Focke-Wulf Fw 61

Focke-Wulf Fw 61

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http://en.wikipedia.org/wiki/Focke-Wulf_Fw_61

Fw 61

First prototype Fw 61
Role	Helicopter
Manufacturer	Focke-Achgelis
First flight	26 June 1936
Introduced	1936
Primary user	Nazi Germany
Number built	2 ^[1]

The Focke-Wulf Fw 61 was the first fully-controllable helicopter, first flown in 1936. It is more popularly known as the Fa 61, as it was a research aircraft of the Focke Achgelis company.

Development

Through his work on the C.19 and C.30 autogyros built by Focke-Wulf under license from Cierva Autogiro, as well as the experience gained through development of the Fw 186, Prof. Heinrich Focke had come to the conclusion that the inadequacies and limited serviceability of autogyros could only be eliminated by a real helicopter. He and engineer Gerd Achgelis started the design for this helicopter in 1932. A free-flying model, built in 1934 and propelled by a small two-stroke engine, brought the promise of success. Today, the model can be seen in the German Museum in Munich.

On 9 February 1935, Focke received an order for the building of a prototype, which was designated the Fw 61, however Focke referred to it as the F 61. Roluf Lucht of the technical office of the RLM extended the order for a second aircraft on 19 December 1935. The airframe was based on that of a well-tried training aircraft, the Focke-Wulf Fw 44 Stieglitz. A single, radial engine drove twin rotors, set on outriggers to the left and right of the fuselage - the counter-rotation of the two rotors solved the problem of torque-reaction as also shown by Louis Bréguet.

Only two aircraft were produced. The first prototype, the V 1 D-EBVU, had its first free flight on 26 June 1936 with Ewald Rohlfs at the controls. By spring 1937, the second prototype, V 2 D-EKRA, was completed and flown for its first flight. On 10 May 1937, it accomplished its first autorotation landing with the engine turned off.

Operational history

In February 1938, it 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) and a straight line flight record of 230 km (143 mi).