Enea Bossi Sr.

Bossi in front of the AAC factory in Port Washington, New York

In October 1928, Bossi founded the American Aeronautical Corporation (AAC), officially located at 730 Fifth Avenue in Port Washington, New York, to build Savoia-Marchetti seaplanes under license.[10] Licenses were acquired for both the S-55 and the S-56 and both were tested at the Miller Army Air Field, but only the latter made it to production.[11] The S-56 became the first plane used by the New York City Police Department, which used it to enforce flying regulations, assist with sea rescues, and to chase rum-runners during the Prohibition era.[12][13] A follow-up design, the more-powerful S-56B, proved even more successful. Whereas the prices for the S-56 and S-56B were modest for the time, the Great Depression caused sales to drop significantly by 1933.[14] Two original AAC S-56 planes exist today: one of which is on display at the Cradle of Aviation Museum in Garden City, New York.[12][13]

Bossi's work was not without its setbacks. In early 1930, he survived the crash of an experimental S-56 off Port Washington which claimed the life of test pilot Peter Talbot. Bossi was rescued by the Coast Guard's ship CG-162.[15]

Budd BB-1 Pioneer in front of the Franklin Institute

The Edward G. Budd Manufacturing Corporation, of Philadelphia, Pennsylvania, was a major manufacturer of railroad cars, which resulted in significant experience in working with stainless steel. In 1930, the company made its first foray into the aviation industry by signing contracts to manufacture aircraft wheels and stainless steel wing ribs. A close friend of Edward Budd, Enea Bossi joined the company as the head of stainless steel research to supervise the design and construction of the 4-seat Budd BB-1 Pioneer – the first aircraft with a structure built out of stainless steel. Occurring in 1931, this was the first aircraft for the Budd Company. Built under Restricted License NR749,[14] its design utilized concepts developed for the Savoia-Marchetti S-31 and was powered by a single 210 horsepower (160 kW) Kinner C-5 motor.[16]

The stainless steel construction process for the BB-1 was patented in 1942.[17] At the time, stainless steel was not considered practical; and only one BB-1 was built. In 1934, this plane was stripped of its fabric covering and mounted outside the Franklin Institute in Philadelphia, where it remains to this day as the longest continuous display of any airplane.[14] The plane has been memorialized in the children's book Spirited Philadelphia Adventure by Deirdre Cimino.[18] In 1931, Bossi sold the controlling interest of the AAC to Dayton Airplane Engine Company.[19] The success which came from the technical innovations of the BB-1 prompted the Budd Company to employ Bossi as its European representative.[1]

The Pedaliante

Enea Bossi in the 1930s

In 1932, Bossi heard of an airplane which had successfully flown while powered only by a 1 hp (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 hp (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.[1]

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.[1]

In 1933, the Frankfurt Polytechnische Gesellschaft (Frankfurt Polytechnic Society) offered a prize to promote human-powered flight. Due to the newly formed Rome-Berlin axis, similar political and military events were staged during the initial period in both Italy and Germany to help strengthen that bond. To this end, in 1936, the Italian government initiated an equivalent contest: offering 100,000 lire for a 1 km (0.62 mi) 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.[1]

Bossi's design for the contest was named the Pedaliante, Italian for "Pedal Glider" – so named because it utilized conventional glider configuration and construction.[20] The design was introduced in 1937 and Vittorio Bonomi, an Italian sailplane manufacturer, was contracted to build the plane.[1] 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 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.[1]

Incorporating a catapult launch to a height of 30 feet (9.1 m), the Pedaliante made a flight on September 13, 1936, which traveled several hundred meters.[3] On March 18, 1937, at Cinisello airport near Milan, the plane was launched at a height of 29.5 feet (9.0 m) and Casco successfully pedaled the craft for its full 0.62 miles (1.00 km).[21] 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.[22] At this time, the Mufli and the Pedaliante were the most advanced Human-powered aircraft ever built.[1][23]