Propeller Ice Protection System for UAVs (Results)

By Nicolas Muller, UBIQ Aerospace

Ice accretion is a serious threat to small UAVs. For this reason, a test campaign was conducted by UBIQ Aerospace and the NTNU to evaluate the influence of ice accretion on the performance of a UAV. The Flight Stand 15 was a key part of the experimental setup.

Experimental Setup:

Figure 1 : The Flight Stand 15 mounted in the Icing Wind Tunnel

A special icing wind tunnel at the VTT Research Center in Helsinki was used to generate the atmospheric conditions for icing research. The wind tunnel is situated in a cold chamber and features a spray system to generate an artificial cloud.

The propeller was based on a Mejzlik propeller modified by UBIQ Aerospace with a carbon fiber-based heating element, which enabled the propeller to remove the ice from the surface.

Figure 2 : View of the propeller with an integrated Carbon Fibre Heating Element

A Hacker Q80 motor is mounted to the Flight Stand, along with a slip ring to connect the heating elements in the propeller to power. The Python Interface of the Flight Stand was used to control the experiment, and enabled real time analysis of the performance of the propeller significantly speeding up the turnaround time of experiments.

Results:

Figure 3 : Propeller Performance at -10° C without an Ice Protection System

The experiments have shown that without an ice protection system, the propeller can lose up to 80% of its efficiency in 60 s. The efficiency loss is mostly due to the reduction of thrust in the propeller. The propeller efficiency stabilizes at 20% of the clean efficiency, as ice starts to shed of the propeller.

Figure 4 : Performance of the Protected Propellers at -10° C

The protected propellers can reduce the efficiency loss and maintain the propeller efficiency in icing conditions. The Flight Stand 15 is a key part of the experimental setup, to enable and accelerate the analysis propellers with an ice protection system.

The full research study can be read here and a video of the system in operation is available here.