The Friedrichshafen FF.33 was a German single-engined amphibious reconnaissance biplane designed by Flugzeugbau Friedrichshafen in 1914.
The initial production version was powered by a Mercedes D.II engine inline water-cooled engine, six examples of this variant were built. The basic design was refined and improved. The FF.33e main production reconnaissance variant was powered by a Benz B.III inline engine. This version had longer twin floats, and the under tail central float was eliminated. A radio transmitter replaced its armament, aproximately 180 examples of the FF.33e variant were built.
The FF.33l was the main production armed scout/fighter version. The design underwent aerodynamic improvements, including a reduction in length and wingspan, about 135 of this version built.
The FF.33 served in both the German and Austrio-Hungarian navies. Several other nations purchased the Friedrichshafen FF.33e during the first world war, including: Bulgaria, Denmark, Netherlands, and Sweden. The Finnish Air Force purchased two FF.33Es from Germany in February 1918. The first one arrived on April 20, 1918 to Vaasa and the other one in the summer of 1918.
- FF.33 Initial production version powered by a Mercedes D.II engine, six built
- FF.33b FF.33 with pilot and observers positions reversed, additional observers-operated machine-gun and powered by 119 kW (160 hp) Maybach inline piston engine, five built.
- FF.33e Main production reconnaissance variant powered by a Benz B.III inline engine, longer twin floats, under tail central float removed, and radio transmitter instead of armament, about 180 built.
- FF.33f Scout/Fighter version based on FF.33e with reduced span wings and reduced length but fitted with a machine-gun on a pivoted mount, five built.
- FF.33h FF.33f with aerodynamic refinements, and duplication of wing-bay bracing cables as a safeguard if the observer has to fire his machine-gun forward through the wings, about 50 built.
- FF.33j FF.33e with aerodynamic refinements and the provision of a radio transmitter and receiver.
- FF.33l Main production scout/fighter version, with further aerodynamic improvements and a fixed machine gun, about 130 built
- FF.33s dual-control trainer version
- FF.39 Refined version of the FF.33e with a 149 kW (200 hp) Benz Bz.IV engine, 14 built.
- FF.49c Further improved FF.39 with strengthened structures, balanced controls, a radio receiver and transmitter, machine-gun for observer, over 200 built.
- FF.49b Bomber variant of the FF.49c, crew positions reversed, deletion of observers machine-gun and provision to carry a light bombload, 15 built.
- FF.59a Development aircraft based on FF.39 with different tail, one built.
- FF.59b Development aircraft based on FF.39 with different tail, one built.
- FF.59c FF.39 with modified tail unit, wing interplane struts moved outwards and inner-bay bracing wires removed.
- C.I A landplane version of the FF.33l with wheeled landing gear, one built.
- Friedrichshafen FF.33. (2010, August 15). In Wikipedia, The Free Encyclopedia. Retrieved 21:57, August 29, 2010, from http://en.wikipedia.org/w/index.php?title=Friedrichshafen_FF.33&oldid=379054818
- Timo Heinonen. Thulinista Hornetiin - 75 vuotta Suomen ilmavoimien lentokoneita. Tikkakoski: Keski-Suomen ilmailumuseo. (1992) ISBN 9519568824.