B-17 Flying Fortress
The Boeing B-17 Flying Fortress was the first mass produced, four engine heavy
bomber. It is still one of the most recognized airplanes ever built. It was most
widely used for daylight strategic bombing 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 July 28, 1935, as the Boeing Model 299, with
Boeing chief test pilot Les Tower at the controls. 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. On October 30,
1935, Army Aircorps test pilot Ployer Hill took the Model 299 on a second
evaluation flight. Forgetting to take off the control lock, the aircraft took
off into a steep climb, nosed over, and crashed. In January, 1936, thirteen YB-17s
with a number of significant changes from the Model 299, most notably that of
the engines to more powerful Wright R-1820-39 Cyclones, were ordered as were 99
B-18s (successor of the DB-1).
The first B-17 went into service in 1938. By December 7, 1941, 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 12,700 aircraft had been built.
Operational History
The name "Flying Fortress" was coined by Richard Williams, a reporter for the
Seattle Times who gave this name to the Model 299 when it was rolled out showing
off its machine gun installations. Boeing was quick to see the value of the
title and had it copyrighted for use. 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 caliber
(12.7 mm) machine guns under the nose. This eliminated the airplane's main
defensive weakness of head on attacks.
Variants/Design stages
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 carrier, 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
with an additional power turret in the radio room, a chin turret (which went on
to become standard with the B-17G), and twin .50 caliber (12.7 mm) guns in the
waist positions. The ammunition load was over 11,000 rounds making the YB-40
well over 10,000 pounds (4,500 kg) heavier than that of a fully loaded B-17F.
Unfortunately the YB-40s, with their numerous heavy modifications, had trouble
keeping pace with empty bombers and the project was abandoned with the
arrival of the Mustang and phased out in July, 1943.
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.
During and after World War II a number of weapons were tested and used
operationally on B-17's. Some of these weapons included razons
(radio guided), glide bombs, and the JB-2 Thunderbugs, the equivalent of the
German V-1 Buzz Bomb.
Units Using the B-17
The B-17 was an ubiquitous aircraft and it served in dozens of units in theaters
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 Theater. 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 in roles other than those it
had been designed for. The first B-17s used by the Royal Air Force, known to the \
RAF as "Fortress I"s, 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. They regarded the B-17
as uneconomical due to its larger crew and relatively small bomb load. Instead,
they used them for patrol bombing and later equipped a number of them with
sophisticated radio countermeasures equipment where they served in some of the
first electronic countermeasures operations with RAF 100 Group.
During World War II some forty B-17s were repaired by the Luftwaffe after being
captured and put back into the air. Many of these were codenamed "Dornier Do 200"
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.
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 first aircraft acquired by the Israeli Air Force were
three surplus American B-17s, smuggled via South America and Czechoslovakia to
avoid an arms trading ban imposed by the United States. A fourth plane was
captured and confiscated by American officials. In their delivery flight from
Europe, the aircraft were ordered to bomb the Royal Palace of King Farouk in
Cairo before continuing to Israel in retaliation for Egyptian bombing raids on
Tel-Aviv. They performed the mission, despite some of the crew fainting
alternately due to defective oxygen equipment, but caused little damage to the
target. The B-17s were generally unsuitable for the ideal needs of the Israeli
Air Force and the nature of the conflict in which long-range bombing raids on
large area targets were relatively unimportant. They were mainly used in the
1948 Arab-Israeli War, flown by 69th Squadron Israeli Air Force. They saw more
limited usage until being phased out in 1958.
This article is licensed under the
GNU Free Documentation License.
It uses material from the
Wikipedia article "B-17 Flying Fortress".
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