Uncrewed Systems Technology 049 - April/May 2023

93 2019) uses a ducted and centrally mounted Wankel rotary engine for power and thrust, although its design differs from the ducted aerial vehicle principle by including eight outboard BLDC rotors around the duct for VTOL-transitioning and attitude control. “I realised that a ducted air vehicle would be ideal for flying into chemical tanks and other tight, hazardous spaces for various reasons,” Eleryan explains. “One, they’re very thrust-efficient relative to their size, meaning they can be made a lot smaller than quadcopters of a similar power output, and second they can carry more weight, meaning more sensors and more computational power. “And of course, the fact that the propellers are shrouded is essential, because no matter howmuch intelligence you have on board in your obstacle recognition and collision avoidance system, it’s still really easy to bump into a wall or pipe, or snag a blade on a cable. Any kind of catastrophic failure in those kinds of environments is going to be costly for the asset’s owner.” However, ducted air vehicles are inherently difficult to control, which is why very few have beenmade and none successfully commercialised, despite having been first proposed back in the 1950s. Thanks tomodern technologies such as advanced processors, MEMS IMUs and ESCs though, Eleryan and Czarnota saw they could resolve the control issues andmake the first commercially viable ducted (and uncrewed) aircraft. Design andmaterials The result of that, the X1, was unveiled in 2022. It weighs about 440 g and is built largely from polycarbonate. Very little carbon composite is used, as prioritising impact resistance over weight is more important to the Dronut’s design than strength alone, given the impacts it might suffer when in use. Cleo Robotics Dronut X1 | In operation A ducted air vehicle is very thrust- efficient relative to its size, so it can be made smaller, and it can carry more weight, sensors and computing power Uncrewed Systems Technology | April/May 2023 The Dronut X1’s unique architecture enables it to operate safely in tight and potentially dangerous spaces such as underground tanks and air vents (Images courtesy of Cleo Robotics) By having its propellers completely shrouded, the Dronut tends to get safety clearances for indoor flights that cannot be carried out even by caged UAVs, as fingers and cables won’t snag on its blades