The Arado SD I was one of the first new fighter aircraft designed in Germany after the First World War and was a single-seat sesquiplane produced in 1927.
Although the revival of German air power is normally associated with the Nazis, it actually began in secret under the Weimar Republic. A small aviation section was formed within the Defence Ministry (Reichswehr Ministerium) in 1921, and from 1923 air crews were trained in secret in the Soviet Union. At the same time specifications were issued for new military aircraft, amongst them a single-seat fighter.
The SD I was designed by Ing. Walter Rethel, a former employee at Fokker. He produced a single-seat sesquiplane (a biplane with one wing significantly smaller than the other - in this case the lower wing). It was powered by a Gnome-Rhône Jupiter radial engine, and was entirely conventional construction for the time, with a welded steel fuselage and wooden wings, covered by plywood and fabric. It was armed with two 7.92mm machine guns.
Two prototypes were constructed, with the first making its maiden flight in 1927. Work then moved on to the Arado SD II and Arado SD III, two similar but larger sesquiplanes that became the basis of the Arado Ar 64. The first prototype SD I was lost in a crash at Rechlin on 11 October 1927, killing the pilot.
Engine: Gnome-Rhône Jupiter VI radial engine
Wing span: 26ft 6 3/4in
Length: 22ft 1 3/4in
Empty Weight: 1,874lb
Maximum take-off Weight: 2,712lb
Max Speed: 171mph at 16,405ft
Armament: Two fixed forward firing 7.92mm machine guns