Trajectory design and optimization of powered common aero vehicles

The fuel optimal cruise trajectory of a powered common aero vehicle was analyzed. The problem was divided into determining the optimal steady-state cruise and optimal periodic cruise problems. The global optimal steady-state cruise trajectory was determined based on steady-state dynamic equations. The optimal periodic cruise trajectory was solved by the direct shooting method. The decrease of vehicle mass was considered in each case. The result shows that compared with the global optimal steady-state cruise trajectory the periodic cruise trajectory achieves better fuel consumption and heat load performances in one period. The fuel savings of 4.75% with a scramjet engine and 3. 96% with a rocket engine are achieved by the optimal periodic cruise trajectory over the optimal steady-state cruise trajectory. The heat loads are respectively 10.4% and 5.9% lower than those of the optimal steady-state cruise trajectory.