Human-powered aircraft

A human-powered aircraft (HPA) is an aircraft belonging to the class of vehicles known as human-powered transport.

As its name suggests, HPAs have the pilot not only steer, but also power the aircraft with a system similar to a bicycle. A pair of pedals, moved by the pilot's feet, is connected to a propeller, or in the case of earlier prototypes, an ornithopter mechanism, which powers the aircraft.

Often, a hybrid system is used; where sometimes the pedals would charge a battery, which would, at the push of a button, power an electric motor that is connected to the propeller.

Human-powered aircraft have been successfully flown over considerable distances. However, they are still primarily constructed as engineering challenges rather than for any kind of recreational or utilitarian purpose.

Early attempts at human-powered flight were unsuccessful because of the difficulty of achieving the high power-to-weight ratio. Prototypes often used ornithopter principles which were not only too heavy to meet this requirement but aerodynamically unsatisfactory.

In 1904, Scientific American published an article and a photograph of a bicycle plane built by Steward Winslow of Riparia, Washington. He attempted to fly his plane on 30 July 1904, but one of the wheels failed.

An early human-powered aircraft was the Gerhardt Cycleplane, developed by W. Frederick Gerhardt at McCook Field in Dayton, Ohio in 1923. Its only human-powered takeoff was a short hop of 6 metres (20 ft) with the craft rising 60 centimetres (2 ft).

In 1934, Engelbert Zaschka from Germany completed a large human-powered aircraft, the Zaschka Human-Power Aircraft. On 11 July 1934, the Zaschka-HPA flew about 20 metres (70 ft) on the Berlin Tempelhof Airport; the HPA took off without assisted takeoff.