Oh well, that was short and sweet and very well timed, as I was just about to say that I'm off home soon and will be offline for an hour! Well done Ton
The De Bothezat Quadrotor helicopter, also known as the Jerome-de Bothezat Flying Octopus.
Extract from Wikipedia:
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 Russian refugee 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.
Although de Bothezat's invention was hailed by Thomas Edison as "the first successful helicopter", full control of the aircraft in flight remained elusive; in addition, the aircraft required a favorable wind to achieve forwards flight. However, despite its faults, the de Bothezat helicopter did prove to be remarkably stable. De Bothezat wanted to build an improved version of the craft, but in 1924, the Army Air Service decided to terminate further work on the project, canceling the contract and ordering the helicopter to be scrapped. However, the aircraft's control column has survived, and is on display in the Smithsonian Institution's Steven F. Udvar-Hazy Center.
Although considered a failure by the Army on account of its complexity and unreliability, de Bothezat's difficult personality not helping his cause, the "Flying Octopus" had still reached a significant level of achievement, and it would be over twenty years before an American helicopter would better the machine's performance.
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