The influence of wind shear to the performance of high-altitude solar-powered aircraft

Abstract

There is a greatly persistent wind shear in the upper atmosphere, especially at the altitude of 10–20 km. For the idea of dynamic soaring, the wind shear can be treated as a kind of energy resource for aircraft if the aircraft is flying in a proper manner. Based on the above facts, the influence of wind shear to the performance of high-altitude solar-powered aircraft from a new prospect is systemically studied: The wind shear in the upper atmosphere is treated as a kind of energy resource for aircraft, and to be used to compensate the energy consumed by drag. The results of simulations show that the energy extracted from wind shear can compensate about 30–50% of the energy consumed by drag in climbing and 20–40% in descending for high-altitude aircraft when the strength of wind shear is greater than 0.005 s−1 and smaller than 0.01 s−1. This is a valuable conclusion for the high-altitude aircraft, since the strength of wind shear between 10 km and 20 km has fallen into this interval. By defining the dynamic soaring parameter, it has been found that the dynamic soaring parameter is possibly greater than 1 in the place that great enough strength of wind shear can be found, which implies that it is possible for high-altitude aircraft to perform unpowered flight by dynamic soaring if the wind shear can be unitized properly.