Екінші дүниежүзілік соғыстың «Манчестер» бомбалаушысы

British twin engine heavy bomber
the Second World War bomber

The Avro 679 Manchester was a British twin engine heavy bomber developed and manufactured by the Avro aircraft company in the United Kingdom. While not being built in great numbers, it was the forerunner of the more famed and more successful four engined Avro Lancaster, which was one of the most capable strategic bombers of the Second World War. Avro designed the Manchester in conformance with the requirements laid out by the British Air Ministry Specification P.13/36, which sought a capable medium bomber with which to equip the Royal Air Force (RAF) and to replace its inventory of twin engine bombers, such as the Armstrong Whitworth Whitley, Handley Page Hampden and Vickers Wellington. Performing its maiden flight on 25 July 1939, the Manchester entered squadron service in November 1940, just over twelve months after the outbreak of the war. Operated by both RAF and the Royal Canadian Air Force (RCAF), the Manchester came to be regarded as a complete operational failure, primarily as a result of its Rolls Royce Vulture engines, which were underdeveloped and hence underpowered and unreliable, and production was terminated in 1941. However, the Manchester was redesigned into a four engined heavy bomber, powered by the Rolls Royce Merlin engine instead, which became known as the Lancaster.

The Manchester has its origins in a design produced by Avro in order to fulfil the British Air Ministry's Specification P.13/36. This was the same specification to which Handley Page had also produced their initial design for what would become the Halifax bomber. Issued in May 1936, Specification P.13/36 called for a twin engine monoplane "medium bomber" for "worldwide use", which was to be capable of carrying out shallow (30°) dive bombing attacks and carry heavy bombloads (8,000 lb/3,630 kg) or two 18 in (457 mm) torpedoes. Additionally, provisions to conduct catapult assisted takeoffs, which would permit the carriage of the maximum payload, was also a stated requirement, although this provision was removed in July 1938. The envisioned cruising speed of the bomber was to be a minimum of 275 mph at 15,000 feet. The Air Ministry had expectations for an aircraft of similar weight to the B.1/35 specification, but smaller and faster. Avro had already started work on a corresponding design prior to having received a formal invitation to tender. The company was in competition with Boulton Paul, Bristol, Fairey, Handley Page and Shorts. Vickers also had its Warwick, which had Napier Sabre engines, but eventually chose against tendering it. In early 1937, both the Avro design and the rival Handley Page HP.56 were accepted and prototypes of both ordered; but in mid 1937, the Air Ministry exercised their rights to order the types "off the drawing board". This skipping of the usual process was necessary due to the initiation of a wider expansion of the RAF in expectation of large scale war in Europe. From 1939, it was expected that the P.13/36 would begin replacing the RAF's existing medium bombers, such as the Armstrong Whitworth Whitley, Handley Page Hampden and Vickers Wellington. The Avro design used the Rolls Royce Vulture 24 cylinder X block engine, which was two Rolls Royce Peregrine Vee cylinder blocks mounted one on top of the other, the bottom one inverted to give the "X" shape. When developed in 1935, the Vulture engine had promise — it was rated at 1,760 hp (1,310 kW) but it proved woefully unreliable and had to be derated to 1,480–1,500 hp (1,100–1,120 kW). Avro's prototype Manchester L7246, was assembled by their experimental department at Manchester's Ringway Airport and first flew from there on 25 July 1939, with the second aircraft following on 26 May 1940. The Vulture engine was chosen by Avro and not stipulated by the Air Ministry as is sometimes claimed; other engine layouts considered included the use of two Bristol Hercules or Bristol Centaurus radial engines. While the Manchester was designed with a twin tail, the first production aircraft, designated the Mk I, had a central fin added and twenty aircraft like this were built. They were succeeded by the Mk IA which reverted to the twin fin system but used enlarged, taller fin and rudders mounted on a new tailplane, with span increased from 22 ft (6.71 m) to 33 ft (10.06 m). This configuration was carried over to the Lancaster, except for the first prototype, which also used a central fin and was a converted, unfinished Manchester. Avro constructed 177 Manchesters while Metropolitan Vickers completed 32 aircraft. Plans for Armstrong Whitworth and Fairey Aviation at Ringway (now Manchester Airport) to build the Manchester were abandoned. Fairey's order for 150 Manchesters was replaced by orders for the Halifax.

The Avro Manchester was designed with great consideration for ease of manufacture and repair. The fuselage of the aircraft comprised longitudinal stringers or longerons throughout, over which an external skin of aluminium alloy was flush riveted for a smooth external surface. The tail shared a similar construction to the wing, featuring a twin fin and rudder configuration that provided good vision for the dorsal gunner. The cockpit housed the pilot and fighting controller's position underneath the canopy, and these two crew members were provided with all round vision. The navigator was seated aft of the fighting controller and the position included an astrodome for use of a sextant. For crew comfort on lengthy missions, a rest area was situated just to the rear of the main cabin. The aircraft's undercarriage was entirely retractable via hydraulic systems, or in an emergency, a backup air system. The Manchester was powered by a pair of Vulture engines; in service these proved to be extremely unreliable. Aviation author Jon Lake stated of the Vulture: "The engine made the Manchester mainly notable for its unreliability, poor performance, and general inadequacy to the task at hand" and attributed the aircraft's poor service record to the engine troubles.</blockquote>