Armstrong Whitworth F.K.6

The Armstrong Whitworth F.K.6 was an experimental British escort fighter triplane of the First World War, the reworked successor to the F.K.5, which never flew. In early 1916 the War Office asked for a multi-seat escort fighter powered by a Rolls-Royce Eagle engine, with at least seven hours of endurance, to protect bomber formations from German fighters such as the Fokker E.I, and Armstrong Whitworth, Sopwith and Vickers all received prototype orders. Designer Frederick Koolhoven made the F.K.6 a larger two-bay triplane whose middle wing had a far greater span than the upper and lower wings, with two gunners in short nacelles slung under the middle wing, sitting behind and outboard of the propeller. Four were ordered in April 1916, two of them for the Royal Naval Air Service, but only one was built and its performance was poor. Effective synchronising gears had arrived, and the type was abandoned.