Parameters determination for concept design of solar-powered, high-altitude long-endurance UAV

Purpose - The purpose of this paper is to propose a methodology to determine the designing parameters for solar powered high-altitude, long-endurance (HALE) unmanned aerial vehicles (UAV). Design/methodology/approach - By depicting solar power distribution on earth, along with the efficiencies analysis of photo-voltaic cells (P-cell) and lithium-sulfur battery (LS-battery), the influence of energy to concept design parameters is analyzed first. Second, the lift efficiency is determined from ground to 20 km for HALE UAV. Third, the methodology to determine design parameters for HALE UAV is generalized by analyzing the carrying ability of some famous HALE UAVs, such as Zephyr, Helios, and so on. Findings - Energy is the key constraint on design of HALE UAV. The questions about where HALE UAVs are capable of operating and how long they could work can be answered according to power density distribution on earth. The total mass of HALE UAV can be divided into two parts: one is the constant mass, the other is the mass increasing with area of wing. The total mass can be estimated by the former one; the later one plays an important role in estimating wing load in the designing process. Practical implications - The only way to enhance carrying ability of HALE UAVs is to redistribute their wing load: lighter structure materials and a better method to fix P-cell with lighter fundus are the key technologies to enhance HALE UAVs' carrying ability. At current technological levels, it is not easy to design a UAV to achieve the aim of high-altitude long-endurance. Originality/value - This paper presents a very efficient and convenient method to determine the designing parameters of HALE UAV.