Westland Welkin - Operational History

Operational History

By the time the Welkin Mk.I was complete and rolling off the line, it was apparent that the Luftwaffe was no longer conducting high altitude missions, due largely to successful interceptions by specially modified Supermarine Spitfires. In the end, only 77 complete Welkins were produced, plus a further 26 as engine-less airframes. 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. A two-seat, 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.

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

The Welkin was seriously handicapped by compressibility problems exacerbated by its long but thick wings, causing 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, it was distinguished by noticeably short wings.