A study of solar-powered, high-altitude unmanned aerial vehicles

Purpose - Aims to present a methodology for analysing a solar-electric, high-altitude, long-endurance, unmanned aircraft.Design methodology approach - The study focuses on the aerodynamics, flight performance and power requirements of a heavier-than-air, solar-electric, HALE UAV. The methodology is founded on using an analytical approach to determine the power required to undertake various flight manoeuvres. An analytical approach is also undertaken in determining the intensity of the solar radiation available to the aircraft. Finally to demonstrate the methodology, a HALE concept was generated and evaluated.Findings - When using estimates of current solar-electric propulsion and energy conversion efficiencies, the HALE concept was only able to sustain year round, level flight up to latitudes of 10°N.Research limitations implications - Further analysis needs to be undertaken into the effect of altitude on the intensity of solar radiation, which could be as much as 25 per cent higher at an altitude of 21.3 km (70,000 ft). Further study into this subject area may provide proof that sustained flight is possible at more northerly latitudes.Originality value - This paper provides a simple methodology for persons wishing to undertake an initial feasibility study of a solar-electric HALE concept.