Westland P.9 Whirlwind

Discussion in 'Aviation' started by Hobilar, Nov 7, 2007.

  1. Hobilar

    Hobilar Member

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    The Westland P.9 Whirlwind was designed in 1936 by W.E.W. Petters (see note 1) to the requirements of Air Ministry specification F.37/35 for a high-performance fighter, armed with four cannon. It would become the Royal Air Force's first twin-engined single-seat fighter and the first such aircraft to be used in numbers by any of the belligerent powers. Of orthodox all metal stressed-skin construction, the Whirlwind introduced several design innovations later to be widely adopted. It had an extremely slim fuselage (the cross section of which was less than that of the engine nacelles), and the four Hispano cannon were closely grouped in the fuselage nose to give a dense concentration of fire. The all-round vision cockpit was an advanced feature, and the coolant radiators were ducted within the centre section of the wing, In addition the Whirlwind incorporated Fowler-type flaps which extended from aileron to aileron.

    A contract for two prototypes (L6844 and L6845) was placed in February 1937, with the first of these flying on the 11th October 1938. An initial production order for 200 machines was placed in January 1939 (followed by a second order for a similar number), with deliveries to fighter squadrons being scheduled to commence during the following September. Unfortunately deliveries the first Peregrine engines (in essence a modernised version of the classic Kestrel) did not reach Westland until January 1940, and, in consequence, the first Whirlwinds did not enter service until June, 1940.

    Teething and delivery problems with the Peregrine engines (See Note 2) coupled with a number of flying accidents and a high landing-speed which restricted the number of airfields from which it could operate, resulted in production being terminated in January 1942 after the completion of just 112 production aircraft. These aircraft equipped just two squadrons of the RAF (No.263 Squadron from June 1940, and No.137 Squadron from November 1941. Both would re-equip with Typhoons in November 1943.

    Notes:

    1. W.E.W. Petters would later be the chief designer of the post-war English Electric Canberra.
    2. Rolls-Royce being, at that time, more concerned with improving and maximising production of the important Merlin engine.

    Bibliography:

    • Aircraft of World War II (Chris Chant, Dempsey-Parr, 1999)
    • The Complete Book of Fighters (William Green and Gordan Swansborough, Salamandar, 1997).
    • Warplanes of the Second World War-Fighters Volume 2 (William Green,MacDonald,1961).
    • World Aircraft Information Files (Aerospace Publishing Periodical).
     
  2. Hobilar

    Hobilar Member

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    No.263 Squadron R.A.F. undertook a number of light day bomber escort duties with their Whirlwind fighters. The best known of the operations undertaken being the escort of six Blenheim squadrons as far as Antwerp on August 12, 1941. In the summer of 1942, the Whirlwinds of both squadrons were fitted with racks for two 250-lb or 500-lb bombs (redesignated Whirlwind IA), These subsequently undertook low-level cross-channel attacks on locomotives, bridges, shipping, harbour installatons, and other targets until 1943 when both Squadrons re-equipped with Typhoons.
     
  3. Hobilar

    Hobilar Member

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    One Whirlwind(P6972) underwent night fighting trials in 1940 with No.25 Squadron and at one period the first prototype (L6844) was fitted with twelve 0.303-in Browning guns. Another Whirlwind was fitted experimentally with a single 37-mm cannon.
     
  4. Hobilar

    Hobilar Member

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    For a twin-engined aircraft the Whirlwind was highly manouvrable and its handling characteristics were frequently referred to as delightful. Also its performance at low altitude was superior to that of many contemporary single engined fighters. Unfortunately, rather poor maintenance characteristics and continuous teething troubles suffered by its Peregrine geared and supercharged engines (which powered no other service type), coupled with serious delays in engine deliveries conspired to restrict the Whirlwinds career to only two R.A.F. squadrons.
     
  5. Aggie08

    Aggie08 Active Member

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    Good post, you could have probably combined all those into your first post though. I never really heard much about this bird but I liked its look. And 12 .303's? Good god! How many bullets/second does that work out to?
     
  6. Hobilar

    Hobilar Member

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  7. Graeme

    Graeme Well-Known Member

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    Petter's original design layout.

    [​IMG]
     
  8. Graeme

    Graeme Well-Known Member

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    Another source says that the 12 Browning gun arrangement was produced in mock up form only, by Martin-Baker, but never fitted. It was an 'insurance policy' in case the 4 cannon arrangement proved too difficult. It wasn't.

    [​IMG]

    37mm cannon experimentally fitted to L6844.

    [​IMG]

    The four cannon arrangement finally adopted.

    [​IMG]
     
  9. Airborne

    Airborne Banned

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    For 1940 it sure was futuristic.
    The Whirlwind was the only product from Westland Aviation to reach front line status in WW2.

    Hi Hobilar, Good to see you again. PM me if you'd like to.
     

    Attached Files:

  10. Trautloft

    Trautloft Member

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    great post,thanks:) The Whirlwind is one of my fav.ww2 a/c at all.

    im interested in the total losses/claims.
    i found on luftwaffe.cz a german ace who claimed 2 whirlwinds, how many of the 112 been lost finally? how was its sortie/loss ratio, and how many crashes been caused by the teething Peregrine engine?
     
  11. Hobilar

    Hobilar Member

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    Westland P.9 Whirlwind

    Country of Origin: United Kingdom

    Type: Single-seat Escort fighter and fighter-bomber

    Powerplant: Two 885 hp Rolls-Royce Peregrine 1 liquid cooled V-12 engines

    Span: 45 ft (13.72 m)
    Length: 32 ft 3 in (9.83 m)
    Height: 10 ft 6n (3.20 m)
    Wing Area: 250 sq ft (23.22 m²)

    Weight: Empty 8,310 lb (3,969 kg)
    Maximum takeoff (with bombs) 11,388 lb (5,166 kg)

    Speed: 360 mph (579 km/h)
    Service Ceiling : 30,000 ft (9,145 m)
    Range: 800 miles (1,287 km)

    Crew: 1

    Armament: Four 20mm Hispano Mk.I cannon plus two 250-lb (115 kg) or 500-lb (230 kg) bombs
     
  12. SteveH

    SteveH Member

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    I've always wondered how much more successful it would have been with Merlins. Can you imagine?

    Steve
     
  13. merlin

    merlin Member

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    Not very successful at all, probably the wings would fall off,or else the props would slice through the fuselage.
    The aircraft was designed for the small Peregrine engine. Anything larger just would not fit!!
     
  14. johnbr

    johnbr Well-Known Member

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    That is why I would have gone with the RR exe.
     
  15. freebird

    freebird Active Member

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    Westland DID make designs for a Merlin powered Whirlwind, but the Air ministry did not proceed. It sure would have been fast! But they decided to concentrate on the Beaufighter instead
     
  16. merlin

    merlin Member

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    From British Secret Projects: Fighters Bombers '35 - '50, P. 38

    "Early in the war Rolls-Royce decided to abandon development of the Peregrine and concentrate its efforts on the Merlin, a move that curtailed the Whirlwinds career since the engine was not required for any other production aircraft type and its teething problems, though not severe, would never be fully addressed.
    Some alternative powerplants were suggested. Roy Fedden at Bristol pressed strongly for the installation of two radial engines but Westland knew that fitting larger powerplants was impossible. The original concept had been to build the smallest possible fighter compatible with two engines and so its structure was neither roomy enough nor strong enough to take anything larger. Thus the Whirlwind was to be denied the prolonged RAF career enjoyed by the Hurricane and Spitfire and when it entered service in autumn 1940 the demand for more speed and height made it appear, at least in official eyes, to be verging on obsolescence.

    The biography of William Freeman by Anthony Furse P. 109

    The cannon fighters.
    The size of the Westland Whirlwind was restricted to the absolute minimum required to carry four 20-mm cannon in the nose of the fuselage. It then became possible to mount such cannon in the wings of single-engined fighters. Production of its Peregrine engines ceased and the Whirlwind airframe was too small for other engines and too specialised for other roles.
     
  17. Watanbe

    Watanbe Member

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    The only real reason the Whirlwind was pursued with the merlin engines was that there simply was no need for the aircraft at that stage. The RAF already had Mosquiots and Beaufighters...twin engine fighters which could perform a similar role.


    I think the Whirlwind had the potential to be an excellent aircraft and it looks awesome!!!
     
  18. freebird

    freebird Active Member

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    Westland asked the air ministry to go ahead with the Mk II, so they obviously thought the modifications to the frame could be done. They did in fact go ahead with a "Merlin" powered aircraft, the Welkin, designed for high altitudes.
     
  19. SPYINTHESKY

    SPYINTHESKY New Member

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    Actually the size of the Peregrine compared to the Merlin was not that different, weight was obviously higher. However Petter wanted to use the Merlin in the original design and later proposed it again when Peregrine was cancelled so the option was not out of the question. The reason it was not used originally was because the Air Ministry were ironically concerned that the Merlin might suffer delays as a new design as opposed to the Kestral inspired Perigrine. They wanted an option should the Hurricane/Spitfire suffered as a result the opposite unfortunately of what did occur.
     
  20. zoomar

    zoomar Member

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    I've always considered the Whirlwind one of the most attractive and lethal-looking WW2 fighters ever.

    The situation with the Whirlwind seems somewhat reminiscent to that of the Fw-187. Engines. In the case of the Whirlwind, the plane was abandoned after a small operational run because of problems with its Peregrine engine, which as was noted, powered no other type. Probably retooling it to take Merlins or something else would have hampered the supply of these engines for other fighters - and in any event the roles planned for the Whrlwind were going to be handled better by Typhoons and Tempests. A major reason the RLM supposedly gave for abandoning the Fw-187 (especially the single seat version) was "why use two engines on a single seat fighter" when one suffices. Thus they made Tank turn it into a two-seater with a useless second crewmember and then cancelled it anyway. As I understand it, neither the Whirwind nor Fw-187 were conceived as heavy twin engined fighters in the Bf-110/Beaufighter mold. From the beginning, they were intended to be fast and agile single seaters capable of mixing it up with single-engined fighters, in the same manner as the P-38 or later the DH Hornet and F7F.
     
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