NATO STO

Operating Unmanned Aerial Vehicles (UAVs) in cold and/or humid environments can expose them to the dangerous hazard of in-flight icing, which is a common aviation threat for both manned and unmanned aircraft. While icing impacts the operation of all types of aircraft, unmanned aerial vehicles are particularly vulnerable to in-flight icing because of their lower cruising altitudes, lower speeds and smaller excess power and payload margins. Unlike icing of manned aircraft, which is relatively well established, icing of UAVs presents a different set of challenges as these aircraft operate in low Reynolds number flow regimes where ice formation and its effects on the performance of the vehicle are far from being well understood. Unfortunately, most of the existing icing data were obtained for manned aircraft at high Reynolds numbers and are not applicable to UAVs, and very limited icing data currently exist for UAVs. Furthermore, existing ice protection and ice detection technologies that are used on manned aircraft are not suitable for unmanned aerial vehicles because of their small size and their payload and power limitations. To enable UAVs to operate safely, efficiently and reliably in icing environments, further research and collaboration is required. This will help achieve an in-depth understanding and characterization of icing of UAVs, which will guide the identification/development of existing and/or emerging ice protection and ice detection technologies that are suitable for application to UAVs. Two NATO AVT collaboration activities on icing of air and sea vehicles are ongoing. These are AVT-299 and AVT-332. Although the main focus of these two activities are anti-icing and de-icing technologies for manned aircraft, their outcomes will be leveraged as much as possible in the proposed AVT Research Task Group (AVT-RTG) activity.