SPITFIRE F Mk.21 "N°91 Sq RAF in WWII"

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. (Scale : 1/72e)