The Avro Lancaster, commonly known as the Lancaster Bomber, is a British World War II heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to the same specification, as well as the Short Stirling, all three aircraft being four-engine heavy bombers adopted by the Royal Air Force (RAF) during the same era.
The Lancaster has its origins in the twin-engine Avro Manchester, which had been developed during the late 1930s in response to the Air Ministry Specification P.13/36 for a medium bomber for "world-wide use" to carry a torpedo internally and make shallow dive-bombing attacks. Originally developed as an evolution of the Manchester, which had proved troublesome in service and was retired in 1942, the Lancaster was designed by Roy Chadwick and powered by four Rolls-Royce Merlin engines and in one of the versions, Bristol Hercules engines. It first saw service with RAF Bomber Command in 1942 and as the strategic bombing offensive over Europe gathered momentum, it was the main aircraft for the night-time bombing campaigns that followed. As increasing numbers of the type were produced, it became the principal heavy bomber used by the RAF, the Royal Canadian Air Force (RCAF) and squadrons from other Commonwealth and European countries serving within the RAF, overshadowing the Halifax and Stirling, two other commonly-used bombers.McKinstry 2009, pp. 9–10.
A long, unobstructed bomb bay meant that the Lancaster could take the largest bombs used by the RAF, including the , and "blockbusters", loads often supplemented with smaller bombs or incendiaries. The "Lanc", as it was known colloquially,Cotter 2005, p. xiii. became one of the most heavily used of the Second World War night bombers, delivering of bombs in 156,000 sorties.Taylor 1969, p. 314. The versatility of the Lancaster was such that it was chosen to equip 617 Squadron and was modified to carry the Upkeep "bouncing bomb" designed by Barnes Wallis for Operation Chastise, the attack on German Ruhr Valley dams. Although the Lancaster was primarily a night bomber, it excelled in many other roles, including daylight precision bombing, for which some Lancasters were adapted to carry the Tallboy and then the Grand Slam earthquake bombs (also designed by Wallis)."Second World War propaganda film of "Grand Slam" in action." youtube.com. Retrieved: 3 January 2012. This was the largest payload of any bomber in the war.
In 1943, a Lancaster was converted to become an engine test bed for the Metropolitan-Vickers F.2 turbojet. Lancasters were later used to test other engines, including the Armstrong Siddeley Mamba and Rolls-Royce Dart turboprops and the Avro Canada Orenda and STAL Dovern turbojets. Postwar, the Lancaster was supplanted as the main strategic bomber of the RAF by the Avro Lincoln, a larger version of the Lancaster. The Lancaster took on the role of long range anti-submarine patrol aircraft (later supplanted by the Avro Shackleton) and air-sea rescue. It was also used for photo-reconnaissance and aerial mapping, as a flying tanker for aerial refuelling and as the Avro Lancastrian, a long-range, high-speed, transatlantic passenger and postal delivery airliner. In March 1946, a Lancastrian of BSAA flew the first scheduled flight from the new London Heathrow Airport."First to South America." Flight, 20 January 1946.
Development Origins In the 1930s, the Royal Air Force (RAF) was primarily interested in twin-engine bombers. These designs put limited demands on engine production and maintenance, both of which were already stretched with the introduction of so many new types into service. Power limitations were so serious that the British invested heavily in the development of huge engines in the class to improve performance. During the late 1930s, none of these were ready for production. Both the United States and the Soviet Union were pursuing the development of bombers powered by arrangements of four smaller engines; the results of these projects proved to possess favourable characteristics such as excellent range and fair lifting capacity. Accordingly, in 1936, the RAF also decided to investigate the feasibility of the four-engined bomber.Norris 1966, p. 3.
The origins of the Lancaster stem from a twin-engined bomber that had been submitted to British Air Ministry Specification P.13/36 of 1936 for a twin-engined medium bomber for "worldwide use" which could carry a torpedo internally, and make shallow dive-bombing attacks.Mason 1994, pp. 324–325.Robertson 1964, p. 7. Further requirements of the specification included the use of a mid-mounted cantilever monoplane wing, and all-metal construction while the use of the Rolls-Royce Vulture, which was in development was encouraged.Moyes 1966, p. 3. Twin-engine designs were submitted by Fairey, Boulton Paul, Handley Page and Shorts, using Rolls-Royce Vulture, Napier Sabre, Fairey P.24 or Bristol Hercules engines. Most of these engines were still under development and while four-engined bomber designs were considered for specification B.12/36 for a heavy bomber, the extra engines required the wing and overall aircraft structure to be stronger, increasing the structural weight.Buttler 2004, p. 104.
Avro submitted the Avro 679 to fulfil Specification P.13/36 and, in February 1937, Avro's submission was selected, along with Handley Page's bid as a backup. In April 1937, a pair of prototypes for each design was ordered.Buttler 2004, p. 102. Avro's aircraft, named the Manchester, entered RAF service in November 1940. Although a capable aircraft, the Manchester was underpowered and its Vulture engines proved to be unreliable.Goulding and Garbett 1966, p. 3.Robertson 1964, pp. 9–11. As a result, only 200 were constructed and the type was withdrawn from service in 1942.Jackson 1990, pp. 355–356.
Flight testing By mid-1940, Avro's chief design engineer, Roy Chadwick, was working on an improved Manchester powered by four of the more reliable but less powerful Rolls-Royce Merlin engines, specifically adopting the "Power-egg" installation developed for the Beaufighter II, and installed on a wing of increased span.Gunston 2006, p. 190. Initially, the improved aircraft was designated as the Type 683 Manchester III but was subsequently renamed the Lancaster. The prototype, serial number BT308, was assembled by the Avro experimental flight department at Ringway Airport, Manchester, being modified from a production Manchester airframe, combined with the new wing to accommodate the additional engines. The first flight was made by test pilot H. A. "Sam" Brown on 9 January 1941 at RAF Ringway, Cheshire.Robertson 1964, p. 14.
Flight testing of the new aircraft quickly proved it to be a substantial improvement over its predecessor.Winchester 2005, p. 27. The first prototype was initially outfitted with the Manchester I's three-finned tail but this was revised on the second prototype, DG595, and subsequent production Lancasters used the larger elliptical twin-finned tail unit that was also adopted for the last Manchesters built. This not only increased stability but also improved the dorsal gun turret's field of fire. The second prototype was also fitted with more powerful Merlin XX engines.
Manchesters still on the production line were converted into Lancaster B.Is. Based upon its performance, a decision was taken early on to reequip twin-engine bomber squadrons with the Lancaster as quickly as possible. L7527, The first production Lancaster made its first flight in October 1941, powered by Merlin XX engines.
Production
Avro received an initial contract for 1,070 Lancasters. The majority of Lancasters manufactured during the war years were constructed by Avro at its factory at Chadderton near Oldham, Lancashire and were test-flown from Woodford Aerodrome in Cheshire. As it was quickly recognised that Avro's capacity was exceeded by the wartime demand for the type, it was decided to form the Lancaster Aircraft Group, which comprised a number of companies that undertook the type's manufacture, either performing primary assembly themselves or producing various subsections and components for the other participating manufacturers.Goulding and Garbett 1966, pp. 3–4. Wythenshawe Bus Garage, built of reinforced concrete during 1939–42 and designed by the Manchester City Architect, G. Noel Hill, was immediately taken over by the Ministry of Aircraft Production and Avro used it in its Lancaster aircraft production.
In addition to Avro, further Lancasters were constructed by Metropolitan-Vickers (1,080, also tested at Woodford) and Armstrong Whitworth. They were also produced at the Austin Motor Company works in Longbridge, Birmingham, later in the Second World War and post-war by Vickers-Armstrongs at Chester as well as at the Vickers Armstrong factory, Castle Bromwich, Birmingham. Belfast-based aircraft firm Short Brothers had also received an order for 200 Lancaster B.Is, but this was cancelled before any aircraft had been completed.Goulding and Garbett 1966, p. 4.Robertson 1964, pp. 79–81.
The Lancaster was also produced overseas. Attempts to set up an Australian line resulted in post war production of the Lincoln. During early 1942, it was decided that the bomber should be produced in Canada, where it was manufactured by Victory Aircraft in Malton, Ontario. Of later variants, only the Canadian-built Lancaster B X was produced in significant numbers. A total of 430 of this type were built, including 8 as transport versions, earlier examples differing little from their British-built predecessors, except for using Packard-built Merlin engines and American-style instruments and electrics. In August 1942, a British-built Lancaster B.I was dispatched to Canada as a pattern aircraft, becoming the first of the type to conduct a transatlantic crossing. The first Lancaster produced in Canada was named the "Ruhr Express". The first batch of Canadian Lancasters delivered to England suffered from faulty ailerons; this error was subsequently traced to the use of unskilled labour.Brown 2016, p. 80. By the end of the conflict, over 10,000 Canadians were employed on the production line, peak production was 50 in March 1945.Robertson 1964, p. 81. Most references agree on total mark I plus mark III production but can have minor differences in the breakdown between the two versions.
+Production by factoryManufacturerLocationI prototypeIII prototypeIIIIIVIIXNumber producedA. V. RoeWoodford289712,7732,978October 1941 to October 1945ChaddertonYeadon695Armstrong WhitworthCoventry9173001121,329August 1942 to January 1946Austin MotorsLongbridge150180330March 1944 to December 1945Marston GreenMetropolitan-VickersTrafford Park9491311,080January 1942 to August 1945Vickers-ArmstrongsCastle Bromwich300300November 1943 to August 1945Chester235235June 1944 to September 1945Victory AircraftMalton (Canada)430430August 1943 to October 1945Total23,44813003,0161804307,377
Further development
The Lancaster B.I was never fully superseded in production by a successor model, remaining in production until February 1946. According to aviation authors Brian Goulding and M. Garbett, the Lancaster B.I altered little during its production life, partially as a result of the sound basic structure and design; of the visible changes, the fuselage side windows were deleted, the Perspex chin of the bomb-aimer was enlarged, and a larger astrodome was provided. Various additional bumps and blisters were also added, which typically housed radar equipment and radio navigational aids. Some Lancaster B.I bombers were outfitted with bulged bomb bay doors to accommodate increased armament payloads.Goulding and Garbett 1966, pp. 4–5.