Smallest crewed x-plane

The smallest crewed aircraft to receive a X-plane designation from the US Air Force was the Bensen X-25B, which was a 3.45-m-long one-person autogyro with a maximum take-off weight of just 248 kg (547 lb). This tiny aircraft was first flown at Edwards Air Force Base in California, USA, on 5 June 1968.

X-Planes are experimental aircraft operated by the US Department of Defence. Not all x-planes are wholly new designs, sometimes they are existing military or civilian aircraft under evaluation by the US Air Force. The X-25B, for example, was actually a Bensen B-8 – a hobbyist autogyro that had been sold by the Bensen Aircraft Corporation since 1955.

The US Air Force were evaluating the X-25B as part of the development of a possible escape vehicle for downed airmen, referred to as the "discretionary descent vehicle" or (DDV). The idea was that a tiny foldable autogyro could be used in place of a conventional ejection seat. The pilot would be launched clear of their striken aircraft in this tiny autogyro, which would then deploy its rotors, allowing the pilot to fly back to friendly territory.

The DDV was deemed operationally infeasible, but not after the X-25B had been extensively tested by pilots at Edwards Air Force Base. With a top speed of just 128 km/h (80 mph) the X-25B is also the slowest x-plane.