The Avro Rota Mk I was a British-built version of the Cierva C.30A autogyro, produced under license by Avro in the 1930s. While it might look like a quirky mix between a plane and a helicopter, it was actually an autogyro, meaning it had a free-spinning rotor that provided lift, but propulsion came from a conventional engine-driven propeller at the front. The Rota Mk I was used primarily by the Royal Air Force for radar calibration work, especially during and after the early stages of World War