The B-17 Flying Fortress

A magnificent machine, the B-17 Flying Fortress remains an iconic image of the strength and power which the United States of America brought to the European theater’s air war during the Second World War.  Boeing designed and produced the B-17 in response to the United States Army’s call for a long-range bomber.  Boeing’s B-17 would be the key tool used in the Allies’ strategic bombing campaign against Nazi Germany.  Due to the B-17’s heavy armament, its long range, and large pay load, the B-17 flew in massed formations that enabled the bomber groups to deliver precision bombing against targets deep within German held territories. B17-3

The desire for a long-range bomber arose from the air war theories put forth by American General Billy Mitchell, and General Giulio Douhet, an Italian.  While Mitchell appreciated the need for a large variety of aircraft for an array of tactical and strategic uses, Douhet focused primarily upon the need for powerful bombers.  The strategic bomber, specifically long-range bombers, Douhet argued, were necessary to destroy the industrial, civilian, and governmental centers of an opponent.  In order to succeed in the next generation of warfare, according to Douhet, nations needed to prepare intense and prolonged bombardment campaigns.  The development of long-range, self-sufficient strategic bombers were of the utmost importance for a nation’s offensive capabilities.

The United States Army took the exhortations of Douhet and Mitchell to heart, and sought out a manufacturer to create a plane which would meet the specifications of Giulio Douhet for the future of strategic air warfare.  The United States Army brought its need to the Boeing Aircraft Company in Seattle, Washington, and in 1934 Boeing began work on the project.  By July 28, 1935, Boeing had developed and built the Boeing 299, whose designation would change to the B-17.  Within 12 months Boeing had put what would be one of the Second World War’s greatest weapons into the air.  The Army was so impressed with the B-17, and the possibilities it held, that the Army placed an order for 65 of the B-17 production models.  The purse strings of the Army Air Force were drawn tight, however, and only 13 could be ordered and purchased.

Even with this small number – which arrived in the first eight months of 1937 – the United States Army Air Force began the creation of what would be the world’s largest, long-range strategic bomber force.  By 1939, and the outbreak of hostilities initiated by Nazi Germany in Europe, the United States was the only nation which had developed and produced a long-range bomber capable of seeing the theories of strategic air warfare brought to fruition.  By the end of the Second World War the original B-17 as delivered to the Army Air Force in 1937 had undergone improvements and modifications.  In 1945 the B-17s taking to the air against the Axis Powers were fearsome, deadly bombers.

Each bomber had a large crew, which usually consisted of 5 gunners, a bombardier, a radio operator, and two pilots.  The pilots were in control of an aircraft that was 74 feet 9 inches in length; 103 feet 9 inches in width; and weighed an impressive 65,000 pounds.  The B-17 was powered by four Wright R-1820-97 engines, each one being 1,200 horsepower.  These engines allowed the B-17 to reach a top speed of 287 mph, and maintain a cruising speed of 150 mph.  The B-17, so equipped, could climb to a ceiling of 35,600 feet, and had a maximum range of 3,750 miles.  The B-17 also carried a bomb load of 9,600 pounds, and as the plane made its way to its target, it was protected by 11 to 13 .50 caliber machine guns placed strategically around the plane.

The machine guns were the impressive M2 Browning .50 caliber, a belt-fed, air cooled weapon that operated on a short recoil principle, firing a cyclic rate of an average of 450 to 600 rounds per minute.  The World War Two era M2 had a maximum effective range of 1.8 kilometers, and a maximum range of 7.4 kilometers.  The M2 was also designed to meet a wide range of tactical needs, and for use on multiple weapons platforms.  As such, the M2, as a belt-fed weapon, could be adapted to accept ammunition fed from either the right or left sides.  The M2s, in the hands of the trained machine gunners of the bomber crews, were essential for a B-17’s survival from the airfield to the target, and back again.

Once at the target the pilots and bombardiers worked together to deliver the payload onto the marks.  The tool necessary for this deliver was the Norden bomb sight.  Designed and built b Carl L. Norden, the Mark XV bomb sight was made up of over 2,000 components which allowed the bombardier to release a bomb from four miles up, and place the weapon within the confines of a 100 foot circle.  In order to do this the plane needed to maintain a fixed altitude and speed for 15 to 20 seconds, a feat accomplished by an autopilot also designed by Norden.  The Norden bomb sight was such an integral part of the success of the strategic bombing campaign that bombardiers swore an oath to destroy the sight rather than let it fall into enemy hands.

Equipped with the Norden bomb sights, defended by the M2 .50 caliber machine guns, powered by the Wright R-1820-97 1,200 horsepower engines, and built with a flexible frame, the B-17 could absorb massive amounts of damage.  Even when seemingly fatally crippled, the B-17 could deliver its payload and return to base – all without a long-range fighter escort through most of the war.  B-17s could fly in massed formations as large as a thousand planes, and together they would muscle their way to their targets, losing large numbers of planes to German interceptors and ground fire, suffering a casualty rate comparable to that of the submarine fleets of the various combatants.  The intense and harrowing nature of their missions has earned the B-17s and their crews a hallowed place in not only the history of the Second World War, but in the long history of warfare itself.

One thought on “The B-17 Flying Fortress

  1. When I lived in New Jersey, I heard about a route that ferried aircraft from a plant in Wichita, KS to Port Elizabeth, NJ for shipment to Europe during WW II.
    It was called “Bombers Crossing.”
    Are you familiar with that?

    Thanks.

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