In 1914, he and Wulf both reported for military service and Focke was deferred due to heart problems, but was eventually drafted into an infantry regiment.
Focke established the Focke-Achgelis company on 27 April 1937 in partnership with pilot Gerd Achgelis, and began development work at Delmenhorst in 1938.
A powered version of the kite would have been the Fa 336 which was in the design phase when the war ended and built in France postwar for testing.
On 1 September 1945, Focke signed a contract with the French company SNCASE and assisted in development of their SE-3000 passenger helicopter, which was based on the Focke-Achgelis Fa 223 "Drache" and which first flew in 1948.
[1] While working at the CTA Focke also developed the BF-1 Beija-Flor (hummingbird) two-seater light helicopter from 1954, which made its first flight at Sao Jose dos Campos on 22 January 1959.
The BF-1 was similar in design to the Cessna CH-1, with a 225 hp Continental E225 engine in the nose and the rotor mast running vertically between the front seats.
[1] Focke returned permanently to Germany in 1956 and began developing a three-seater helicopter named the "Kolibri" ("hummingbird") at the Borgward company in Bremen, with its first flight taking place in 1958.
[2] After Borgward collapsed in 1961, Focke became a consulting engineer with Vereinigte Flugtechnische Werke of Bremen and Deutsche Forschungsanstalt für Luft-und Raumfahrt.
Focke was awarded the Ludwig-Prandtl-Ring from the Deutsche Gesellschaft für Luft- und Raumfahrt (German Society for Aeronautics and Astronautics) for "outstanding contribution in the field of aerospace engineering" in 1961.