Avro Manchester

The Avro 679 Manchester was a British twin-engine heavy bomber developed during the Second World War by the Avro aircraft company in the United Kingdom. Serving in the Royal Air Force and Royal Canadian Air Force, the Manchester was an operational failure due to its underdeveloped, underpowered, and unreliable engines. However, the aircraft was the forerunner to the successful four-engined Avro Lancaster, which would become one of the most capable British strategic bombers of the war.

Development
The Manchester was originally designed to the Air Ministry Specification P.13/36 which was the same specification that Handley Page followed in their design of the Halifax bomber. The specification called for a twin-engine "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. Provision for catapult assisted takeoff to permit the maximum load was also part of the specification. Cruising speed was to be a minimum of 275 mph at 15,000 feet. The Air Ministry were expecting an aircraft of similar weight to the B.1/35 specification but smaller and faster.

Avro had already started work on a design before the invitation to tender. They were in competition with Boulton Paul, Bristol, Fairey Handley Page and Shorts. Vickers had a design but did not tender it. In early 1937 the Avro design and the Handley Page were accepted, and prototypes of both ordered but in mid-1937, the Air Ministry exercised their rights to order "off the drawing board". This skipping of the usual process was necessary because of the expansion of the RAF in expectation of war. From 1939, it was expected that the P.13/36 would replace existing medium bombers in production.

The design used the Rolls-Royce Vulture 24-cylinder X-block engine, which was essentially 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 engine had promise &mdash; 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 Rolls-Royce engine was chosen by Avro and not stipulated by the Air Ministry as is sometimes claimed. The Handley Page HP.56, always intended as the backup to the Avro, was redesigned to take four engines on the orders of the Air Ministry in 1937 as the Vulture was already showing problems.

While the Manchester was designed with twin tails, the first production aircraft, designated the Mk I, had a central fin added and a total of 20 aircraft with this configuration were completed. 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; this first prototype Lancaster was produced from converting an unfinished Manchester aircraft.

Avro built 177 and Metropolitan-Vickers completed 32 aircraft. Plans for Armstrong Whitworth and Fairey Aviation at Stockport/Ringway to build the Manchester were abandoned. Fairey's order for 150 Manchesters was replaced by orders for Halifaxes.

Design
The Avro Manchester was designed with great consideration to easing the manufacturing and repair processes. The fuselage of the aircraft comprises longitudinal stringers or longerons throughout, over which an external skin of aluminium alloy flush-riveted for a smooth external surface. The wings are of a two spar construction, the internal ribs being made out of aluminium alloys; fuel was contained with several self-sealing fuel tanks within the wings. The tail shares a similar construction to the wing, featuring a twin fin-and-rudder configuration that provides good vision for the dorsal gunner's position.

The cockpit houses both the pilot and fighting controller's position underneath the canopy, as such these two crew members were provided with all-round vision. The navigator is seated aft of the fighting controller, the position includes an astral dome for use of a sextant. The bomb aimer's station is housed inside the aircraft's nose, beneath the forward turret, bombing runs were targeted via optical sights housed in this compartment.

The aircraft's undercarriage was entirely retractable via hydraulic systems or, in emergency situations, a backup air system. The doors to the bomb bay were also operated by these same systems, an additional safety measure was installed to ensure that the aircraft's payload could not be launched if the doors were not open. The aircraft's armaments were housed within various bomb racks inside the internal bomb bay compartment.

To protect the crew and the Manchester itself, vulnerable or key locations throughout the aircraft were armoured; the pilot's position had additional armouring and bullet-proof glass is also fitted, an armoured bulkhead is also present to the rear of the navigator's position. The Manchester features three hydraulically operated turret positions for self-defence purposes, located in the nose, rear, and mid-upper fuselage. Access to all crew stations was provided by a walkway, and all crew positions had nearby escape hatches where suitable.

The Manchester was powered by a pair of Vulture engines; in service these proved to be extremely problematic. 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.

"I was one of the six original pilots to have flown with the first Manchester squadron. That was a disaster. The aircraft itself, the airframe, had many shortcomings in equipment in the beginning, but as we found out Avro were excellent in doing modifications and re-equipping the aeroplane. The engines never were and never did become reliable. They did not give enough power for the aeroplane, so we ended up with two extremely unreliable 1,750 hp engines having to haul a 50,000-pound aircraft. We should really have had 2,500 hp engines. You felt that if you'd lost one, that was it, you weren't coming home. It didn't matter if you feathered the propeller or not. There was only one way you went and that was down. I have seen an aircraft doing a run up on the ground and have two pistons come right out through the side of the engine. The original bearings were made without any silver as an economy measure, so they weren't hard enough. The bearings would collapse the connecting rod and the piston would fling out through the side of the engine and bang! Your engine just destroyed itself."

Operational history
The Avro Manchester entered service with No. 207 Squadron of RAF Bomber Command in November 1940; its first operational mission was conducted on 24–25 February 1941 in a raid on the French port of Brest. Eventually 209 Manchesters entered service, before production finished in November 1941, equipping eight bomber squadrons, serving with two others and also being used by Coastal Command.

The Mk III Manchester, BT308, which first flew on 9 January 1941, was essentially the first Lancaster, being powered by four Merlin engines and with increased wingspan, although initially retaining the three fins and twin outboard rudders (the central fin had no movable control surface) of the Manchester I. BT308 received the "Lancaster" name immediately after its first flight. The second prototype Lancaster DG595 featured the twin, enlarged fins and rudders of the Manchester IA. Manchester production continued until November of that year but some aircraft still in production were completed as Lancasters.

In June 1942 Flying Officer Leslie Manser was awarded the Victoria Cross while piloting Manchester L7301 of 50 Squadron.

The 193 operational Manchesters flew 1,269 operations with Bomber Command, dropping 1,826 tons (1,657 tonnes) of bombs and losing 78 aircraft in action, flying its last operation against Bremen on 25 June 1942. A further 45 were non-operational losses of which 30 involved engine failure. The Manchester was withdrawn from operations in mid-1942 in favour of more capable aircraft, the type persisted in use for training purposes into 1943 before being completely retired.

Variants

 * Manchester L7246
 * First prototype originally with twin tail. Due to lack of directional stability, it had a third fin added. Became a training airframe in November 1942.


 * Manchester L7247
 * Second prototype first flown 26 May 1940, fitted with armament, became a training airframe in October 1941.


 * Manchester I
 * First production version with twin tail and additional central fin added; 20 of this type were built.


 * Manchester IA
 * Main production version with twin tail with enlarged tailplane. It also had taller fins and rudders.


 * Manchester II
 * Projected version re-engined with a pair of Napier Sabre or Bristol Centaurus engines. None built.


 * Manchester III BT308
 * This version was powered by four Merlin engines with increased wingspan; also, the three fins and rudders of the Manchester I were retained. This variant was the first prototype of the later Avro Lancaster.

Orders and production
In total two prototypes and 200 production aircraft were built before the production lines changed to building the four-engine Lancaster.
 * Two prototypes were ordered against specification P.13/36 and were built by Avro at Ringway.
 * Production contract for 200 Manchesters placed with Avro to be built at Chadderton, contract changed to Lancaster I production after 157 had been built, delivered between August 1940 and November 1941.
 * Production contract for 150 Manchesters placed with Fairey to be built at Ringway, order cancelled.
 * Production contract for 200 Manchesters placed with Metropolitan-Vickers at Trafford Park, contract changed to Lancaster I production after 43 had been built, delivered between March 1941 and March 1942. The first 12 aircraft being built on the Trafford Park production line were destroyed in a German air raid on 23 December 1940, not being completed they are not included in the total aircraft built.
 * Production contract for 150 Manchesters placed with Armstrong-Whitworth, order cancelled.

Operators

 * 🇨🇦 Canada
 * Royal Canadian Air Force
 * No. 408 Squadron RCAF
 * No. 420 Squadron RCAF


 * Royal Air Force
 * No. 49 Squadron RAF at RAF Scampton (April 1942-June 1942)
 * No. 50 Squadron RAF at RAF Skellingthorpe (April 1942-June 1942)
 * No. 61 Squadron RAF at RAF Hemswell (June 1941-June 1942)
 * No. 83 Squadron RAF at RAF Scampton (December 1941-June 1942)
 * No. 97 Squadron RAF at RAF Waddington then RAF Coningsby (February 1941-February 1942)
 * No. 106 Squadron RAF at RAF Coningsby (February 1942-June 1942)
 * No. 207 Squadron RAF at RAF Waddington then RAF Bottesford (November 1940-March 1942)
 * No. 25 Operation Training Unit at RAF Finningley
 * No. 44 Conversion Flight
 * No. 1485 Flight RAF
 * No. 1654 Heavy Conversion Unit
 * No. 1656 Heavy Conversion Unit
 * No. 1660 Heavy Conversion Unit
 * No. 1668 Heavy Conversion Unit
 * Airborne Forces Experimental Establishment
 * Torpedo Development Unit at RAF Gosport
 * Torpedo Development Unit at RAF Gosport