Asked by: Ben Hume, Oxted
At first sight an autogyro looks like a rudimentary helicopter as they both have large horizontal rotor blades. But unlike a helicopter, the rotors on an autogyro are not powered. Instead, the thrust comes from a propeller either at the front or rear of the aircraft.
The blades spin because of the air rushing up through them, providing lift and stability. Though this is an unusual design, autogyros are popular with recreational pilots and they’re well suited to low-speed flight.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.