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 ) torpedo es . 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 block s mounted one on top of the other , the bottom one inverted to give the " X " shape . When developed in 1935 , the 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 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 tail s , 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 . 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 . In total two prototypes and 200 production aircraft were built before the production lines changed to building the four - engine Lancaster .