically focus on a single flight phase, this study is based on a multiphase formulation, in which the rejected takeoff and continued takeoff trajectories are optimized simultaneously, subject to a field length balancing constraint. The advantage of this approach is that, for any given engine failure time, it allows the flight phase where all engines are still operating to be optimized in such a way that the solution represents the best possible compromise between the conflicting requirements set by the rejected takeoff and continued takeoff flight phases. In addition to balanced field length calculations, the optimization of unbalanced rejected takeoff has been addressed. Combined considerations of balanced and unbalanced rejected takeoff give insight in the choice of the critical decision point. The most important result of the overall optimization process is the optimal all-engines-operating takeoff flight path up to the critical decision point