Sopwith 1½ strutter

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Sopwith 1½ strutter
Sopwith 1B2 Strutter Front.jpg
Type: bomber
Design country:

United Kingdom 1801United Kingdom of Great Britain and Ireland United Kingdom


Sopwith Aviation Company

First flight:

December 16, 1915



Production time:


Number of pieces:

approx. 5720

The Sopwith 1½ Strutter was a British biplane - fighter aircraft of the First World War . It was used both as a single-seat bomber and as a two-seat fighter aircraft.


The 1½ Strutter was designed by Harald Smith at Sopwith Aviation Company , based on the "Sigrist Bus" (named after Sopwith's works manager Fred Sigrist), a small two-seater aircraft with an 80 HP (60 kW) Gnôme rotary engine, and the from this developed successor Sopwith LCT (Land Clerget Tractor) with 110 HP (82 kW) Clerget engine. The fuselage of the aircraft was a wooden structure covered with fabric in the rear, but the bow and engine were clad with aluminum sheets. Control surfaces and wings were made of welded steel tubes and covered with canvas. The fuel tank was placed between the pilot and the observer in the middle of the aircraft in order to minimize the changes in the center of gravity as a result of the variable fuel filling. However, the distance between the pilot and observer seats made it difficult for the crew to communicate verbally. One often made do with a pull rope with which the observer gave the pilot agreed signals.

The aircraft was initially powered by a 110 hp Clerget 9Z rotary engine , and from autumn 1916 the more powerful 130 hp (97 kW) Clerget 9B was installed. A single-seat and a two-seat variant were built. The Strutter was the first British aircraft with a synchronized machine gun , mostly with the more reliable Scarff-Dibovski gearbox, with the other unsatisfactory gearbox types (Vickers Challenger, Ross, Sopwith-Kauper) the synchronized MG was often removed again. In addition to the 7.62 mm Vickers machine gun, the observer operated a rotatable 7.62 mm Lewis machine gun , which was mounted on a Nieuport or Lewis, later on a Scarff mount and had a good field of fire. The bomb load was approx. 100 kg. Particularly innovative were aerodynamic air brakes , which were attached to the trailing edge of the lower wing, as well as an elevator that could be trimmed in flight to adapt the rear lift to the payload.

The prototype (3686) was successfully tested from December 16, 1915 to January 24, 1916 despite adverse weather conditions and was ordered by the Royal Naval Air Service (RNAS) in February ; Two months later, the order was placed by the Royal Flying Corps . The aircraft was then officially referred to as the Admiralty Type 6400 ; the single-seater version was called the Admiralty Type 6700 and, as a long-range bomber, was equipped with an additional tank instead of the observer seat . However, the unofficial name 1½ Strutter , which was used by the troops and was derived from the arrangement of their central W-shaped strut pairs , soon prevailed .


The 1½ Strutter gradually replaced the outdated Airco DH1 and Royal Aircraft Factory FE2 with their pusher propellers from April 1916 and helped to regain air superiority for the Allies against the German Fokker monoplane . It was first used on the Western Front , later also in other theaters of war in Palestine , Macedonia , Italy and in the Aegean Sea and was used on some sections of the front until the end of the war.

Despite the difficult-to-maintain Clerget engine, the Strutter was considered reliable and easy to use, but was already out of date by mid-1917 because of its low bomb load and speed. One pilot described it as a "good touring plane, but not a war plane". It served primarily as a bomber, but also as a fighter, reconnaissance aircraft, ground attack aircraft, as well as for coastal protection and submarine hunting.

Use against Germany

From its airfield in Luxeuil , the No. 3 Wing RNAS bombing missions and escort for French Farman and Breguet Michelin bombers of the 4ème Groupe de Bombardement during their attacks on the petrol depot in Mülheim on July 30, 1916 and the Mauser works in Oberndorf on October 12, 1916, where they mistakenly bombed Donaueschingen .

Use in France

  • 1520 Sopwith 1½ Strutters were ordered by the British armed forces - from the Royal Flying Corps des Heeres and the Royal Naval Air Service of the Navy - and in eight different plants (Sopwith, Fairey Aviation, Hooper & Co, Mann, Egerton & Co, Ruston, Proctor & Co, Vickers Ltd, Wells Aviation and Westland Aircraft). The first strutters were delivered to No. 5 wing of the RNAS delivered. In April, the wing had a full swarm of strutters used to escort the wing's Caudron G.IV and Breguet Bre.5 . The next Strutter were initially the No. 70 Squadron of the Royal Flying Corps so that it was ready in time for the Somme Offensive that began on July 1, 1916 . In October 1916, No. 45 Squadron deployed with the Sopwith 1½ Strutter; Captain Geoffrey Hornblower Cock became the most successful fighter pilot on a Strutter with 13 aerial victories. At the beginning of 1917, Squadrons 37, 39, 43, 44, 46, 78 and 143 of the RFC and Wing 1, 2 and 6 of the RNAS followed. Between July and October 1917, the British Strutter on the Western Front were withdrawn from service and, above all, by the Sopwith Camel replaced as they were meanwhile inferior to the new German fighter aircraft in terms of speed and maneuverability. The last of the interceptors flew with Squadron 78 in Martlesham and Suttons Farm until July 1918. Numerous strutters continued to be used as training or liaison aircraft.
  • After an initial delivery of 50 British aircraft, the French Aéronautique Militaire and the French Navy had 4,200 machines built under license by the companies Amiot, Bessoneau, Darracq, Lioré et Oliver, Hanriot, Sarazin Frères, SFA and REP. These were given the designation SOP. 1 A2 (reconnaissance two-seater ), SOP.l B2 (two-seat bomber) and SOP.1 Bl (single-seat bomber) and were with 150-hp LeRhône-9Jby-, 130-hp-Clerget-9Bc- and 135-hp-Clerget- 9Ba engines equipped. The first machines went to the Escadrilles SOP 129, 131 and 132 in June 1917; At this point, however, they were already clearly inferior to the German albatross hunters . When production ran out in April 1918, 395 reconnaissance planes and 47 bombers were still in use, the last of which were not eliminated until October 1918.
  • In 1918 the American Expeditionary Forces bought 514 Strutter from the French Army: 384 SOP. 1 A2 and 130 SOP. 1 B1. Since they were no longer considered to be powerful enough for front-line service, they were mainly used as training aircraft for training in Issoudun . However, the 80th, 90th, and 99th Aero Squadrons used the Strutter for a while until more modern combat aircraft became available.
  • Four strutters went to the US Navy and were used at their bases in Mouchic and Pauillac.

Use in Belgium and the Netherlands

  • Some Sopwith 1½ Strutter, which had made an emergency landing on mission flights on Dutch soil, were interned there and used by the Luchtvaart Afdeeling of the Dutch army.
  • The 2ème, 3ème and 4ème Escadrille of Aviation Militaire Belge received a total of 27 strutters,

Use in other countries


  • Ship Strutter : Some strutters were used on the aircraft carriers HMS Argus , HMS Furious and other warships. These ship strutters were used to test deck take-offs and landings, safety gears and ditching. The ship strutters were partially equipped with skid landing gear and also had floating bodies attached to the fuselage to prevent the aircraft from sinking in the event of a ditching.
  • Comic Fighter : At the instigation of Captain FW Honnett, Flight Commander of the "A" Flight of the 78th Squadron, it was converted into a single-seat version of the Comic Fighter for home defense : the front cockpit was covered, a double MG and searchlight were mounted, and the aircraft equipped as a night fighter and interceptor against zeppelins and heavy German long-range bombers.

The very successful single-seater Sopwith Pup appeared as a reduced version of the Strutter at the end of 1916 .

Technical specifications

Parameters Data
crew Pilot and observer
length 7.7 m
span 10.21 m
height 3.12 m
Wing area 32.14 m²
Empty mass 570 kg
Takeoff mass 975 kg
drive a rotary engine Clerget 9B, 130 PS (97 kW)
Top speed at NN: 164 km / h
at 1980 m altitude: 161 km / h
Rise time at 2000 m: 10:30 min
at 3000 m: 20 min
at 4000 m: 35 min
Service ceiling 3960 m
Range 565 km
Armament 1 × 7.7 mm Vickers MG, 1 × 7.7 mm Lewis MG,
Bomb load as a single-seater: 4 × 29 kg
as a two-seater: 4 × 25 kg
as a submarine hunter: 2 × 30 kg
4 × 29.5 kg bombs

Performance comparison

The Sopwith 1½ Strutter in a performance comparison (approx. Spring 1917):

Surname country Motor power Max. speed Takeoff mass MG Summit height
Sopwith 1½ strutter United Kingdom 1801United Kingdom of Great Britain and Ireland United Kingdom 130 hp 164 km / h 975 kg 2 3960 m
Nieuport 12 Third French RepublicThird French Republic France 110 hp 144 km / h 875 kg 2 4300 m
RAFFE2 United Kingdom 1801United Kingdom of Great Britain and Ireland United Kingdom 160 hp 147 km / h 935 kg 1 3353 m
RAFRE8e United Kingdom 1801United Kingdom of Great Britain and Ireland United Kingdom 150 hp 164 km / h 1302 kg 2 4115 m
Roland C.II German EmpireThe German Imperium German Empire 160 hp 160 km / h 1340 kg 2 4500 m
Albatros C.III German EmpireThe German Imperium German Empire 160 hp 140 km / h 1353 kg 2 3350 m

See also


  • Enzo Angelucci, Paolo Matricardi: The planes. From the beginning to the First World War. Falken-Verlag, Wiesbaden 1976, ISBN 3-8068-0391-9 , p. 182. ( Falken manual in color )
  • JM Bruce: The Sopwith 1½ Strutter. Profile # 121, Profile Publications, Leatherhead.
  • JM Bruce: The Sopwith 1½ Strutter. In: Flight. September 1956, p. 542ff and October 1956, p. 570ff. (English)
  • Kenneth Munson: Bomber 1914-1919. 2nd revised edition. Orell Füssli Verlag, Zurich 1968, p. 137. ( Airplanes of the world in colors )
  • Karlheinz Kens, Hanns Müller: The aircraft of the First World War 1914–1918. Munich 1966, ISBN 3-453-00404-3 .
  • Heinz Nowarra: The Development of Airplanes 1914–1918. Munich 1959, p. 102.
  • Michael Sharpe: biplanes, triple decks & seaplanes. Bindlach 2001, ISBN 3-8112-1872-7 , p. 290.

Web links

Commons : Sopwith 1½ Strutter  - collection of images, videos and audio files

Individual evidence

  1. ^ Karlheinz Kens, Hanns Müller: The aircraft of the First World War 1914-1918. Munich 1966, ISBN 3-453-00404-3 , p. 138.
  2. cf. [1] accessed March 15, 2013.
  3. [2]
  4. cf. Enzo Angelucci, Paolo Matricardi: The planes. From the beginning to the First World War. Falken-Verlag, Wiesbaden 1976, ISBN 3-8068-0391-9 , p. 182.
  5. - accessed on March 15, 2013
  6. [3]
  7. [4]
  8. [5]
  9. [6]
  10. [7]
  11. cf. Enzo Angelucci, Paolo Matricardi: The planes. From the beginning to the First World War. Falken-Verlag, Wiesbaden 1976, ISBN 3-8068-0391-9 , p. 182.
  12. contradicting information: 5,000 m according to Heinz Nowarra: The Development of Airplanes 1914–1918. Munich 1959, p. 102.
  13. [8]