O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Friedrichshafen D I
  This clean little single-seat fighter was built during 1916, but as it offered no improvement over the Albatros lighters, which had obviously influenced its design, it did not go into production. Engine, 160 h.p. Mercedes D III. Armament, twin Spandau machine-guns forward.

W.Green, G.Swanborough The Complete Book of Fighters

FRIEDRICHSHAFEN FF 43 Germany

  In September 1916, the Flugzeugbau Friedrichshafen presented the Idflieg (Inspektion der Fliegertruppen - Inspectorate of Flying Troops) with a proposal for a single-seat, land-based fighter based on the FF 43 floatplane. This, the FF 46, received an order for three prototypes, which, like the FF 43, were to be powered by the 160 hp Mercedes D III, but were to be armed with twin synchronised 7,92-mm MG 08/15 machine guns. The FF 46, or D I, was a single-bay staggered biplane, the first prototype having vertical cabane strutting, but the second having splayed struts to improve forward vision. The Idflieg testing of the FF 46 was not completed until 28 April 1917, when it was concluded that the type was not acceptable for series production as its flight characteristics and performance were inferior to those of its contemporaries. There is no record of the third prototype being completed.

Empty weight, 1,512 lb (686 kg).
Loaded weight, 1,986 lb (901 kg).
Span, 29 ft 6 1/3 in (9,00 m).
Length, 23 ft 3 1/2 in (7,10 m).
Height, 8 ft 10 1/3 in (2,70m).
Wing area, 277.72 sqft (25,80 m2).