Akaflieg Berlin B4 F.F.

The Akaflieg Berlin B4 F.F. was a single-seat aircraft built in Germany in the early 1930s. It was a high-wing monoplane of all-wood construction with fabric-covered foldable wings
Design and development.
In 1931 the "Deutsche Luftfahrt-Verband e.V." (DLV) opened a competition for an inexpensive light aircraft. Two entries were put forward; Akaflieg Berlin's B4 F.F. (D-2229) and Dipl.-Ing. Hermann Mayer's MM-1 (D-2230), with both aircraft exhibited at the 1932 "Deutschen Luftsport-Ausstellung" (DELA) in Berlin.
Like the Mayer MM-1 the B4 F.F. was constructed at the DLV workshops in Adlershof. Design took eight months and construction a further nine.