De Bothezat helicopter
| "Flying Octopus" | |
|---|---|
 |
|
| Role | Experimental rotorcraft |
| Manufacturer | George de Bothezat |
| Designer | George de Bothezat Ivan Jerome |
| First flight | 18 December 1922 |
| Retired | 1924 |
| Primary user | U.S. Army Air Service |
| Number built | 1 |
| Program cost | $200,000 USD |
The de Bothezat helicopter, also known as the Jerome-de Bothezat Flying Octopus, was an experimental quadrotor helicopter built for the United States Army Air Service by George de Bothezat in the early 1920s, and was said at the time to be the first successful helicopter. Although its four massive six-bladed rotors allowed the craft to successfully fly, it suffered from complexity, control difficulties, and high pilot workload, and was reportedly only capable of forward flight in a favorable wind. The Army canceled the program in 1924, and the aircraft was scrapped.
Self-described as "the world's greatest scientist and outstanding mathematician", and having written one of the first scientific papers on the aerodynamics of rotary-wing flight, George de Bothezat was a refugee from the Russian Empire who had fled to the United States in the wake of the Russian Revolution. Having written and lectured extensively on rotorcraft theory, de Bothezat received a contract from the United States Army in 1921 for the construction of an experimental helicopter based on his own principles and those of his assistant Ivan Jerome.
Establishing a workshop at McCook Field in Dayton, Ohio and working almost entirely without models or wind tunnels for testing, de Bothezat's helicopter was completed in December 1922. Featuring four six-bladed rotors at the end of massive, bridge-like girders braced with piano wire, the craft had two vertical propellers – "steering airscrews" – for lateral control, and two additional three-bladed propellers mounted horizontally above the Le Rhône engine to provide airflow for cooling. The girders were angled such that the rotors tilted in towards the craft's center at an angle of five degrees, enhancing stability. The aircraft had two control wheels, a control stick, and foot pedals for control, with each rotor featuring variable-pitch blades for individual collective control.
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