AVRO 683 Lancaster - Engine Variations

(Monochrome Photograph showing a - Lancaster Mk.II DS689 OW-S of 426 Sqn., showing the Bristol Hercules radial engines.)

With the expansion of Bomber Command as the war progressed, more heavy bomber squadrons were formed and as a consequence more Lancasters were ordered. This, in turn, put a greater demands on Rolls Royce Merlin engine production.

Two solutions to this problem were undertaken. The first was to redesign the engine nacelles to accept four 1,650 hp.(1,230 kW.) Bristol Hercules air-cooled radial engines.

Following acceptance test of a prototype, production of this variant was undertaken by Armstrong Whitworth with the designation Lancaster Mk.II and deliveries started in September 1942.

The second proposal was to fit Packard (North American) built Merlin engines and this version was given the designation Lancaster Mk.III. In the event these became available very quickly and deliveries commenced early in1943.

(Monochrome Photograph showing a - Lancaster Mk. III PD235 UL-N2 of 576 Squadron 1945.)