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Anton Flettner

Born on 1 November, 1885, in Eddersheim on the Main, Anton Flettner became a teacher. In his spare time he almost entirely addressed himself to engineering: mechanics, physics and fluid mechanics. With the age of 29, he designed a steerable torpedo as his first invention and presented it to the Reichsmarineamt (German Navy Office). However, it was rejected because such a construction was thought to be impossible. It was not before the end of World War I that finally Flettner had the opportunity to enter the field of engineering. His first working place was the experimental station in Göttingen. Only a few years later, he appeared before the public with a startling experiment involving a novel propulsion for ships. Between 1922 and 1926, the Flettner company founded by himself experimented with large rotating cylinders harnessing the Magnus Effect. To test its efficiency an old schooner called "Buckau" was bought. The mast and cloth sails were removed. They were replaced with two chimney-like 50-foot sheet-steel cylinders mounted onto the forward and aft ends of the vessel and rotating vertically. This kind of propulsion was, however, less efficient than conventional engines. In 1927, Flettner moved on to projects in the aviation field. He decided to give a new impetus on aviation by designing a rotary-wing aircraft. His initial experiments failed, and it took another eight years to become successful. In these years he invented the Flettner rudder that made his name well known in Germany and beyond.

It was not before 1935 that Flettner’s name was more frequently mentioned in aviation. The high command of the navy took a great interest in using rotary-wing aircraft on cruisers and intensively supported Flettner’s plans. His first construction, the Fl-184, had characteristics reminding of de la Cierva’s Autogiro. Its successor, the Fl-185, was a helicopter with a concept of its own. This was the first helicopter with torque balance utilizing two small airscrews mounted on lateral outriggers.

In 1938, Flettner in cooperation with Dr. Kurt Hohenemser and Dr.-Ing. Gerhard Sissingh started the design of a helicopter with intermeshing counterrotating rotors mounted above the cabin. This was a very smart, albeit complicated, solution to balance the torque, but for the first time it was possible to switch automatically from helicopter to gyrocopter flight. This conversion had always been the critical point of a helicopter, as it would lose its ability to fly in case of an engine failure. After extensive testing of this machine (Fl-265) in the Mediterranean and the Baltic Sea by the navy it was clear that a helicopter of this type would prove its value as observation aircraft even on naval ships.

In 1940, an order by the Reichsluftfahrtministerium (RLM, Reich Air Ministry) followed, and Flettner developed his Fl-282 "Kolibri" ("Hummingbird") with a design similar to that of its predecessor. With its intermeshing counterrotating rotors and a nose-wheel undercarriage, the Fl-282 might very well be regarded as state-of the-art in helicopter design during World War II. 24 aircraft of this type were built, and some of them were used on naval ships. At the end of the test phase it was the rotary-wing aircraft with the highest flight stability in the world. This testimonial came from American pilots and technicians after the war after two captured machines had been tested in the U.S.

In 1947, Anton Flettner followed an invitation to America, where he stayed. There he started a new era in helicopter manufacturing. He was the chief designer of the Kaman Corporation. In this position he designed a number of modern machines, which are still in serial production. They all had Flettner’s distinctive design characteristics. In 1958, he left Kaman and started a new company, Flettner Aircraft Corporation, in New York. His research still focussed on a safe large helicopter. Flettner died at the age of 76 in a New York hospital on 29 December, 1961, after a life full of disappointment and with only a few highlights.