Shown here as a model in scale of 1 : 4.6 – built by Dieter Störig
The Flettner Fl 265 was an experimental helicopter designed by Anton Flettner.
This helicopter, developed in 1938 with the support of Nazi Germany’s Kriegsmarine (= Navy), made it possible, for the first time, to transition from powered rotary-wing flight to autorotation and back again, making it the safest helicopter of its time. In contrast to the Fl 185, the Fl 265, believed to be the pioneering example of a synchropter, had two intermeshing rotors 12 m in diameter, powered by a 160 horsepower (120 kW) BMW-Bramo Sh 14 A radial engine in the nose of the fuselage, fitted with a fan to assist cooling. Six helicopters were constructed, but series production was curtailed in favour of the Flettner Fl 282.
Text from Wikipedia, the free encyclopedia