Boeing B-17 Flying Fortress
|B-17 Flying Fortress|
|A B-17G performing at the 2014 |
|National origin||United States|
|First flight||28 July 1935|
The Boeing B-17 Flying Fortress is a four-engined
The B-17 was primarily employed by the USAAF in the daylight
From its prewar inception, the USAAC (
As of October 2019,
On 8 August 1934, the USAAC tendered a proposal for a multiengine bomber to replace the
They also desired, but did not require, a range of 2,000 mi (3,200 km) and a speed of 250 mph (400 km/h). The competition for the air corps contract was to be decided by a "fly-off" between Boeing's design, the
The prototype B-17, with the Boeing factory designation of Model 299, was designed by a team of engineers led by E. Gifford Emery and
The first flight of the Model 299 was on 28 July 1935 with Boeing chief test pilot Leslie Tower at the controls. The day before, Richard Williams, a reporter for
Boeing was quick to see the value of the name and had it trademarked for use.[note 1] Boeing also claimed in some of the early press releases that Model 299 was the first combat aircraft that could continue its mission if one of its four engines failed. On 20 August 1935, the prototype flew from Seattle to Wright Field in nine hours and three minutes with an average cruising speed of 252 miles per hour (406 km/h), much faster than the competition.
At the fly-off, the four-engined Boeing's performance was superior to those of the twin-engined DB-1 and Model 146.
Development continued on the Boeing Model 299, and on 30 October 1935, Army Air Corps test pilot Major
The crashed Model 299 could not finish the evaluation, disqualifying it from the competition. While the air corps was still enthusiastic about the aircraft's potential, army officials were daunted by its cost; Douglas quoted a unit price of $58,200 (equivalent to $1.06 million today) based on a production order of 220 aircraft, compared with $99,620 ($1.82 million today) from Boeing. Army Chief of Staff
The loss was not total... but Boeing's hopes for a substantial bomber contract were dashed.— Peter Bowers, 1976
Regardless, the USAAC had been impressed by the prototype's performance, and on 17 January 1936, through a legal loophole, the Air Corps ordered 13 YB-17s (designated Y1B-17 after November 1936 to denote its special F-1 funding) for service testing. The YB-17 incorporated a number of significant changes from the Model 299, including more powerful
Between 1 March and 4 August 1937, 12 of the 13 Y1B-17s were delivered to the 2nd Bombardment Group at Langley Field in Virginia for operational development and flight tests. One suggestion adopted was the use of a
A 14th Y1B-17 (37-369), originally constructed for ground testing of the airframe's strength, was upgraded and fitted with exhaust-driven General Electric turbochargers. Scheduled to fly in 1937, it encountered problems with the turbochargers, and its first flight was delayed until 29 April 1938. The aircraft was delivered to the army on 31 January 1939. Once service testing was complete, the Y1B-17s and Y1B-17A were redesignated B-17 and B-17A, respectively, to signify the change to operational status.
Opposition to the air corps' ambitions for the acquisition of more B-17s faded, and in late 1937, 10 more aircraft designated B-17B were ordered to equip two bombardment groups, one on each U.S. coast. Improved with larger flaps and rudder and a well-framed, 10-panel
A total of 155 B-17s of all variants was delivered between 11 January 1937 and 30 November 1941, but production quickly accelerated, with the B-17 once holding the record for the highest production rate for any large aircraft.[note 4] The aircraft went on to serve in every
Though the crash of the prototype 299 in 1935 had almost wiped out Boeing, now it was seen as a boon. Instead of building models based on experimental engineering, Boeing had been hard at work developing their bomber and now had versions ready for production far better than would have been possible otherwise. One of the most significant weapons of World War II would be ready, but only by a hair.— Jeff Ethell, 1985