Maximum Range Performance of Motor Gliders with Retractable Jet Engine

The maximum-range flight of a motor glider equipped with a retractable jet engine is treated as a periodic optimal control problem. The maximum-range flight is of periodic nature because it consists of cycles where a climbing phase with the engine extended is followed by a gliding phase with the engine retracted. This kind of flight is termed saw-tooth mode. It is shown that the maximum range of optimal saw-tooth flight is larger than the greatest range achievable with the best steady-state cruise. An efficient optimization method is applied for solving the periodic optimal control problem, using a realistic mathematical modeling.