prototypes to be produced by July 1941. In fact a contract was awarded for four prototypes of a four-engine bomber to replace the Manchester. The first was to feature a modified Manchester fuselage powered by four Merlin X
engines, the second was to be representative of the final production airframe and the third was to be fitted with four Bristol Hercules engines, while the fourth prototype was never built. Chadwick and Dobson had earned a reprieve and the Manchester Mark III was born.
The making of a legend
Authority to go ahead with the four prototype Manchester III airframes was given to A. V. Roe on 19 November 1940. In order to save time, a Manchester Mark I airframe, BT308, was taken off the production line and fitted with four 15
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General view of the Lancaster
Merlin X engines to become the first prototype Manchester III. A. V. Roe cockpit. The pilot’s seat is at
experienced some difficulty in getting supplies of Merlin engines due to the the extreme left, the fold-down
Ministry of Aircraft Production’s determination that all Merlin production second pilot’s seat to the
should be reserved for desperately needed Spitfire and Hurricane production, right. The dark area at the
bottom right leads to the
but Chadwick and Dobson acquired four engines for BT308 from a close
bomb aimer’s position and the
friend at Rolls-Royce. Yet another obstacle in their path had been overcome.
front turret.
Chadwick and Davies then agreed that BT308 should remain a standard
Manchester fuselage assembly but that the wings would be modified with new outer wing and power-plant assemblies. The aircraft would retain the standard Manchester undercarriage and electrical system powered by the inner engines, but would have a larger 33ft tail plane with standard Manchester fins. BT308
would also retain the third central fin on the rear fuselage section. The inner engines were located at the same points on the wing but in redesigned fairings to accommodate the new engines. The outer engines were fitted in locations determined by the diameter of the propeller arcs, but as far inboard as was possible. The cockpit of BT308 retained a similar layout to production
Manchester Mark Is, but with a wider centre console to accommodate the four engine throttle levers side by side, with the propeller controls mounted underneath as opposed to their position alongside the throttle in the Mark I.
All flight instruments remained the same as for a Mark I other than the increased instruments for the additional pair of engines.
BT308 was completed and transported to Ringway (now Manchester
International Airport) for its first flight, which was delayed by changes to the hydraulic system and fog. The flight took place on 9 January 1941 with A. V.
Roe test pilots ‘Sam’ Brown and Bill Thorn at the controls. The flight was successful, and nine more test flights followed in quick succession before BT308 was handed over to A&AEE at Boscombe Down on 27 February for
intensive flight trials.
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Meanwhile, it had been decided at A. V. Roe that the new bomber should
adopt a new name. The designers had informally christened the project with the name ‘Lancaster’ and used that name for some time when referring to the Type 683, although the term had not been recognized by the Air Ministry. On 28 February 1941 the name was formally approved and the new aircraft was officially christened. A legend had arrived to take its place in aviation history.
A new bomber for the RAF
After trials at A&AEE, BT308 arrived back at A. V. Roe to be fitted with a new tail section, including the removal of the central fin. The trials at Boscombe Down had proved successful, with only slight directional stability issues being reported, and it was expected that these would be solved by the new tail assembly. After modification BT308 returned to Boscombe Down for
preliminary service evaluation and in September 1941 it was delivered to RAF
Waddington for familiarization and crew training.
Meanwhile the second prototype, DG595, made its maiden flight of 20
minutes on 13 May 1941. DG595 was built to be as close as possible to
production airframes. It was stressed to the maximum production weight of 60,000lb all up and was capable of carrying a full war load, including the addition of Nash and Thompson FN50 dorsal and FN64 ventral gun turrets.
DG595 was powered by four Rolls-Royce Merlin XX 12-cylinder, 60-degree
ATA Pilot Mrs Ruth Moore
upright vee, liquid-cooled inline engines with single-stage centrifugal performs pre-flight checks on superchargers. The third prototype, DT810, made its first flight on a new Lancaster. The ground crewman is standing in the
26 November 1941, by which time the first production Lancaster Mark I well leading to the steps into had already flown. DT810 was, according to the initial order, to be the the bomb aimer’s position.
prototype Lancaster Mark II. It
was powered by four Bristol
Hercules VI air-cooled, two-row,
14-cylinder, sleeve-valve radial
engines with two-speed centrifugal
superchargers. The fourth
prototype, DT812, was never built.
In anticipation of the Lancaster
being successful, the original
production order for 1,200
Manchesters was amended. The
contract awarded to A. V. Roe at
Newton Heath was altered so that
the first 157 aircraft would be
completed as Manchester Mark I/Ia
airframes, the remaining 43 as
Lancasters. The contract awarded
to Metropolitan Vickers for 100
Manchesters required the first 43
to be completed as Manchester
Mark I/Ia, while the remaining 57
aircraft were to be completed as
Lancasters. The initial orders for
Fairey Aviation and Sir W. G.
Armstrong Whitworth and Co. for
300 Manchesters were cancelled.
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In order to co-ordinate Lancaster production across different factories, the Lancaster Production Group was set up in September 1941. The group
originally consisted of three members, A. V. Roe in Newton Heath and the new factory at Chadderton, Metropolitan Vickers at Trafford Park and Sir W. G.
Armstrong Whitworth and Co. in Coventry. The group was later joined by
Vickers-Armstrong at Castle Bromwich. Increased demand for Lancasters
resulted in expansion of the group to include Vickers at Chester and the Austin Motor Company (Austin Aero) in Birmingham.
The first production Lancaster, L7527, commenced production as a
Manchester I airframe but was modified on the production line to Lancaster Mark I standard. L7527 made its maiden flight from Woodford Aerodrome
on 31 October 1941, and several suggestions for modifications were made.
The most significant change was the removal of the Nash and Thompson
FN64 ventral turret, which was conceived to be of little use, especially in night operations. The aircraft was declared fit for service with Bomber Command by A&AEE at Boscombe Down. It had been decided to re-equip one of the squadrons operating the obsolete Hampden first as part of the phasing out of that aircraft rather than a squadron already using Manchesters. The first three airframes were delivered to No. 44 (Rhodesia) Squadron at Waddington on 24 December 1941, with four more received four days later to begin the replacement of its Hampdens. The decision meant that the Lancaster would serve for a short time alongside its less illustrious forebear. The Royal Air Force now had its new capable bomber.
In order to equip Bomber Command
with the new aircraft, new production
orders for Lancasters were awarded to the Lancaster Production Group.
Contract B.69274/40 was awarded to A. V. Roe at Newton Heath for a total of 650 Lancaster Mark I aircraft. The figure was later revised to 407 aircraft, to be delivered in two batches. The first batch of 200 was to be delivered between February and July 1942, the second batch of 207 between July and November 1942. Contract B.69275/40 was awarded to Metropolitan Vickers
for 170 Mark I and 30 Mark III aircraft to be delivered between September 1942
and May 1943.
TECHNICAL SPECIFICATIONS
The Lancaster was designed from the start to be flown by a crew of seven, which initially included a second pilot. The role of second pilot was removed early in the type’s gestation when a shortage of pilots available to the Royal Air Force made the provision of a second pilot a luxury that the force could not afford. Instead, one of the other crew members was given training as the pilot’s assistant. Increased specialization of navigation and bomb aiming resulted in the two tasks being split into two separate crew roles, provision for which had always been included in the design of the Lancaster. Another role designed into the crew of the Lancaster was that of specialist flight engineer, which had resulted from the complexity of the modern four-engine bombers LANCASTER B. MARK II
B
Lancaster B. Mark II, DS685 of 115 Squadron, 2 August 1943. DS685 is equipped with the standard engine cowling fitted to all but the first few production machines. DS685 is fitted with bulged bomb bay doors and the FN.64 ventral turret.
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Avro Lancaster B. Mark I,
received by Bomber Command. The standard crew of a Lancaster was made
HK564 (JN-F) of No. 75
up of the pilot, who also commanded the aircraft, navigator, flight engineer, Squadron. The general layout
bomb aimer (who also doubled up as front gunner when not engaged in his of the Lancaster is shown well
bomb-aiming role), wireless operator, mid-upper gunner and tail gunner.
in this image. The aircraft is
fitted with the bulged bomb
The Lancaster airframe was of all-metal construction, 69ft in length with bay doors fitted to later
a wingspan of 102ft, and 20ft in height. The fuselage was constructed of light production Mark Is. The mid-alloy monocoque, which accommodated the crew and their equipment, the
upper turret is fitted with the
bomb bay and defensive armament. The fuselage, roughly oval in cross section, fairing to prevent the gunner
shooting at his own aircraft
was broken down for production into five modular sections: the nose section, accidently. The position of the
front fuselage, intermediate section, rear-centre, and the rear fuselage. Each ailerons is shown clearly by
section was fully assembled and equipped before being brought together.
the gaps in the trailing edge of
The nose section consisted of the fuselage section, which was fitted with the wing. The aircraft lost
both ailerons during a raid on
a hemispherical transparent Perspex dome that incorporated a flat circular 25 August 1944 and still
glass vision panel for bomb aiming (although this was not fitted on all brought its crew home.
aircraft). The floor of the section was fitted with the forward escape hatch, and the walls with numerous windows for the bomb aimer. The forward
power-operated Nash and Thompson FN5 turret was fitted above and
behind the bomb aimer’s blister.
The front fuselage section contained the main cockpit area, in which was sited the pilot’s position on a raised platform on the forward port side of the cabin. The rest of the cabin in the front fuselage accommodated the navigator, wireless operator and flight engineer with their equipment. Below the floor of the cabin could be found the forward part of the bomb bay. The nose and front fuselage sections when connected together were just over 20ft in length and for transportation the two sections would remain joined.
The intermediate centre section was 8ft in length and was constructed
around the front and rear main spars for the wing. The centre section also contained the emergency escape hatch in the roof for escape should the aircraft be forced to ditch on water. The bomb bay continued under the cabin floor on the centre section.
The rear-centre section was over 20ft in length, and extended from the
trailing edge of the wing to the tail. The section was fitted with a Nash and Thompson power-operated FN50 dorsal turret and, on early aircraft, a Nash 20
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and Thompson FN64 ventral turret in the bottom of the section aft of the rear of the bomb bay. A small emergency escape hatch was located in the roof of the rear-centre section. Underneath the floor of the cabin, which consisted of a walkway to the rear of the aircraft, lay the rear of the bomb bay, which extended for a total length of 33ft across the front fuselage, intermediate and rear-centre sections.
The rear fuselage section was 21ft in length and built around the tail plane spars, which passed through the rear of the section underneath which was located the tail wheel assembly. The rear section contained the main crew entrance and exit doorway, situated on the starboard side of the fuselage, and a Nash and Thompson power-operated FN20 turret at the extreme rear of the section. The tail unit was fitted to the rear section and consisted of a tail plane of 33ft span with large 12ft high fins and rudders at the ends of the tail plane, which including elevators measuring 237sq. ft.
The Lancaster’s wings were of dihedral cantilever structure, built around the front and rear main spars in the centre section of the fuselage. The wings were divided for construction and transportation into five sub-assemblies: the centre section, two outer wing sections (port and starboard) and two wing tip sections (port and starboard).
The wing centre section had a span of 25ft and was integral with the
fuselage centre section. The inboard engine nacelle was located on the wing centre section and also housed the main undercarriage, which retracted
backwards into the extended rear of the engine nacelle.
The outer wing section and wing tip sections had a span of 74ft with the outer engine nacelle fitted to the outer wing section. The ailerons were mounted in the trailing edge of the outer wing section.
The wings were fitted with hydraulically operated split flaps, and initially four fuel tanks within the wing structure, which later increased to six tanks.
When assembled the wings had a total area of 1,300sq. ft.
The undercarriage fitted to the inner engine nacelles consisted of a
retractable Dowty oleo-pneumatic system equipped with a single wheel and tyre. The undercarriage lever in the cockpit was locked down by a safety bolt to prevent accidental retraction on the ground, which had to be moved aside to raise the undercarriage in flight. Undercarriage indicators in the cockpit showed two green lights when the undercarriage was locked down and two
red lights when it was locked up. The Lancaster Mark X differed in having a pictorial undercarriage fitted. A warning horn sounded if either inboard throttle was closed when the undercarriage was not locked down. The tail wheel was a non-retracting Dowty oleo-pneumatic assembly.
The Lancaster was fitted with a dazzling variety of electronic equipment during its service life, which will be covered later in this volume.
THE LANCASTER: MARK BY MARK
Identifying marks of the Lancaster can at best be described as tricky due to the variety of equipment fitted to various aircraft over time. For example, not all Mark I Lancasters were fitted with H2S radar with its obvious blister, and other differences, such as those between Mark I and Mark III, are almost impossible to discern
without reference to serial numbers. Even then this is not conclusive, as will be discussed in the analysis of the main salient differences between marks of the Lancaster that follows.
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Lancaster B. Mark I
Power:
4 1,280hp Rolls-Royce Merlin XX engines with 3-bladed De-Havilland D.H.5/40 variable pitch airscrews, interchangeable with Hamilton A 5/138 airscrews
Dimensions:
Span: 102ft
Length: 59ft 6in
Height: 20ft
Wing area: 1,300sq ft
Weight:
Empty: 37,000lb
Normal take-off weight: 65,000lb
Performance: Max speed: 275mph at 15,000ft
Service ceiling: 24,500ft
Range: 2,530 miles (7,000lb load) or 1,700 miles (12,000lb load)
Armament:
Early aircraft: 9 Browning .303 machine guns in power-operated turrets: 2 in FN5 nose, 2 in FN50 mid-upper, 1 in FN64
ventral and 4 in FN20 tail turrets
Later aircraft: 8 Browning .303 machine guns in power-operated turrets: 2 in FN5 nose, 2 in FN50 mid-upper, and 4 in FN20 tail turrets
8,000lb of bombs or 12,000lb with bulged bomb doors
Serials:
A. V. Roe: L7527-L7549, L7565-L7584, R5482-R5517,R5537-R5576, R5603-R5640, R5658-R5703, R5274-R5763, W4102-W4140, W4154-W4201, W4230-W4279,W4301-W4340, W4355-W4384, ED303-ED334, ED347-ED386, ED389, ED391-ED392, ED394, ED409, ED411-ED412, ED414, ED418, ED420, ED422, ED425, ED430, ED436, ED439, ED443, ED446-ED447, ED451, ED498, ED521-ED522. ED525, ED528, ED533, ED537, ED548, ED550, ED552, ED554, ED567, ED569, ED586, ED591, ED594, ED600-ED601, ED604, ED610, ED622,ED631, ED661, ED692, ED703, ED715, ED732, ED735, ED749, ED751, ED754-ED755, ED757-ED758, ED761-ED763, ED766, ED769-ED770, ED773-ED774, ED777-ED778, ED780-ED782, PB643-PB647, PB671-PB674, PB686-PB692, PB695-PB696, PB703-PB705, PB708, PB721-PB727, PB730-PB732, PB734-PB757, PB759-PB768, PB780-PB823, PB836-PB881, PB893-PB922, PB924-PB936, PB949-PB959, PB961, PB981-PB994, LM301-LM310, ME328, ME330, ME350, ME352, ME371-ME374, ME383-ME384, ME419-ME421, ME431-ME440, ME445-ME451, ME455-ME458, ME470, ME475-ME477, ME479-ME480, ME482, ME490, ME495
Avro Lancaster Page 3