Beauforts were most widely used, until the end of the war, by the Royal Australian Air Force in the Pacific theatre. Most of these planes were manufactured under licence in Australia. Beauforts also saw service with the Royal Air Force's Coastal Command — including Commonwealth squadrons serving with the RAF — and then the Fleet Air Arm from 1940, until they were withdrawn in 1944.
The Beaufort spawned a long-range heavy fighter variant called the Beaufighter, which proved very successful.
Although the design looked similar in many ways to the Blenheim, it was in fact somewhat larger, with an 18-inch increase in wingspan. With the fuselage being made longer in the nose and taller to accommodate a fourth crew member, it was also considerably heavier. The larger bomb-bay was designed to house a semi-recessed torpedo, or it could carry an increased bomb load. Because of the increased weight the Blenheim's Mercury engines were to be replaced by the more powerful, sleeve valve, Bristol Perseus. It was soon determined that even with the Perseus, the Beaufort would be slower than the Blenheim and so a switch was made to the larger Taurus engine, also a sleeve valve design. For these engines chief designer Roy Feddan developed special low-drag NACA cowlings which exhausted air through vertical slots flanking the nacelles under the wings. Air flow was controlled by adjustable flaps.
The basic structure, although similar to the Blenheim, introduced refinements such as the use of high-strength light alloy forgings and extrusions in place of high-tensile steel plates and angles; as a result the overall structural weight was lighter than that of the Blenheim. In addition the wing centre section was inserted into the centre fuselage and the nacelle structure was an integral part of the ribs to which the main undercarriage was attached. Transport joints were used on the fuselage and wings: this feature allowed sub-contracters to manufacture the Beaufort in easily transportable sections, and was to be important when Australian production got underway.
The Vickers main undercarriage units were similar to, but bigger than those of the Blenheim and used hydraulic retraction retraction with a cartridge operated emergency lowering system.
The first prototype rolled out of Filton in mid-1938. Problems immediately arose with the Taurus engines continually overheating during ground testing. New more conventional engine cowlings with circumferential cooling gills had to be designed and installed, delaying the first flight which took place on 15 October 1938. As flight testing progressed it was found that the large apron-type undercarriage doors, similar to those on the Blenheim, were causing the aircraft to yaw on landing. These doors were taken off for subsequent flights. On the second prototype and all production aircraft more conventional split doors, which left a small part of the tyres exposed when retracted, were used..
With Blenheim production taking priority and continued overheating of the Taurus engines there were delays in production, so while the bomber had first flown in October 1938 and should have been available almost immediately, it was not until November 1939 that production started in earnest. Several of the first production Beauforts were engaged in working-up trials and final service entry began in January 1940 with 22 Squadron of Coastal Command.
A total of 1,013 Taurus powered Mark Is were produced and a number of changes were introduced into the line:
When it became apparent that the Taurus engines had problems, planning commenced to repower the aircraft with 1,200 hp (895 kW) Pratt & Whitney R-1830 Twin-Wasp radials, which were of similar diameter and slightly lighter. These engines drove Hamilton Standard bracket-type variable pitch propellers. However there was no guarantee that supply of the Twin Wasp would not be cut off, and production reverted to the Taurus-engined Mark Is after 165 Beaufort Mark IIs had been built, starting with AW244 which first flew in September 1941. Performance with the Twin-Wasps was marginally improved: maximum speed went up from 271.5 mph (437 km/h) to 277 mph (446 km/h) and the service ceiling increased from 16,500 ft (5,029 m) to 18,000 ft (5,486 m). However normal range was reduced from 1,600 miles (2,575 km) to 1,450 miles (2,333 km). Other modifications introduced on the Mk II and continued on late Mk Is were:
The final British-built version of the Beaufort was the Pratt & Whitney powered T Mark II, produced from August 1943. In this version the turret was removed and the position was faired over. The last ever Beaufort was a T II which left the Bristol Banwell factory on 25 November 1944.
As the design for the Beaufort began to mature the Australian Government invited a British Air Mission to discuss the defence needs of Australia and Singapore. It was also a step towards expanding Australia's domestic aircraft industry. The Beaufort was chosen as the best General Reconnaissance (G.R) aircraft available and, on 1 July 1939 orders were placed, for 180 airframes and spares, with the specially formed Beaufort Division of the Commonwealth's Department of Aircraft Production (DAP). The Australian made variants are often known as the DAP Beaufort.
The Australian Beauforts were to be built at the established DAP plant in Fisherman's Bend, Melbourne, and a new factory at Mascot, New South Wales; to speed up the process drawings, jigs and tools and complete parts for six complete airframes were supplied by Bristol. The bulk of Australian-built Beauforts used locally available raw materials.
One of the decisive factors in choosing the Beaufort was the ability to produce it in sections. Because of this railway workshops were key subcontractors:
Taurus engines, aircraft components and the associated equipment were shipped out to be joined, in October 1939, by the eighth production Beaufort L4448. With the outbreak of war the possibility that supplies of the Taurus engines could be disrupted or halted was considered even before the British government placed an embargo on exporting war materials with the Blitzkrieg on France, the Netherlands and Belgium in May 1940. It was proposed that a change of powerplant could be made to the Pratt & Whitney Twin Wasp, which was already in use on RAAF Lockheed Hudsons. Orders for the engine were placed and a factory was set up at Lidcombe N.S.W. and run by General Motors-Holden Ltd. The locally built engines were coded S3C4-G, while those imported from America were coded S1C3-4. Three-bladed Curtiss-Electric or Hamilton-Standard propellers were fitted to all Australian manufactured Beauforts. In early 1941, L4448 was converted as a trials aircraft and the combination was considered a success.
The first Australian-assembled Beaufort A9-1 flew on 5 May 1941 with the first Australian-built aircraft A9-7 coming off the production line in August. Australian Beauforts were manufactured in the following series:
A distinguishing feature of Australian Beauforts was a larger tailfin, which was used from from the Mk VI on. Armament fit also varied from British aircraft: British or American torpedoes were able to be carried and the final 140 Mk VIII were fitted with a locally manufactured Mk VE turret with .50 cal machine guns.
The Mk XI was a transport conversion, stripped of armament, operational equipment and armour and rebuilt with a redesigned centre fuselage. Maximum speed was 300 mph (483 km/h) and a payload of 4,600 lb (2,086 kg) could be carried.
Production of the Australian Beaufort ended in August 1944 when production switched to the Beaufighter.
For its envisaged role the Beaufort's performance and armament was considered adequate at the time. Few light or medium twin engine bombers designed in the 1930s carried more than a handful of light, rifle calibre machine guns and few of them had a higher maximum speed than the Beaufort. When faced with modern fighter opposition, as encountered around the coasts of German–occupied Europe and Japanese-occupied parts of Asia and the Pacific, the light armament and a speed deficit of over 70 mph (112 km/h) made the Beaufort an easy target. Even with the Twin-Wasps, which were the most powerful engines installed, the Beaufort was underpowered and, in the event of the loss of one engine, it was impossible to keep the aircraft flying for any length of time. For an aircraft operating in a maritime environment this often meant the crew as well as the airframe were lost.
On the plus side was the Beaufort's rugged construction and air cooled radial engines, which had no vulnerable cooling systems. These features meant that many heavily damaged Beauforts were able to get their crews back to base.
Although it did see some use in the torpedo bomber role, notably in attacks on the battlecruisers Scharnhorst and Gneisenau while in port in Brest, the Beaufort more often used bombs or mines while in European service. It saw considerable action in the Mediterranean theatre, where it helped put an end to Axis shipping supplying Rommel in North Africa.
By early 1940 22 Squadron was fully equipped, although a great deal of training in the specialised art of torpedo-dropping was needed by the crews. Because of this, and because of a shortage of torpedoes the squadron's first operations consisted of laying magnetic mines (\"Gardening\" in RAF parlance) and dropping conventional bombs. The first operation took place on the night of 15/16 April when nine Beauforts successfully laid mines in the Schilling Roads (north of Wilhelmshaven). One Beaufort failed to return. In the meantime A second unit 42 Squadron was also re-equipped with Beauforts, starting in April.
The first RAF torpedo attack of the war came on 11 September 1940, when five aircraft of 22 Squadron attacked a convoy of three merchant ships off Ostend. One torpedo hit a 6,000 ton (6,096 tonne) ship. Four days later the first \"Rover\" was mounted; a Rover was an armed reconnaissance mission carried out against enemy shipping by a small number of aircraft operating independently. \"Rovers\" became a major part of Beaufort operations over the next next 18 months. Other more hazardous operations were to follow, with one Beaufort pilot being awarded a posthumous VC.
A successful torpedo drop required that the approach run to the target needed to be straight and at a speed and height where the torpedo would enter the water smoothly: too high or too low and the torpedo could \"porpoise\" (skip through the water), dive, or even break up. Height over the water had to be judged without the benefit of a radio altimeter and misjudgement was easy, especially in calm conditions. For the Beauforts using the 18 inch (45.72 cm) Mk XII aerial torpedo the average drop-height was 68 feet (20.7 m) and the average range of release was 670 yards (612 m). During the run-in, the aircraft was vulnerable to defensive anti-aircraft fire, and it took courage to fly through it with no chance of evasive manoeuvres. The Beaufort's optimum torpedo dropping speed was a great deal higher than that of the Vildebeests it was replacing and it took practice to accurately judge the range to, and speed of, the target ship. A ship the size and speed of the Scharnhorst, for example, would look huge, filling the windscreen at well over a mile (1.609 km) and it was easy to under-estimate the range. In action torpedoes were often released too far away from the target, although there were instances of torpedoes being released too close.
Once the torpedo had been dropped, if there was room, a sharp turn away from the enemy was possible: more often than not the aircraft had to fly around or over the ship, usually at full-throttle and below mast height. A sharp pull-up could be fatal, as it could expose a large area of the aircraft to the guns.
Some of the Beaufort's most notable actions were attacks on warships of the German Kriegsmarine:
One of the conclusions reached by a later Court of Inquiry was that a faster, longer-ranged torpedo bomber than the Beaufort was needed: Bristol already had under way a torpedo carrying conversion of their Beaufighter, itself a development of the basic Beaufort airframe, and were later to produce the Brigand.
In spite of its failure this operation set the pattern for Coastal Command for future operations: Beaufighters were used for the first time in the flak-suppression and escort roles and there had been diversionary tactics used to try and reduce attention on the attacking torpedo aircraft. It also marked the end of Beaufort operations from Britain.
The remaining Beaufort squadrons now started moving east:
The first operation in which Beauforts took part was an attack on an Italian convoy on 28 January 1942. The three Beauforts of 39 Squadron included in a large strike force succeeded in crippling the 14,000 ton (14,224 tonne) merchant ship Victoria (Count Ciano in his diaries called her "The pearl of the Italian Merchant Fleet"), which was then sunk by Albacores.
In another operation during the early hours of 15 June 1942, nine Beauforts of 217 Squadron, which had just flown in from England, took off from RAF Luqa, Malta to intercept ships of the Regia Marina which had sailed from Taranto. Few of the Beaufort crews had experience in night-flying: four aircraft failed to find the agreed rendezvous point and set out independently. One, flown by Flying Officer Arthur Aldridge discovered the Italian Fleet some 200 miles to the east of Malta. Like Loviett's attack on the Lūtzow, his Beaufort was mistaken for a friendly aircraft by Italian lookouts. Aldridge successfully torpedoed and crippled the heavy cruiser Trento. The anti-aircraft fire started only after Aldridge had escaped.
The main formation of Beauforts came in to attack guided in by the gunfire. In the confusion and the smokescreen which had been laid down by the Italian warships, 217 Squadron claimed several torpedo hits for one Beaufort which, because of heavy damage, belly-landed at Luqa. None of the other ships were hit. Trento was later sunk by two torpedoes fired by the submarine HMS Umbra, which had witnessed the aerial attack.
By July 1942, 86 Squadron Beauforts and crews had arrived on Malta and were soon absorbed into a reconstituted 39 Squadron, at first under the command of the inspirational Wing Commander Patrick Gibbs, while 217 squadron moved on to Ceylon. Most of the Beauforts used were the Twin-Wasp powered Mk. IIs which were modified with tropical sand filters over the carburettor air intakes. These created a great deal of drag, slowing down the aircraft and reducing range.
Over the next 11 months the Beaufort force, now usually accompanied by Beaufighters, was instrumental in crippling the convoy supply lines which were vital to Rommel's Afrika Korps. At night torpedo carrying Wellingtons of 38 Squadron also played an important part in attacking convoys. Some important ships destroyed or badly damaged were:
In June 1943 39 Squadron, the last operational Beaufort unit, converted to Beaufighters.
Some 45 minutes into the flight, Sgt Wilkinson distracted the guard who was overpowered and disarmed. The five Italian crew were forced to surrender the Cant and Lt Strever took over the controls, altering course to fly to Malta. There were no proper maps on board and a rough heading to the south-west was set. Eventually Cape Spartivento, the southernmost point of Italy, was recognised and a new course was set for Malta, some 100 miles to the south. The aircraft was soon detected by radar on Malta and a section of four Spitfires of 603 Squadron was scrambled to intercept. They found the Cant about 10 miles off the coast and forced it to alight with a burst through the port wing.
HSL 107 (an RAF High Speed Launch, used to rescue aircrew) arrived an hour later and found the five Italians and four Beaufort crew sitting on the wings enjoying wine and brandy provided by the Italians. Cant No. MM45352 13 of 139 Squadrilia was taken into service by the RAF and used for air/sea rescue duties. Lt Strever and Plt Off Dunsmore were awarded the DFC and Sgts Wilkinson and Brown, the DFM.
The first six Australian built Beauforts reached Singapore just after the Japanese invasion of Malaya in December 1941. It was soon decided that these Beauforts were under-armed and their crews were insufficiently trained and they were soon returned to Australia. Production continued to increase, reaching almost one a day in 1943. The Beaufort served with 19 squadrons and played an important role in the South West Pacific Area, as a maritime patrol and strike aircraft and bomber. Beauforts sank an impressive tonnage of merchant and naval shipping.