Mission Analysis of Solar UAV for High-Altitude Long-Endurance Flight

This study presents the analysis of a hybrid solar high-altitude, long-endurance unmanned aerial vehicle (HALE UAV) designed to perform meteorological observation and surveillance-related missions. For this purpose, the methodology minimizes the energy consumption of the aerial platform considering the energy balance for a climb, cruise, and descent cycle. The flight methods take into account the seasonal and diurnal variation of solar radiation in the middle latitudes. In addition, to reduce the weight of the onboard battery and regenerative fuel cell (RFC), this study analyzes the daily mission profile that consists of a climb, high-altitude cruise, descent, low-altitude cruise, and reclimb. During the daytime cruise at 18km, extra energy is stored in the RFC. In the nighttime, the aircraft descends to 14km using energy stored in the RFC. On the following day, the aircraft climbs again to 18km and cruises during the daytime. The energy consumption of this one-day mission profile is compared to that of a continuous-cruise flight at 18-km altitude for a day. The effects of takeoff time on the total time and energy consumption to reach the mission altitude are investigated, and the drift due to the westerlies are calculated. The analysis of the configuration parameters and aerodynamic coefficients was conducted using software tools. (c) 2018 American Society of Civil Engineers.