Aviation Archive Issue 25 - 2016 UK

(Jacob Rumans) #1



esembling a Whirlwind on steroids,
the Westland Welkin was designed
to counter the threat of high-altitude
bombers attacking the British Isles. In the
event, the threat never materialised and the
aircraft’s raison d’être disappeared, along
with its production
The definition of the Welkin is ‘the sky of
heaven’, so naming Westland’s high-flying
interceptor was the easy part. First conceived
in 1940, the Welkin was developed in
response to a perceived threat from
very high altitude German aircraft,
most notably the Junkers Ju 86P. This
reconnaissance aircraft first appeared over
Britain in the summer of 1940, and proved

Westland Welkin

impossible to catch. The Air Ministry issued
specification F.4/40, calling for a cannon-
armed high altitude fighter. Westland had just
finished development work on the Whirlwind
and its proposal followed the same basic
configuration, but with a number of significant
differences. The most visible feature was the
enormous high aspect ratio wing, with a span
on the production aircraft of 70ft (21m). The
extra wing area also required more stability,
so the tail was lengthened to provide a longer

moment arm. The compact but troublesome
Rolls-Royce Peregrine engines of the Whirlwind
were also replaced by the more powerful two-
stage Rolls-Royce Merlin Mk76/77. However,
perhaps the most technologically challenging
element of the design was a bullet-proof
pressurised cabin, attached to the wing front
spar. The armament – four Hispano 20mm
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,

Below: The Whirlwind lineage of the Welkin is apparent. The bullet-proof pressurised
cockpit 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.
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