Determination of Mission Failure for Propeller-Driven High-Altitude, Long-Endurance UAVs Under Icing Conditions

High-altitude, long-endurance (HALE) unmanned aerial vehicles (UAVs) are optimized for stratospheric missions with long wingspans and lightweight structures, but these features make them highly vulnerable to icing, especially during climb. While previous research about HALE UAV icing has focused on icing effects on the fuselage and wings, the impact on small propellers has not been adequately considered. However, propellers are particularly vulnerable to icing due to their short chord lengths and high rotational speeds. Recent work has shown that propeller icing can significantly degrade UAV performance, underscoring the need for detailed analysis. This study addresses this gap by performing three-dimensional icing simulations for the UAV, including propellers, using a multiple reference frame approach. The icing model is validated against rotor icing experiments, and continuous ice accretion without shedding is assumed for conservative performance estimation. The simulation results are used to quantify performance degradation in terms of increased battery capacity requirements and DC motor limitations. The findings demonstrate that propeller icing can critically impact the UAV’s ability to reach its mission altitude, highlighting the importance of including propeller effects in UAV icing assessments and system design.