The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester.

The Halifax has its origins in the twin-engine HP56 proposal of the late 1930s, produced in response to the British Air Ministry's Specification P.13/36 for a capable medium bomber for "world-wide use." The HP56 was ordered as a backup to the Avro 679, both aircraft being designed to use the underperforming Rolls-Royce Vulture engine. The Handley Page design was altered at the Ministry to a four-engine arrangement powered by the Rolls-Royce Merlin engine; the rival Avro 679 was produced as the twin-engine Avro Manchester which, while regarded as unsuccessful mainly due to the Vulture engine, was a direct predecessor of the famed Avro Lancaster. Both the Lancaster and the Halifax would emerge as capable four-engined strategic bombers, thousands of which would be built and operated by the RAF and several other services during the War.

On 25 October 1939, the Halifax performed its maiden flight, and it entered service with the RAF on 13 November 1940. It quickly became a major component of Bomber Command, performing routine strategic bombing missions against the Axis Powers, many of them at night. Arthur Harris, the Air Officer Commanding-in-Chief of Bomber Command, described the Halifax as inferior to the rival Lancaster (in part due to its smaller payload) though this opinion was not shared by many of the crews that flew it, particularly for the MkIII variant. Nevertheless, production of the Halifax continued until April 1945. During their service with Bomber Command, Halifaxes flew a total of 82,773 operations and dropped 224,207 tons of bombs, while 1,833 aircraft were lost. The Halifax was also flown in large numbers by other Allied and Commonwealth nations, such as the Royal Canadian Air Force (RCAF), Royal Australian Air Force (RAAF), Free French Air Force and Polish forces.

Various improved versions of the Halifax were introduced, incorporating more powerful engines, a revised defensive turret layout and increased payload. It remained in service with Bomber Command until the end of the war, performing a variety of duties in addition to bombing. Specialised versions of the Halifax were developed for troop transport and paradrop operations. Following the end of the Second World War, the RAF quickly retired the Halifax, after the type was succeeded as a strategic bomber by the Avro Lincoln, an advanced derivative of the Lancaster. During the post-war years, the Halifax was operated by the Royal Egyptian Air Force, the French Air Force and the Royal Pakistan Air Force. The type also entered commercial service for a number of years, used mainly as a freighter. A dedicated civil transport variant, the Handley Page Halton, was also developed and entered airline service; 41 civil Halifax freighters were used during the Berlin Airlift. In 1961, the last remaining Halifax bombers were retired from operational use.



The Avro Lancaster is a British Second World War 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-engined heavy bombers adopted by the Royal Air Force (RAF) during the same wartime 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" which could 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 Merlins 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 bombersA long, unobstructed bomb bay meant that the Lancaster could take the largest bombs used by the RAF, including the 4,000 lb (1,800 kg), 8,000 lb (3,600 kg) and 12,000 lb (5,400 kg) blockbusters, loads often supplemented with smaller bombs or incendiaries. The "Lanc", as it was known colloquially, became one of the most heavily used of the Second World War night bombers, "delivering 608,612 long tons (618,378,000 kg) of bombs in 156,000 sorties". 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 12,000 lb (5,400 kg) Tallboy and then the 22,000 lb (10,000 kg) Grand Slam earthquake bombs (also designed by Wallis). 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.