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The Vickers Type 271 (K4049), predecessor of the Wellington, which was flown for the first time on June 15, 1936 |
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Few
if any bombers of the Second World War enjoyed a longer or more
distinguished operational career than the Vickers Wellington. Blooded in
combat at the very outset of hostilities, it carried the lions share of
R.A.F. Bomber Commands night bombing offensive until the operational
debut of the first four-engined heavies, and was still first-line
equipment when the war ended. Indeed, such was the brilliant battle record
of the Wellington that any tribute can be but a pale reflection of the
distinctions that this remarkable warplane won for itself. The
Wellingtons docility combined with a lively performance and its ability
to absorb a fantastic amount of battle damage rapidly endeared it to its
crews, and its portly, well-fed appearance engendered the nickname
Wimpey after Popeyes obese friend J. Wellington Wimpy of
strip-cartoon fame, an appellation that became as widely known as that with
which it was officially christened. More than any other bomber, the Wellington
proved the power-operated gun turret to be a formidable defensive weapon,
but it disproved the widely-held belief that large bombers could undertake
daylight bombing attacks against heavily defended areas without fighter
escort. Like
most successful combat aircraft, the Wellington was the result of team work,
but it undoubtedly owed its success to the revolutionary geodetic, or
basket weave, system of construction, an ingenious idea the more
remarkable for its essential simplicity. When Vickers Limited, through a
subsidiary company known as the Airship Guarantee Company, received a
contract from H. M. Government to build the airship R.100, they employed an
outstanding engineer named Barnes N. Wallis to design the structure. From an
airship designed for use on an experimental commercial air service between
the United Kingdom and the Commonwealth to a medium bomber built by the
thousand in the Second World War may seem a long step indeed, but in the R.
100s construction lay the germ of an idea which was to see fruition years
later in the Wellingtons structure. The
geodetic system of construction the name being derived from geodeses,
imaginary geographical lines following the curvature of the earth along
a straight path was designed to carry all loads in the structure along the
shortest possible paths. It produced a criss-cross pattern of
self-stabilising members by means of which loads in any direction were
automatically equalised by forces in the intersecting set of frames. High
strength was obtained at low weight. Vickers were not slow to see the
advantages which might accrue from this form of construction and Barnes
Wallis was teamed up with Rex K. Pierson, then Vickers chief designer, to
produce structural designs. The complex shape of the aeroplane, coupled with
the need to cut away some of the multitudinous geodetic members for
cockpits, bomb-bays, and gun turrets, presented such difficulties that the
originators might well have given up hope of reaping the rewards of their
ingenuity. Vickers enjoyed no subsidy to cover the expense of developing the
geodetic system, but with faith and perseverance the many hurdles were
surmounted, and the company's belief in the soundness of Barnes Wallis's
invention was amply vindicated. The first aeroplane to employ geodetic construction was the Type 246 Wellesley which was built as a private venture to meet the general requirements of specification G.4/3 1 which called for a general-purpose bombing and torpedo-carrying aircraft. Vickers actually received a prototype contract for a biplane fulfilling this specification, the Type 253, which was in fact built and flown, but the company had implicit faith in the superiority of their monoplane which, in the event, was adopted for the Royal Air Force. The Wellesley prototype (K7556) did not fly until June 19, 1935, and by that time lessons learned in its design were already being applied to the next, even more ambitious Vickers bomber. |
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In
December 1933 Vickers were awarded an official contract for the construction
of one prototype of their design which, bearing the designation Type 271,
was powered by two Goshawks. Six months later, however by which time
construction had already begun the Air Ministry realised that the Goshawk
was not fulfilling its earlier promise, and the specification again had to
be changed. As no alternative power plant with a similar power-to-weight
ratio as that of the Goshawk presented itself, it was necessary to relax the
limit on the bomber's tare weight in order to permit the installation of
the heavier and more powerful Bristol Perseus or Pegasus nine-cylinder
air-cooled radials. There can be no doubt that this decision saved the
design from the early demise which would have resulted if the Goshawk
installation, with its complex steam cooling, had been continued. Vickers
eventually elected to use the Bristol Pegasus engine which, in its PE5.SM
version, was rated at 850 h.p. for take-off. In production, this engine was
designated the Pegasus X, and two of them powered the Vickers Type 271
(K4049) bomber prototype when J. Mutt Summers took the aircraft into the air at Brooklands on
its maiden flight on June 15, 1936, Although the Type 271 was destined to be
completely redesigned before it emerged as the Wellington I, ii was itself a
major step forward in British bomber design. The fuselage, although portly,
was remarkably well streamlined, and the wings were of a higher aspect ratio
at 8.83:1 than had previously been attempted in a twin-engined aeroplane,
with consequent benefit on performance. The Wellesley-type tail unit
initially planned had given place to one of larger area the single fin and
rudder design was borrowed directly from the Supermarine Stranraer flying
boat which had twin vertical tail surfaces. The span was 85 ft. 10 in., and
the overall length was 60 ft. 6 in., and the Type 271 was designed to be
operated by a crew of four, with provision for a fifth crew member when
required. The
warload was a maximum of nine 500-lb. bombs, or nine 250-lb. bombs with fuel
for maximum range, and defensive armament comprised two Lewis 0.303-in.
machine guns, one forward- and one rearward-firing in enclosed,
hand-operated cupolas at each end of the fuselage. Provision was made in the
design for a hand-operated gun in a retractable dorsal turret, but this was
never implemented. At an all-up weight of 21,000 lb., the Type 271 reached
250 m.p.h. at 8,000 ft. Immediately after making its first flight, the prototype appeared in the new-types park at the R.A.F. Display at Hendon in June 1936, where it created a most favourable impression. This was subsequently confirmed in official trials which followed, and before the end of the year in August 1936, in fact a production specification was drawn up around the Type 271 design, and 180 aircraft were ordered to be build to this standard. Hence the Wellington I met the requirements of specification 29/3 6, and appeared in quite different guise to the basic B.9/32 design. |
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