The first production model of the series was the Mk I, also originally designated the Manchester Mk III.[N 2]The Lancaster was powered by 4 Rolls-Royce Merlin engines[N 3] and could normally hold up to 6,300 kg of bombs. For its own defense, the aircraft was usually armed with 8 Browning M1919 machine guns - two each in nose and dorsal turrets, and four in the tail turret.
The aircraft carried 14,000 rounds of ammunition - 1,000 rounds per gun for the nose and dorsal turrets, and 2,500 rounds per gun for the tail turret. In order to operate efficiently, the Lancaster required a crew of eight men while the service ceiling of the Lancaster was 7,400 metres. Its total length was 21 metres, wingspan was 31 metres, and its total weight was about 30,000 kg. Operational range was 4,300 kilometres.
The first variant of the Lancaster was the B.Mk II that came with Bristol Hercules radials, developed to ensure deliveries of Lancaster aircraft in the event of disruption in deliveries of the Merlin. 300 examples were built by W. G. Armstrong Whitworth Aircraft. Also produced at this time were the PR.Mk I and ASR.Mk I, the PR.Mk I was fundamentally the Mk I fitted with additional camera equipment for reconnaissance purposes while the ASR.Mk I was an at sea rescue platform. Following came the B.Mk III which sported Packard constructed Merlin Engines of differing models as the war progressed. The first sub-variant of the Mk III was the GR.Mk III which was a maritime patrol unit.
The Mk VI and VII models were introduced following what would have been the Mk IV and V but were then redesignated as the Avro Lincoln. The VI featured Merlin 87 engines while the Mk VII featured redesigned turret layouts.
Due to the chronic unreliability of the Avro Manchester, Avro decided in 1940 to suggest development of an improved version, with longer span wings carrying four Rolls Royce Merlins. This prompted the Air ministry to write a specification around Avro's proposal, calling for a cruising speed of 250 mph (402 km/h) at 15,000 ft (4,575 m) and ability to carry a bombload of 7,500 lb (3,405 kg) over a range of 2,000 miles (3,218 km). Maximum range was to be 3,000 miles (4,827 kg). The prototype Lancaster - BT308 - was first flown on 9 January 1941. Originally known as the Manchester III, the aircraft performed so well that Avro decided to commence large scale production by completing Manchester airframes already on the production line as Lancaster aircraft.[N 4]
The Lancaster was introduced into RAF service by 44 (Rhodesia) Squadron in early 1942, who had previously operated the Handley Page Hampden. On March 1942, the squadron carried out the Lancaster's first operation mission, dropping mines in the Heligoland Blight. Later in 1942, the Lancaster was used in its first ever raid upon the German city of Essen. By the end of the war, around 156,000 sorties had been flown by Lancasters and out of the 7,300 produced during the war, over 3,000 had been lost in combat operations. Most notably, the Lancasters were used in the infamous Dambusters Raid in 1943, as well as the sinking of the German battleship Tirpitz in 1944.
After the war, Lancasters were among the aircraft types used for the repatriation of Allied Prisoners of war.
- 300 production aircraft were powered by 4 Bristol Hercules VI Engines, in order to maintain production in the event of interruption of Merlin production.
- By 1942, all Lancaster models were redesignated to B.Mk #
- The exception was the Mk II, which was fitted with Bristol Hercules radials.
- Starting with L7527, the early Manchester fuselage Lancaster can be identified by the row of small windows on the upper rear fuselages. 300 Lancasters - 243 by Avro and 57 by Metropolitan Vickers - had originally been the subject of production contracts for the Manchester.
- Gunston, Bill. Illustrated Directory of Fighting Aircraft of World War II. Salamander Books. (1988), pg. 332/334 ISBN 0-86101-390-5 Cite error: Invalid
<ref>tag; name "IGTFAOWW2 p332/334" defined multiple times with different content
- Green, William. Famous Bombers of the Second World War. (1975), Page 216
- World Aircraft Information Files Aviation Partwork. Midsummer Books Ltd. File 21 Sheet 1:World Military Aircraft:Avro Lancaster - Introduction
- Green, William - Bombers. 1975. Page 207
- Green, William - Bombers. 1975. Page 210