Study of flight path for solar-powered aircraft based on gravity energy reservation

Varied-height flight paths for solar-powered aircraft and their application are studied based on the theory of gravity energy reservation. Detailed components of varied-height paths and their motion modes are described and a mathematical-physical model of each component and time node is established. Furthermore, a general-parameters design method for a solar-powered aircraft with varied-height paths is introduced. The flight path and power curve for a specific design index are plotted, and the influence of some technology parameters on the application of varied-height paths is studied through comparing with constant-height paths. The results show that varied-height paths can effectively reduce the discharge time of the energy storage battery and wing area. There exists an optimal climbing height for each design height, which can minimize the wing area. The higher the design height is, the farther away the design date is from Summer Solstice, the lower is the energy density of the energy storage battery and the higher is the power-weight ratio of the propulsion system, the more effective is the application of a varied-height path.