The B-17 Flying Fortress was the first mass-produced, four-engine heavy bomber. It is still one of the most recognised aeroplanes ever built.
It was most widely used for daylight strategic bombings of German
industrial targets during World War II as part of the United States
Eighth Air Force.
Development
The prototype B-17 first flew on 1935 July 28 as the Boeing Model 299. During a demonstration later that
year at Wright Field in Dayton, Ohio, Model 299 competed with the Douglas DB-1 and
Martin Model 146. While the Boeing design was obviously superior, Army officials were daunted by the much greater expense per
aircraft. It did not help that the Model 299 had crashed (http://www.wpafb.af.mil/museum/research/bombers/b2-13a.htm) during the demonstration, despite
the fact that this crash was due to pilot error. In 1936, only 13 B-17s were ordered, next to 99 B-18s (successor of the DB-1).
The first B-17 went into service in 1938. By 1941 December 7, few
B-17s were in use by the Army. Following the attack on
Pearl Harbor, production was quickly accelerated. The aircraft served in every World War II combat zone. Production ended in May 1945 after 12,726 aircraft had been built.
Operational history
Contrary to the common misperception that the aircraft was named the "Flying Fortress" because of the number of heavy machine guns it carried, it received that sobriquet from newspaper reporters in the
1930s based on its original mission as a coastal patrol bomber, a 'flying fortress' that
would guard the nation's offshore limits beyond the range of the heavy guns sited at major harbours. Among the combat aircrews
that flew bombers in World War II, noted aviation writer Martin Caidin
reported that the B-17 was referred to as the "Queen of the Bombers."
The B-17 was noted for its ability to take battle damage, still reach its target and bring its crew home. It reportedly was
much easier to fly than its contemporaries, and its toughness more than compensated for its shorter range and lighter bomb load
when compared to the Consolidated B-24 Liberator or the British
Avro Lancaster heavy bombers.
The design went through eight major changes over the course of its production, culminating in what some consider the
definitive type, the B-17G, differing from its immediate predecessor by the addition of a chin turret with two 0.50-calibre (12.7 mm) machine guns under the
nose. This eliminated the aeroplane's main defensive weakness.
Variants/Design stages
- Main article: B-17 Flying Fortress
variants
The B-17 went through several iterations in each of its design stages and variants. Of the thirteen YB-17s ordered for service
testing, only one was actually used. Experiments on this plane led to the use of a turbo-supercharger, which would become
standard on the B-17 line. When this aircraft was finished with testing, it was redesignated the B-17A, and was the first plane
to enter service under the B-17 designation.
As the production line developed, Boeing engineers continued to improve upon it. To improve performance, the original design
was altered to include larger flaps, a larger rudder, and a new nose. The engines were upgraded to more powerful versions several
times. Similarly, the gun stations were altered on numerous occasions to enhance their effectiveness.
By the time the B-17G appeared, the number of guns had been increased from seven to thirteen, the designs of the gun stations
were finalised, and other adjustments were complete. In this, it incorporated all changes made in its predecessor, the B-17F
(which was the first mass-produced version of the B-17). The B-17G is generally considered the defining version of the B-17. Some
8680 were built, and many were converted for other missions, such as cargo-carrying, engine testing, and reconnaissance.
Two versions of the B-17 were flown under different designations. These were the XB-38 and the YB-40. The
former was an engine test bed for Allison V-1710 liquid-cooled engines,
to test the engine should the Wright engines normally used on the B-17 become unavailable. The YB-40 was a modification of the
standard B-17 used before the P-51 Mustang became available. Since no
fighters had the range to escort the B-17, a heavily armed modification was used instead. Unfortunately, the YB-40s with their
numerous heavy modifications had trouble keeping the pace with empty bombers, and the project was abandoned with the arrival of
the Mustang.
Late in World War II, at least 25 B-17s were fitted with radio controls, loaded with 12,000 lb (5443 kg) of high explosives,
dubbed 'BQ-7 Aphrodite missiles,' and used against U-boat pens and bomb-resistant
fortifications. Because few (if any) BQ-7s hit their target, the
Aphrodite project was scrapped in early 1945. (×24)
Units Using the B-17
- Main article: List of units using the B-17 Flying Fortress
The B-17 was an ubiquitous aircraft, and it served in dozens of units in theatres of combat throughout World War II. Its main
use was in Europe, where its
shorter range and smaller bombload relative to other aircraft available did not hamper it as much as in the Pacific Theatre. Only three B-17 groups were
stationed in the Pacific, but dozens were stationed in Europe.
It was also used by the Royal Air Force, though mainly roles other
than those it had been designed for. The first B-17s used by the Royal Air Force had been tragic disasters, and despite its
overwhelming success in American hands, the British were reluctant to use the B-17 for its original mission profile of heavy
bombing, instead relegating it to offshore patrol bombing and reconnaissance duty.
When Israel achieved statehood in 1948, the
Israeli Air Force had to be assembled quickly to defend the new
nation from the war it found itself embroiled in almost immediately. Among the aircraft aquired by the Israeli Air Force were
several surplus B-17s, which were used by 69 Squadron Israeli Air Force. Additionally, some forty B-17s were repaired by the
Luftwaffe after being captured, and put back in the air. Many of these were
codenamed as "Dornier Do 200"s and given German markings to disguise their origin, while other B-17s were kept in Allied markings
to infiltrate B-17 squadrons and report on their positions.
Noted B-17 pilots
Specifications (B-17G)
General Characteristics
- Crew: 10
- Length: 74 ft 4 in (22.7 m)
- Wingspan: 103 ft 10 in (31.6 m)
- Height: 19 ft 1 in (5.8 m)
- Wing area: 1527 ft² (141.9 m²)
- Empty: 54,900 lb (24,900 kg)
- Loaded: 72,134 lb (32,720 kg)
- Maximum takeoff: 74,000 lb (34,000 kg)
- Powerplant: 4× Wright R-1820-97 turbo-supercharged radials,
1,200 hp (895 kW)
Performance
- Maximum speed: 300 mph (480 km/h)
- Cruising speed: 160 mph (260 km/h)
- Combat Range: 1,850 miles (2,980 km)
- Ferry Range: 3,400 miles (5,500 km)
- Service ceiling: 35,600 ft (10,900 m)
- Rate of climb: ft/min ( m/min)
- Wing loading: 47.2 lb/ft² (231 kg/m²)
- Power/Mass: .0655 hp/lb (.110 kW/kg)
Armament
- 13× Browning M-2 0.50-calibre (12.7 mm) machine guns
- 8,000 lb (3,600 kg) of bombs
External links
 
Related Content
Related development: Boeing XB-15
Comparable aircraft: B-24 Liberator - Avro Lancaster - Handley-Page Halifax
Designation sequence: XB-14 - XB-15 - XB-16 - B-17 - B-18 - XB-19 - Y1B-20
Related lists: List of military aircraft of the United States - List of bomber aircraft
See also: XB-38 Flying Fortress - YB-40 Flying Fortress
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