BRISTOL BEAUFIGHTER HISTORY & SPECS Design and development The idea of a fighter development of the Beaufort was suggested to the Air Ministry by Bristol. The suggestion coincided with the delays in the development and production of the Westland Whirlwind cannon-armed twin-engine fighter. By converting an existing design, the "Beaufort Cannon Fighter" could be expected to be developed and produced far more quickly than starting a completely fresh design. Accordingly, the Air Ministry produced Specification F.11/37 written around Bristol's suggestion for an "interim" aircraft pending proper introduction of the Whirlwind. Bristol started building a prototype by taking a part-built Beaufort out of the production line. The prototype first flew on 17 July 1939, a little more than eight months after the design had started, possibly due to the use of much of the Beaufort's design and parts. A production contract for 300 machines had already been placed two weeks before the prototype flew, as F.17/39. By fighter standards, the Beaufighter Mk.I was rather heavy and slow. It had an all-up weight of 16,000 lb (7,000 kg) and a maximum speed of only 335 mph (540 km/h) at 16,800 ft (5,000 m). Nevertheless this was all that was available at the time, as further production of the otherwise excellent Westland Whirlwind had already been stopped due to problems with production of its Rolls-Royce Peregrine engines. The Beaufighter found itself coming off the production line at almost exactly the same time as the first British Airborne Intercept (AI) radar sets. With the four 20 mm cannon mounted in the lower fuselage, the nose could accommodate the radar antennas, and the general roominess of the fuselage enabled the AI equipment to be fitted easily. Even loaded to 20,000 lb (9,100 kg) the plane was fast enough to catch German bombers. By early 1941, it was an effective counter to Luftwaffe night raids. The various early models of the Beaufighter soon commenced service overseas, where its ruggedness and reliability soon made the aircraft popular with crews. A night-fighter Mk VIF was supplied to squadrons in March 1942, equipped with AI Mark VIII radar. As the faster de Havilland Mosquito took over in the night fighter role in mid to late 1942, the heavier Beaufighters made valuable contributions in other areas such as anti-shipping, ground attack and long-range interdiction in every major theatre of operations. In the Mediterranean, the USAAF's 414th, 415th, 416th and 417th Night Fighter Squadrons received 100 Beaufighters in the summer of 1943, achieving their first victory in July 1943. Through the summer the squadrons conducted both daytime convoy escort and ground-attack operations, but primarily flew defensive interception missions at night. Although the Northrop P-61 Black Widow fighter began to arrive in December 1944, USAAF Beaufighters continued to fly night operations in Italy and France until late in the war. By the autumn of 1943, the Mosquito was available in enough numbers to replace the Beaufighter as the primary night fighter of the RAF. By the end of the war some 70 pilots serving with RAF units had become aces while flying Beaufighters. Coastal Command 1941 saw the development of the Beaufighter Mk.IC long-range heavy fighter. This new variant entered service in May 1941 with a detachment from No. 252 Squadron operating from Malta . The aircraft proved so effective in the Mediterranean against shipping, aircraft and ground targets that Coastal Command became the major user of the Beaufighter, replacing the now obsolete Beaufort and Blenheim. Coastal Command began to take delivery of the up-rated Mk.VIC in mid 1942. By the end of 1942 Mk VICs were being equipped with torpedo-carrying gear, enabling them to carry the British 18 in (457 mm) or the US 22.5 in (572 mm) torpedo externally. The first successful torpedo attacks by Beaufighters came in April 1943, with No. 254 Squadron sinking two merchant ships off Norway. The North Coates Strike Wing of Coastal Command, based at RAF North Coates on the Lincolnshire coast, developed tactics which combined large formations of Beaufighters using cannon and rockets to suppress flak while the Torbeaus attacked at low level with torpedos. These tactics were put into practice in mid 1943, and in a 10-month period, 29,762 tons (27,000 tonnes) of shipping were sunk. Tactics were further adapted when shipping was moved from port during the night. North Coates Strike Wing operated as the largest anti- shipping force of the Second World War, and accounted for over 150,000 tons (136,100 tonnes) of shipping and 117 vessels for a loss of 120 Beaufighters and 241 aircrew killed or missing. This was half the total tonnage sunk by all strike wings between 1942-45. The Beaufighter arrived at squadrons in Asia and the Pacific in mid-1942. It has often been said - although it was originally a piece of RAF whimsy quickly taken up by a British journalist - that Japanese soldiers referred to the Beaufighter as "whispering death", supposedly because attacking aircraft often were not heard (or seen) until too late. The Beaufighter's Hercules engines used sleeve valve s which lacked the noisy valve gear common to poppet valve engines. This was most apparent in a reduced noise level at the front of the engine. Variants Beaufighter Mk IF: Two-seat night fighter variant. Beaufighter Mk IC: The "C" stood for Coastal Command variant; many were modified to carry bombs. Beaufighter Mk II: However well the Beaufighter performed, the Short Stirling bomber program by late 1941 had a higher priority for the Hercules engine and the Rolls Royce Merlin XX- powered Mk II was the result. Beaufighter Mk IIF: Production night fighter variant. Beaufighter Mk III/IV: The Mark III and Mark IV were to be Hercules and Merlin powered Beaufighters with a new slimmer fuselage carrying an armament of six cannon and six machine guns which would give performance improvements. The necessary costs of making the changes to the production line led to the curtailing of the Marks. Beaufighter Mk V: The Vs had a Boulton Paul turret with four 0.303 in (7.7 mm) machine guns mounted aft of the cockpit supplanting one pair of cannon and the wing-mounted machine guns. Only two Mk Vs were built. Beaufighter Mk VI: The Hercules returned with the next major version in 1942, the Mk VI, which was eventually built to over 1,000 examples. Beaufighter Mk VIC: Torpedo-carrying variant dubbed the "Torbeau". Beaufighter Mk VIF: This variant was equipped with AI Mark VIII radar. Beaufighter Mk VI (ITF): Interim torpedo fighter version. Beaufighter TF Mk X: Two-seat torpedo fighter aircraft. The last major version (2,231 built) was the Mk X, among the finest torpedo and strike aircraft of its day. Beaufighter Mk XIC: Built without torpedo gear for Coastal Command use. Beaufighter Mk 21: The Australian-made DAP Beaufighter. Changes included Hercules CVII engines, a dihedral tailplane, four 20 mm cannon in the nose, four Browning .50 in (12.7 mm) in the wings and the capacity to carry eight 5 in (130 mm) High-Velocity Aircraft Rockets (HVAR), two 250 lb (110 kg) bombs, two 500 lb (230 kg) bombs and one Mk 13 torpedo. Beaufighter TT Mk 10: After the war, many RAF Beaufighters were converted into target tug aircraft. BEAUFIGHTER ENGINE TESTS SUMMARY ...........Level speed and climb performance has been measured on Beaufighter VI X.7542. During the course of the tests, the engines were re-rated. At the later rating the following performance figures were obtained at a weight of 19,750 lb. 2,325 feet/minute at 4,600 Maximum rate of climb feet. Time to reach 15,000 feet 7.5 minutes Time to reach 25,000 feet 19.0 minutes Service ceiling 28,000 feet Maximum level speed in M.S. 327 m.p.h. at 8,500 ft. supercharger gear Maximum level speed in F.S. supercharger gear 333 m.p.h. at 15,600 ft. 1. Introduction: ...........Performance measurments were required on Beaufighter VI, fitted with the Hercules VI engines. 2. Scope of tests. ...........The performance of the aeroplane on climb and in full throttle flight has been measured. Partial climb tests showed that the best climbing speed was 120 m.p.h. A.S.I. Subsequent climbs made at an initial climbing speed of 140 m.p.h. A.S.I., to give improved cooling, showed a nearly equally rapid rate of climb compared with the climbs made at 120 m.p.h. A.S.I. At 120 m.p.h. A.S.I., the aeroplane climbs at a very steep attitude, and pilots much preferred to climb the aeroplane at an initial speed of 140 m.p.h. A.S.I. Since there is no measururable loss of performance our results are quoted at the higher climbing speed. ...........After these tests had been completed, information was received that the Hercules VI engine had been re-rated and that the R.P.M. boost limitations had been increased. Climb and level speed performance tests were repeated at the new limitations. The climbs were made at the higher climbing speeds. ...........The old and new engine limitations are:- Old limitations New limitations Boost Boost R.P.M. R.P.M. lb/sq.in lb/sq.in Maximum permitted for take-off 2800 +7 2900 +8 and full throttle level speed. Maximum permitted for 2400 +5 2400 +6 climb ...........The performance results under each condition are included in the Report.