RJ Mitchell. A life in aviation.
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Spitfire Marks

This section of the website provides an insight into some of the changes and developments to Spitfires during and after the War. It should be noted that this is not a comprehensive list but is produced to show how the initial designs Mitchell was responsible for were adapted for the different roles the Spitfire undertook. Even with increases in technical knowledge and combat requirements, Mitchell's original design was able to accommodate all of these additionas and developments.

Type 300 Mk IA and Mk IB

This was basically the same airframe as the K5054 prototype fitted with either a Merlin II or III engine giving a top speed of 364mph. The airscrew was initially 2-blade fixed pitch, but was soon changed to a 2-pitch 3-blade design. The MkIA was armed with eight 0.303 Browning machine guns whereas the MkIB had four machine guns and two 20mm cannon. Altogether 1566 Mk I Spitfires were produced.

Type 300 Mk IA
MKII > MKIV
Type 329 Mk II

The major change from the Mk I was the use of the 1175hp Merlin XII engine and a top speed of 370mph. 920 were produced.

Types 330 & 348 Mk III

The Mk III was powered by the 1390hp Merlin XX engine with a 2-speed and single stage supercharger and a constant-speed airscrew. A retractable tail wheel and clipped wings were also introduced. A top speed of 385mph was achieved. Only 2 were produced, although many of the new features were developed into future models.

Type 348 Mk III
Type 337 Mk IV

The Mk IV was the first attempt to install a Rolls-Royce Griffon engine to counter low-level raids by intruders.

MKV > MKVI
Type 349 Mk VA, Mk VB and Mk VC

Powered by a 1230hp Merlin 45 or 46, 3 patterns of wing armament were introduced-

  •  Mk VA - eight 0.303 Browning machine guns
  •  Mk VB- two 20mm cannon, and four Browning machine guns
  •  Mk VC- either four cannon or either of the other combinations

In total 6479 of the Mk Vs were produced. In a number, the wings were adapted for low altitude (clipped wing tips, for faster roll rate), and the supercharger settings adapted for the selected altitude. The Mk V could be called the "workhorse" of all the Spitfires.

(Picture shows: Mk VB tropicalized for the Western Desert. The intake duct housed a vokes Millevee dust filter)

Mk VB tropicalized for the Western Desert
Type 350 Mk VI

This was introduced to combat the threat of high flying German bombers. It was fitted with a Merlin 47 driving a 4-bladed propeller, and extended wing tips for high altitude. The most notable change was the addition of a partially pressurized cabin, with a canopy that was fixed in place on the ground, except for emergency jettisoning. It was an interim model, and only 100 were built.

MKVII > MKIX
Types 351 and 360 Mk VII

MkVIIs were fitted with two-speed two-stage supercharged Merlin 60 and 70 series engines. The aircraft consequently had the symmetrical larger radiators under each wing, rather than the asymmetric radiator/oil cooler combinations of earlier Marks, a pressurised cockpit and a larger rudder. Top speed was 416mph.

Type 351 Mk VII
Type 359 Mk VIII

Mk VIII was an unpressurised VII fitted with versions of the Merlin 60 and 70 series according to its intended role. It had extended wing tips for high altitude duty, clipped wings for low-level and standard for normal roles.

Type 361 Mk IX

The Mk IX started life as a strengthened MkV airframe with the latest, 60 series, Merlin engines driving a 4-bladed airscrew. It proved so successful that around 5665 were produced.

Type 361 Mk IX
MKXI > MKXVIII
Type 366 Mk XII

This was an interim Spitfire designed to take advantage of the new Griffon engine. Around 100 were produced. A retractable tail wheel appeared early in the production run, and were clipped-wing in service, for low altitude interception.

Type 366 Mk XII
Type 379 Mk XIV

In classic Spitfire tradition, the new engine, a Griffon 65, was "engineered" into an available airframe, in this case a Mk VIII. To absorb the power generated, a 5-bladed airscrew was introduced. Various figures have been quoted for the Mk XIV but its low-level performance was good enough for it to be used to chase V1 flying bombs. Some were produced with a cut-down rear fuselage and "teardrop" canopy for increased rear visibility. 957 were produced in total.

Type 373 Mk XIV
Type 361 Mk XVI

A large number of Mk IX Spitfires were produced with Packard of Detroit built Merlin 266 engines and were thus designated Mk XVI. Clipped wings were standardised as the type was largely used for ground attack.

Type 394 Mk XVIII

The basic Mk VIII airframe was fitted with 2-stage, 2-speed Griffon 65 or Griffon 67 engines. 300 were produced. They were externally similar to the Mk XIV but with revised unternal structure.

MK21 > MK24
Type 356 Mk 21

Along with a new way of writing the Mark numbers, the 20 series Spitfires were a major rebuild of the design. Although superficially similar, there was very little structurally in common with the earlier Marks with a totally new wing design with revised plan form. The long nose of the Griffon engine was prominent. 120 were produced.

Type 356 Mk 21
Type 356 Mk 22

This was essentially a Mk 21 with a cut-down fuselage and a teardrop canopy. 278 were built.

(Picture shows: Mk 22 the newer ‘teardrop’ canopy can be clearly seen)

Type 356 Mk 22
Type 356 Mk 24

Although introducing short-barrelled Hispano cannon, it was essentially the same as the Mk 22. Only 54 were built. The engines powering the 20-series Spitfires were the Griffon 61 and Griffon 64.

MK PRX > Tr 9
Type 362-Mk PRX

This photo reconnaissance aircraft was a converted Mk VII airframe. Many had the MkVII pressurization removed. 16 were produced.

Type 365-Mk PRXI

The photo reconnaissance variant of the successful Mk IX was similar in many ways, but with cleaned up wings carrying no armament and integral fuel tanks. In total 471 were produced.

Types 389 & 390-Mk PRXIX

This aircraft was the photo reconnaissance derivative of the Mk XIV. 225 were built.

Type 509 Tr 9

After the end of the War, with widespread sales of Spitfires, up to thirty Mark IX Spitfires were bought back by Vickers Armstrongs of which 21 were converted to the Trainer (Tr) Mk IX. The front cockpit was moved forwards, and a second cockpit with raised seat and high domed canopy was added behind it.

Type 509 Tr 9
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