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The Focke-Wulf Fw 61 (aka Fa 61) was an experimental helicopter of supreme historical significance. The Fw 61 was built by Focke-Achgelis and designed by Professor Henrich Focke. The Fw 61 is widely considered to be the first practical helicopter and first took flight on 26 June 1936. Prior to the creation of the Fw 61 Professor Focke had experimented with various autogyros, which are a type of precursor to modern helicopters and continue to be flown in parallel even today. His experience with autogyros made their limitations clear and in partnership with engineer Gerd Achgelis they produced a prototype aircraft powered by a small two-stroke engine that proved the feasibility if true helicopters. Apart from the single radial engine the Fw 61 had two rotors in order to counter the torque effect produced by each. What we think of as conventional helicopter design today of course did not exist at the time. The tubular steel airframe was borrowed from a well-tested aircraft known as the Focke-Wulf Fw 44 Steiglitz. The rotors were set on steel outriggers and driven by a complex shaft and gear system. Interestingly, the small horizontal- axis propeller had nothing to do with propulsion and was simply a way to cool the engine while hovering or in low-speed flight. In February 1938, the Fw 61 was demonstrated by Hanna Reitsch indoors at the Deutschlandhalle sports stadium in Berlin, Germany. It subsequently set several records for altitude, speed and flight duration culminating, in June 1938, with an altitude record of 3,427 m (11,243 ft), breaking the unofficial 605-meter altitude record of the TsAGI 1-EA from the Soviet Union set in August 1932, and a straight line flight record of 230 km (143 mi). Only two units were ever built and they were primarily put to use by Nazi Germany. It is no accident that Germany enjoyed significant air supremacy for quite some time thanks to its advanced helicopter technology, no doubt directly as a result of the work by Focke and Achgelis.
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