All-weather Drone

The demand for multicopters and uncrewed aircraft systems (UAS) is growing continuously. According to estimates, the European drone market will reach a size of 10 billion euros by 2035. However, poor weather conditions such as rain, snow and icing pose significant challenges for the safe operation of these systems. There is currently a lack of civil, weather-related certification regulations for drones, which severely limits their availability.

The All-Weather Drone project, funded by the Austrian aeronautics research programme TAKE OFF via FFG and BMIMI, focuses on developing solutions to enable the safe operation of multicopters even in difficult weather conditions.

The research project uses climatic wind tunnel tests to simulate typical flight missions under adverse weather conditions. Unlike conventional wind tunnels, the climatic wind tunnel enables the targeted simulation of temperature, humidity, and types of precipitation. These test conditions are based on existing aviation standards such as EASA CS-25 and CS-29. Two test series were conducted:

• Tests with individual UAS propellers.
• Tests with complete multicopters up to 25 kg take-off mass.

The results include the documentation of ice accumulation using 3D scanning technology and the measurement of performance degradation. Tests conducted in the climatic wind tunnel, which specifically simulated rain and icing, showed that even short icing encounters of less than 300 seconds can have a significant impact on the performance of multicopters. Depending on the conditions and the type of system used, noticeable performance losses occurred within the first 60 to 120 seconds. Even less intense icing conditions with low liquid water content (LWC) had partly negative effects on performance, as natural shedding of ice accumulations occurred with a delay (Kozomara et al., 2024, online: https://arc.aiaa.org/doi/10.2514/6.2024-4072).

The findings will be prepared in the form of regulatory recommendations to ensure the safe operation of UAS in adverse weather conditions.

In the All-weather Drone project, AIRlabs Austria developed a practical concept for carrying out icing tests under real conditions. Thanks to extensive practical experience in drone operation and in-depth knowledge of the current state of the art, it was possible to build a suitable prototype that was specifically tailored to the requirements of the tests. The flight tests were carried out in AIRlabs’ high alpine test areas, which offer optimal conditions for realistic weather and icing scenarios.