Investigating the role of propeller geometry and surface characteristics in UAV ice accretion: An experimental study

A lab based experimental study of atmospheric ice accretion on UAV propellers with different geometric and surface characteristics was conducted to study the ice accretion physics and resultant changes in propeller thrust and electrical power consumption. These experiments were conducted at the Anti-icing Materials International Laboratory (AMIL) Icing Wind Tunnel (IWT) at the Université du Québec à Chicoutimi (UQAC), Canada. The experimental icing conditions are determined in accordance with the 14 CFR Part 29 Appendix C for rotorcraft operating at altitudes below 10,000 feet. In this study the influence of following four geometric parameters and two surface characteristics of UAV propeller on ice accretion is analysed: 1) propeller diameter, 2) propeller pitch, 3) propeller chord length, 4) propeller winglets, 4) propeller surface finish and 6) Icephobic coatings. The analysis of results shows that the change in these features does not significantly impact the nature and shape of ice accretion but mainly influence the surface area affected by ice accretion. The thrust coefficient and electrical power coefficients vary considerably with change in propeller geometric features. The variation in propeller blade surface characteristics has a significant impact on the ice shedding characteristics of UAV propeller blade. Considering the high-power requirements of active ice mitigation techniques for UAV propellers, the results obtained from this study can be employed to develop a passive/hybrid ice mitigation approach and further optimize the geometric parameters of UAV propeller blades for efficient operations in icing conditions.