Researchers at Perm National Research Polytechnic University have proposed a method to assess how effectively small unmanned aerial vehicles withstand icing. The university’s press service provided the key details of the study.
Small drones play important roles in search and rescue, aerial photography, and monitoring large areas. Yet operating them in subzero temperatures with high humidity leads to ice forming on the wings, which can disrupt flight stability and performance.
Because their compact size prevents the integration of large anti-icing systems used in commercial aviation, these drones rely on an approach known as “overthrottle.” This technique momentarily raises rotor speed to counteract ice buildup. PNIPU researchers suggest that the process of ice removal during overthrottle can alter wing stiffness and the geometry of the blade design, with consequences for control and endurance.
To analyze these dynamics, technicians constructed a testing setup featuring an air-cooling tube capable of maintaining temperatures from -30 °C to +25 °C. Inside, an electric motor drives the drone propeller under test.
A high-speed camera records the process at up to 960 frames per second. A spray of cooled liquid droplets is delivered through a nozzle into a chamber under compressor-generated pressure, creating a controlled icing environment.
The sensor system monitors vibration across different icing levels and captures instantaneous readings for humidity, pressure, and temperature. Specialized software enables researchers to adjust the electric motor’s operating mode and regulate the cooling chamber’s power, while collecting signals from all measuring instruments.
In a representative experiment, a propeller was placed inside a pipe and ice was formed around it for two minutes at a rotation speed of 5000 rpm and a temperature of -10 °C.
The speed was then increased to 7000 rpm. Ice on the blade that had its properties altered by the process melted away, but ice remained on the other three blades. Complete ice removal from the remaining blades occurred after reaching 11500-12000 rpm.
Researchers observed that local heterogeneity in surface properties influenced how ice adhered to the blade, causing the ice to melt more slowly on specific areas.
“Controlled changes in the fan surface properties can reduce energy consumption for propulsion during flight and extend overall endurance,” noted a candidate of technical sciences and a specialist at the High Performance Center. An associate professor in the Department of Aviation Information Technology Systems commented on the study, highlighting its potential to inform drone propulsion efficiency and reliability [PNIPU study].
Earlier work at PNIPU included the development of an installation for testing experimental aviation fuels, reflecting a broader program to improve performance and safety in unmanned and manned aviation alike [PNIPU study].