English Electric Canberra (1951-2006) (RAF)
Posted: 15 Nov 2015, 23:11
^ Canberra T.4 WJ874 in 2005, it had been painted in 1999 to represent the first prototype VN799, first flown in 1949
The English Electric Canberra is a British first-generation jet-powered medium bomber manufactured in large numbers through the 1950s. The Canberra could fly at a higher altitude than any other bomber through the 1950s and set a world altitude record of 70,310 ft (21,430 m) in 1957. Due to its ability to evade the early jet interceptors and its significant performance advancement over contemporary piston-engined bombers, the Canberra was a popular export product and served with air forces of many nations.
In addition to being a tactical nuclear strike aircraft, the Canberra proved to be highly adaptable, serving in varied roles such as tactical bombing and photographic and electronic reconnaissance. Canberras served in the Suez Crisis, the Vietnam War, the Falklands War, the Indo-Pakistani wars, and numerous African conflicts. In several wars, each of the opposing sides had Canberras in their air forces. The Canberra was retired by its first operator, the Royal Air Force (RAF), in June 2006, 57 years after its first flight. Three of the Martin B-57 variant remain in service, performing meteorological work for NASA, as well as providing electronic communication (Battlefield Airborne Communications Node or BACN) testing for deployment to Afghanistan.
The Canberra had its origins in a 1944 Air Ministry requirement for a successor to the de Havilland Mosquito – a high altitude, high-speed bomber with no defensive armament. Several British aircraft manufacturers submitted proposals. Among the companies short-listed to proceed with development studies was English Electric, a well-established industrial manufacturer with very little aircraft design experience, though when a desperate need for bombers arose during the early years of the Second World War, English Electric had built the Handley Page Hampden and later the Handley Page Halifax four-engined bomber under licence.
In 1944, Westland Aircraft's technical director and chief designer W. E. W. Petter prepared a design study for a twin-engined fighter bomber, the P.1056, based on two fuselage-mounted Metrovick F.2/4 "Beryl" engines. The authorities doubted its suitability for operations from unprepared fields and at low altitude but could see its potential as a bomber design; numerous manufacturers refused to take on the design. Petter left Westland to join the English Electric company in December 1944, where he was encouraged to develop his design, EE formed its own in-house aircraft design team in the following year.
In June 1945, the aircraft that was to become the Canberra bore many similarities to the eventual design, despite the placement of a single, centrally mounted turbojet engine; two wing-mounted engines were adopted later that year. On 7 January 1946, the Ministry of Supply placed a contract for the development and production of four English Electric A.1 aircraft. It continued to be known as the English Electric A.1 until it was given the name Canberra after the capital of Australia in January 1950 by Sir George Nelson, chairman of English Electric, as Australia was the aircraft's first export customer. Although jet powered, the Canberra design philosophy was very much in the Mosquito mould, providing room for a substantial bomb load, fitting two of the most powerful engines available, and wrapping it in the most compact and aerodynamic package possible. Rather than devote space and weight to defensive armament which historically could not overcome fighter aircraft, the Canberra was designed to fly fast and high enough to avoid air-to-air combat entirely.
The Air Ministry specification B.3/45 had requested the production of four prototypes. English Electric began construction of these in early 1946. All the prototypes were built on jigs. However, due to post-war military reductions, the first aircraft did not fly until 13 May 1949. By the time the first prototype had flown, the Air Ministry had already ordered 132 production aircraft in bomber, reconnaissance, and training variants. The prototype proved vice-free and required only a few modifications. A new glazed nose had to be fitted to accommodate a bomb-aimer because the advanced H2S Mk9 bombing radar was not ready for production, the turbojet engines were upgraded to the more powerful Rolls-Royce Avon R.A.3s, and distinctive teardrop-shaped fuel tanks were fitted under the wingtips.
The resultant aircraft, designated the Canberra B2, first flew on 21 April 1950, piloted by Roland Beamont. Proving to be fairly free of problems, this first flight was almost immediately followed by the manufacturing of production Canberras, entering squadron service with RAF No. 101 Squadron in May 1951. In a testament to the aircraft's benign handling characteristics, the transition program consisted of only twenty hours in the Gloster Meteor and three hours in the dual-control Canberra trainer.
With a maximum speed of 470 knots (870 km/h; 540 mph), a standard service ceiling of 48,000 ft (14,600 m), and the ability to carry a 3.6-tonne (7,900 lb) payload, the Canberra was an instant success. It was built in 27 versions that equipped 35 RAF squadrons, and was exported to more than 15 countries, including Australia, Argentina, Chile, Ecuador, Ethiopia, France, India, New Zealand, Pakistan, Peru, Rhodesia, South Africa, Sweden, Venezuela and West Germany.
Photo-reconnaissance and conversion roles
The strategic reconnaissance role within the RAF had been carried out by the de Havilland Mosquito; in 1946 the Air Ministry issued Specification PR.31/46 as a jet-powered replacement for the Mosquito. To meet the requirement, the B2 design was modified by adding a 14-inch (36 cm) bay forward of the wing behind the cockpit to house seven cameras. It also had an additional fuel tank in the forward part of the bomb bay and only needed a two-man crew. The prototype, designated PR3, first flew on 19 March 1950, followed by the first of 35 production aircraft on 31 July 1952. It entered service in December 1952 when No. 540 Squadron RAF began to convert from the Mosquito PR.34. The Canberra PR3 was the first aircraft designed for the RAF purely for photo-reconnaissance.
To enable crews to convert to flying the Canberra, a trainer version was developed to meet Air Ministry Specification T2/49. The prototype designated T4 first flew on 12 June 1951. It was the same basic design as the B2 apart from the introduction of side-by-side seating for the pilot and the instructor and the replacement of the glazed nose with a solid nose. The first production T4 flew on 20 September 1953 and the variant entered service with No. 231 Operational Conversion Unit RAF in early 1954 As well as the operational conversion unit, all the B2-equipped bomber squadrons received at least one T4 for training.
The design of the Canberra has been described as being of a simple nature, somewhat resembling a scaled-up Gloster Meteor fighter, except for its use of a mid-wing. The fuselage was circular in cross section, tapered at both ends and, cockpit aside, entirely without protrusions; the line of the large, low-aspect ratio wings was broken only by the tubular engine nacelles. The Canberra had a two-man crew under a fighter-style canopy, but delays in the development of the intended automatic radar bombsight resulted in the addition of a bomb aimer's position in the nose. Each crew member has a Martin-Baker ejection seat, except in the B(I)8 and its export versions where the navigator has an escape hatch and parachute provided.
The wing is of single-spar construction that passes through the aircraft's fuselage; the wingspan and total length of the Canberra were almost identical at just under 20 metres. Outboard of the engine nacelles, the wing has a leading-edge sweep of 4° and trailing-edge sweep of −14°. Controls are conventional with ailerons, four-section flaps, and airbrakes on top and bottom surfaces of the wings. The use of swept-wings was examined but decided against as the expected operational speeds did not warrant it, and it would have introduced unresolved aerodynamic problems to what was aimed at being a straightforward replacement for the RAF's Hawker Typhoon and Westland Whirlwind fighter-bombers.
The fuselage of the Canberra is of semi-monocoque construction with a pressurised nose compartment. Due to the use of a new alloy, DTD683, the undercarriages of the Canberra suffered from stress corrosion, which caused them to decay within a few years. The extreme hazard posed of undercarriages collapsing during landings, especially if the aircraft were carrying nuclear weapons, led the RAF to institute regular inspections, at first using radiography before moving to more effective and reliable ultrasound technology. The Canberra is made up mostly of metal, only the forward portion of the tail-fin is made from wood.
Thrust was provided by a pair of 30 kN axial flow Rolls-Royce Avon turbojets. The manufacturer specified that Coffman engine starters should be used to start the engine. An improvised method of starting the engine using compressed air was heavily discouraged by Rolls-Royce, but some operators successfully operated the Canberra's engines in such a manner, the benefit being significant cost savings over cartridges. The aircraft's maximum take-off weight was a little under 25 tonnes.
The Canberra could deploy many conventional weapons, typical weapons used were 250-pound, 500-pound, and 1000-pound bombs, the total bomb load could weigh up to 10,000 pounds (4.5 t). Two bomb-bays are housed within the fuselage, these are normally enclosed by conventional clam-shell doors; this was substituted for a rotating door on the Martin-built B-57 Canberras. Additional stores up to a total of 2,000 pounds (0.91 t) could be carried upon underwing pylons. Operators often developed and installed their own munitions, such as Rhodesia's anti-personnel bomblets, the Alpha bomb, a varied range of munitions were employed on Canberra fleets around the world. Anti-personnel flechette bombs were tested successfully from the Canberra by Rhodesia, but not used operationally due to international agreements.
In part due to its range limitation of just 2,000 miles (3,200 km), and its inability to carry the early, bulky nuclear bombs, the Canberra was typically employed in the role of a tactical bomber as opposed to that of a strategic one. In British service, many of the Canberras that were stationed at remote overseas locations did not undertake modifications to become nuclear-capable until as late as 1957.
Royal Air Force
The Canberra B2 started to enter service with 101 Squadron in January 1951, with 101 Squadron being fully equipped by May, and a further squadron, No. 9 Squadron equipping by the end of the year. The production of the Canberra was accelerated as a result of the outbreak of the Korean War, orders for the aircraft increased and outpaced production capacity, as the aircraft was designated as a "super priority". A further five squadrons were able to be equipped with the Canberra by the end of 1952; however, production in the 1951–52 period had only been half of the level planned, due to shortages in skilled manpower, material, and suitable machine tools.
The Canberra replaced Mosquitos, Lincolns and Washingtons as front line bombers, showing a drastically improved performance, and proving to be effectively immune from interception during air defence exercises until the arrival of the Hawker Hunter. The Canberra also replaced the RAF's Mosquitos in the reconnaissance role, with the Canberra PR3 entering service in December 1952. The improved Canberra B6, with more powerful engines and a greater fuel capacity, started to supplement the B2s in the UK based squadrons of Bomber Command from June 1954, when they replaced 101 Squadrons B2s. This freed up older B2s to allow Canberra squadrons to form overseas, with bomber and reconnaissance Canberra wings forming in RAF Germany and on Cyprus, with squadrons also being deployed to the Far East.
The PR7 variant of the Canberra, equipped with longer, fuel-filled wings and the Avon 109 engines, executed a 1953 reconnaissance flight over the Soviet rocket launch and development site at Kapustin Yar, although the UK government has never admitted the existence of such a flight. Warned by either radar or agents inside the British government, the Soviets damaged and almost shot down the aircraft. Further reconnaissance flights are alleged to have taken place along, and over, the borders of the Soviet Union in 1954 under the code name Project Robin, using the Canberra B2 WH726. The USAF also used the Canberra for reconnaissance flights. The aircraft were no longer required after June 1956, following the introduction of the US Lockheed U-2 purpose-built reconnaissance aircraft; Project Robin was then terminated. These RAF Canberra overflights were later featured in the 1994 BBC Timewatch episode; "Spies in the Sky", and included interviews with some of the Soviet MiG-15 pilots who had attempted to intercept them.
The Canberra was the victorious aircraft flown in The Last Great Air Race from London to Christchurch in 1953, piloted by Flight Lieutenant Roland (Monty) Burton, which touched down at Christchurch 41 minutes ahead of its closest rival – after 23hr 51min in the air; to this day the record has never been broken.
The Vickers Valiant entered service in 1955, capable of carrying much heavier weapon loads (including the Blue Danube nuclear weapon) over longer ranges than the Canberra. This led to the Bomber Command force of Canberras equipped for high-level conventional bombing to be gradually phased out. This did not mean the end of the Canberra in front line service, as it proved suitable for the low-level strike and ground attack role, and versions dedicated to this role were brought into service. The interim B(I)6, converted from the B6 by adding provision for a pack of four Hispano 20 mm cannon in the rear bomb bay and underwing pylons for bombs and rockets, entered service in 1955, with the definitive, new build B(I)8, which added a new forward fuselage with a fighter-style canopy for the pilot, entering service in January 1956.
An important role for the new low-level force was tactical nuclear strike, using the Low Altitude Bombing System (LABS) to allow a nuclear bomb to be delivered from low level while allowing the bomber to escape the blast of the weapon. RAF Germany's force of four squadrons equipped with the B(I)6 and B(I)8 could carry US-owned Mark 7 nuclear bombs, while three squadrons based on Cyprus and one at Singapore were armed with British-owned Red Beard nuclear weapons.
Bomber Command retired the last of its Canberras on 11 September 1961, but the Germany, Cyprus and Singapore based squadrons continued in the nuclear strike role. The Cyprus-based squadrons and one of the RAF Germany squadrons disbanded in 1969, with the Singapore-based unit followed in 1970. The three remaining RAF Germany units, which by now had replaced the old Mark 7 bombs with newer (but still US-owned) B43 nuclear bombs, remained operational until 1972, the last Canberra bombers in RAF service.
The RAF continued to operate the Canberra after 1972, employing it for reconnaissance (with Squadrons equipped with PR7s and PR9s being based at RAF Wyton in the UK and RAF Luqa in Malta). The PR9s were fitted with special LOROP (Long-Range Optical Photography) cameras, reportedly based on those used by the Lockheed U-2, to allow high-altitude of targets deep into Eastern Europe while flying along the inner German border, as well as infrared linescan cameras for low level night reconnaissance. The RAF used Canberras to search for hidden arms dumps using false-colour photography during Operation Motorman in July 1972, when the British Army re-took Irish republican held "no go areas" in Belfast and Londonderry. Canberras were used for reconnaissance during the Bosnian War during the 1990s, where they were used to locate mass graves and during the Kosovo War in 1999. They were also operated from Uganda during the First Congo War, where they were used to search for refugees. Small numbers of specially equipped Canberras were also used for signals intelligence, being operated by 192 Squadron and then 51 Squadron from 1953 to 1976.
During the Falklands War, a plan to supply two PR9s to the Chilean Air Force, and secretly operate them with RAF crews over the war zone, was abandoned for political reasons. The aircraft got as far as Belize before the operation was cancelled. The PR9 variant remained in service with No. 39 (1 PRU) Squadron until July 2006 for strategic reconnaissance and photographic mapping, seeing service in the 2003 invasion of Iraq and, up to June 2006, in Afghanistan. During a ceremony to mark the standing down of 39 (1 PRU) Squadron at RAF Marham on 28 July 2006, a flypast by a Canberra PR9 on its last ever sortie was conducted.
Specifications (Canberra B(I)6)
Length: 65 ft 6 in (19.96 m)
Wingspan: 64 ft 0 in (19.51 m)
Height: 15 ft 8 in (4.77 m)
Wing area: 960 ft² (89.19 m²)
Empty weight: 21,650 lb (9,820 kg)
Loaded weight: 46,000 lb (20,865 kg)
Max. takeoff weight: 55,000 lb (24,948 kg)
Powerplant: 2 × Rolls-Royce Avon R.A.7 Mk.109 turbojets, 7,400 lbf (36 kN) each
Maximum speed: Mach 0.88 (580 mph, 933 km/h) at 40,000 ft (12,192 m)
Combat radius: 810 mi (700 nm, 1,300 km)
Ferry range: 3,380 mi (2,940 nm, 5,440 km)
Service ceiling: 48,000 ft (15,000 m)
Rate of climb: 3,400 ft/min (17 m/s)
Wing loading: 48 lb/ft² (234 kg/m²)
Guns: 4 x 20 mm Hispano Mk.V cannon mounted in rear bomb bay (500 rounds/gun), or 2 x 0.30 in (7.62 mm) machine gun pods
Rockets: 2 x unguided rocket pods with 37 2-inch (51 mm) rockets, or 2 x Matra rocket pods with 18 SNEB 68 mm rockets each
Missiles: A variety of missiles can be carried according to mission requirements, e.g: 2 x AS-30L air-to-surface missiles
Bombs: Total of 8,000 lb (3,628 kg) of payload can be mounted inside the internal bomb bay and on two underwing hardpoints, with the ability to carry a variety of bombs. Typically, the internal bomb bay can hold up to 9 x 500 lb (227 kg) bombs, or 6 x 1,000 lb (454 kg) bombs, or 1 x 4,000 lb (1,814 kg) bomb; while the pylons can hold 4 x 500 lb (227 kg) bombs, or 2 x 1,000 lb (454 kg) bombs.
Nuclear Weapons: in addition to conventional ordnance, the Canberra was also type-approved for tactical nuclear weapon delivery, including the Mk 7, B28 (Mod 2, 70 kiloton yield), B57 and B43 (as part of a joint program with the United States) plus the Red Beard and WE.177A (Mod A, 10 kiloton yield) nuclear bombs. All nuclear weapons were carried internally.