Design of an unmanned aircraft system for high-altitude 1 kW fuel cell power system

A proton exchange membrane (PEM) fuel cell is particularly considered as a prime power supply for a fuel cell-powered unmanned aircraft system (UAS) as it possesses a very high-power density in comparison with other fuel cell types, hence a high potential to be used for high altitude long endurance (HALE) UAS flights. This paper will focus on examining the design requirements for the UAS-based 1 kW PEM fuel cell for high altitude operation (10–11 km), which can be correlated into a quantitative data to produce a design constraints diagram. The maximum take-off mass, endurance, and geometries for potential UAS design are estimated. Four different geometrical design profiles are developed and presented. The resulting geometries are analysed and the design parameters of the estimated 1 kW design yielded an aircraft of maximum take-off mass 34.8 kg, wingspan of 10.4 m, cruising speed 20 m/s, stall speed 11.23 m/s, and maximum endurance of 4 h. The constraint diagram deploys these assumptions as well as values generated through the design calculations to form a possible design of which the 1 kW UAS falls slightly outside of the possible design space; this is due to the minimum thrust-to-weight ratio required to achieve the desired service ceiling; however, further alterations and adjustments on the design and mission requirements are provided to place the design of the UAS within the possible design space.