The Sopwith 1 ½ Strutter was the first Sopwith aircraft to be produced in large numbers during the First World War, and performed as a scout, a bomber and a fighter for the RAF, the RNAS and for the French.
The 1 ½ Strutter gained its name from the layout of its wing struts. Rather than have two sets of struts on each side, connecting the upper and lower wings, the 1 ½ Strutter only had the outer struts. The lower wing was directly connected to the lower fuselage, while the upper wing was carried on W-form cabane struts that connected the central portion of the wing to the top of the fuselage.
The struts were the only unconventional element of the aircraft. The fuselage was built with spruce longerons and spacers, braced by wires. Most of the outer surface was made of fabric, although the area around the cockpit was plywood and the section behind the engine was aluminium.
The aircraft was powered by a Clerget engine, which gave it its official Sopwith designation of LCT, or Land Clerget Tractor.
When the Strutter was designed no British machine-gun synchronising mechanism existed and early examples of the aircraft were armed with a single Lewis gun carried on a cumbersome Etévé mounting in the rear cockpit. Two rival synchronising mechanisms soon appeared – the Vickers-Challenger, designed by G. H. Challenger, and the Scarff-Dibovksy. This second mechanism was designed by Warrant Officer F. W. Scarff using ideas submitted to the R.N.A.S. by Lt. Cmdr V. V. Dibovsky of the Imperial Russian Navy. Of these two systems the Scarff-Dibovksy was better, but early Strutters carried the Vickers-Challenger. Scarff also produced a more efficient mounting for the Lewis gun – the Scarff ring – which would remain in use on some aircraft at the start of the Second World War.
The original Strutter was a two-seat fighter-reconnaissance aircraft, given the Admiralty designation of 9400 Type 1 ½ Strutter, fighting. A single-seat bomber version was also developed, and was give the Admiralty designation 9700 Type 1 1/2 Strutter, bombing.
The ½ Strutter entered service with No.5 Flight, “A” Squadron, No.5 Wing, RNAS, based at Coudekergue. This flight had two aircraft on strength on 14 April 1916, and they flew their first mission on 24 April. At this point the Strutters were normally used to escort the Breguet Type V and Caudron G.IV bombers operated by the wing. As more modern fighters appeared, the two-seat Strutters were more frequently used as bombers.
Nos.1, 3 and 5 Wings all used the 1 ½ Strutter, although No.3 Wing used the 9700 Type single seat Strutter bomber. A specific naval version – the Ship Strutter – was also developed and could be launched from platforms built on top of the gun turrets of battleships and battlecruisers.
The RFC placed its first order for the 1 ½ Strutter in March 1916, eventually placing orders with Ruston, Proctor & Co Ltd, Vickers, Hopper, Fairey, Wells Aviation and Morgan. These aircraft were desperately needed for the planned offensive on the Somme, but production was slow, and as the battle came closer the War Office was forced to ask the Admiralty for aircraft. Eventually 70 Strutters were transferred from the RNAS to the RFC.
These aircraft allowed No.70 Squadron to move to France with the Strutter between 24 May and 30 July 1916. Two more RFC squadrons would receive the type – No.45 in October 1916 and No.70 in January 1917. The RFC used the Strutter as a fighter-reconnaissance aircraft, but it was not well suited to this role. The same placid flying characteristics that made it a good bomber meant it lacked the manoeuvrability to serve as a fighter.
The 1 ½ Strutter had a relatively short service live on the Western Front. By the summer of 1917 it was badly outclassed by more modern German aircraft, and by 3 October all three Strutter squadrons had converted to the Sopwith Camel.
The aircraft was also used by three of the Home Defence squadrons (Nos. 37, 44 and 78) during the summer of 1917, in an attempt to counter the German air raids that caused such a panic in London.
A night fighter version of the 1 ½ Strutter was created by Captain F. W. Honnett of No.78 Squadron, RFC. This squadron was part of the Home Defence Group, operating from bases in Britain against German bombing raids. To improve pilot visibility Honnett faired over the forward cockpit, and moved the pilot to the rear cockpit. A pair of upward firing Lewis guns could be carried, and the aim was to attack the German bombers from below.
The night fighter Strutters were only used by No.78 Squadron. They were first used on the night of 31 October-1 November 1917 to oppose a German raid on London and last used on the night of 17-18 February 1918, apparently without success.
Three times more 1 ½ Strutters were built in France than in Britain (at least 4,500 compared to just under 1,280 in Britain). The French designated the two-seat reconnaissance aircraft as the Sopwith 1.A 2, the two-seat bomber as the Sopwith 1.B 2 and the single-seat bomber as the Sopwith 1.B 1. It was soon realised that far too many aircraft had been ordered, for by the time the French produced Strutters appeared in large numbers it was already obsolescent. Although both one and two seat versions were produced, the French Strutters were mainly used as bombers.
Statistics (British aircraft)
Engines: 110hp Clerget 9Z; 130hp Clerget 9B; 135hp Clerget 9Ba or 9Bb, 145hp Clerget 9Bc, 110-135hp Le Rhône
Length: 25ft 3in
Width: 33ft 6in
Height: 10ft 3in
Max Speed at 10,000ft: 87-97mph
Fixed forward firing 0.303in Vickers gun, 0.303in Lewis gun in observers position.