Maximum range for battery-powered aircraft

T HE interest in electrically-driven propeller airplanes has been steadily increasing over the last 15 years with applications ranging from small electric remotely piloted vehicles [1] up to large high-altitude/long-endurance aircraft [2], passing through general aviation size airplanes powered by means of hydrogen fuel cells [3]. The art and science of preliminary sizing of conventional aircraft has been the subject of many textbooks over the years [4,5] and, in this framework, reasonably accurate range and endurance prediction against design performance requirements plays quite obviously a crucial role. Unfortunately, the extension of the results valid for conventional configurations to electrically powered aircraft is not always straightforward. In a recent paper, [6] the equations for the evaluation of range and endurance of battery operated electrical aircraft are derived, keeping into account the effects of Peukert’s law on the battery discharge process [7]. Wilhelm Peukert performed tests on lead–acid batteries and discharging them with a constant current. His analysis proved that the discharge time Δt and the discharge current i satisfy the law [7]