Supermarine Spitfire

The first test of the aircraft was in intercepting V1 flying bombs, and the Mk XIV was the most successful of all Spitfire marks in this role.

When 150 octane fuel was introduced in mid-1944 the "boost" of the Griffon engine was able to be increased to
+25 lbs, allowing the top speed to be increased by about 30 mph (26 kn; 48 km/h) to 400 mph (350 kn; 640 km/h) at 2,000 ft (610 m).

The Mk XIV was used by the [Vous devez être inscrit et connecté pour voir ce lien] as their main high-altitude air superiority fighter in northern [Vous devez être inscrit et connecté pour voir ce lien]
with six squadrons operational by December 1944.

One problem which did arise in service was localised skin wrinkling on the wings and fuselage at load attachment points; although Supermarine advised that the Mk XIVs had not been seriously weakened, nor were they on the point of failure, the RAF nevertheless issued instructions in early 1945 that all F and F.R Mk XIVs were to be restrospectivaly fitted with clipped wings.

Spitfire XVIs also began to arrive in the [Vous devez être inscrit et connecté pour voir ce lien] theatre in June 1945, too late to operate against the Japanese.

FR Mk XIV


Late in 1944 a number of Mk XIVs were converted to have a single camera fitted, facing to port or starboard.

To achieve this a new hatch, similar to the radio hatch on Merlin-engine Spitfires, was installed.

Otherwise this version of the FR Mk XVI was essentially the same as the standard aircraft.

Later, purpose built conversions, also known as the F.R Mk XIV, had the cut down rear fuselage with its tear drop–shaped canopy, and a port facing fuselage camera, with an additional rear fuel tank of 34 gallons which extended the Spitfire's range to about 610 miles (980 km) on internal fuel.

Because it was used mainly at low altitudes the FR Mk XIV had clipped wingtips.

In total, 957 Mk XIVs were built, over 430 of which were FR Mk XIVs.

After the war, second hand Mk XIVs were exported to a number of foreign air forces; 132 went to the [Vous devez être inscrit et connecté pour voir ce lien],
70 went to the [Vous devez être inscrit et connecté pour voir ce lien] and 30 of its reconnaissance variant went to the [Vous devez être inscrit et connecté pour voir ce lien].

Mk XV and Mk XVII


The mark numbers XV and XVII (15 and 17) were reserved for the naval version, the [Vous devez être inscrit et connecté pour voir ce lien], in an effort to reconcile
the Spitfire numbering scheme with that of the Seafire.

Mk XVIII (Mk 18) (type 394)

The Mk 18 was a refinement of the Mk XIV. It was identical in most respects including engine (the Griffon 65) and cockpit enhancements, but it carried extra fuel and had a revised, stronger wing structure.

Its handling was also nearly identical and so it was not put through any performance tests. Like the Mk XIV there were fighter and fighter reconnaissance variants built.

The Mk 18 missed the war. It was built up until early 1946 but it was not until January 1947, that an RAF squadron, [Vous devez être inscrit et connecté pour voir ce lien] which operated from [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien], was re-equipped with the variant.

Later, other squadrons in the Far East and Middle East would receive them.

Some 300 Mk 18s were built but they saw little action apart from some involvement against guerrillas in the [Vous devez être inscrit et connecté pour voir ce lien].

The Royal Indian Air Force purchased 20 ex-RAF Mk 18s in 1947.

300 F and F.R Mk 18s before production ended in early 1946.

Mk XIX (Mk 19) (types 389 and 390)


The Mk XIX was the last and most successful photographic reconnaissance variant of the Spitfire.

It combined features of the Mk XI with the Griffon engine of the Mk XIV.

After the first 25 (type 389s) were produced, later aircraft were also fitted with the pressurised cabin of the Mk X and the fuel capacity was increased to 256 gallons, three-and-a-half times that of the original Spitfire

This version was the type 390.

The first Mk XIXs entered service in May 1944, and, by the end of the war, the type had virtually replaced the earlier
Mk XI.

A total of 225 were built with production ceasing in early 1946, but they were used in front line RAF service until April 1954.

In fact, the last time a Mk 19 was used to perform an operational sortie was in 1963 when one was used in battle trials against an [Vous devez être inscrit et connecté pour voir ce lien] to determine how best a Lightning should engage piston-engined aircraft.

This information was needed in case RAF Lightnings might have to engage [Vous devez être inscrit et connecté pour voir ce lien] in the [Vous devez être inscrit et connecté pour voir ce lien] conflict of the time.

MK XIX

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Mk XX (type 366)


Mark XX was given to the original Mk IV Griffon engine prototype DP845 to avoid confusion with the retitled Spitfire
PR Mk IVs.

The second Mk XX, DP851, initially had a Griffon II engine and made its first flight in August 1942.

In December, it was refitted with a Griffon 61 and re-designated as a Mk 21 initial prototype.

Mk 21 (type 356)


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.

The Griffon engine drove an 11 ft (3.35 m) diameter five-bladed propeller, some 7 inches (17.8 cm) larger than that fitted to the Mk XIV.

To ensure sufficient ground clearance for the new propeller, the undercarriage legs were lengthened by 4.5".

The undercarriage legs also had a 7.75 inch (19.7 cm) wider track to help improve ground handling.

The designers then devised a system of levers to shorten the undercarriage legs by about eight inches as they retracted, because the longer legs did not have enough space in which to retract.

These same levers extended the legs as they came down.

The larger diameter four spoke mainwheels were strengthened to cope with the greater weights; post-war these were replaced by wider, reinforced three spoke wheels to allow Spitfires to operate from hard concrete or asphalt runways.

When retracted the wheels were now fully enclosed by triangular doors which were hinged to the outer edge of the wheelwells.

In other respects, the first production Mk 21s used the same basic airframe as the Mk XIV.

The first true Mk 21 prototype, PP139 first flew in July 1943, with the first production aircraft LA187 flying on 15 March 1944.

However the modifications over the Mk XIV made the Mk 21 sensitive to trim changes. LA201's poor flight control
qualities, during trials in late 1944 and early 1945, led to a damning report from the [Vous devez être inscrit et connecté pour voir ce lien]:

"...it must be emphasised that although the Spitfire 21 is not a dangerous aircraft to fly, pilots must be warned...in its present state it is not likely to prove a satisfactory fighter. No further attempts should be made to perpetuate the Spitfire family."

Supermarine were seriously concerned because [Vous devez être inscrit et connecté pour voir ce lien] had been converted to produce Mk 21s, and more were coming off the production lines daily.

Jeffrey Quill commented that "The AFDU were quite right to criticise the handling of the Mark 21...Where they went terribly wrong was to recommend that all further development of the Spitfire family should cease.

They were quite unqualified to make such a judgement and later events would prove them totally wrong."

After intensive test flying the most serious problems were solved by changing the gearing to the trim tabs and other subtle control modifications, such that the Mk 21 was cleared for instrument flying and low level flight during trials in March 1945.

An AFDU report on LA215issued that month noted that the Spitfire 21 was now much easier to fly;

General Handling The modifications carried out to this aircraft have resulted in an improvement of the general handling characteristics at all heights...Conclusions The critical trimming characteristics reported on the production Spitfire 21 have been largely eliminated by the modifications carried out to this aircraft. Its handling qualities have benefitted to a corresponding extent and it is now considered suitable both for instrument flying and low flying. It is considered that the modifications to the Spitfire 21 make it a satisfactory combat aircraft for the average pilot.

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Mk 22 (type 356)


The Mk 22 was identical to the Mk 21 in all respects except for the fitting of a cut-back rear fuselage and tear-drop canopy and a more powerful 24 volt electrical system in place of the 12 volt system of all earlier Spitfires.

Most of the Mk 22s were built with further enlarged tail surfaces, similar to those of the [Vous devez être inscrit et connecté pour voir ce lien].

A total of 272 Mk 22s were built: 250 at Castle Bromwich and 27 by Supermarine at South Marston.

The Mk 22 was used by only one regular RAF unit, [Vous devez être inscrit et connecté pour voir ce lien] in the Middle East.

However 12 squadrons of the [Vous devez être inscrit et connecté pour voir ce lien] used the variant and continued to do so until March 1951 and the aircraft was also used at Flying refresher schools.

May 1955the remaining F.22s were declared obsolete from all RAF units.

Mk 23 (type 372)


The Mk 23 was to be a Mk 22 incorporating a revised wing design which featured an increase in incidence, lifting the leading edge by 2 inches (51 mm).

It was hoped that this wouldimprove the pilot's view over the nose in flight and increase the high speed and dive performance of the aircraft.

The modified, handbuilt wing was first fitted to a Mk VIII JG204 which was tested from July 1944.

However the tests were disappointing and after discussions at Supermarine it was decided to build a new prototype using the Mk 21 prototype PP139; the aircraft was designated F Mk 23 to be renamed the Supermarine Valiant.

However once again the new wing gave less than perfect handling characteristics and so the Mk 23 was never built from the Mk 22 airframe as intended.

Mk 24 (type 356)


The final Spitfire variant, the Mk 24, was similar to the Mk 22 except that it had an increased fuel capacity over its predecessors, with two fuel tanks of 33 gal (150 l) each installed in the rear fuselage.

There were also zero-point fittings for rocket projectiles under the wings.

All had the larger "[Vous devez être inscrit et connecté pour voir ce lien]" tail units: modifications were also made to the trim tab gearings in order to perfect the F 24's handling characteristics. Late production aircraft were built with the lighter, short-barrelled, electrically fired
Mark V Hispano cannon.

Performance was impressive – the F 24 achieved a maximum speed of 454 mph (731 km/h), and could reach an altitude of 30,000 ft (9,100 m) in eight minutes, putting it on a par with the most advanced piston-engined fighters of the era.

Although designed primarily as a fighter-interceptor aircraft, the Spitfire proved its versatility in several different roles.

In fighter configuration the F 24's armament consisted of 4 × short-barrelled 20 mm Hispano cannon – operational experience had proved that the hitting power of these larger weapons was necessary to overcome the thicker
armoured plating encountered on enemy aircraft as the war progressed.

The aircraft also served successfully in the fighter-bomber role, being capable of carrying 1 × 500 lb (230 kg) and
2 × 250 lb (110 kg) bombs, with rocket-projectile launch rails fitted as standard.