B-17 Flying Fortress

The B-17 Flying Fortress was an American four-engine heavy bomber developed by Boeing in the mid-1930s for the United States Army Air Corps, entering service in April 1938. It became the most prolific American heavy bomber of the Second World War, dropping over 640,000 tons of bombs on Nazi Germany and occupied Europe, roughly 42.6 percent of the total tonnage the United States Army Air Forces delivered against those targets. The aircraft earned a lasting reputation for structural toughness, built on repeated accounts and photographs of severely battle-damaged B-17s, missing engines or large sections of tail or wing, that nonetheless limped home to friendly airfields. Flying in massed daylight formations over occupied Europe, B-17 crews absorbed extremely heavy losses to German fighters and flak before long-range fighter escorts became available, a costly campaign that nonetheless became central to the Allied strategic bombing effort against Germany.