Country of origin:

United Kingdom

Description:

Single-seat fighting scout and bomber

Power Plant:

One 82 kw (110 hp) Clerget nine-cylinder rotary engine

Specifications:

Armament:

One 7.7 mm (0.303 in) fixed synchronised Vickers machine-gun; one 7.7 mm (0.303 in) Lewis machine-gun in rear cockpit; four 29.5 kg (65 lb) bombs

History:

The Sopwith 1½ Strutter was the first Sopwith aircraft to achieve widespread use as a fighting aeroplane.  The prototype (serial 3686) was completed and flown for the first time on 12 December 1915 for the British Admiralty and the type entered service with No 5 Wing RNAS in April 1916.  Officially known as the Sopwith Type 9700, it was a two-seater normally but when used as a single-seater it had provision for 12 bombs to be stowed internally . Some 550 examples were built for the RNAS.  The type saw service in Macedonia when it was used for bombing ammunition dumps, aerodromes and railway communications.  It was also used for anti-submarine patrols.

The 1½ Strutter was put into service with the Royal Flying Corps and was fitted with the Scarff-Dibovski interrupter gear. It was ordered in quantity for the RNAS.  A Scarff ring with a Lewis machine gun was mounted on the second cockpit for the observer.  A variant was a single-seat bomber which was produced at the same time and was known as the Sopwith Type 9700. First production aircraft was built by Ruston Proctor & Co, and production also took place at the facility of Vickers Ltd. Early in its service it was very successful, bombers of No 70 Squadron being able to penetrate deep into enemy territory to attack troop movements and rail heads, due to their long range.  However, after German heavily-armed single-seaters were introduced into service in 1916, the 1½ Strutter was found to be outclassed and losses mounted.

A number of engines were installed in the series, including the 82 kw (110 hp) Clerget 9Z, 82 kw (130 hp) Clerget 9B, 101 kw (135 hp) Clerget 9B2, 101 kw (135 hp) Clerget 9Bb, 108 kw (145 hp) Clerget 9Bc, 82 kw (110 hp) Le Rhone 9J and the 101 kw (135 hp) Le Rhone 9Jby. Construction of the airframe was wood with wire cross bracing and fabric covering.

The type was supplied to a number of nations and was produced in some numbers in France.  In Russia it was manufactured by the Dux Company in Moscow and by V A Lebedev in St Petersburg. Examples found their way to Romania and Japan.

Late in World War I the type was developed for use by the RNAS for use for spotting naval artillery fire and arrangements were made to operate them from capital ships, the aircraft being fitted with wireless sets and an Aldis signalling lamp.  The Australian Heavy Cruiser, ‘HMAS Australia’, had a wooden platform installed over P and Q 30.48 cm (12 in) gun turrets.  The platform was quite short. The ship for launching aircraft had to increase speed, rotate the turret to face directly into the wind and, with men holding the lower wings, a trolley was placed under the tail. When engine revolutions were suitable, the pilot indicated to the ship’s crew, a quick-release line was disengaged, and the aircraft took off from the 9 m (30 ft) deck.  The first flight by an aircraft from ‘HMAS Australia’ was made on 4 April 1918 by aircraft serial 5644. When ‘HMAS Australia’ returned to Australia the platform had been removed and the aircraft remained in the United Kingdom.  Fourty aircraft of the 1½ Strutter type were used by the British Grand Fleet for the purpose, and also for operation from aircraft carriers such as ‘HMS Furious’, which carried 11 examples.

Although built in quite large numbers in the United Kingdom, the 1½ Strutter was built in even larger numbers in France. The French Air Force was impressed by the performance of the type and arranged to obtain some examples via the RNAS, at the same time obtaining a licence to construct the aircraft.  An office of the Sopwith Aviation Company was set up in Paris to deal with the French firms which had been chosen to build the type, and to supply drawings.  Companies chosen to build the aircraft in France were Amiot, Bessoneau, Darracq, Hanriot, Loire et Oliver, REP and Sarazin Freres.  These companies incorporated various modifications to the design and fitted a number of rotary engines, including the 101 kw (135 hp) Clerget 9Bb and Le Rhone 9Jby, or the 108 kw (145 hp) Clerget 9Bc, these variants becoming known as the 1A2, 1B1 and 1B2.

Production began in mid-1917, by which time the type was already obsolete as a fighter, but it served well as a bomber.  It is not known precisely how many were built in France but estimates indicate between 4,200 and 4,500, and it was still operated by 60 Squadrons at the time of the Armistice.

The last 1½ Strutters in operational service were the aircraft flown between May and July 1918 by the 88th, 90th and 99th Aero Squadrons of the American Expeditionary Force which had obtained 514 from France, but most of these were used in the training role.  In the United Kingdom the type remained in service after the Armistice for a short period.

A number of replicas have been built over the years. One (G-BIDW / A8226) was flown in the United Kingdom twice in 1980 and was eventually placed on display at the RAF Museum in Hendon. Another (C-FSOP – 9739/17) was flown with the Great War Flying Museum in Canada before being placed on display in the Canadian Air & Space Museum at Downsview.  Aircraft serial B619 is on display at the RAF Manson History Museum in Mansgate, this having been built for the film “Flyboys” in 2005.  Another was constructed at the National Museum of Flight at East Fortune, UK, this having been fitted with an Australian-built Rotec 3600 radial engine and being expected to fly in 2020.

A number of original examples survive, one (Serial 555) in the Brussels Military Museum in Belgium; and two (serials 556 and 2897) have been placed on display in France.

One, a former Argentinian aircraft which was obtained and stored at the Fantasy of Flight Museum in Florida for some years, was obtained by The Vintage Aviator Limited (TVAL) at Masterton in New Zealand. In Wellington work commenced to restore the aircraft to airworthiness.  This aircraft was built in France, four Sopwith 1½ Strutters being sent to Argentina at some stage where they were rebuilt into two aircraft, using the best parts of the four. The survivor was airworthy up to the 1950s.  It was stored until obtained by an American collector.

A restored 1B2 aircraft is operated by the La Ferte-Alais collection in France, and a replica is held by the Military Aviation Museum at Virginia Beach, California.

American kit producer Replicraft produces plans to build 80% scale replicas of the 1½ Strutter, these being able to be fitted with Rotec or HCI Aviation radial engines, or the 75 kw (100 hp) Subaru EA-81 or Mazda 12A rotary engine producing 90 kw (120 hp).  Construction of one example is known to have been commenced by Cobra Aviation in Australia at Bayswater, VIC.  In recent years this company, Replicraft, has produced plans to build scale replicas of the SPAD VII, SPAD XII, Roland D.VI, Hanriot HD.1, Sopwith Pup, Thomas Morse, Fokker D.VII, Sopwith Camel, Sopwith Triplane, RAF SE.5a and Sopwith Snipe.

In the United States Kip Aero of Dallas, Texas built a replica Sopwith 1½ Strutter to original construction techniques as N5539 (c/n N5539).  The aircraft had a 75 kw (100 hp) replica Gnome Monosoupape rotary engine built by Classic Aero Machining Service at Omaka, NZ.  This was a full-sclae replica and had a ‘kiwi’ painted on the side of the fuselage. Kip Aero subsequently commenced production of a kit of the aircraft which could be fitted with the replica rotary engine, also producing kits of the Sopwith Scout, Sopwith Camel and Sopwith Triplane. However, in June 2020 whilst landing at Alstyne in Texas it crashed and was destroyed.