Avro Lincoln
The Avro Type 694 Lincoln is a British four-engined heavy bomber, which first flew on 9 June 1944. Developed from the Avro Lancaster, the first Lincoln variants were initially known as the Lancaster IV and V; these were renamed Lincoln I and II. It was the last piston-engined bomber operated by the Royal Air Force ; the later Avro Shackleton, though piston-engined, served in maritime patrol rather than bomber roles.
The Lincoln attained operational status in August 1945. It had been initially assigned to units of the Tiger Force, a Commonwealth heavy bomber force which had been intended to play a role in the Japan campaign in the closing stages of the Second World War, but the war ended before the Lincoln could participate. Production of the type proceeded and the type was adopted in quantity, complementing and progressively replacing the Lancaster in RAF service during the late 1940s.
The Lincoln was deployed on operations during the 1950s. RAF squadrons equipped with the type fought against guerrilla fighters during the Mau Mau Uprising in Kenya; the RAF and the Royal Australian Air Force also operated the Lincoln during the Malayan Emergency. The type also saw significant peacetime service with the RAF, RAAF and the Argentine Air Force. Lincolns were also operated in civil aviation, including use as aerial test beds for aero-engine research.
In RAF service, the Lincoln was replaced by a new generation of bombers using jet propulsion. In 1967 the last Lincoln bombers in service, in Argentina, were retired.
Design and development
Origins
The Avro Lincoln originated from a design produced by Roy Chadwick as a development of the earlier Lancaster bomber which had been produced with the purpose of conforming with the requirements of the Specification B.14/43. Known initially as the Lancaster IV and Lancaster V, the envisioned aircraft, while considerably similar to the Lancaster, had numerous improvements such as the adoption of stronger, longer span, higher aspect ratio wings, and two-stage supercharged Rolls-Royce Merlin 85 engines fitted within Universal Power Plant installations. The new bomber also had an enlarged fuselage that accommodated increased fuel and bomb loads and allowed up to 11 tons of various armaments and equipment fittings, including the Grand Slam bomb, to be carried. It had a higher operational ceiling and longer range than the Lancaster, with a maximum altitude of and a maximum range of.The prototype Lancaster IV, later renamed the Lincoln I, was assembled by Avro's experimental flight department at Manchester's Ringway Airport. According to aviation author Kev Delve, development of the Lincoln had proceeded relatively smoothly. On 9 June 1944, the prototype conducted its maiden flight from Ringway Airport. Testing of the prototype quickly proved it to have favourable flight characteristics. In February 1945 the first production Lincoln was completed.
The type was mainly produced at Avro's Woodford, Cheshire and Chadderton Lancashire factories; additional aircraft were also constructed by Armstrong Whitworth at their Coventry facilities. Separate production lines were also established in Canada and Australia, although, as a consequence of the end of the war, production in Canada was halted after only a single aircraft had been constructed. Lincolns were manufactured in Australia and operated by the Royal Australian Air Force.
From early 1945 the British Government set about restoring the country to a peacetime stance, with drastic reductions to the armed forces including the disbanding of many squadrons of the Royal Air Force. A new emphasis was soon placed on 'quality over quantity' during the rationalisation process, seeking to employ fewer but more capable aircraft to perform their envisioned roles; while there was no longer any urgency in bringing new types of aircraft into service, limited procurement of equipment that fell within this ethos did proceed. In accordance with this aim, the British Air Ministry proceeded to formulate and release Specification B.14/43, which sought an improved piston-engined heavy bomber to replace the wartime four-engine bombers, the Short Stirling, the Handley Page Halifax, and the Avro Lancaster.
Further development
One Lincoln B Mk XV pattern aircraft was completed in Canada by Victory Aircraft; a follow-up order for a total of six RCAF variants was cancelled shortly following the end of hostilities. Along with two additional Lincoln aircraft on loan from the RAF, the type was briefly evaluated postwar by the RCAF. The Lancaster V/Lincoln II differed mainly in that it was fitted with Merlin 68A engines.Prior to the Lincoln being developed, the Australian government had already formulated plans for its Department of Aircraft Production, later known as the Government Aircraft Factory, to construct the earlier Lancaster Mk III. In its place, it was decided to proceed with manufacturing a variant of the Lincoln I, re-designated the Lincoln Mk 30, to replace the Consolidated Liberators. This model was manufactured between 1946 and 1949, and is the largest aircraft ever constructed in Australia. Orders for a total of 85 Mk 30 Lincolns were placed by the RAAF, although only 73 were produced.
The first five Australian examples, were assembled at Fishermans Bend using a large proportion of imported British-made components. On 17 March 1946, A73-1 conducted its début flight; the first entirely Australian-built Lincoln, A73-6, was formally delivered in November 1946. The Mk 30 initially used four Merlin 85 engines, this arrangement was later changed to a combination of two outboard Merlin 66s and two inboard Merlin 85s. A further improved later version, the Lincoln Mk 30A, had four Merlin 102s.
During the 1950s, the RAAF modified some of their Mk 30 aircraft for anti-submarine warfare re-naming them Lincoln GR.Mk 31. These examples had a longer nose to house acoustic submarine detection gear and its operators, larger fuel tanks to provide the aircraft with a 13-hour flight endurance, and a modified bomb bay to accommodate torpedoes. According to pilot feedback, the Lincoln Mk 31 was particularly difficult to land at night, as the bomber had a tailwheel undercarriage and the long nose obstructed the pilot's view of the runway. In 1952, 18 aircraft were rebuilt to this standard, and were reallocated new serial numbers. Ten were subsequently upgraded to the MR.Mk 31 standard, which included an updated radar.
Further aircraft were also derived from the Lincoln. A dedicated maritime patrol aircraft, designated the Avro Shackleton, was developed for the RAF and the South African Air Force. Avro decided to develop a commercial airliner, known as the Tudor, which used elements of the Lincoln, such as its wings, in combination with various new elements, such as the adoption of a pressurised fuselage, to perform passenger operations.
Operational history
Royal Air Force
During 1945, the RAF received its first Lincoln, which was delivered to 57 Squadron based at RAF East Kirkby, Lincolnshire. In August 1945, 75 Squadron began to re-equip with the Lincoln at RAF Spilsby, Lincolnshire. The New Zealand squadron had received just three aircraft prior to VJ Day, and was disbanded quickly thereafter.In the postwar climate, the Lincoln quickly equipped the bomber squadrons of the RAF. Nearly 600 Lincolns were constructed to equip 29 RAF squadrons, the majority of which were based in the United Kingdom. They were supplemented and partially replaced by 88 Boeing Washingtons, on loan from the USAF, which had longer range and could reach targets inside the Iron Curtain. Small numbers remained in use with 7, 83 and 97 Squadrons until the end of 1955, at which point the type was phased out, having been replaced by the first of the V bombers.
During the 1950s, RAF Lincolns participated in operations in Kenya against Mau-Mau insurgents. During this action, they were operated from Eastleigh. The Lincoln was also deployed to Malaya during the Malayan Emergency, where it was used against insurgents aligned to the Malayan Communist Party. In Malayan theatre, RAF Lincolns were operated from Changi Air Base and Tengah Air Base. In excess of 3,000 sorties were flown during their -year deployment, during which half a million pounds of bombs dropped, 85 per cent of the total bomb tonnage dropped during the Malayan emergency.
On 12 March 1953, an RAF Lincoln of Central Gunnery School was shot down NE of Lüneburg, Germany by several Soviet MiG-15s as it flew to Berlin on a radar reconnaissance flight, killing the seven crew members.
In November 1955, four Lincolns of 7 Squadron were detached for duties in British territories in the Middle East. In Bahrain, they carried out border patrols of the Trucial States at the time of the Buraimi dispute. When 7 Sqn was disbanded in December 1955, the four detached crews and aircraft became 1426 Flight, officially a photographic reconnaissance unit. It was later sent to Aden, carrying out patrols in the lead-up to the Aden Emergency.
As the RAF Lincolns became unserviceable, primarily due to wear and tear, they were replaced by jet-powered aircraft. The Lincolns of Bomber Command were phased out from the mid-1950s and had been replaced by jet bombers by 1963. The last Lincolns in RAF service were five operated by 151 Squadron, Signals Command, at RAF Watton, Norfolk, which were retired on 12 March 1963.
Royal Australian Air Force
From late 1946, Australian-built Lincolns began to equip 82 Wing, based at RAAF Base Amberley, Ipswich, Queensland. The type quickly replaced the Liberator bombers that had been operated by 12, 21 and 23 Squadrons. In February 1948, these units were renumbered 1, 2 and 6 Squadrons respectively; a fourth RAAF Lincoln squadron, 10 was formed on 17 March 1949 at RAAF Townsville as a reconnaissance unit.During the 1950s, RAAF Lincolns participated in combat operations in Malaya, operating with the RAF. The RAAF based the B.Mk 30s of 1 Squadron at Tengah, for the duration of operations in Malaya. These Lincolns served with 10 Squadron RAAF at RAAF Base Townsville, Garbutt, Queensland; the discovery of corrosion in the wing spars led to the type's premature retirement in 1961. The Lincoln MR.Mk 31 was the final variant to see service in Australia.