| FF.31 | |
|---|---|
 A FF.31 with axles installed underneath its floats | |
| General information | |
| Type | Two-seat maritime reconnaissance floatplane |
| Manufacturer | Flugzeugbau Friedrichshafen |
| Primary user | Imperial German Navy |
| Number built | 2 |
| History | |
| First flight | 12 April 1915 |
TheFriedrichshafen FF.31 was a two-seatprototype Germanmaritime reconnaissancefloatplane built byFlugzeugbau Friedrichshafen during theFirst World War. Although primarily intended for reconnaissance duties, the aircraft was provided with a machine gun to engage other aircraft. Although it was satisfactory for its intended mission, it lacked the performance necessary for use as afighter. A pair of aircraft were built in 1915 and it was not accepted for production by theImperial German Navy's (Kaiserliche Marine) Naval Air Service (Marine-Fliegerabteilung).
Developed from the prewarFriedrichshafen FF.27 maritime reconnaissance floatplane, the FF.31 was fitted with amachine gun for the observer who had an excellentfield of fire from his position in the frontcockpit. The aircraft was intended by Flugzeugbau Friedrichshafen to be able to intercept enemy aircraft in addition to its primary reconnaissance mission, but its lack of speed and poorrate of climb made this difficult at best. Furthermore, by this time, the vulnerability ofpusher-configuration aircraft to attacks from the rear had been realized. The first prototype flew on 12 April 1915 and was deemed an acceptable maritime patrol aircraft, but its poor performance as a fighter caused the Naval Air Service to reject it for service.[1][2]
The FF.31 was atwin-boombiplane with a centralnacelle with the 160-metric-horsepower (120 kW)Maybach Mb.IIIstraight-six engine mounted at its rear. Two open-frame booms extended aft from the wings to carry thetail structure. It was fitted with two open cockpits in the nacelle. The observer was armed with a 7.92-millimetre (0.312 in)Parabellum MG14 machine gun on a flexible mount. The two forwardfloats were attached to the lower wing by four pairs of V-shapedstruts while the third float was connected directly to the tail. To speed construction of the aircraft, the wings and floats from theFriedrichshafen FF.29 reconnaissance aircraft were used.[1] A version of the FF.31 withconventional landing gear and a 150 PS (110 kW)Benz Bz.III engine was designated the FF.37, but it was also rejected for service.[3]
Data from Flugzeugbau Friedrichshafen GmbH: Diplom-Ingenieur Theodor Kober;[6] Friedrichshafen Aircraft of WWI: A Centennial Perspective on Great War Airplanes[1]
General characteristics
Performance
Armament
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