Westland Welkin

Last updated

Welkin
Westland Welkin.jpg
Welkin Mk I
RoleHigh altitude fighter
National originUnited Kingdom
Manufacturer Westland Aircraft
Designer W.E.W. Petter
First flight1 November 1942
IntroductionMay 1944
RetiredNovember 1944
Primary user Royal Air Force
Produced1940-1945
Number built77

The Westland Welkin was a British twin-engine heavy fighter from the Westland Aircraft Company, designed to fight at extremely high altitudes, in the stratosphere; the word welkin meaning "the vault of heaven" or the upper atmosphere. [1] First conceived in 1940, the plane was built in response to the arrival of modified Junkers Ju 86P bombers flying reconnaissance missions, [2] which suggested the Luftwaffe might attempt to re-open the bombing of England from high altitude. Construction was from 1942 to 1943. The threat never materialised; consequently, Westland produced only a small number of Welkins and few of these flew.

Contents

Design and development

Westland put forward their P.14, essentially an adaptation of Westland's Whirlwind fighter layout (and a more experimental twin, the P.13) to meet Air Ministry Specification F.4 of 1940 for a high altitude fighter. [3] The most obvious feature was the enormous high aspect ratio wing, with a span on the production aircraft of 70 feet (21 m). [lower-alpha 1] The compact but troublesome Rolls-Royce Peregrine engines of the Whirlwind were replaced by the more powerful two-stage Rolls-Royce Merlin Mk.76/77. The most significant feature was a pressurised cockpit, which took the majority of effort in the design. After extensive development a new cockpit was developed that was built out of heavy-gauge duraluminium bolted directly to the front of the main spar. The cockpit hood used an internal layer of thick perspex to hold the pressure, and an outer thin layer to form a smooth line. Heated air was blown between the two to keep the canopy clear of frost.

In January 1941, the Ministry of Aircraft Production authorised the building of two P.14 prototypes DG558 & DG562. The F.4/40 specification was revised into F.7/41 that year. The Welkin design was now in competition with the Vickers Type 432 with Merlin 61 engines.

The pressurisation system was driven by a Rotol supercharger attached to the left-hand engine (this was the difference between the Merlin 76 and 77), providing a constant pressure of 3.5 psi (24 kPa) over the exterior pressure. This resulted in an apparent cabin altitude of 24,000 feet (7,300 m) when the aircraft was operating at its design altitude of 45,000 ft (14,000 m). This cabin altitude was still too high for normal breathing, so the pilot had to wear an oxygen mask during flight. A rubber gasket filled with the pressurized air sealed the canopy when the system was turned on, and a valve ensured the pressure was controlled automatically. Moreover, the pilot also had to wear a high altitude suit as he might have been required to bail out at altitude.

The Welkin required a sophisticated electrical system. This was to minimise the number of seals and points of entry in the cockpit for the controls and instrumentation. It took an electrician experienced in the features of the Welkin four hours to undertake a pre-flight check of this system. The wings were so large that the high lift Fowler flaps of the Whirlwind were not needed, and were replaced by a simple split flap. The extra wing area also required more stability, so the tail was lengthened to provide a longer moment arm. The armament − four Hispano 20 mm cannon − was the same as the Whirlwind's, but the Welkin carried the guns in a tray in its belly, which facilitated loading. In that position, muzzle flash was also less likely to dazzle the pilot.

The Welkin was seriously handicapped by compressibility problems caused by its long, high aspect-ratio wing which needed to be thick at the root (thickness-to-chord ratio of about 19%) for strength reasons. [4] Compressibility caused the flight envelope (flyable speed range) between high-incidence stall and shock-stall to become very small at high altitudes – any decrease in airspeed causing a "normal" stall, any increase causing a shock-stall due to the aircraft's limiting critical Mach number. This reduction of the speed envelope is a problem common to all subsonic high-altitude designs and also occurred with the later Lockheed U-2. When W.E.W. Petter came to design his next high-altitude aircraft, the English Electric Canberra jet bomber, the required wing area was distinguished by noticeably short wings, with thickness-to-chord ratio (t/c) at the root of 12%, [5] a t/c ratio which delays compressibility effects to an aircraft speed of about Mach 0.85. [6]

Information on the Welkin was only released at the end of the war. [7]

A two-seat radar-equipped night fighter version known as the Welkin NF.Mk.II for specification F.9/43 was developed but only one was eventually produced as the variant was not ordered into production. [8] [9]

Operational history

By the time the Welkin Mk.I was complete and in production, it was apparent that the Luftwaffe was no longer conducting high altitude missions, due largely to successful interceptions by specially modified Supermarine Spitfires. Only 77 complete Welkins were produced, plus a further 26 as engine-less airframes. [10] Although two Welkins served with the Fighter Interception Unit based at RAF Wittering from May to November 1944, where they were used to gain experience and formulate tactics for high altitude fighter operations, the Welkin was never used operationally by the RAF. [11]

Variants

Operators

Flag of the United Kingdom.svg  United Kingdom

Specifications (Welkin Mk I)

Data from British Aircraft of world War Two : Westland Welkin, [12] RAF Fighters, Part 3 [13]

General characteristics

Performance

Armament

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

Related Research Articles

de Havilland Mosquito British multi-role combat aircraft of WW2

The de Havilland DH.98 Mosquito is a British twin-engined, multirole combat aircraft, introduced during the Second World War. Unusual in that its airframe was constructed mostly of wood, it was nicknamed the "Wooden Wonder", or "Mossie". Lord Beaverbrook, Minister of Aircraft Production, nicknamed it "Freeman's Folly", alluding to Air Chief Marshal Sir Wilfrid Freeman, who defended Geoffrey de Havilland and his design concept against orders to scrap the project. In 1941, it was one of the fastest operational aircraft in the world.

<span class="mw-page-title-main">Rolls-Royce Merlin</span> Aircraft engine family by Rolls-Royce

The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litre capacity. Rolls-Royce designed the engine and first ran it in 1933 as a private venture. Initially known as the PV-12, it was later called Merlin following the company convention of naming its four-stroke piston aero engines after birds of prey. The engine benefitted from the racing experiences of precursor engines in the 1930s.

<span class="mw-page-title-main">Gloster Meteor</span> Britains first jet fighter, 1943–1980s

The Gloster Meteor was the first British jet fighter and the Allies' only jet aircraft to engage in combat operations during the Second World War. The Meteor's development was heavily reliant on its ground-breaking turbojet engines, pioneered by Frank Whittle and his company, Power Jets Ltd. Development of the aircraft began in 1940, although work on the engines had been under way since 1936. The Meteor first flew in 1943 and commenced operations on 27 July 1944 with No. 616 Squadron RAF. The Meteor was not a sophisticated aircraft in its aerodynamics, but proved to be a successful combat fighter. Gloster's 1946 civil Meteor F.4 demonstrator G-AIDC was the first civilian-registered jet aircraft in the world. Several major variants of the Meteor incorporated technological advances during the 1940s and 1950s. Thousands of Meteors were built to fly with the RAF and other air forces and remained in use for several decades.

<span class="mw-page-title-main">Bristol Beaufighter</span> British heavy fighter aircraft of the WWII era

The Bristol Type 156 Beaufighter is a British multi-role aircraft developed during the Second World War by the Bristol Aeroplane Company. It was originally conceived as a heavy fighter variant of the Bristol Beaufort torpedo bomber. The Beaufighter proved to be an effective night fighter, which came into service with the Royal Air Force (RAF) during the Battle of Britain, its large size allowing it to carry heavy armament and early airborne interception radar without major performance penalties.

<span class="mw-page-title-main">Westland Whirlwind (fighter)</span> 1938 fighter aircraft family by Westland

The Westland Whirlwind was a British twin-engined fighter developed by Westland Aircraft. A contemporary of the Supermarine Spitfire and Hawker Hurricane, it was the first single-seat, twin-engined, cannon-armed fighter of the Royal Air Force.

Westland Aircraft was a British aircraft manufacturer located in Yeovil, Somerset. Formed as a separate company by separation from Petters Limited just before the start of the Second World War, Westland had been building aircraft since 1915. During the war the company produced a number of generally unsuccessful designs, but their Lysander would serve as an important liaison aircraft with the Royal Air Force. After the war the company focused on helicopters, and was merged with several other British firms to create Westland Helicopters in 1961.

<span class="mw-page-title-main">Junkers Ju 388</span> Type of aircraft

The Junkers Ju 388Störtebeker is a World War II German Luftwaffe multi-role aircraft based on the Ju 88 airframe by way of the Ju 188. It differed from its predecessors in being intended for high altitude operation, with design features such as a pressurized cockpit for its crew. The Ju 388 was introduced very late in the war, and production problems along with the deteriorating war conditions meant that few were built.

<span class="mw-page-title-main">Hawker Tempest</span> British fighter aircraft

The Hawker Tempest is a British fighter aircraft that was primarily used by the Royal Air Force (RAF) in the Second World War. The Tempest, originally known as the Typhoon II, was an improved derivative of the Hawker Typhoon, intended to address the Typhoon's unexpected deterioration in performance at high altitude by replacing its wing with a thinner laminar flow design. Since it had diverged considerably from the Typhoon, it was renamed Tempest. The Tempest emerged as one of the most powerful fighters of World War II and at low altitude was the fastest single-engine propeller-driven aircraft of the war.

<span class="mw-page-title-main">Fairey Fulmar</span> British carrier-borne reconnaissance aircraft/fighter aircraft

The Fairey Fulmar is a British carrier-borne reconnaissance aircraft/fighter aircraft which was developed and manufactured by aircraft company Fairey Aviation. It was named after the northern fulmar, a seabird native to the British Isles. The Fulmar served with the Royal Navy's Fleet Air Arm (FAA) during the Second World War.

<span class="mw-page-title-main">Supermarine Spitfire (late Merlin-powered variants)</span> Late Merlin-powered variants of the Supermarine Spitfire

The British Supermarine Spitfire was facing several challenges by mid-1942. The debut of the formidable Focke-Wulf Fw 190 in late 1941 had caused problems for RAF fighter squadrons flying the latest Spitfire Mk Vb. Rolls-Royce engineers were already working on a new version of the Merlin incorporating a two-stage supercharger; the combination of the improved Merlin and the Spitfire Mk Vc airframe in a "stop-gap" design allowed the RAF to combat the Fw 190 on equal terms.

<span class="mw-page-title-main">Westland Wyvern</span> Type of aircraft

The Westland Wyvern is a British single-seat carrier-based multi-role strike aircraft built by Westland Aircraft that served in the 1950s, seeing service in the 1956 Suez Crisis. Production Wyverns were powered by a turboprop engine driving large and distinctive contra-rotating propellers, and could carry aerial torpedoes.

<span class="mw-page-title-main">W. E. W. Petter</span> British aircraft designer (1908 – 1968)

William Edward Willoughby "Teddy" Petter was a British aircraft designer. He is noted for Westland's wartime aeroplanes, as well as the Canberra, the early design of the Lightning, and his last plane, the Folland Gnat.

<span class="mw-page-title-main">Supermarine Spiteful</span> 1944 British fighter aircraft

The Supermarine Spiteful was a British Rolls-Royce Griffon–engined fighter aircraft designed by Supermarine to Air Ministry specification F.1/43 during the Second World War as a successor to the Spitfire. It had a new wing design to improve its critical Mach number, and allow safe operations at higher speeds. The new design also had a modern inwards-retracting undercarriage. Other changes included a larger fin to improve the somewhat marginal stability of Griffon Spitfires and changes to the mounting of the engine to tilt it down slightly for better visibility over the nose.

<span class="mw-page-title-main">Vickers Type 432</span> British high-altitude fighter aircraft

The Vickers Type 432 was a British high-altitude fighter aircraft developed by the Vickers group during the Second World War. Intended to enable the Royal Air Force to engage the enemy's high-altitude bomber aircraft, it was to be armed with six cannons.

<span class="mw-page-title-main">Short Sturgeon</span> Post war British target tug

The Short Sturgeon was a planned British carrier-borne reconnaissance bomber whose development began during Second World War with the S.6/43 requirement for a high-performance torpedo bomber, which was later refined into the S.11/43 requirement which was won by the Sturgeon. With the end of the war in the Pacific production of the aircraft carriers from which the Sturgeon was intended to operate was suspended and the original reconnaissance bomber specification was cancelled.

The Hawker Hurricane was a British single-seat fighter aircraft designed and predominantly built by Hawker Aircraft. Some versions were built in Canada by Canadian Car and Foundry.

The Fighter Interception Development Unit RAF was a special interceptor aircraft unit of the Royal Air Force (RAF) during the Second World War. It was part of Air Defence of Great Britain and was previously the Fighter Interception Unit (FIU).

<span class="mw-page-title-main">Supermarine Spitfire (early Merlin-powered variants)</span> Early variants of the Supermarine Spitfire

Supermarine Spitfire variants powered by early model Rolls-Royce Merlin engines mostly utilised single-speed, single-stage superchargers. The British Supermarine Spitfire was the only Allied fighter aircraft of the Second World War to fight in front line service from the beginnings of the conflict, in September 1939, through to the end in August 1945. Post-war, the Spitfire's service career continued into the 1950s. The basic airframe proved to be extremely adaptable, capable of taking far more powerful engines and far greater loads than its original role as a short-range interceptor had called for. This would lead to 19 marks of Spitfire and 52 sub-variants being produced throughout the Second World War, and beyond. The many changes were made in order to fulfil Royal Air Force requirements and to successfully engage in combat with ever-improving enemy aircraft. With the death of the original designer, Reginald J. Mitchell, in June 1937, all variants of the Spitfire were designed by his successor, Joseph Smith, and a team of engineers and draftsmen.

<span class="mw-page-title-main">Supermarine Spitfire</span> British single-seat WWII fighter aircraft

The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Griffon-engined Mk 24 using several wing configurations and guns. It was the only British fighter produced continuously throughout the war. The Spitfire remains popular among enthusiasts; around 70 remain airworthy, and many more are static exhibits in aviation museums throughout the world.

Harald James Penrose, O.B.E, CEng, F.R.Ae.S, A.M.I.N.A was the chief test pilot at Westland Aircraft between 1931 and 1953, a naval architect, and an aviation author. His flying experience ranged from man carrying kites before the First World War to early jet fighters and helicopters. He designed, built and flew his own glider in the 1930s, designed 36 boats and yachts, and wrote many books describing his flying career and the history of British aviation.

References

Notes

  1. ↑ For comparison, the Avro Lancaster four-engined heavy bomber had a span of 102 feet (31 m) and the de Havilland Mosquito twin-engined light bomber and fighter had a 54-foot (16 m) span.[ citation needed ]
  1. ↑ "welkin, n." . OED Online. Oxford University Press. September 2013. Retrieved 13 September 2013.
  2. ↑ Velek, Ovčáčík & Susa 2005, p. 1.
  3. ↑ Buttler 2004 , p. 47.
  4. ↑ Boot 1990, p. 12.
  5. ↑ Gunston 1973, p. 16.
  6. ↑ Gunston 1962, p. 26.
  7. ↑ "New Aircraft Types", Flight, p. 664, 21 June 1945
  8. ↑ Buttler 2004 , p. 48.
  9. ↑ Velek, Ovčáčík & Susa 2005, pp. 13–14.
  10. ↑ Velek, Ovčáčík & Susa 2005, p. 3.
  11. ↑ Thetford 1962, p. 552.
  12. 1 2 "Westland Welkin". British Aircraft of World War Two. Archived from the original on 7 January 2009. Retrieved 2 May 2019.
  13. 1 2 Green & Swanborough 1981, p. 60.
  14. ↑ Lednicer, David. "The Incomplete Guide to Airfoil Usage". UIUC Applied Aerodynamics Group. Retrieved 16 April 2019.

Bibliography

  • Boot, Roy (1990). From Spitfire To Eurofighter 45 Years of Combat Aircraft Design. Airlife Publishing. ISBN   1-85310093-5.
  • Buttler, T. (2004). British Secret Projects: Fighters and Bombers 1935–1950. Hinckley, UK: Midland. ISBN   1-85780-179-2.
  • Goulding, James; Jones, Robert (1971). "Meteor, Whirlwind and Welkin". Camouflage and Markings: RAF Fighter Command Northern Europe, 1936–45. London: Ducimus Books. ISBN   0-903234-00-9.
  • Green, W.; Swanborough, G. (1981). RAF Fighters, Part 3 (WW2 Aircraft Fact Files). London: Jane's Publishing. ISBN   0-7106-0119-0.
  • Gunston, Bill (1973). Bombers of the West. New York: Charles Scribner's Sons. ISBN   0-684-13623-6.
  • Gunston, W. T., ed. (1962). Flight Handbook The Theory and Practice of Powered Flight (6th ed.). Iliffe Books. LCCN   39-30641.
  • James, Derek N. (2002). Westland: A History. Gloucestershire UK: Tempus Publishing. ISBN   0-7524-2772-5.
  • Mondey, David (1982). Westland. Planemakers. Vol. 2. London: Jane's Publishing Company. ISBN   0-7106-0134-4.
  • Thetford, Owen (1962). Aircraft Of The Royal Air Force Since 1918 (3rd ed.). Putnam& Co.
  • Velek, M.; Ovčáčík, M.; Susa, K (2005). Westland Welkin F Mk.1, NF Mk.II. Prague, Czech Republic: Mark I Ltd. ISBN   80-86637-01-8.
  • Webb, D. Collier (February 1996). "Tested & Failed, Flight Test Accidents of the 1940s–1960s: Westland Welkin". Aeroplane Monthly.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.