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

Friedrichshafen C I
   This C I product of the Friedrichshafen factory was no more than a FF 33 L seaplane (No. 1267) fitted with a conventional land undercarriage chassis. Only the single example was built. Engine, 150 h.p. Benz III. Span, 13.3 m. (43 ft. 7 3/4 in.). Length, 8.0 m. (26 ft. 3 in.). Armament, one Parabellum machine-gun in rear cockpit.

J.Herris Friedrichshafen Aircraft of WWI (A Centennial Perspective on Great War Airplanes 21)

Friedrichshafen C.I

   The Friedrichshafen C.I was a land-plane conversion of FF33L seaplane Marine Number 1267. Apparently it was intended as a reconnaissance plane for a Marine unit in Flanders. As would be expected, the observer had a flexible machine gun. The pilot likely did not have a fixed gun in the first version of the aircraft as #1267 was from a batch of FF33L aircraft that lacked a fixed gun for the pilot. The photo is not definitive because a fixed gun, if present, would be on the starboard side of the engine and not visible in any case. Interestingly, a second variant of the Friedrichshafen C.I featured a Mercedes engine without spinner and a fixed gun for the pilot. It is not known if this was modified from #1267 or a second airframe was built.

Friedrichshafen C.I Specifications
Engine: 150 hp Benz Bz.III
Wing: Span, Upper 13.20 m
Span, Lower 11.70 m
General: Length 8.0 m
Height 3.70 m