The Sopwith Long Range Tractor Triplane (L.R.T.Tr) was a prototype British long-range three-seat triplane escort fighter of the First World War. Its unusual layout had a small gunner's nacelle mounted on the upper wing for an all-round field of fire. Only a single example was built, as other, smaller fighters proved more practicable.
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, 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 and Vickers (the F.B.11). All three designs were driven by the nee