G Warwick, Tech Take, Aviation Week & Space Technology, 21 April-4 May 2025, p 62

In Canada, Unither Bioelectronics has completed the first piloted flight of a gaseous hydrogen fed fuel-cell helicopter. The R44 aircraft is fitted with a low temperature proton exchange membrane fuel cell system. A R66 model is planned followed by liquid hydrogen with a range of 250 nm and payload of 600 lb.