The Triplane began as a private venture by the Sopwith Aviation Company. Chief engineer Herbert Smith gave the aircraft three narrow-chord wings to provide the pilot with the optimum field of view. The new fighter featured a fuselage very closely following the design of the Pup's, apart from minor changes needed to fit the new wing structure and a larger motor. The original empennage was also identical with that of the Pup - but later triplanes were built with new tailplanes and elevators of reduced span and chord. The type was initially powered by a 110 hp Clerget 9Z nine-cylinder rotary engine, but most production examples were fitted with a 130 hp Clerget 9B rotary. At least one Triplane was tested with a 110 hp Le Rhône rotary engine. In July 1916, the prototype Triplane, serial N500, was sent to Dunkirk for evaluation with "A" Naval Squadron, 1 Naval Wing. It proved highly successful. A second prototype fitted with a 130 hp Clerget 9B, serial N504, was also sent to France for evaluation. The Triplane was a pleasant and easy aircraft to fly, with effective, well-harmonised controls. By using the variable incidence tailplane (at the time a novel feature), the fighter could be trimmed to fly hands-off. The introduction of the new eight-foot span tailplane in February 1917 improved elevator response. While the Triplane climbed faster and was more agile than its opponents, it was slower in a dive. The Triplane also gained a reputation for structural weakness. The wings were prone to lose their alignment ("get out of true") after combat manoeuvrers, and sometimes even collapsed in flight, especially under the strain of steep dives. This defect has been attributed to the use of light gauge bracing wires in the 47 aircraft built by subcontractor Clayton & Shuttleworth, although it may also have been the fault of the basic design, which used very few bracing wires. In any case, the fairly small number of surviving aircraft that were used as advanced trainers after the end of the triplane's operational career were fitted with additional bracing to the upper centre section. Another drawback of the type in comparison with the opposing Albatros fighters was the Triplane's light armament; most were armed with a single fixed synchronizedVickers machine gun. At least six aircraft were fitted with twin guns, but performance was reduced, and the single gun remained standard.
Operational history
Sopwith Triplane in the Aero Space Museum of Calgary, 2005
Production commenced in late 1916. Apart from a few examples supplied to Great Britain's allies, the Triplane was flown exclusively by the Royal Naval Air Service. Originally a batch of aircraft were also destined for the Royal Flying Corps (RFC) [1], but in February 1917, the RFC orders were exchanged for the SPAD VIIs on order for the RNAS. For unknown reasons, most of the Triplanes ordered for the RFC were simply cancelled, rather than being transferred to the RNAS, and only 150 or so were built. No. 1 Naval Squadron was fully operational with the Triplane by December 1916. Nos. 8, 9 and 10 Naval Squadrons were equipped with the type by the middle of 1917. The only other major operator of the Triplane was a French Aviation Maritime squadron based at Dunkirk, which received 17 aircraft. The type's combat debut was highly successful. The exceptional rate of climb and high service ceiling of the Triplane gave it a marked advantage over the Albatros D.III - the only British type to have this edge during the period of German air superiority known as "Bloody April" 1917. The Triplane was famously flown by the "Black Flight" (of No. 10 Naval Squadron) which was commanded by the Canadian ace Raymond Collishaw. The unit claimed 87 German aircraft in three months while equipped with the Triplane. Collishaw himself scored 33 victories in the aircraft, making him the top scorer with the type. In June 1917, No. 4 Squadron RNAS received the first Sopwith Camels and the advantages of the sturdier, better armed fighter quickly became evident. Although the Triplane squadrons were still doing well, they were all slated for early conversion to Camels – Nos. 8, 9 and 10 Naval Squadrons converted to the new type between July and September 1917, and the last unit to operate the Triplane, No. 1 Naval Squadron, received its Camels in December. Some Triplanes were used as advanced trainers during 1918. The Germans were so impressed by the performance of the Triplane that it spawned a brief triplane craze among German aircraft manufacturers – although of all the German triplane designs only the Fokker Dr.I saw front line service. The French firm of Nieuport also experimented (unsuccessfully) with triplane designs.
United Kingdom: Royal Naval Air Service
France (17 aircraft)
Russian Empire (1 aircraft)
United States (1 aircraft)
