Development of an Icing Test Facility for Rotors and Propellers of Remotely Piloted Aircraft Systems (RPAS)

The development and calibration of a new facility to test medium size rotors for Remotely Piloted Aircraft Systems (RPAS) under in-flight icing conditions is described. This facility has made use of a 3 m x 6 m cold room available at the NRC which includes a spray system to provide the icing cloud as well as a dedicated rotor stand assembly that incorporates a load cell and dynamometer. Calibration data of the spray drop sizes and liquid water content are provided and compared to conditions of the natural environment as detailed in icing regulations for transport category airplanes, i.e., CFR 14 Part 25 Appendix C and O. Data to examine the sensitivity of rotor performance, under a constant liquid water content to various droplet sizes are provided for a medium sized rotor. Tests have also been performed that examine the ability of the rotor to maintain predefined thrust, torque and power performance throughout an icing encounter of fixed duration. For the purposes of this study, the rotor performance is determined by considering a hypothetical quadcopter RPAS concept with a baseline vehicle weight (15 kg), and a minimum operation time (122 seconds) during which rotor performance, and hence controlled flight, must be maintained.