Boeing B-17 Flying Fortress
The B-17 Flying Fortress was Boeing's four-engined heavy bomber, designed in the 1930s for daylight precision bombing and first flown in 1935. More than 12,700 were built. Flying the American daylight campaign over Europe, it dropped more bombs than any other U.S. aircraft of the Second World War and earned a lasting reputation for bringing damaged crews home; fewer than 50 complete airframes survive.
Why It Mattered
The B-17 dropped more bombs than any other American aircraft in the Second World War. It was the aircraft around which the United States Army Air Forces built their doctrine of high-altitude precision bombing in daylight. More than 12,700 were built, and photographs of shattered aircraft that still came home gave it a reputation for toughness that made it a symbol of American air power. Its name, too, came from outside the service: a Seattle journalist coined it after seeing the prototype's guns. Behind the symbol was arithmetic: in the campaign's first year, only 36 per cent of crewmen completed the 25-mission tour.
Design Notes
Boeing designed the B-17 to a 1934 Army Air Corps specification that called for a four-engined bomber when most bombers had two. The prototype, Boeing's Model 299, flew on 28 July 1935. Turbo-supercharged radial engines were fitted to give the altitude performance the bombing doctrine required. Bombing accuracy was to come from the Norden bombsight, developed in great secrecy during the 1930s. Defensive armament, not bomb load, took priority as the design matured: the gun count rose from seven on early models to thirteen on the definitive B-17G, which entered service in 1943. A crew of ten flew it, four of them dedicated gunners. The design nearly died at birth: the Model 299 crashed on takeoff in October 1935 because its gust locks had not been released, killing two of those aboard, and Boeing lost the first production contract. The Air Corps still ordered thirteen more for evaluation, and the type entered service in 1938.
Operational History
The type's first combat missions were flown by Britain's Royal Air Force in 1941, and American B-17s were in action in the Pacific from the war's first months. Its main work was the daylight strategic bombing campaign over Europe, flown by the Eighth Air Force from England alongside RAF Bomber Command's night offensive. In 1943 the assumption behind that campaign — that tight formations of heavily armed bombers could fight their way to distant targets without fighter escort — was tested on deep raids into Germany, and it failed. On 17 August 1943 the Regensburg and Schweinfurt missions together cost 60 B-17s; a second Schweinfurt raid on 14 October cost 60 more and is remembered as Black Thursday. Deep daylight raids into Germany were suspended until an escort fighter existed that could stay with the bombers all the way. By the time production ended in May 1945, Boeing, Douglas and Vega — the last a Lockheed subsidiary — had built 12,731 B-17s between them. In all, B-17s dropped over 640,000 tons of bombs on Germany and occupied Europe — 42.6 per cent of everything Allied aircraft dropped there. Around 5,000 B-17s were lost in accidents or shot down across the war.
Afterlife
The peace left the type surplus overnight: thousands of B-17s were retired and sold for scrap. A minority found second work: many B-17Gs were converted for cargo hauling, engine testing and reconnaissance, and others for search-and-rescue duties. Fewer than 50 complete airframes survive today, most of them museum exhibits; the standard survivors list counts 45 surviving aircraft. Fewer than ten are kept in airworthy condition. The best-known survivor is the B-17F Memphis Belle, among the first Eighth Air Force bombers to complete a 25-mission tour, restored and on display at the National Museum of the U.S. Air Force since 17 May 2018.