Flettner, Anton

SUBJECT AREA: Aerospace

[br]

b. 1 November 1885 Eddersheim-am-Main, Germany

d. 29 December 1961 New York, USA

[br]

German engineer and inventor who produced a practical helicopter for the German navy in 1940.

[br]

Anton Flettner was an engineer with a great interest in hydraulics and aerodynamics. At the beginning of the First World War Flettner was recruited by Zeppelin to investigate the possibility of radio-controlled airships as guided missiles. In 1915 he constructed a small radio-controlled tank equipped to cut barbed-wire defences; the military experts rejected it, but he was engaged to investigate radio-controlled pilotless aircraft and he invented a servo-control device to assist their control systems. These servo-controls, or trim tabs, were used on large German bombers towards the end of the war. In 1924 he invented a sailing ship powered by rotating cylinders, but although one of these crossed the Atlantic they were never a commercial success. He also invented a windmill and a marine rudder. In the late 1920s Flettner turned his attention to rotating-wing aircraft, and in 1931 he built a helicopter with small engines mounted on the rotor blades. Progress was slow and it was abandoned after being damaged during testing in 1934. An autogiro followed in 1936, but it caught fire on a test flight and was destroyed. Undeterred, Flettner continued his development work on helicopters and in 1937 produced the Fl 185, which had a single rotor to provide lift and two propellers on outriggers to combat the torque and provide forward thrust. This arrangement was not a great success, so he turned to twin contra-rotating rotors, as used by his rival Focke, but broke new ground by using intermeshing rotors to make a more compact machine. The Fl 265 with its "egg-beater" rotors was ordered by the German navy in 1938 and flew the following year. After exhaustive testing, Flettner improved his design and produced the two-seater Fl 282 Kolibri, which flew in 1940 and became the only helicopter to be used operationally during the Second World War.

After the war, Flettner moved to the United States where his intermeshing-rotor idea was developed by the Kaman Aircraft Corporation.

[br]

Bibliography

1926, Mein Weg zum Rotor, Leipzig; also published as The Story of the Rotor, New York (describes his early work with rotors—i.e. cylinders).

Further Reading

W.Gunston and J.Batchelor, 1977, Helicopters 1900–1960, London.

R.N.Liptrot, 1948, Rotating Wing Activities in Germany during the Period 1939–45, London.

K.von Gersdorff and K.Knobling, 1982, Hubschrauber und Tragschrauber, Munich (a more recent publication, in German).

JDS