Flettner

Anton Flettner, Flugzeugbau GmbH was a German helicopter and autogyro manufacturer during World War II, founded by Anton Flettner.

Flettner aircraft included:

Anton Flettner's interest in aerodynamics (specifically the Magnus effect, which produces a force from a cylinder rotating in a fluid flow) also led him to invent the Flettner rotor which he used to power a Flettner ship which crossed the Atlantic, and the Flettner ventilator which is still widely used as a cooling device for buses, vans and other commercial vehicles and which is based upon the Savonius principle.