Peculiarities of UAV Construction for Flights at High Altitudes
A mathematical model of UAV power supply system is developed, consisting of a set of solar cells, a set of electric batteries and a subsystem of transmission and distribution of electricity. The mathematical apparatus was based on the indicators of solar radiation power, the level of battery charge, the efficiency of electric batteries and solar cells, and geographical coordinates as well as the height of the aircraft position. In this case, the basic model was improved through the inclusion of algorithms for the analysis of losses of electric batteries and averaging the function of solar radiation power by time in accordance with the set of time ranges. The mathematical apparatus for calculation and optimization of aerodynamic parameters of UAV was also suggested on the basis of such indicators as the coefficient of lifting force, drag coefficient, air density as a function of flight altitude and total wing area of the aircraft. The suggested methods of analysis of structural features of HALE-class UAV provide an opportunity to both build automated evaluation algorithms and to carry out the procedure of expert evaluation of aircraft through the analysis of the corresponding dependencies: the ratio of the lifting force factor on the angle of attack and the drag coefficient, the ratio of the lifting force and aerodynamic resistance as a function of the drag coefficient, the dependence of the specific power on the load on the wing produced by the height of the UAV aircraft.
