An experimental study to evaluate the effectiveness of a Rotor-Integrated-Heating system for UAV inflight icing protection

An experimental investigation was conducted to evaluate the effectiveness of a Rotor-Integrated Heating System (RIHS) for Uncrewed-Aerial-Vehicle (UAV) inflight icing protection. The RIHS is composed of a flexible electric film heater that is wrapped around the blades of a UAV rotor model to heat the blade surfaces for icing mitigation. The experimental study is conducted in the Icing Research Tunnel of Iowa State University (ISU-IRT) with the rotor model exposed to a variety of typical icing conditions experienced by UAVs flying in low-altitude airspace. During the experiments, while a phase-locked technique is employed to record the anti-/de-icing features over the surface of the rotor blade with the activated RIHS, the aerodynamic forces generated by the rotor model and the electric power required by the UAV rotor spinning at a pre-selected angular speed are also measured during the icing experiments to quantify the benefits of employing the RIHS for UAV inflight icing mitigation. While the RIHS is found to be effective in ensuring that the rotor model generates almost the same amount of aerodynamic forces over the entire duration of the icing experiments, the minimum power density required by the RIHS to remove/shed ice accretion from the rotor blade is found to be P_D = 2.0, 6.0 and 10.0 kW/m² under the glaze, mixed and rime icing conditions, respectively. It is also demonstrated that, in comparison to the scenario without taking any anti-/de-icing measures, the successful anti-/de-icing with the activated RIHS can lead to at least 65 %, 63 % and 57 % saving in the required power consumption for the UAV rotor generating required lifting forces to ensure the UAV stay airborne under the glaze, mixed and rime icing conditions, respectively.