Well, kinda, sorta.
In January 1941 Mensforth and Petter went directly to Fighter Command with his proposal for a Merlin powered Whirlwind, which would still have been a Whirlwind. We can only guess how his attempt to short circuit the established British aircraft procurement system went down at the Air Ministry and Ministry of Aircraft Production. I doubt that it was met with a positive reaction. We know that in February Sir Henry Tizard did examine the possibility but his report noted that the Whirlwind used two engines and twice as much alloy (the actual figure is three times as much) as the Spitfire to do fewer jobs less well. Tizard allowed the original cancellation of the type to stand.
A more realistic scenario was an earlier proposal for a Whirlwind II powered by developed Peregrine engines. The ever optimistic Petter thought, in conjunction with new propellers, would give such an aircraft an extra 40 mph in speed and a service ceiling of 36,000 feet! Despite Petter's ludicrous figures this would have been a good aeroplane, but fell victim to Rolls-Royce's rationalisation of production
and development.
The Welkin was built to a different specification, F.4/40, for a high altitude fighter to deal with the Luftwaffe's high altitude reconnaissance aircraft. The Ju 86 P had proven itself immune to interception in 1940/41. Westland and Petter were very clear that the Welkin would use many structural elements of the now discontinued Whirlwind. It was an attempt to salvage something from the Whirlwind programme and to reassure the Air Ministry that the Welkin could be built more economically by utilising parts, tools and jigs already purchased for the Whirlwind.
The Welkin gets a lot of stick, but it met the specification. It flew higher than any previous British production aircraft and helped to reveal some of the secrets of compressibility. It was important to the development of pressure cabins which would become vital a few years later at the dawning of the jet age. What it never did was fire its guns at an enemy reconnaissance aircraft. Just as the Whirlwind was outdone by aircraft that could perform several roles better than it could (notably the Spitfire and larger Beaufighter) the Welkin ran up against one of the best aircraft of the era in the Mosquito.
The Welkin was a beautiful aircraft.
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I'd build a model of one, though I have no idea where I could put it!