Supermarine Spitfire

The early Spitfires
The Supermarine Spitfire was designed in the mid 1930s by the man responsible for the highly successful series of Schneider cup racing aircraft, Reginald J. Mitchell. The initial Spitfire prototype fitted with an early example of the Rolls Royce Merlin engine took to the skies around the 5th March 1936, pulled along with a two bladed propeller.
The prototype K5054 Spitfire was an early success and the next month an order was placed for the new aircraft by the British Air Ministry for some 310 machines, initial deliveries of these aircraft being made in late 1938.
The first production Spitfires were much improved over the prototype aircraft but they still had a number of problems. Amongst the early shortcomings were an undercarriage requiring manual pumping for retraction and extension, fabric covered control surfaces causing manouverability problems at high speeds and a propellor which was still a wooden fixed pitch unit more suited to a old ww1 antique. The Spitfire also suffered from engine trouble under negative G loads, a problem which would effect the Spitfire for some time.

The Battle of Britain begins

The Spitfire is almost certainly most famous for it's vital role during the Battle of Britain. Mitchell's foresight really payed off here, the aircraft becoming mainstream at just the right moment to take up arms alongside the very capable but slower Hawker Hurricane. While the Hurricane still out-numbered the Spitfire by roughly 2-1 during this period and also had the higher tally, it had a hard time against the German BF109. The RAF would surely have had a bruising time of it without the Spitfire which proved itself a match for the fast Messerschmitt.

The Spitfires used at this time were largely MK1 aircraft now fitted with a higher more rounded canopy for better visibiity, a three bladed twin pitch (later fully variable pitch) metal propellor and a Merlin type 2 or 3 with around 1030hp on tap (more than 1300 hp if run on 100 octane petrol with 12 pounds boost). Armament at this time was eight 303 machine guns in the wings. The MK1 was subsequently subdived into MK1a and MK1b depending on the armament fitted, MK1b aircraft having four 303s and two 20mm cannon while the MK1a had the original eight Browning arrangement.

The Spitfire was incrementally improved and modified over this period. The MKII aircraft were largely like a fully upgraded Mk1 Spitfire and were fitted with an improved Merlin 12 engine producing around 1,175hp, these joining squadrons from late 1940.

MKV Spitfire series
The next major type was the MKV Spitfire, this being handed out to the RAF from March 1941 onwards. This aircraft consisted of the new Merlin 45 aero engine being mated to a MK2 airframe. The new mkv Spitfire flew in February 1941 and was intended as an interim aircraft. It proved itself highly successful however and became one of the main Spitfire variants. To suppliment the production lines turning out the mkv Spitfire existing earlier marks of the aircraft were upgraded with the new engine and became redisignated mkv Spitfires.

The MKV was subdivided into MKVa and MKVb in a similar manner to the earlier Spitfires. The Va aircraft were fitted with eight 303 caliber mgs whilst the Vb had the four 303 plus two 20mm cannon arrangement.
This mark of the aircraft was used in overseas theatres as well in Britain. When operating in the dusty conditions of North Africa the MKV was fitted with the unsightly Vokes filter to avoid sucking in the damaging sand and dust. These filters were not only ugly but also took the edge off performance.

With the MKVc variant a new wing was introduced, this being known as the universal wing. This improved wing design allowed for interchangable armament, a choice of eight 303 mgs, four 303 plus two 20mm cannon or four 20mm could be fitted to this wing. The provision for ammo rounds was also improved with the use of a newly designed feed system.

The MKV was Continually modified and improved throughout it's production run and around 6,500 MKV Spitfires of various types were produced. The aircraft was a match for pretty much everything at the time until the appearance of the Focke Wulf FW190 which could cause a MKV serious trouble.

Spitfire MKXI photo reconaisance aircraft

The MKIX Spitfire emerges
With the emergence of the Focke Wulf 190 aircraft in the skies over Europe the need for upgrading the Spitfire became especially apparent. To quickly regain parity with the FW190, engineers took a Spitfire MKV aircraft and fitted the new 1,565 hp Merlin 61 engine, producing the MKIX Spitfire. This power upgrade was extremely well received by RAF pilots, the MKIX gave them the machinery to match the FW190 and out perform virtually anything else put up against it at the time.
The new aircraft could also operate at high altitude thus making high level interceptions vastly easier. Over 7,000 MKIX and MKXVI (basically Packard Merlin MKIX) Spitfires were produced, the largest of any Spitfire version.
During the MKIX Spitfire production run the E wing was introduced. This new wing incorporated two Hispana cannons plus two heavy half inch Browning mgs.

Once again this combination of an old airframe with a new upgraded Merlin engine was meant to be a temporary stop gap aircraft. It turned out to be one of the major types produced however and entered service before some lower marks that were 'proper redesigns' . One of the major redesign versions was the MKVIII Spitfire which used a Merlin 60 series engine. This much re-engineered unpressurised Spitfire was intended primarily for low level work and had various advancements including wing & fuselage modifications, and a retractable tail-wheel. These MKVIII aircraft served largely as fighter-bombers in overseas theatres of operation.

Underside view of the Spitfire MKVB

The Mighty Griffon
The next major development of the Spitfire was highly significant. Rolls-Royce had been developing a new V12 aircraft engine of enormous power, this engine became known as the Griffon and would form a new breed of super high performance Spitfires.
The first production Griffon Spitfire was the MKXII. Only around a hundred of this mark were constructed in 1943. These first production Griffon engined Spitfires were based on modified MKIX and MKVIII airframes and used the early Griffon IIIs and IVs of around 1,735hp.

The next version of Griffon Spitfire was the MKXIV, this was a major production model with 957 being manufactured. This aircraft used the uprated Griffon 65 which had over 2,000hp on tap making the MKXIV an extremely formidable aircraft. The new powerful machine was also a formidable challenge for the pilot on take off. The huge torque of the Griffon which rotated in the opposite direction the the Merlin coupled with the Spitfire's rather narrow undercarriage track could easily induce a wild ground looping takeoff run.
Performance of the MKXIV varied according to various parameters such as supercharger boost pressure, fuel octane rating, altitude as well as on the sub-mark of the aircraft. Some were capable of over 400mph in level flight at tree top height. At higher altitudes speeds in the region of 439 mph straight and level could be attained.

Supermarine Spitfire MK1a
Engine	Rolls-Royce Merlin 2 V-12 1,030 hp	Top Speed	346mph at medium altitude
Weight	Empty 4,517 lb Loaded 5,844lb	Wingspan	36ft 10"
Length	29ft 11"	Weapons	8x Browning .303 mg
Country	UK	Crew	Pilot only

Supermarine Spitfire MK9
Engine	Rolls-Royce Merlin 61 V-12 1,565 hp	Top Speed	408mph at medium altitude
Weight	Empty 5,816 lb Loaded 7,296lb	Wingspan	36ft 10"
Length	30ft 6"	Weapons	2x Hispano 20mm cannon 4x Browning .303 mg
Country	UK	Crew	Pilot only