Both bombers having been developed to the same specification, as well as the Short Stirling, all three aircraft being four-engined heavy bombers adopted by the Royal Air Force (RAF) during the same wartime era. The Lancaster was designed by Roy Chadwick and powered by four Rolls-Royce Merlins and in one version, Bristol Hercules engines. It first saw service with RAF Bomber Command in 1942 and as the strategic bombing offensive over Europe gathered momentum, it was the main aircraft for the night-time bombing campaigns that followed. As increasing numbers of the type were produced, it became the principal heavy bomber used by the RAF, the RCAF and squadrons from other Commonwealth and European countries serving within the RAF, overshadowing the Halifax and Stirling. A long, unobstructed bomb bay meant that the Lancaster could take the largest bombs used by the RAF, including the 4,000 lb (1,800 kg), 8,000 lb (3,600 kg) and 12,000 lb (5,400 kg) blockbusters, loads often supplemented with smaller bombs or incendiaries. The "Lanc", as it was known colloquially, became one of the most heavily used of the Second World War night bombers, "delivering 608,612 long tons of bombs in 156,000 sorties". The versatility of the Lancaster was such that it was chosen to equip 617 Squadron and was modified to carry the Upkeep "bouncing bomb" designed by Barnes Wallis for Operation Chastise, the attack on German Ruhr valley dams. A total of 7377 units were built. For more details o the development and operational history of the Lancaster, click here.
