The British attempt to produce an armoured aircraft, 1917 – 1918
Although reconnaissance was the first duty to be undertaken by the aeroplane during the First World War, it was not long before aerial fighting and the attacking of the enemy on the ground followed. Soon, dedicated fighters, or ‘scouts’, were appearing, as well as bomber aircraft, such as the Airco D.H.4 and the Handley Page O/100.
It became common, especially during offensives, for British fighters to participate by strafing and bombing ‘targets of opportunity’ in the enemy trenches or further behind the lines. These included columns of troops, vehicle convoys, gun batteries and other targets.
Royal Flying Corps (RFC) fighter squadrons were used in large numbers for this work, notably during 1917 in the Third Battle of Ypres, although actual results were generally underwhelming. By the time of the Battle of Cambrai in November, the RFC was expected to support the advance attacking ground targets such as artillery positions (which could be lethal to the British tanks) and trenches.
The unarmoured Airco D.H.5s and Sopwith F.1 Camels employed suffered heavy casualties – around 30% for each day of operations. Arthur Gould Lee, flying Camels with 46 Squadron, remembered:
‘During the eleven days between November 20th and November 30th, when I took part in low-flying work in the Battle of Cambrai, I was engaged on only seven ground attack sorties, but on three of them I was shot down from the ground…The squadron in this period suffered seven casualties.’
As with the operations around Ypres, results were mixed, often the result of poor visibility and general confusion. Lee recalled that ‘some pilots could not find their targets, and those that did were too occupied with not crashing into each other or into the ground to concentrate on meticulous bombing.’ The battle fizzled out with little result but the RFC gained further valuable experience in attacking well-defended targets on the ground.
During the last months of 1917, the Deutsche Luftstreitkräfte began to deploy the new Junkers J.I armoured biplane. These heavy two-seaters attracted much attention and a report on them was made by the Ministry of Munitions Technical Department. It was clear that armouring an aircraft would be an advantage and the heavy losses suffered by the RFC squadrons over the year versus the apparent invulnerability of the Junkers seemed to bear this theory out.
This led to a request in November 1917 for an aircraft specifically intended for low-level work. Two machine-guns, angled downwards at a 45° angle and capable of 20° of movement, i.e. 35°-55°, were specifically requested.
In January 1918, the Technical Department asked that both a tractor and a pusher type for ground attack duties be produced for evaluation. The Royal Aircraft Factory accordingly began work on a design resembling the earlier N.E.1 night-fighter prototype.
The resulting A.E.3, (Armoured Experimental 3), later known as the Royal Aircraft Establishment Ram, was an ungainly two-seat pusher in which the observer sat in front of the pilot in an armoured nacelle, armed with two downward-firing Lewis guns for attacking enemy trenches, with a third Lewis gun provided for a measure of rearward defence.[1] Three different engines were proposed: the 200hp Hispano-Suiza (in short supply); the Sunbeam Arab (unreliable) and the Bentley B.R.2 (new and in short supply.)
The aircraft did not look promising and the Bentley-engined Ram II won no admirers when it went to France in July 1918 for evaluation. In a damning report, Captain Cyril Ridley of 201 Squadron wrote that:
‘Having flown this machine, I consider it very slow, exceedingly heavy on controls, and unmanageable for manoeuvring near the ground. I therefore consider it unsuitable for low-flying and ground-strafing work.’
His opinion was backed by Major-General John Salmond, commanding the RAF in the Field, who informed the Air Ministry that:
‘I do not consider this machine useful for any military purpose. It is very slow, heavy on controls and unmanageable for manoeuvring near the ground. It…offers a large target. I would recommend that all further work on this machine should cease.’
For the tractor design, the Department asked that a modified Sopwith Camel be provided to test the tractor configuration, fitted with armour plating.
The problem of sighting the angled machine guns was answered by the experimental station at Orfordness. A periscopic arrangement of two mirrors, one underneath the upper wing and one in front of the pilot was submitted and this system, despite attracting scepticism, was fitted to the aircraft. The two Lewis guns were angled downwards as requested, the breeches within reach of the pilot for reloading and the muzzles protruding between the undercarriage legs. Another Lewis gun was fitted to the upper-wing centre-section for self-defence.
Jack Bruce wrote that:
‘It comes as no surprise to learn that initial experiments with mirror sights were not encouraging’ and vibration from the engine would certainly have presented problems.
Two Camels were modified, although it is probable that one, serial B6218, never received any armour plating. The other, serial B9278, became the Sopwith T.F.1 (Trench Fighter 1) and both went to France for evaluation in March 1918.
However, the downward-firing armament did not meet with approval from the pilots who tested it and on 13 March, Major-General Salmond wrote to the Chief of the Air Staff:
‘It is not considered that either of these machines are of any practical value from the point of view of firing into enemy trenches or at hostile parties on the ground. The present Sopwith Camel is considered more efficient in every way for this purpose.’
A proposal for Sopwith Camels fitted with standard armament and light armour underneath the fuselage was raised at this time and although it went no further, it is known that some Camels later had seats fitted with armour-plating.[2]
However, in early 1918, Sopwith began work on an armoured derivative of its new Snipe fighter. Six prototypes were ordered and it was initially requested that three examples, like the T.F.1, be fitted with a pair of downward-firing Lewis guns and one forward-firing Vickers but the practical problems associated with this armament meant that work on this was quickly halted. However, the requirement for a ‘semi-free’ and ‘upward-firing’ Lewis gun on the upper-wing centre-section remained.
Although the resulting aircraft strongly resembled the Snipe, there was in fact very little in common between the two (the two most significant shared items were the tailskid and late-production rudder.) As was usual with Sopwith designs by this time, the engine, fuel tanks, pilot and guns were concentrated at the extreme front of the aircraft.
The armour plating protected the cockpit and the fuel and oil tanks. It was formed in to a box shape and made from 8mm plate at the front, 11mm on the underside and 6mm at the sides. The back armour was double-walled, made from sheets of 6 gauge and 11 gauge steel. However, Jack Bruce wrote that the box ‘had no basic structure of any kind, but relied on the rigidity of the armour plate for its form and structural integrity.’
The total weight of the armour was about 605lb. The engine chosen for this heavy little aircraft was the 200hp Bentley BR.2 rotary, another asset it shared with the Snipe.
The 200hp Clerget 11E was nominated to supplement the Bentley and several squadrons were to have been equipped with this version. In addition to the two Vickers guns, provision was made for the carrying of four 20lb bombs.
Work proceeded rapidly: on 9 April the name Sopwith T.F.2 Salamander[3] was approved for the aircraft and on 27 April the first prototype, serial E5429, made its maiden flight from Brooklands. Despite Sopwith’s impressive speed with the Salamander programme, it was clear that the RAF continued to harbour reservations about the aircraft, with Brigadier-General Robert Brooke-Popham writing on 19 April:
‘This machine [the Salamander] has about 500lb of armour but will probably be unsuitable owing to its poor view and the fact that it will not be very handy…I pointed out to Weir [Sir William Weir, at that time the Air Board Controller of Aeronautical Supplies] that all we had ever asked for was a lightly-armoured single-seater machine and a heavily-armoured two-seater machine, [possibly Brooke-Popham meant the Sopwith Buffalo[4]] and that the T.F.2 did not fulfil either of these two requirements.’
The first prototype, serial E5429, was sent to France for testing in May and received generally favourable reports before it was wrecked on 19 May when its pilot was forced to avoid a tender being driven to the scene of another crash on the same airfield. The main criticism seemed to be directed at the aircraft’s poor lateral control, a trait it shared with the Snipe.
Salmond reported that he thought it ‘very promising for low flying purposes’ but requested that it be fitted with balanced ailerons (as the Snipe was) and the flying and control wires duplicated for safety.
Before Salmond’s report was received, large production orders were placed for the Salamander, eventually totalling 1,400 aircraft, in anticipation of the Allied offensives planned for the spring of 1919. Apart from Sopwith, contractors included National Aircraft Factory No.1, Wolseley, Air Navigation, Glendower and Palladium Autocars.
Meanwhile, the fourth prototype was sent to France for trials in September but was immediately criticised by the RAF in the Field as it did not incorporate the balanced upper-wing ailerons that had been requested. Production Snipes had the balanced ailerons fitted (or retro-fitted) and later-production examples were given an enlarged tailfin and balanced rudder, as seen on the Snipe.
Early production was plagued by persistent problems with distortion of the armour plating, meaning the armour could not be fitted or that it induced warping in the whole of its parent airframe. A report written in 1919 found that measurements taken from the forward interplane struts to the sternpost on one aircraft differed by as much as two inches from the original design and the problem was not solved until later in the year.
A further issue was the fitting of Snipe upper-wing centre-sections in error to several early batches of around seventy Sopwith-built Salamanders. The mistake was recognised in December 1918 but any operational flying would have resulted in a number of accidents, as the safety factors were far lower than necessary: 3.1 instead of 7 for the front spar and 2.8 instead of 5 for the rear spar.
One prototype was flown at Brooklands by Captain J.W. Pinder, who made the following remarks in his report:
‘The machine is considerably heavier on controls than a Camel by reason of its weight… manoeuvrability is about the same as a Bristol Fighter and it is capable of being looped and half rolled and turns fairly fast. Below 10,000 feet it could almost be used for fighting an Albatros Scout. In dives a great speed is obtained in a short distance but the machine answers well to the controls all the while. It is also easily manageable flying along close to the ground with engine at full revolutions. The visibility is somewhat poor…the [armour] plates are…capable of stopping German armour-piercing bullets at 150ft range except at the sides; these plates (at the side) will stop any bullet hitting at an angle of over 15 degrees from the vertical and any of the plates will stop shrapnel from anti-aircraft fire.’
The Pilot’s Notes of 1920 included a brief summary:
‘The Salamander is heavy on control laterally, but is quite sensitive fore and aft, although her rudder is not very effective…The Salamander is very heavy to take out of a turn. The control column must be pulled well over to the opposite side and quite a lot of opposite rudder is required to bring her level.
Jack Bruce observed that the Salamander’s handling ‘would have made ground attack immensely hard work for its pilots.’
A distinctive and unique disruptive camouflage pattern was designed for the Salamander. It had been accepted that merging any aircraft completely with the terrain over which it was flying was impossible and attention was therefore given to making its identification and retention in view more difficult.
Exhaustive trials at Orfordness, as well as experience at the Front, showed that it was the shadow of the upper wing upon the lower which rendered biplanes conspicuous, especially on sunny days.
Accordingly, the Salamander’s lower wing was finished in a lighter tone than the upper. Dark purple-earth and green patches were applied to the upper wing in order to break up the shape and light earth-brown covered much of the lower wing. The fuselage sides were finished a light grey-green. These patches of colour were separated by black lines. The red and blue areas of the upper surface roundels were darkened and the white areas replaced with light grey-green.
Meanwhile, the lower surface roundels were made as clear as possible to minimise the chances of ‘friendly fire.’ The scheme, officially approved by the Ministry of Munitions, was applied to the third prototype, serial E5431, but the aircraft was crashed before any meaningful tests on its effectiveness could be made.
However, it is known that a number of production aircraft were finished in the scheme. There is also an interesting reference to a ‘lozenge’ camouflaged example, possibly inspired by the printed German fabric of the time. This aircraft reportedly found its way to Farnborough for comparative camouflage tests with an aircraft in the Ministry of Munitions scheme. The tests were scheduled in July 1919, by which time official interest in the Salamander had faded almost completely.
The original intention was for there to be thirteen squadrons of Salamanders in France by the end of May 1919. Five of these squadrons would have been equipped with the 200hp Clerget 11E-engined model, although this engine may have experienced teething problems, leading to delays in the formation of the Clerget squadrons. Ultimately, the Armistice was signed some ten days before the first Bentley-engined unit, 157 Squadron, was due to leave for the continent.
Although the Salamander did not see action during 1918, or indeed at any time, it is estimated that 497 were eventually built, many going straight into store. The coming of peace made an aircraft tailored to the demands of the Western Front superfluous overnight and only a handful of Salamanders found their way into RAF service. The type appeared to soldier on until at least 1922, when a few were listed as being in Egypt, possibly in connection with the Chanak Crisis with Turkey.
One aircraft was tested by the Section Technique de l’Aéronautique at Villacoublay and another was sent for evaluation to the United States, where it was based at McCook Field. The aircraft bore the warning ‘This machine is not to be flown’ underneath the cockpit, suggesting it was a victim of the distortion which afflicted so many early-production aircraft.
Although the Salamander is an ‘unknown’ in terms of the First World War, it remains an interesting historical footnote and a rare example of an RAF aircraft specifically designed for the ground attack role. It would also seem to have the dubious distinction of being the last Sopwith aircraft to enter RAF squadron service.[5]
[1] The Royal Aircraft Factory was renamed the Royal Aircraft Establishment soon after the RAF’s formation in April 1918.
[2] It is known that seat armour was available for the Royal Aircraft Factory R.E.8 and that this armour was also fitted to Bristol F.2bs in some squadrons.
[3] The name was possibly inspired by the Salamander’s mythical ability to pass through fire unscathed.
[4] The Sopwith 3F.2 Buffalo was an armoured two-seater based on the Sopwith Bulldog. It was intended for Contact Patrol work and two prototypes were completed before the Armistice stopped further work.
[5] The Cuckoo entered RAF service in August 1918, when training commenced in Scotland. The Snipe entered service the same month. The unfortunate Dragon was never issued to a squadron.
