World War II Database

Contributor: Alan Chanter

ww2dbaseConceived to meet the requirements of Air Ministry Specification F.4/40 which called for a single-seat day and night fighter to combat any threat from very high altitude attack, William Edward Willoughby "Teddy" Petter and his design team at Westland submitted, in early 1940, their P.14 design, for a two-seat fighter armed with six 20-mm Hispano cannon. Preliminary investigations, however, revealed that to meet the entire design emphasis, which was directed towards attaining the highest possible ceiling combined with the maximum possible speed, would require a high aspect ratio wing of inordinately large span. Consequently a modified design for a single-seat fighter with four cannon was submitted, and it was this design, allocated the Specification number F.7/41 by the Ministry, that would be accepted for production with the name of Welkin.

ww2dbaseThe first Welkin prototype (DG558/G) powered by two 1,290-hp Merlin 61 two-speed two-stage supercharged engines made its maiden flight on November 1, 1942, with a second (DG562/G) similarly powered aircraft following in March 1943. This second prototype would later be used in experiments with volatile liquid oxygen injected into modified engines as a means of boosting power at high altitudes.

ww2dbaseDuring tests with the prototypes at the Armament and Experimental Establishment, Boscombe Down (A&AEE), there were a number of forced-landing accidents brought about largely by engine problems and propeller failures. Nevertheless an order was placed for 100 machines with a further 100 to follow when supply of a significant numbers of Merlin engines could be arranged. Production began in early 1943 with the first Welkin I (DX278) flying in September of that year. These production aircraft were powered by a Rolls Royce Merlin 72 or 76 in the starboard wing nacelle and a Merlin 73 or 77 in the port wing nacelle. The latter drove the Rotol supercharger to pressurize the cockpit to the equivalent of 24,000 feet at a true altitude of 45,000 feet. The pressurized cabin was a self-contained unit constructed of extremely heavy gauge bullet resisting light alloy bolted to the front face of the main wing spar, with an armoured bulkhead at the rear and a special openable bulkhead at the nose. Cockpit access was via a sliding canopy of unique hollow-sandwich construction specifically designed to facilitate de-icing and demisting at high-altitudes.

ww2dbaseWhen the expected German high-altitude bomber threat failing to materialize the need for the Welkin disappeared. The order was cancelled after seventy-five aircraft (plus 26 airframes awaiting engines) had been completed, none of which were delivered to RAF squadrons, going immediately into store for eventual breaking-up. A few Welkin Is were later removed from store for Service trials. One of these was experimentally fitted with Merlin RM16SM engines with "beard" radiators replacing those normally mounted between the fuselage and the nacelles. This machine was flight tested in June 1945 and whilst it proved somewhat faster, achieving 398-mph at 30,000 feet, no further development would take place.

ww2dbaseIn October 1944 a proposal for a high-flying two-seat night-fighter led to an order for two prototypes based on the Welkin I. One machine (DX386) was taken out of store and converted into the Welkin NF.II (Serial, PF370 later re-serialled WE997) which flew on October 23, 1944. The Welkin II had a lengthened bulbous nose to accommodate the Airborne Interception radar Mark VIII and the dihedral on the outboard wing panels was increased by one and a half degrees. In addition the pilot's cockpit was moved forward to allow for the incorporation of a rear facing observer's seat covered by a new one-piece canopy. The sole Welkin II (the second was not completed) eventually served only as a radar test bed and, due to its disappointing performance, was not ordered into production.

Welkin Timeline

SPECIFICATIONS

Welkin I

Machinery	Two 1,650hp Rolls Royce Merlin 12-cyl Vee liquid cooled engines
Armament	4x20mm Hispano cannon with 480rpg
Crew	1
Span	21.34 m
Length	12.65 m
Height	4.65 m
Wing Area	42.73 m²
Weight, Empty	6,520 kg
Weight, Loaded	8,970 kg
Speed, Maximum	623 km/h
Service Ceiling	13,410 m

Welkin II

Machinery	Two 1,650hp Rolls Royce Merlin 12-cyl Vee liquid cooled engines
Armament	4x20mm Hispano cannon with 480rpg
Crew	2
Span	21.34 m
Length	13.44 m
Height	4.90 m
Wing Area	42.73 m²
Weight, Empty	7,092 kg
Weight, Loaded	9,930 kg
Speed, Maximum	579 km/h
Service Ceiling	12,500 m

Photographs

Visitor Submitted Comments

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1.  Alan Chanter says:
15 Oct 2016 12:08:37 AM

Please amend specifications for Welkin 2 to read: Crew - 2

2.  C. Peter Chen says:
15 Oct 2016 05:19:41 PM

Alan, the correction has been made, thanks!