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Aviation History
1950
1950 - 0342.PDF
-'32 FLIGHT, x6 February i95o BRISTOL ARMAMENT DEVELOPMENT FROM the earliest daysBristol designers have beenup to the minute with air- craft weapons. It appears that bombs were first dropped in the Italo-Turkish war in Tripoli during 1912, and in the follow- ing year they were used at the siege of Adrianople, in the Bal- kan war. At this time the Roumanian Army was flying Bristol T.B.8 biplanes, and several of these were equipped with an automatic device for the dropping of small bombs. Guns were not fitted to aircraft—except as afterthoughts— until late 1915, and in the early days of World War I many ingenious ideas were tried out in the way of lashed-up carbines, machine guns and even such small artilliery as duck-guns firing chain-shot. Some of these were fitted to the early Bristol Scouts C and D, but the problem of firing through the airscrew disc was not solved until the interrupter gear appeared. This was applied to most tractor aircraft in 1916, but the gun remained an external attachment until Captain BarnweU designed the Bristol Fighter literally round a submerged Vickers gun. The observer had one or two Lewis guns on a standard Scarff ring (Bristol always built their own rings), and this type of mounting continued in service until about 1930, when it became apparent that better protection and some power assistance would soon be required to counteract the effect of higher speeds. Bristol's first move was seen in Type 120, which carried an enclosed turret. Various methods of improving rotation were investigated, and in 1935 the proto- type Type 130 appeared with a barrel-type front turret, carry- ing a Lewis-gun mounting balanced by the gunner's weight, and rotated by hand-operated gearing. A further improve- ment was proposed in the shape of a flywheel-operated servo mechanism as a means of obtaining rapid traversing. After the beginning of the rearmament drive of 1935, atten- tion was directed to hydraulic controls for turrets, and a design was developed for the Blenheim. This was the first officially accepted hydraulic turret and was designated Type B.I, Mark I. It carried a Lewis gun and had spade-grip control handles. Later a straight handle-bar control was fitted and . the turret became B.I, Mark II. Before going into production this was superseded by the similar Mark III carrying a Vickers " K " gun, installed in the majority of Blenheims up till 1939. After the outbreak of war, the R.A.F. called for increased fire power and a prototype Mark IIIA turret with two " K " guns was built, but was eventually abandoned in favour of the Mark IV with twin Browning guns, which became standard on all front-line Blenheim IVs. The Mark IVF was designed to fire forwards and was experimentally installed in two Blenheim night fighters. Later developments of the B.I. turret were the Mark V for the Beaufort, and the Mark VI fitted to Anson gunnery trainers. Mark VE was an Australian variant carry- ing two 0.5U1 Brownings. The second hydraulic turret design was the B.II, which was produced for the nose position of the production Bombay and was entirely different from that on the prototype Type 130. The B.III turret was a similar design for the tail position of the Bombay. Late in 1937 a mid-upper turret was required for the Beau- fort and Bristol were keen to make this a twin-Browning design. However, the Air Ministry decided to retain the " K " gun and the B.IV Mk. I was the result. Later this was adapted (as the B.IV Mk. IE) to mount two "K" guns. A prototype B.IV Mk. II turret carrying twin Brownings was also built but did not go into production. Concurrently with the B.IV, a hydraulic pillar turret, the B.V, was designed for the Type 148 monoplane. During the summer of 1938, the Air Ministry asked for a day-bomber development of the Beaufort. For this project, the first Bristol cannon turrets (B.VI and B.VII) were designed. Both were under-defence turrets mounting twin 20mm His- panos, having 60-round magazines. In January, 1939, the company tendered for the construction of a four-engined bomber (Type 159), to carry two large turrets, one dorsal and one ventral, each mounting four 20mm guns. The Bristol tender B.I7 turret on Lmcotn was accepted and detail design of the turrets (B.VIII-upper, and B.IX-lower) began. No satisfac- tory continuous feed for the His- pano cannon existed at that time and three separate schemes were examined, all recoil-oper- ated. About this time the Beau- fighter was also being designed and it was intended to adapt the continuous feed to the four- cannon installation of this air- craft. However, the Type 159 was cancelled in 1940 when the turrets were half completed, and in spite of the success of trials of the Bristol feed, it was officially decided to standardize the Mark I feed. During 1940 an all-hydraulic twin-Browning turret—the B.X —was designed for the Blenheim V; it had complete rotation and accommodated a Mark Ic gyro sight. Later the same year, the company was asked to design a four-Browning turret based on the B.I and fitting the same 30-inch diameter ring. This, the B.XI turret, was intended for the Mosquito, but after two prototypes had been built and tested, it was decided not to arm the Mosquito bomber for defence. Early in 1941 three turrets were designed for the Bucking- ham. They were a dorsal turret (B.12), an under-defence turret (B.13) and a remotely controlled nose mounting for four Brownings (B.14). Until the U-boat menace became serious in 1942, Coastal Command had been using fixed 20mm cannon on Liberators and heavier weapons had been designed. Originally an adapted 40mm Bofors had been contemplated, but guns of similar calibre were designed by Vickers and Rolls Royce. A proto- type Beaufighter was equipped with a Vickers "S" and a Rolls Royce "B.H." in place of the usual four cannon, and successful firing trials were performed. The Vickers " S " was fitted to Hurricanes and, after initial experience had been gained. Coastal Command proposed to install it in anti-sub- marine aircraft. Bristol's part in this scheme was to design a new nose section, including an underslung gunner's position, for a Fortress II, to carry a Vickers "S" gun in a powered mounting. This turret, the B.16, was all-electric. In 1943 two new bombers—the Lincoln and Windsor—were being planned. Bristol designed turrets for both—the B.17 for the Lincoln's dorsal position, and the B.18 and B.19 for the Windsor's tail position, the last-named mounting four o.5in Brownings and the others twin 20mm cannon. The Windsor turrets were abandoned in favour of Vickers' own remotely controlled barbettes, but a large number of B.17S were po- duced for the Lincoln. The last Bristol armament designs which may be mentioned are the B.20 and B.21 rear defence mountings, which are not, strictly speaking, "turrets." The B.20 was a mounting for a single hand-held 0.303m Browning gun for the observer on the Beaufighter X, and was produced in large numbers. A further development of this mounting, to carry a single 0.5m Browning gun, is fitted to the Brigand B.I and is known as the B.21. In Charge of Bristol Tradition : Senior Executive* of tha Company Director!: Sir W. G. Verdon Smith, C.B.E., J.P, (Chairman) ; Sir G. Stanley White, Bt. Managing Director); G. S. M. White (Joint Assistant Managing Director); W. R. Verdon Smith (/oint Assistant Managing Direcor); N. Rowbotham. C.B.E., B.Sc, F.R.Ae.S., M.I.A.E., M.I.P.E. (Divisional Managing Director, Aero Engine Division) ; C. F. Uwins, O.B.E., A.F.C., F.R.Ae.S., (Divisional Monaging Director, Aircraft Division) ; K. L. G. Bartlett, (Sales Director). Chief Designer (Aircraft): A. E. Russell, B.Sc., F.R.Ae.S., F.I.A.S. Chief Engineer (Engines): F. FT. Owner, C.B.E., Chief Test Pilot: A. i. Heg«, M.B.E. Personnel Manager : F. R. Imison. >-' B.Sc.. F.R.Ae.S.. M.S.A.E. Secretary : W. Masterton.
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