|Weights and loads|
|Wing Load (kg/m2)||33|
|Power load (kg/hp)||5.45|
|Gun type||1*7.7mm Vickers|
|Position||in front of cockpit|
The Sopwith 'Triplane' was designed in early 1916 by Sopwith's chief designer Herbert Smith. Its fuselage and tail assembly were structurally similar to that of the Sopwith Pup, but were merged with a new triplane wing arrangement. This led to the first single-seat triplane fighter to be produced and to go into action. The idea was to produce a fighter with the exceptional maneuverability of the Pup, but with much better view from the cockpit. The triplane layout made possible narrow-chord wings with relatively short span, which only marginally impaired the pilot's view and simultaneously had aerodynamic advantages enhancing the aircraft's maneuverability.
The first prototype (which later received the serial N500) began its tests at the end of May 1916. It demonstrated exceptional maneuverability and a phenomenal rate of climb (for its day). So the Admiralty and the War Office immediately placed production contracts for the Royal Naval Air Service (RNAS) and the Royal Flying Corps (RFC) respectively. In fact the RFC did not receive the 'Triplane', for this service exchanged all these aircraft for all of the 120 SPAD S.VII fighters then on order for the RNAS. But one example (N5430) was later transferred to the RFC for test purposes. Total production of the 'Triplane' was only 148 aircraft (including prototypes) from three different contractors. Some sources state 152 machines, but it seems that this figure contains four double-counted aircraft (due to a change of their serial numbers) loaned to the French.
Most 'Triplanes' were powered by the 130hp Clerget 9B air-cooled 9-cylinder rotary engine. A few early machines had the 110hp Clerget 9Z and at least one was tested with a 110hp Le Rh˘ne 9J. Two test aircraft were flown with Hispano-Suiza liquid-cooled vee-type engines of 150 and 200hp respectively. Standard armament was one 7.7mm Vickers gun in front of the cockpit, firing synchronized (Scarff-Dybovskij interrupter gear) through the propeller arc. Six aircraft of one of the last production batches were completed with two Vickers guns. Otherwise relatively little changes were made to the 'Triplane' during its production run - one of the most significant being the adoption of a shorter-span tailplane.
In service with the RNAS the 'Triplane' proved highly successful, ending the predominance of the German Albatros fighters. Indeed such were its exploits that this inspired a real triplane 'boom' among the aircraft designers in Germany and Austria-Hungary, finally leading to the famous Fokker Dr.I. Besides the RNAS, where the type served until March 1918, the only other service using the 'Triplane' in numbers was the French Navy which received about 17-18 aircraft of this type (and had at least seven of them still on strength in January 1918). It seems that with one exception (N5431 in the Aegean) all 'Triplanes' were used on the Western Front. One example was sent to the USA for an exhibition in December 1917.
There was only few examples of the 'Triplane' which was delivered to Russia. Aircraft N5486 is known to have been dispatched from the RNAS depot at White City to Russia on May 4, 1917. It is known to have been used by the Imperial Russian Air Service and was still in use in the winter of 1917/ 1918, fitted with skis. Another source states that in 1919 an Aircraft Group specially established to combat the White Guards Cavalry Corps of Mamontov was led by Yu.A.Bratolubov, flying a Sopwith 'Triplane' until the early 1920s. It is most likely that this was the same aircraft (which is on exhibition today at the Air Force Museum at Monino). The same source also states that there was more than one 'Triplane' which reached Russia (delivered in May 1917 or captured from the Allied Forces intervening in Russia after the Revolution).
Russian sources mention about 'few' Sopwith fighters. One small photo depicts 'Triplane' with factory number 5492 and drawing of 5493, light digits on dark background.