Supermarine Spitfire Mk XIV

Altitude was the weakness of the first Griffon Spitfires, and no single-stage supercharger was going to fix it. By 1943 Rolls-Royce had the two-stage Griffon 61 series running, and a lightly modified version, the 65 series, went into the Mk XIV. The conversion was first tried on six Mk VIII airframes redesignated Mk VIIIG; Jeffrey Quill flew the first on 20 January 1943 and found an aeroplane of spectacular performance and unacceptable handling, because Mk VIII tail surfaces could not hold that much power straight. The answer was a substantially larger fin and a broader rudder, which gave the Mk XIV its unmistakable outline.

The Griffon 65, of some 2,050 hp, sat 25 cm further forward and forced a reorganisation of half the airframe: deeper radiator housings under both wings, circular-section ejector exhausts, a larger oil tank and radio equipment moved aft to balance the nose. A five-blade Rotol propeller of 3.18 m replaced the four-blade unit; one prototype, JF321, tested a six-blade contra-rotating assembly that promised to cancel the take-off swing but proved unreliable, and the idea waited for the late Seafires. The numbers were emphatic: 6,100 m in a little over five minutes and about 718 km/h at 7,700 m.

The mark entered service with 610 Squadron in December 1943. Pilots coming off earlier Spitfires often disliked it at first, describing an aircraft that left the ground slightly sideways, but the performance won them over: it could climb almost vertically and repeatedly astonished Luftwaffe pilots who thought they had bounced it from above. It was the most effective of all Spitfires against V-1 flying bombs, and the 150-octane fuel introduced in mid-1944 added roughly another 48 km/h at low level. By December 1944 six Second Tactical Air Force squadrons were flying it as their high-altitude fighter.

Service use revealed localised skin wrinkling on wings and fuselage at load attachment points. Supermarine insisted the structure was not seriously weakened, but in early 1945 the RAF ordered every F and FR Mk XIV refitted with clipped wingtips. The first aircraft reached South-East Asia in June 1945, too late for combat against Japan. Of the 957 built, over 430 were armed-reconnaissance FR machines; after the war second-hand examples were exported to Belgium, India and Thailand.