| Spitfire Mk VI | The Spifire HF.VI was a dedicated high-altitude interceptor intended to counter the pressurized Junkers Ju86P and R which could roam England unmolested at altitudes of 40,000 ft (12,200 m) or more during 1940/41. This was the first Spitfire variant to make use of the extended-span wing with pointed tips, and the first with a pressurised cockpit. Powered by a Merlin 47 driving a four-bladed propellor, it was just adequate for the task, but it was not a great success. One fault was that the canopy was fixed in order to seal the cabin, a feature disliked by the pilots, although it could be jettisoned in an emergency. Production: 100 |
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| Spitfire Mk VII | The Spitfire HF.VII was an extensive redesign based on the HF.VI. The extended span wing was retained, while the chord and area of the rudder were increased. In an effort to squeeze even more performance out of the Merlin, Rolls-Royce had developed a two-stage supercharger with aftercooler, often incorrectly called an intercooler. The reult was the Merlin 60 series: longer and heavier than the previous engines, but which doubled the available horsepower at 30,000 ft (9,150 m ), giving an unprecedented performance increase at high altitudes. The Merlin 61 was fitted to the Mk VII, needing extra cooling capacity, and one of the identifying characteristics of this variant was that it had two radiators, one under each wing. The tailwheel was retractable, as had been proposed for the Spitfire III. The HF.VII was slightly longer than previous Spitfires, mainly to accommodate the extra length of the engine. Service ceiling was increased to 42,500 ft (12,962 m), and maximum speed rose to 408 mph (656 km/hr). Rate of climb was vastly superior at higher altitudes. Production: 140 |
| Spitfire Mk VIII | Entering service in August 1943, the Spitfire VIII combined the best of the engine and airframe advances made over the preceeding years. Some were powered by the Merlin 70, some by the Merlin 61 or 63, and some with the Merlin 66. C-type wings (which could accommodate either two cannon, one cannon and two machine guns, or four machine guns) were used on many of the Mk VIII's, along with added fuel tanks, while many late-production aircraft featured a pointed rudder. In many ways the Mk VIII was the best of the Spitfires, but as it never saw service in Northern Europe, its capabilities largely went unrecognized. There were two reasons for this: firstly it was overtaken by events, being overshadowed by the numerically later, but operationally earlier, Mk IX; secondly, the performance-reducing Vokes filter fitted to the tropical Mk VC was long gone. Filters were now incorporated in the intake as standard, which made the Mk VIII eminently suitable for hot climes, and they were all sent overseas. Two interesting modifications were tried on individual Mk VIII's: the first was a six-bladed, contra-rotating propeller; the second was a teardrop canopy to improve the pilot's rearward view. Both these features were adopted as standard on later production variants. Production: (Merlin 70) 160; (Merlin 61/63) 267; (Merlin 66) 1,231 |
| Spitfire Mk IX | The event that was to overtake the development of the Mk VIII was the emergence late in 1941 of the German Focke-Wulf FW 190. This new radial-engined fighter outclassed the Spitfire V by a wide margin. Trials between a captured FW 190A-3 and a Spitfire VB showed that the German fighter was at least 20 mph (32 km/hr) faster at all altitudes; it had better rates of climb and acceleration; it could dive faster initially; and, except in radius of turn, it was far more manoeuvrable. The Spitfire V took a heavy beating and an urgent solution was needed. The Mk VIII had been ordered in quantity, but it would not be available quickly enough. The answer was to fit the Merlin 60 engine into a Mk VC airframe. This became the Spitfire Mk IX, the second most widely used variant. Produced in LF (the most numerous), F and HF sub-types, the Mk IX had a performance very close to that of the FW 109A-3: slightly worse in transient performance but better in the turn. The only difference between the sub-types was the Merlin fitted; there were no external differences. From the air, the Mk IX was indistinguishable from the Mk VC, and the German fighter pilots could not tell just what they were up against until combat was under way. The Spitfire IX was still widely used at the end of the war, many examples being fitted with the E-wing. This carried a single .50 machine gun in place of the two .303's. The 20mm cannon was retained. With the advent of the Griffon engine, the Mk IX was largely devoted to low-level attack missions; a role for which its wings were frequently clipped. In later production aircraft, the large rudder became standard, and a 72 Imp gal (327.3 litre) fuel tank was installed in the rear fuselage of some examples. It is generally accepted that the Spitfire VIII's and IX's were the last of the "ladies"; the next generation were not so nicely behaved, as ever-increasing power and weight took their toll of the Spitfire's previously docile handling abilities. Production: (all sub-types) 5,609 |
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