The English Electric Canberra is a British first-generation jet-powered medium bomber that was manufactured during the 1950s. It was developed by English Electric during the mid-to-late 1940s in response to a 1944 Air Ministry requirement for a successor to the wartime de Havilland Mosquito fast-bomber. Amongst the performance requirements for the type was the demand for an outstanding high altitude bombing capability in addition to flying at high speeds. These were partly accomplished by making use of newly developed jet propulsion technology. When the Canberra was introduced to service with the Royal Air Force (RAF), the type's first operator, in May 1951, it became the service's first jet-powered bomber aircraft.
Throughout the majority of the 1950s, the Canberra could fly at a higher altitude than any other bomber or even any other aircraft in the world. In 1957, one Canberra established a world altitude record of 70,310 ft (21,430 m). In February 1951, another Canberra set another world record when it became the first jet aircraft to make a non-stop transatlantic flight. Due to its ability to evade the early jet interceptor aircraft and its significant performance advancement over contemporary piston-engined bombers, the Canberra became a popular aircraft on the export market, being procured for service in the air forces of many nations both inside and outside of the Commonwealth of Nations. The type was also licence produced in Australia and the United States of America, the latter building it as the Martin B-57 Canberra.
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 had a lengthy service life, serving for more than 50 years with some operators. In June 2006, the RAF retired the last of its Canberras, 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.
During the Second World War, a desperate demand for bomber aircraft led to many aircraft being produced by secondary manufacturers via licence manufacturing arrangements. The English Electric company mass-produced thousands of piston-engined bombers, such as the Handley Page Hampden and Handley Page Halifax, in this manner and the firm thus became a well-established British aircraft manufacturer despite having little internal design experience. Sir George Nelson, the chairman of English Electric, decided that the company would seek to remain in the business and produce its own designs. In November 1943, the company was invited to participate in discussions over a prospective bomber which would take advantage of the newly developed jet propulsion technology.
In 1944, Westland Aircraft's technical director and chief designer W. E. W. Petter had 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 design used a relatively conventional aerodynamic design, Petter having determined that the necessary performance could be attained without adopting swept wings or a swept tail. 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 appointed by Nelson to form a design team and encouraged to develop his design. In 1945, English Electric formalised its own in-house aircraft design team to pursuit this design.
The Canberra had its formal origins in a 1944 requirement issued by the Air Ministry for a successor to the de Havilland Mosquito. This requirement, the initial revision being E.3/45, sought a high altitude, high-speed bomber which was to be equipped with no defensive armament. According to aviation historians Bull Gunston and Peter Gilchrist, Air Ministry officials are alleged to have had difficulty defining what they sought for the proposed type, which led to several revisions of the requirement. Further specification refinements were issued, including B.3/45 and B.5/47, issued further details such as a three-man crew and other features such as a visual bombing capability. Several British aircraft manufacturers submitted proposals to meet the requirement, including English Electric. The firm was among those companies to be short-listed to proceed with development studies.
By 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; Petter had held discussions with Rolls-Royce Ltd on the topic of the development of a scaled-up derivative of the Nene engine. In late 1945, the design was modified further with a pair of engines being adopted instead, initially to be set in the wing roots and later to be mounted in a mid-wing position; this change was made principally due to centre of gravity issues imposed by the position and weight of a heavy bombload and centrally-mounted single engine. The new engine position decreased the aircraft's weight by 13 per cent and improved the aircraft's centre of gravity, as well as improved accessibility to the engines and related accessories, downsides were slightly elevated losses in the longer jet pipes and greater yaw during engine-out instances.
During the early design stages, the aircraft had grown from being roughly the same size as the Mosquito to being around double its weight. 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. 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 had become the aircraft's first export customer.
Prototypes and first flights
The first Canberra B2 prototype, VX165
The Air Ministry specification B.3/45 had requested the production of four prototypes. On 9 January 1946, English Electric received a contract to produce four prototypes, which received the Society of British Aerospace Companies (SBAC) designation A.1; work commenced on the construction of these prototype aircraft in that same year, which were all built on production jigs. However, progress was slow due to several factors, such as the protracted development of the Avon engine that powered the type; in October 1947, in response to Rolls-Royce's difficulties, English Electric elected to have the second prototype modified to use the existing Nene engine in place of the Avon. The implementation of post-war military cutbacks also served to slow development.