SPITFIRE F Mk.21 "Post WWII service"

Description

By early 1942, it was evident that Spitfires powered by the new two-stage supercharged Griffon 61 engine would need a much stronger airframe and wings. The proposed new design was designated the Mk 21. At first the Mk 21 displayed poor flight qualities that damaged the otherwise excellent Spitfire reputation. The wings were completely redesigned with a new structure and using thicker-gauge light alloy skinning. The new wing was torsionally 47% stiffer, allowing an increased theoretical aileron reversal speed of 825 mph (1,328 km/h). The ailerons were 5% larger, and were no longer of the Frise balanced type, instead being attached by continuous piano-hinges. They were extended by eight inches, meaning that with a straighter trailing edge, the wings were not the same elliptical shape as in previous Spitfires. The Mk 21 armament was standardised as four 20mm Hispano II cannon with 150 rpg and no machine guns. Spitfire 21s finally became operational on 91 Squadron in January 1945. 91 Squadron had little opportunity to engage the enemy before the war ended, but scored a rare success on 26 April 1945, when two Spitfire Mk 21s shot up and claimed to have sunk a German midget submarine which they caught on the surface. With the end of the war most orders for the Mk 21 were cancelled and only 120 were completed. In 1946 40 Spitfire 21s were delivered to Shoeburyness; once there their leading edges were removed and destroyed in "lethality" tests. Some aircraft had less than five hours flying time (Scale : 1/72e)