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.

Type

Wings

• Type: Mid-wing cantilever monoplane.
• Structure:
  • Composed of five main sections: a centre-section with inboard engine mountings, two intermediate sections, and two outer sections with outboard engine mountings.
  • Centre-section has two spars: a girder structure front spar and a rear spar with T-section booms.
  • Intermediate and outer sections have T-section and L-section spars respectively.
  • Detachable trailing-edge sections behind rear spars; leading-edge of outer sections is armored and equipped with balloon cable cutters.
  • Constructed with former ribs, spanwise stringers, and a smooth light alloy skin.
  • Ailerons: Aluminium-alloy frames covered with fabric.
  • Flaps: Handley Page slotted trailing-edge flaps between ailerons and fuselage.

Fuselage

• Type: Oval-section light alloy monocoque structure in four main sections.
• Structure:
  • Constructed with L-section and U-section frames, L-section stringers, and stressed-metal skin.
  • Two channel-section longerons run the length of the fuselage along the sides, supporting the floor.

Tail Unit

• Type: Cantilever monoplane with twin fins and rudders.
• Structure: Two-spar tailplane with balanced elevators and rudders. Trimming tabs are present in all control surfaces.

Landing Gear

• Type: Retractable, with Messier hydraulic units and auxiliary hand pumps.
• Structure:
  • Wheels retract backward into the inner engine nacelles, partially protruding but covered by doors.
  • Retractable tail-wheel.

Power Plant

• Engines: Four Bristol Hercules fourteen-cylinder radial air-cooled sleeve-valve engines.
• Propellers: Three-blade Rotol constant-speed full-feathering airscrews.
• Fuel: Twelve self-sealing fuel tanks (four in each intermediate wing section, two in each outer wing's inner end). Total capacity: 1,998 gallons.
• Oil Tanks: Located in the outer engine nacelles and the centre-section's leading edge for inboard engines.

Accommodation

• Crew: Seven members, including two pilots, navigator, radio operator, and three gunners.
• Layout:
  • Bomb-aimer's position in the extreme nose, followed by the navigator's compartment and pilots' compartment.
  • Radio operator situated below pilots; engineer's station behind pilots.
  • Upper midships gun-turret and tail-turret are located behind the wings.
  • Bunks for crew rest in the centre-section; walkway throughout the fuselage for access.

Armament, Bombs, Armour, and Equipment

• Machine Guns: Nine Browning 0.303 in. machine-guns.
  • Eight in two hydraulically-operated turrets (midships and tail), one manually-operated in the nose.
  • Ammunition tracks feed the tail turret from magazines aft of the midships turret.
• Bomb Compartments:
  • Main compartment in the lower fuselage (22 ft. long) with eight hydraulically-operated doors.
  • Six compartments in the centre-section, three on each side of the fuselage.
  • Handley Page loading winches for bomb loading.
  • Maximum bomb capacity: 14,500 lbs. (6,580 kg).
• Other Equipment: Full electrical and radio equipment, flares, oxygen, cabin heating, and emergency dinghies located in the trailing-edge of the port wing.

Dimensions

• Span: 104 ft. (31.7 m)
• Length: 71 ft. 7 in. (21.8 m)
• Height: 21 ft. 7 in. (6.6 m)
• Gross Wing Area: 1,275 sq. ft. (118.4 sq. m.)

Weights and Loadings

• Empty Weight: 38,239 lbs. (17,360 kg)
• Maximum Overloaded Weight: 65,000 lbs. (29,510 kg)
• Normal Wing Loading: 51 lbs./sq. ft. (248.8 kg./sq. m.)
• Power Loading: 12.7 lbs./h.p. (5.76 kg./h.p.)

Performance

• Maximum Speed: Over 270 mph (432 km/h)
• Maximum Range: Approximately 3,000 miles (4,800 km)