Sopwith L.R.T.Tr.

The Sopwith Long Range Tractor Triplane, abbreviated L.R.T.Tr. and nicknamed the Egg-Box, was a single prototype three-seat escort fighter built in 1916 for a British War Office specification. The design was modified from an existing two-seat triplane, with a small gunner nacelle on the upper wing for an all-round field of fire, a second gunner in the rear cockpit and a Rolls-Royce Eagle engine. Armstrong Whitworth and Vickers received orders for rival prototypes, all three shaped by the lack of an effective synchronisation gear. Only one example was built, because smaller fighters that could fire through the propeller, including the Sopwith 1 1/2 Strutter, proved more practical, and the three-seat escort fighters were abandoned.