FLETTNER

GERMANY (see also List of Individuals)

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1.11.1885 Eddersheim/D - 29.12.1961 New York/USA

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Anton Flettner was originally a teacher. In World War I he was recruited by Zeppelin to investigate the possibility of radio-controlled airships as guided missiles. In 1924 he invented a sailing ship powered by rotating cylinders. Although one ship crossed the Atlantic, they were never commercialized. At this time he also proposed a windmill and a marine rudder. Around 1930, Flettner turned his attention to rotating-wing aircraft and presented a helicopter with engines mounted on the rotor blades. This design was damaged in 1934; thus, he invented an autogiro in 1936 being destroyed on a test flight. Undeterred, Flettner developed helicopters and produced in 1937 the Fl 185 with a single rotor to provide lift and two propellers on outriggers to combat the torque and provide forward thrust. This arrangement being no success he turned to twin contra-rotating rotors. The Fl 265 with its "eggbeater" rotors was ordered by the German Navy. After exhaustive testing, Flettner produced the two-seater Fl 282 Kolibri in 1940 which was the only helicopter used during World War II.

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Flettner is known for three inventions, namely the Flettner rudder, the Flettner rotor as used for ship propulsion, and the Flettner helicopter. The 1922 founded Instituut voor Aeroen Hydro-Dynamiek of Amsterdam University was directed by Flettner. There practical problems in fluid dynamics were tested. The Flettner rotor was a design in which the Magnus effect as introduced by Heinrich Gustav Magnus (1802-1870) was applied. A rotating cylinder set in a wind current undergoes a transverse force that may be used for ship propulsion. Flettner moved in 1947 to the USA as a chief designer of the Kaman helicopter works, and founded his own company some ten years later.

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_{Anonymous (1924). Flettner's sailless ship explained. Power 60(27): 1054-1056. P}

_{Anonymous (1926). Anton Flettner. Industrieblatt Stuttgart 31(49): 8. P}

_{Anonymous (1996). Flettner, Anton. Biographical dictionary of the history of technology: 261,}

_{L. Day, I. McNeil, eds. Routledge: London.}

_{Flettner, A. (1926). The story of the rotor. Willhoft: New York.}

_{Gohlke, P. (1924). Die Aerodynamik der neuen Flettner-Erfindung. Deutsche Luftfahrer-Zeitschrift 28(17): 281-284.}

_{Pöschl, T. (1925). Das Flettner'sche Rotorschiff und seine physikalischen Grundlagen. Ingenieur-Zeitschrift 5(6): 61-64.}

_{Williams, A., Liljenberg, H. (1983). Revival of the Flettner rotor - beneficial or not for merchant vessels, fishing boats, and recreational craft? Trans. SNAME 91: 125-148.}