Friedrichshafen FF.40

The Friedrichshafen FF.40 was an experimental German two-seat floatplane developed during World War I by the Friedrichshafen Aircraft Company () for the Imperial German Navy's () Naval Air Service (). One aircraft was ordered in 1916 and its ultimate fate is unknown.

Development and design

The FF.40 was designed to evaluate the utility of using a single fuselage-mounted engine to power two propellers via separate driveshafts. The aircraft was otherwise unremarkable in configuration as a two-bay biplane and was built using the company's typical method of wire-braced wood with doped fabric covering. Multiple struts connected the two floats to the fuselage and the lower wing. The aircraft observer was located in the nose of the FF.40 and was armed with a Parabellum MG14 machine gun on a flexible mount. The pilot's cockpit was positioned at the trailing edge of the wings and the distance between the two positions greatly hampered their ability to communicate.

The FF.40 was powered by a Maybach Mb.IV straight-six piston engine in the fuselage. It drove two propellers mounted just forward of and between the wings on each side via driveshafts that protruded from the fuselage and connected to the propeller shafts using ZF bevel gears. The engine was cooled by two radiators hanging from the upper wing. The arrangement proved very heavy and limited the aircraft's payload to the machine gun and a wireless transmitter without a receiver.

Friedrichshafen received the order from the Naval Air Service in February 1916 and the FF.40 made its first flight two months later. It was turned over to the Seaplane Testing Command () for evaluation in either July or August. Its ultimate fate is unknown as it was not found when the Allies inspected the German seaplane bases in December 1918.

See also

Related lists

• List of military aircraft of Germany
• List of flying boats and floatplanes