Originally designed to meet the Air Ministry's specification B.13/36 requesting designs for a twin-engine bomber. The Handley Page twin-engine design designated the HP-56, called for the use of two Rolls-Royce 24 Cylinder Vulture engines. These newly designed engines, which also power the Avro Manchester, were soon to prove unreliable, difficult to service and more importantly were only available in limited production quantities. Upon realising the drawbacks of the Vulture, Handley-Page redesigned the HP-56 to accept four of the proven and widely used Rolls-Royce Merlin engines; and it would be under this new design, designated HP-57 or Halifax Mk.I, that the aircraft would enter service with the Royal Air Force.
In October 1938, the Air Ministry placed an order for 100 production aircraft straight off of the drawing board. But due to development and other unforeseen problems it would not be until October 25, 1939 that the first prototype aircraft (L7244) would make its first flight. Almost another twelve months would past before No. 35 Squadron, RAF stationed at Leeming; began to trade in their Blenheim Mk. IV's for their new Halifax Mk.I's. However, it would not be until the night of March 11/12, 1941 with an attack against Le Havre, that the aircraft finally flew operationally and in doing so became the RAF's second four-engine heavy bomber to fully enter service.
The Halifax however, suffered through several initial teething problems. The most serious of which was that the rudders had a tendency when exposed to violent maneuvers, to overload, jam and therefore become ineffective. When this happened the pilot usually was unable to free the rudder from its locked position and several crashes initially determined to be caused by "unknown circumstances" were eventually traced to this problem. This design flaw along with other minor problems, were to lead to the Halifax squadron's suffering higher than expected losses in the aircraft's early months of service. Various modifications were made to the initial rudder design, including limiting the amount the rudder could be moved, but the problem was not completely eliminated until the introduction of the Mk.III, which had a rectangular, rather than a triangular shaped rudder.
In addition to the revised rudder, the Mk.III also took on a totally new appearance. Where as the Mk.I's had a front turret, a bomb aimers' nose blister, similar in configuration to the Avro Manchester and later the Lancaster, the Mk.III's nose section eliminated both the turret and bomb aimer blister. Replacing these with a streamlined plexiglas nose fairing, which allowed the bomb aimer adequate downward visibility and also included a single 0.303" machine gun on a pivot mount. This also slightly improved the overall performance of the aircraft, although this was probably due more to the replacement of the in-line Merlin X engines with 1,615 hp Bristol Hercules VI radial engines.
Regardless of the aircrafts' early shot comings, the Halifax was to prove itself as a study and reliable aircraft and played a major role in Bomber Commands' offensive against Germany. It was generally liked by the aircrews who flew it and when the time came, very few are said to have had any desire to swap it for the so called "superior" Avro Lancaster.
Although, the Mk.III was by far the most numerous of the variants built, a total of six different variants were to roll off of the production lines. The major differences between each being mainly visual, but also included different engine types, the shape of the nose and the presence or absence of a mid-upper turret.
In addition to its designed roll as a heavy bomber. The Halifax also performed sea mining operations, resupply drops to the resistance groups, performed as a gilder tug and also severed with Coastal Command. During the post war years, Halifaxes were also converted for use as civilian passenger and transport aircraft.
A total 6,176 Halifaxes of all types were built, just over one-half were of the Mk.III variant.
Halifax Mk.I Data
Crew : Seven
Engines : Four Rolls-Royce Merlin X
Span : 98'-8" (30.07 m)
Length : 70'-1" (21.36 m)
Height : 20'-9" (6.34 m)
Empty Weight : 33,720 lbs. (15,295 kg)
Loaded Weight : 58,000 lbs. (26,309 kg)
Maximum Speed : 265 mph at 17,500 ft. (5,334 m)
Ceiling : 18,000 ft. (5,486 m)
Range : 1,552 miles (2,498 km)
2 - 0.303" machine
guns in front turret, 4 - 0.303" machine guns in rear turret,
beam gun positions equipped with 1 - 0.303" machine gun each on some aircraft.
Maximum bomb load 13,000 lbs. (5,897 kg.)
Bomber Command Squadron's equipped the Halifax:
10, 35, 51, 76, 77, 78, 102, 103, 158, 171, 192, 199, 346, 347,
405, 408, 415, 419, 420, 424, 425, 426, 427, 428, 429, 431, 432, 433, 434, 460, 466, 578, 614, 640
Updated: January 2008
Halifax Mk. III
Halifax Mk. III
Halifax Mk. I