H.King Sopwith Aircraft 1912-1920 (Putnam)
To have appended the above prefix 'T.F.' signifying "Trench Fighter' - to the foregoing chapter headed 'F.1" (which constituted one of the first symbolic recognitions of the term 'fighter' instead of the persistent 'scout') would have given the special low-attack version of the Camel now studied unjustified prominence. Yet to grant it this brief chapter to itself incurs no less a risk; though one feels reassurance in that the specially armoured aeroplane which now concerns us was a true sire of the Salamander. There is vindication also here of the emphasis placed in the preceding chapter on the extensive employment of standard F.1 Camels for low-living attack; and one finds a link here, too, with that other armoured Sopwith aeroplane the two-seat Buffalo. Even if the armour be discounted, furthermore, the analogy between the T.F.1 and the special night fighting version of the F.1, with two Lewis guns which could fire upwards from their Foster mountings, is quite a close one, for the T.F.1 had two Lewis guns specially installed for downward fire (the two forward-firing Vickers guns being deleted in both instances).
In the joint context of the Camel and the Battle of Cambrai (November/December 1917) one remarked on the F.1's propensity for 'terrain dodging'; and of that same battle it was officially recorded: 'The feature of the battle so far as concerns the air services was the development of low-flying attacks on the infantry, and an extension of this activity, in future battles, was foreshadowed. That the intervention of the low-flying aircraft had an influence on the battle is beyond dispute, but the lessons of that intervention deserve close examination. The casualties to the low-flying aircraft were high, averaging 30 percent for each day on which aeroplanes were used on this duty. That is to say, a squadron of highly skilled and experienced pilots, flying first-class fighting aircraft, would, so long as it was employed on concentrated low-flying attacks on front-line troops in prepared defensive positions, require to be replaced every four days.’
Here if ever there was one was a loud and clear demand for a specially protected aeroplane, though the nature of its armament was apparently less clear, as the evolution of the forward-firing Salamander showed. Thus it came about in January 1918 (by which time the Snipe was already amassing flying hours) Sopwith were invited to design a special armoured single-seater with the 230 hp Bentley B.R.2 engine, this aircraft later emerging as the Salamander. Meanwhile, however, the company built possibly envisaging the ready conversion of F.1 Camels to the new configuration - the only known T.F.1. This special Camel was itself a conversion of the Boulton & Paul-built B9278, though close scrutiny of the original of Sopwith photograph S.185, now reproduced, discloses on the rudder the Clayton & Shuttleworth trademark a fact that may be wholly insignificant, beyond, perhaps, exemplifying interchangeability. (B9276 of the same Boulton & Paul batch became the Sopwith Swallow monoplane, and B9275 may have formed the basis for the Scooter); but although B9278 is the only known example of the T.F.1 it had the 110 hp Le Rhone engine, and was photographed, apparently complete, on 19 February, 1918 at least two other conversions were contemplated, if not put in hand.
Having regard to the Royal Navy's special interest in the Camel programme from the start, and also to the low-level activities of Naval Camel squadrons, it was fitting (as well as seemingly judicious, as will be explained) to mount one of the three Lewis guns which armed the T.F.1 on a fitting of the kind known as the Admiralty Top Plane mounting - described in the following chapter on the 2F.1. The Firth armour plate might also be reckoned as an Admiralty 'speciality', though the RFC had used armour on their aeroplanes from the war's early days.
The Lewis gun on the Admiralty mounting of the T.F.1 could be used for offensive or defensive frontal fire (over the propeller) as well as affording the means - it may be supposed - of moving-along, by the upward fire that this form of mounting also allowed, any multi-seater that might seek to inhibit the T.F.1's activities by taking station above. But offence was the primary task of the 'Armoured Trench Fighter', as the new Camel-development was called, and for this purpose - the raking of trenches in longish runs, for instance - two fixed Lewis guns fired at 45 degrees forwards and downwards, through the cockpit floor. These guns had their spade grips removed (as had the third one, above) and their barrels and gas cylinders were largely exposed between the struts of the landing gear. Vacant ports in the "hump" proclaimed the absence of the Vickers guns, and no sights of any kind are seen in photographs.
Along the bottom of the fuselage, from the firewall behind the engine aft to the area of the main petrol tank behind the cockpit, and extending slightly laterally under the bottom wing (with cut-outs for the rear landing-gear struts) stretched a sheet of armour plate - a precaution such as had proved its worth as early as 23 August, 1914, when Lieut Joubert avoided thigh-injury from a bullet by virtue of a steel plate under his seat. On 7 March, 1918, the T.F.1 was flown to France, though its visit was apparently brief possibly because the Salamander was already far advanced.
That Sopwith had equipped B9278 with a direct-reading airspeed indicator on the port interplane struts (see 3/4-rear view dated 19 February, 1918) suggests that performance was to be accurately measured, though no figures are available.
To conclude this present chapter some allusion must be made to Sopwith-built Camel B6218 which, although apparently having no extensive armour, and not formally designated as being of T.F.1 type (though three T.F.1s were originally intended) served to test a mirror-sight arrangement - using periscopic principles - for the downward-firing guns. This involved a mirror under the top wing and another in the cockpit. The latter feature notwithstanding, it was evidently quite different from the Periscopic Bomb Sight Mk.1, as used on the R E.7, or the Mk.II (for Martinsyde G.100/G.102) - by means of which sights the ground was viewed, as it were, from below the pilot's seat.
This Camel B6218, with 130 hp Clerget engine, was sent to France, together with the "pukka" T.F.1 numbered B9278 and having a 110 hp Le Rhone (petrol consumption and weight being prominent considerations in the low-attack business), the two pilots concerned having both been involved in the '45-degree shot' (upward firing) experiments at Orfordness. However, for low-level attack, as well as for the high-level interception of enemy aircraft, the ultimately favoured armament was twin fixed forward-firing Vickers guns. Hence the Salamander.
H.King Armament of British Aircraft (Putnam)
Camel T.F.1. Camels were extensively used for low-flying attacks and one experimental 'armoured trench fighter' version was produced early in 1918. This is said to have been built originally by Boulton & Paul, although its rudder proclaimed 'Clayton & Shultteworlh Ltd'; but the experimental installations were made by Sopwith. The armament was three Lewis guns, two firing downwards, with their barrels projecting through the floor at a steep angle and one on an Admiralty Top Plane mounting as on the Camel 2F.1. Like the upper gun, the fuselage guns had their spade grips removed, and the ammunition drums were of the smaller (47-round) type. A sheet of armour-plate, slightly wider than the fuselage, extended from the firewall to the area of the petrol tank behind the cockpit.