The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force (RAF). It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other Commonwealth and European countries serving within RAF Bomber Command.
The "Lanc", as it was affectionately known, became the most famous and most successful of the Second World War night bombers, "delivering 608,612 tons of bombs in 156,000 sorties." Although the Lancaster was primarily a night bomber, it excelled in many other roles including daylight precision bombing, and gained worldwide renown as the "Dam Buster" used in the 1943 Operation Chastise raids on Germany's Ruhr Valley dams.
image source: anselm.edu
flak:
anti-aircraft gunfire, derived during World War II from the German Fliegerabwehrkanone, aircraft defence cannon; also cited as Flugzeug abwehr kanone...
The essence of air defence is to detect hostile aircraft and destroy them. The critical issue is to hit a target moving in three dimensions, which means the attack has to be in four dimensions to put the munition in the right place at the right time. This means that either projectiles have to be guided to hit the target or aimed ahead of the target by estimating, or predicting, their future position at the time of firing plus time of flight of the projectile.
