In the last few years, the interest towards solar powered aircraft has increased significantly for high altitude and long endurance (HALE) missions. Unmanned aerial vehicles (UAV), which stay aloft for many months between 15000 and 30000 m of altitude, can be a less expensive alternative to present satellites for telecommunication, remote sensing, surveillance and control, both in civil and military field. In a previous study, carried out at the Department of Aerospace Engineering of Pisa, a mathematical model for the solar powered UAVs design has been set up and four different aerodynamic solutions have been compared: a wing-tail configuration, a flying wing, a twin boom and a biplane with vertical linking wings. It has been found that the biplane solution has the potential to provide high aerodynamic efficiency and, at the same time, stiffer structures. In this paper, two reference missions are defined: one for surveillance, reconnaissance and intelligence purposes and one for telecommunication. For each of these missions, a new design procedure is applied in order to define a summer and a winter configuration. The mission design strategy is described, underlining the parameters that define the vertical and the horizontal mission profiles and evaluating the influence of the wind as well. In addition, an overview of the design procedure is given. It consists of an iterative process with a convergence check on the total weight; the input block contains atmospheric and geo-graphic data, components’ efficiencies, payload weight and mission profile data. At each it-eration, an inner cycle verifies the energy balance over a 24 hour flight. As a result, four configurations are defined and for two of them the “Operating Domain” chart, that is the envelope of the conditions (day, latitude, altitude) for which the energy balance is checked, is defined. Finally, for one of the winter configurations, the flight envelope is traced and maximum load factors are calculated.
|Titolo:||MISSION DESIGN FOR LONG ENDURANCE FLIGHT WITH SOLAR POWERED AIRCRAFT|
|Anno del prodotto:||2009|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|