Re: Westland Whirlwind

par LysanD Jeu 18 Mar 2010, 19:33

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par LysanD Jeu 18 Mar 2010, 19:34

A serious problem for air planners of the 1930s was that one could only build a nimble combat aircraft if it was small.

Such an aircraft would have limited space for fuel, and would only have enough range to fight in defensive operations.

A multi-engined fighter appeared to be the best solution to the problem of range, but it seemed that any fighter large enough to incorporate a substantial fuel load would be too unwieldy to successfully engage its single-engine counterparts in combat.

Germany and the United States pressed ahead with such programmes anyway, which resulted in the Messerschmitt
Bf 110 and the [Vous devez être inscrit et connecté pour voir ce lien].

par LysanD Jeu 18 Mar 2010, 19:34

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par LysanD Jeu 18 Mar 2010, 19:36

Design and development

The claims made about the Bf 110 piqued the interest of the British [Vous devez être inscrit et connecté pour voir ce lien], who issued [Vous devez être inscrit et connecté pour voir ce lien] in 1935, which called for a single-seat day and night fighter armed with four cannon.

Six aircraft were submitted in response to the specification, of which three were twin-engined types :
the [Vous devez être inscrit et connecté pour voir ce lien] P.88,
the [Vous devez être inscrit et connecté pour voir ce lien],
the Hawker F.37/35 (which was a [Vous devez être inscrit et connecté pour voir ce lien] variant),
the [Vous devez être inscrit et connecté pour voir ce lien] 312 (a [Vous devez être inscrit et connecté pour voir ce lien] variant),
the Supermarine 313
and the Westland P.9 which was successful.

A contract was placed in February 1937 for two prototypes of Westland's design.

par LysanD Jeu 18 Mar 2010, 19:36

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par LysanD Jeu 18 Mar 2010, 19:37

Westland's design team, under the new leadership of [Vous devez être inscrit et connecté pour voir ce lien] (who was later to design the [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien]) designed an aircraft that employed state-of-the-art technology.

The monocoque fuselage was a small tube with a T-tail at the end, although as originally conceived, the design featured a twin tail which was discarded when large [Vous devez être inscrit et connecté pour voir ce lien] were added that caused large areas of turbulence over the tail unit.

The horizontal stabilizer (tailplane) was moved up out of the way of the disturbed air flow caused when the flaps were down.

par LysanD Jeu 18 Mar 2010, 19:38

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par LysanD Jeu 18 Mar 2010, 19:38

The airframe was built completely of stressed-skin [Vous devez être inscrit et connecté pour voir ce lien], with the pilot sitting high under one of the world's first full bubble canopies,
while the low and forward location of the wing made for superb visibility (except for directly over the nose).

Four 20 mm cannon were mounted in the nose, making it the most heavily armed fighter aircraft of its era; the clustering of the weapons also meant that there were no convergence problems as with wing-mounted guns.

par LysanD Jeu 18 Mar 2010, 19:39

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par LysanD Jeu 18 Mar 2010, 19:39

Hopes were so high for the design that it remained "top secret" for much of its development, although it had already been mentioned in the French press.

The first prototype (L6844) flew on 11 October 1938 with further Service Trials carried out at [Vous devez être inscrit et connecté pour voir ce lien].

par LysanD Jeu 18 Mar 2010, 19:40

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par LysanD Jeu 18 Mar 2010, 19:41

It exhibited excellent handling and was very easy to fly at all speeds.

The only exception was the inadequate directional control during takeoff which necessitated an increased rudder area above the tailplane.

Production orders were contingent on the success of the test program; delays caused by over 250 modifications to the two prototypes led to an initial production order for 200 aircraft being held up until January 1939 followed by a second order for a similar number, deliveries to fighter squadrons being scheduled to begin in September 1940.

par LysanD Jeu 18 Mar 2010, 19:41

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par LysanD Jeu 18 Mar 2010, 19:42

The Whirlwind was quite small, only slightly larger than the Hurricane in overall size, but smaller in terms of frontal area.

The landing gear was fully retractable and the entire aircraft was very "clean" with few openings or protuberances.

Radiators were in the leading edge on the inner wings rather than below the engines.

This careful attention to streamlining and two 885 hp Peregrine engines powered it to over 360 mph (580 km/h),
the same speed as the latest single-engine fighters.

The speed quickly garnered it the nick-name Crikey,
(a [Vous devez être inscrit et connecté pour voir ce lien] meaning "my god!" or more accurately "Christ's keys!").

par LysanD Jeu 18 Mar 2010, 19:43

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par LysanD Jeu 18 Mar 2010, 19:44

But there were problems as well.

The aircraft had limited range, under 300 miles combat radius, which made it marginal as an escort.

More troublesome were the continued failures of the Peregrine engines.

Originally intended to be one of Rolls' main designs, the [Vous devez être inscrit et connecté pour voir ce lien] had become much more important to the war effort and the Peregrine was relegated to a secondary status, and the first deliveries of Peregrine engines did not reach Westland until January 1940.

par LysanD Jeu 18 Mar 2010, 19:44

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par LysanD Jeu 18 Mar 2010, 19:45

By 1940, the [Vous devez être inscrit et connecté pour voir ce lien] was mounting 20 mm cannons, so the "cannon-armed" requirement was also being met, and by this time the role of escort fighter was becoming less important as [Vous devez être inscrit et connecté pour voir ce lien] turned to night bomber missions.

The main qualities the RAF were looking for in a twin-engine fighter was range and carrying capacity (to allow the large radar apparatus of the time to be carried),
which the [Vous devez être inscrit et connecté pour voir ce lien] could do just as well as or even better than the Whirlwind.

par LysanD Jeu 18 Mar 2010, 19:46

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par LysanD Jeu 18 Mar 2010, 19:47

Development and delivery problems with the Peregrine engines along with a number of flying accidents and its high landing speed which restricted the number of airfields from which it could operate, resulted in Whirlwind production being ended in January 1942 after the completion of just 112 production aircraft.

Westland campaigned for the creation of a Mk II model, initially designed around a more powerful 1,010 hp Peregrine
which was aborted due to Rolls-Royce's cancellation of further development of the engine.

Additional proposals by Petter similarly remained as "paper projects" and included re-engining with Bristol Hercules, American radials and even using two 1,400 hp Merlin XX engines, each concept being rejected by the [Vous devez être inscrit et connecté pour voir ce lien].

par LysanD Jeu 18 Mar 2010, 19:47

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par LysanD Jeu 18 Mar 2010, 19:48

Operational history

The first squadron to receive the Whirlwind was No. 25, then based at North Weald.

The squadron was fully equipped with [Vous devez être inscrit et connecté pour voir ce lien] night fighters when Squadron Leader K. A. K. MacEwen flew prototype Whirlwind L6845 from [Vous devez être inscrit et connecté pour voir ce lien] to [Vous devez être inscrit et connecté pour voir ce lien] on 30 May 1940.

The following day it was flown and inspected by three of the squadron's pilots, and the next day was inspected by the Secretary of State for Air, Sir Archibald Sinclair, and [Vous devez être inscrit et connecté pour voir ce lien].

par LysanD Jeu 18 Mar 2010, 19:48

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par LysanD Jeu 18 Mar 2010, 19:59

Two days later the second Whirlwind, a production model, was again flown in from [Vous devez être inscrit et connecté pour voir ce lien] by Squadron Leader MacEwen, and later that day a pilot of the squadron solo'ed in it.

On 17 June the AOC-in-C Fighter Command recommended that No. 25 Squadron be re-equipped with [Vous devez être inscrit et connecté pour voir ce lien] night fighters, as it was already an operational night fighter squadron, and Whirlwinds were not being produced fast enough.

The three Whirlwinds supplied to No. 25 Squadron were transferred to No. 263 Squadron.

par LysanD Jeu 18 Mar 2010, 20:00

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