Flying Fortress Summary

  • Last updated on November 10, 2022

A four-engined heavy bomber of World War II; one of the most important bombers of any kind in that war, it was legendary for the amount of battle damage it could absorb and still fly back to its base.

The B-17 was born in 1937. The Boeing company had privately designed and made the Model 299 prototype when the U.S. Air Corps needed a heavy bomber to replace the smaller, slower Martin B-10. The early B-17’s, B through D models, had no tail turret, no forward armament, and no ball turret; they had .30-caliber machine guns, which proved too light for defense against German fighters. After some combat experience with the early B through D models, the B-17E was designed with increased armament, entering service in 1941. This became the general type on which all later models were based. Over twelve thousand B-17’s of all types were built through 1945. Most B-17’s saw service in Europe, although they were also used in the Pacific and other theaters.


The B-17 was a midwing monoplane constructed of aluminum skin over a steel and aluminum framework. The wingspan was just over 103 feet; the plane was just over 74 feet long. The four engines, two in each wing of the aircraft, were turbocharged 1,000-horsepower Wright radial engines, powering the plane to a maximum speed of more than 300 miles per hour, with a service ceiling of between 34,000 and 38,000 feet. The aircraft was unpressurized; aircrew breathed from an oxygen system and were thickly dressed against the thin air and subzero temperatures of the high bombing altitudes. Armor in the plane shielded each position. The B-17 was capable of carrying up to 17,600 pounds of bombs, depending on the length of the flight, the types of bombs carried, the target, and the amount of fuel needed. Without extra tanks in the bomb bay, the maximum amount of fuel that could be carried was 780 gallons.

The B-17 carried a crew of ten men in its fuselage: the pilot and copilot in the cockpit, bombardier and navigator in front of them in the nose of the plane; the flight engineer (who also was top turret gunner) standing in a motorized turret directly behind and slightly above them; and the radio operator (who also operated a machine gun) behind the flight engineer. Beyond the bomb bay were two waist gunners, each with a .50-caliber machine gun; at their feet was the revolving Sperry ball turret, which contained one gunner, curled up in the ball turret and operating two machine guns. The tail of the plane contained two more .50-caliber machine guns, operated by the tail gunner. There were various configurations—some standard, some individually rigged by crews after hard experience—of .50-caliber machine guns in the nose, operated by the navigator and bombardier, until the development of the G model, which had a chin turret containing two .50-caliber machine guns under the nose.

B-17’s were modified in several different configurations. Some B-17’s dropped lifeboats mounted under the belly of the plane; others were fitted with radar and used for search and antisubmarine warfare. The YB-40, conceived as a bomber escort, carried no bombs, but had extra machine guns and ammunition. It proved to be too slow and was not built in numbers.

Combat and After

One major reason for the fame of the Flying Fortress was the amount of battle damage it could absorb and still make it back to base after a bombing run. Flying Fortresses could return to base with only two of the four engines operating; with tail, wing, and nose surfaces sheared off; and with holes made by bullets and cannon shells peppering the fuselage. Many wounded airmen credited the B-17 with saving their lives. The aircraft was not invulnerable, however—four thousand B-17’s were destroyed in combat during the war. Attrition was highest before Allied fighters with auxiliary fuel tanks began escorting the bombers on missions in 1943. B-17’s usually flew in a combat formation that maximized the defensive firepower of the aircraft as well as the aircraft surrounding it. Missions could last up to eight hours from takeoff to the return of the planes to their bases.

B-17’s were superseded in the Pacific by the larger, faster B-29’s. Many B-17’s were converted and used as aerial spraying planes, transports, water-bombing planes for fighting forest fires, and for other uses. Of the over twelve thousand Flying Fortresses built, most were scrapped after the war, but many B-17’s remain intact, retained or reconverted to military status by collectors and historic aircraft foundations. Many serve as static displays or “gate guards” at military (especially Air Force) bases and museums throughout the United States and Europe. Many others are still flying in the United States and Great Britain as part of historic aircraft collections.

  • Caidin, Martin. Flying Forts. New York: Bantam, 1990. A detailed account of the history of the B-17 and its missions around the world during World War II, by one of America’s best aviation writers.
  • Dorr, Robert E. U.S. Bombers of World War II. London: Arms and Armour, 1989. Contains a critical appraisal of the B-17 and its effectiveness in the air war over Europe.
  • Jablonski, Edward. Flying Fortress: The Illustrated Biography of the B-17’s and the Men Who Flew Them. Garden City, NY: Doubleday, 1965. One of the definitive accounts of the history of the B-17 and its operations in World War II.

Air Force, U.S.


Dresden, Germany, bombing

Firefighting aircraft

Military flight

World War II

The B-17 Flying Fortress was legendary for the amount of damage it could sustain on a bombing mission and still return its crew home.

(AP/Wide World Photos)
Categories: History