The Handley Page Halifax was one of the front-line, four-engine heavy bombers of the Royal Air Force during World War II. A contemporary of the famous Avro Lancaster, the Halifax remained in service until the end of the war, performing a variety of duties in addition to bombing.
Handley Page produced the H.P.56 twin-Vulture engined design to meet Air Ministry Specification P.13/36 but performance was found to be lacking. Modifications resulted in the definitive H.P.57 Halifax design; the aircraft was enlarged and powered by four 1,280 hp Rolls-Royce Merlin X engines. Such was the promise of the new model that the RAF had placed their first order for 100 Mk I Halifaxes before the first prototype even flew on September 24, 1939, shortly after the start of the war. The Halifax entered service with No. 35 Squadron RAF at Linton on Ouse in November 1940 and its first operational raid was against Le Havre on the night of March 11-12, 1941.
The Mk I had a 22 ft bomb bay as well as six bomb cells in the wings, enabling it to carry 13,000 lb (5,897 kg) of bombs. Defensive armament consisted of two .303-in Browning machine guns in the nose, four in a tail turret and in some aircraft, two waist guns. Subtle modifications distinguished the Mk I aircraft. The first batch of Mk I Halifaxes were designated Mk I Series I. The Mk I Series II increased the aircraft’s gross weight (from 58,000 lb to 60,000 lb) and the Mk I Series III increased fuel capacity.
Introduction of 1,390 hp Merlin XX engines and a twin .303-in dorsal turret instead of waist guns resulted in the Mk II Series I Halifax. The Mk I Series I (Special) achieved improved performance by removing the nose and dorsal turrets. The Mk II Series IA had a moulded Perspex nose (the standard for future Halifax variants), a four-gun Defiant-type dorsal turret, Merlin 22 engines and larger tail surfaces which solved control deficiencies in the early Marks. The installation of Dowty landing gear and hydraulics (in place of the standard Messier equipment) on the Mk II Series I (Special) and IA produced the Mk V Series I (Special) and Mk V Series IA. A total of 1,966 Mk II and 915 Mk V Halifaxes were built.
The most numerous Halifax variant was the Mk III of which 2,091 were built. First appearing in 1943, the Mk III featured the Perspex nose and modified tail of the Mk II Series IA but replaced the Merlin with the more powerful 1,650 hp Bristol Hercules XVI radial engine. Other changes included DH Hydromatic propellers and rounded wing-tips. The Mk IV was a non-production design using a turbocharged Hercules powerplant.
The definitive version of the Halifax was the Mk VI, powered by the 1,800 hp Hercules 100. The final bomber version, the Mk VII, reverted to the less powerful Hercules XVI. However, these variants were produced in relatively small quantities.
The remaining variants were the Mk C.VIII unarmed transport (8,000 lb cargo pannier instead of a bomb bay, space for 11 passengers) and the Mk A.IX paratroop transport (space for 16 paratroopers and gear).
In addition to bombing missions, the Halifax served as a glider tug, ECM aircraft for RAF 100 Group and special operations such as parachuting agents and arms into occupied Europe. Halifaxes were also operated by Coastal Command for ASW, reconnaissance and meteorological roles.
Total Halifax production was 6,176 with the last aircraft delivered in November 1946. In addition to Handley Page, Halifaxes were built by English Electric, Fairey Aviation, Rootes Motors and the London Aircraft Production Group. Peak production resulted in one Halifax being completed every hour.
Post-WWII, Halifaxes remained in service with the RAF Coastal and Transport commands and the Armée de l’Air until early 1952.
The Halifax was also operated by squadrons of the Royal Australian Air Force, Royal Canadian Air Force and Royal New Zealand Air Force.