The Vickers F.B.11 was a prototype British three-seat escort fighter of the First World War. A large single-engined biplane, it carried one gunner in a nacelle mounted on the upper wing to give an allround field of fire. Only a single example was completed.
Development and design
In early 1916, the British War Office drew up a specification for a multi-seat escort fighter to be powered by one of the new Rolls-Royce Eagle engines, intended to protect formations of bombers from German fighters such as the Fokker E.I, with an additional role of destroying enemy airships. While the specification did not require high speed, a good field of fire for its guns was essential, while the secondary anti-Zeppelin role demanded an endurance of at least seven hours.
Orders were placed for prototypes from Armstrong Whitworth (the F.K.6), Sopwith (the L.R.T.Tr.) and Vickers. All three designs were driven by the need to provide wide fields of fire in the absence