The Pedaliante (Italian for "Pedal Glider") was a human-powered aircraft designed and built by Enea Bossi and Vittorio Bonomi and disputably credited with, in 1936, performing the first fully human-powered flight. The source of contention is that the flights were performed by Emilio Casco -- a pilot with exceptional physical endurance such that sustainable flight was not considered feasible for a typical person. Incorporating a catapult launch, the aircraft successfully traveled 0.62 miles (1 km) as part of an Italian competition.
In 1932, Enea Bossi heard of an airplane which had successfully flown while powered only by a 1-horsepower (0.75 kW) engine. This prompted Bossi to calculate the minimum power that a manned aircraft would need to fly. The calculation yielded a value of approximately 0.94-horsepower (0.70 kW), which convinced Bossi that Human-powered flight might be possible.
During a trip to Philadelphia, Bossi tested the speed at which a glider would take off under tow. The experiment consisted of hiring a professional bicyclist to tow a glider. A spring scale was attached to the tow line to sense the force exerted by the bicyclist. This same experiment procedure was later repeated as part of the development of the Gossamer Condor and the Gossamer Albatross. The results confirmed that a speed at which the necessary lift could be obtained was indeed attainable.
A second experiment conducted during a trip to Paris involved a propeller-driven bicycle designed by Bossi. The test rider achieved a speed of 23 miles (37 km) per hour, but one drawback was noted: the gyroscopic effect of the propeller generated so much torque that the bicycle became unstable. Bossi concluded, erroneously, that a successful human-powered aircraft would therefore require two counter-rotating propellers to cancel out the effects of torque – similar to the design of a helicopter. In light of these findings, Bossi decided to design an aircraft incorporating this difficult requirement.
In 1933, the Frankfurt Polytechnische Gesellschaft (Frankfurt Polytechnic Society) offered a prize to promote human-powered flight. During this period, many German activities were copied by Italy, and in 1936 the Italian government offered an equivalent contest: offering 100,000 lire for a 0.62 mile (1 kilometer) human-powered flight made by an Italian citizen. Bossi was aware that he could not receive the prize due to his American citizenship, but he opted to attempt to win it, anyway.
Bossi’s plane was named the Pedaliante (photo), Italian for "Pedal Glider" – so named because it utilized conventional glider configuration and construction. The high-winged streamlined monoplane design was introduced in 1937 and had a wing span of 58 feet (17.7 m), an area of 252 square feet (23.4 m2).. It featured two laminated balsa wood propellers – each approximately 6.2 feet (2 m) in diameter. The plane had an aspect ratio of approximately 13.4 and a structural factor of 457.9 ft-lb3/2. The airfoil consisted of an American NACA 0012-F1. The control surface consisted of a conventional rear rudder, elevator, and a pair of wing spoilers – all activated by a divided control yoke. The pilot sat semi-upright, and a bicycle chain transmitted the power from the pedals to an overhead transverse shaft that was bevel-geared to the two propellers, which extended from the wing on each side of the fuselage. Its empty weight was 214 pounds (97 kg), of which the wings made up 99 pounds (45 kg) of the weight.
Vittorio Bonomi, an Italian sailplane manufacturer, was contracted to build the plane. The wooden airframe was originally specified to have an empty weight of 160 pounds (72.6 kg), with an overweight contingency of 20 pounds (9.1 kg). While this design would have been feasible, the Italian Air Ministry required that the plane satisfy the same structural requirements of an engine-powered aircraft. This requirement prompted the plane’s empty weight to increase to nearly 220 pounds (100 kg) – a significant amount of additional weight.
Bossi and Bonomi enlisted Emilio Casco to pilot the Pedaliante. Casco was a major in the Italian Army and a very strong bicyclist. After several weeks of trials in early 1936, Casco took off in the Pedaliante and flew approximately 300 feet (91.4 m) completely under his own power, marking the first achievement of an aircraft obtaining and sustaining flight completely via human power. Although subsequent calculations have verified that this flight was physically possible, most agree that it was Casco’s considerable physical strength and endurance which performed the accomplishment; not a feat which could be attained by a typical person.
It was decided that additional thrust was necessary. In response, the propellers were increased in size by about a foot (0.3 m), resulting in a diameter of approximately 7.4 feet (2.25 m). Whereas this increase in propeller length brought a corresponding increase in thrust, the position of the fuselage prohibited any further increases. Despite the additional thrust, the team still found the plane to be too heavy to travel the 0.62 miles (1 km) the contest demanded. However, the German HV-1 Mufli (de) (Muskelkraft-Flugzeug), a human-powered aircraft built by Helmut Hässler & Franz Villinger (de), traveled 770 feet (235 m) on its debut flight in 1935 and attained a distance of 2335 feet (712 m) in 1937 utilizing a tensioned cable launching system.
Incorporating a catapult launch to a height of 30 feet (9 m), the Pedaliante made a flight on 13 September 1936 which traveled several hundred meters. On 18 March 1937, at Cinisello airport near Milan, the plane was launched at a height of 29.5 feet (9 m) and Casco successfully pedaled the craft for its full 0.62 miles (1 km). This set a world record for human-powered flight, but as a catapult launch was not permitted in the rules of the competition, the Pedaliante did not win the prize for which it was designed. The plane was retired the following year having made a total 80 flights – 43 without the assistance of a catapult launch. At the time, the Mufli and the Pedaliante were the most advanced Human-powered aircraft ever built.