Supermarine Spitfire (early Merlin powered variants)

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

Supermarine Spitfire was the only fighter aircraft

Fighter aircraft

A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

of the Second World War

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

to fight in front line service, from the beginnings of the conflict, in September 1939, through to the end in August 1945. Post-war the Spitfire's service career continued into the 1950s. The basic airframe proved to be extremely adaptable, capable of taking far more powerful engines and far greater loads than its original role as a short-range interceptor had allowed for. This would lead to 19 marks of Spitfire and 52 sub-variants being produced throughout the Second World War and beyond. The many changes were made in order to fulfil Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

requirements and to successfully combat ever-improving enemy aircraft. With the death of Reginald J. Mitchell

R. J. Mitchell

Reginald Joseph Mitchell CBE, FRAeS, was an aeronautical engineer, best known for his design of the Supermarine Spitfire.-Early years:...

in June 1937, all variants of the Spitfire were designed by his replacement, Joseph Smith

Joseph Smith (aircraft designer)

Joseph Smith CBE was an English aircraft designer who took over as Chief Designer for Supermarine's upon the death of R. J...

, and a team of engineers and draftsmen.

These articles present a brief history of the Spitfire through all of its variants, including many of the defining characteristics of each sub-type. This article deals with Spitfires powered by early Rolls-Royce Merlin

Rolls-Royce Merlin

The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...

engines which mostly utilised single-speed, single-stage supercharger

Supercharger

A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...

s. The second article describes Spitfire variants powered by later Merlins, with two-stage, two-speed superchargers, while the final article describes the Spitfires powered by Rolls-Royce Griffon

Rolls-Royce Griffon

The Rolls-Royce Griffon is a British 37-litre capacity, 60-degree V-12, liquid-cooled aero engine designed and built by Rolls-Royce Limited...

engines.

Wing types

The Spitfires with the Single Stage Merlin engines used four different wing types, A through to D which had the same dimensions and plan but different internal arrangements of armament and fuel tanks. All Mk Is, IIs, and Vs and their derivatives had small, rectangular undercarriage indicator pins which projected at an angle from the upper wing surfaces when the undercarriage legs were locked down. These supplemented lights on the instrument panel. All of these variants used Dunlop

Dunlop Rubber

Dunlop Rubber was a company based in the United Kingdom which manufactured tyres and other rubber products for most of the 20th century. It was acquired by BTR plc in 1985. Since then, ownership of the Dunlop trade-names has been fragmented.-Early history:...

AH2061 mainwheels which had five openings. The fixed, castering tailwheels were Dunlop AH2184s.

Starting with the Mk V some Spitfires had their rounded wingtips replaced by shorter, squared-off fairings to improve low-altitude performance and enhance the roll rate. These are sometimes referred to as "L.F" versions, e.g. L.F. Mk. VB: this designation referred to the low-altitude versions of the Rolls-Royce Merlin

Rolls-Royce Merlin

with the "cropped" supercharger impellers (known as Merlin 45M, 50M or 55M). While many "L.F" Spitfires had the "clipped" wings, a number did not.

A type

The original wing design, the basic structure of which was unchanged until the C type in 1942. The one major alteration made to this wing, soon after production started was the incorporation of heating for the gun bays: open structures around the gun-bays were blocked off. Ducting, drawing hot air from the back of the radiators, was added to the wings. The heated air was exhausted through underwing vents, covered by streamlined triangular blisters, just inboard of the wingtips. Towards the end of 1940 the fabric covered ailerons were replaced by ones covered in light-alloy. The only armament able to be carried was 8 × .303"

.303 British

.303 British, or 7.7x56mmR, is a .311 inch calibre rifle and machine gun cartridge first developed in Britain as a blackpowder round put into service in December 1888 for the Lee-Metford rifle, later adapted to use smokeless powders...

Browning

M1919 Browning machine gun

The M1919 Browning is a .30 caliber medium machine gun that was widely used during the 20th century. It was used as a light infantry, coaxial, mounted, aircraft, and anti-aircraft machine gun by the U.S. and many other countries, especially during World War II, the Korean War, and the Vietnam War...

machine guns with 300 rpg.

B type

This was the A type modified to carry one 20 mm Hispano cannon. The retractable underwing landing lamp was repositioned and the innermost machine gun bays were replaced with a single cannon bay, plus a compartment for the drum magazine outboard of the wheel well. The upper and lower wing skins incorporated blisters to clear the ammunition drum. Under the wings there were two possible blister shapes. One type of armament could be fitted to a Spitfire with this wing: Two 20 mm Hispano Mk II cannon, each with 60 round drums and four .303" Browning machine guns with 350 rpg. The alloy covered ailerons were standardised on this wing type.

C type

"Universal wing". The wing was structurally modified to reduce labour and manufacturing time plus allowing mixed armament options; A type, B type, or four 20 mm Hispano cannon.
The undercarriage mountings were redesigned and the undercarriage doors were bowed in cross section allowing the legs to sit lower in the wells, eliminating the upper-wing blisters over the wheel wells and landing gear pivot points.
The stronger undercarriage legs were raked 2 inches (5.08 cm) forward, making the Spitfire more stable on the ground and reducing the likelihood of the aircraft tipping onto its nose. In addition the retractable landing lights were no longer fitted. Strong-points were added outboard of the wheel-wells allowing racks capable of carrying one 250 lb (113 kg) bomb to be fitted under each wing.

The Hispano Mk IIs fitted in all cases were now belt fed from box magazines allowing for 120 rounds each (the "Chattellerault" system). The fairings over the Hispano barrels were shorter and there was usually a short rubber stub covering the outer cannon port.The redesigned upper wing gun bay doors incorporated blisters to clear the cannon feed motors, and the lower wings no longer had the gun-bay heating vents outboard of the gun bays. Finally, the inner machine gun bays were moved outboard to between ribs 13 and 14. In practice, most aircraft carried two 20 mm Hispano IIs with 120 rpg and four .303" Browning machine guns with 350 rpg. Several Spitfire Vcs which were transported to Malta were initially fitted with four Hispanos, although they soon reverted to the standard B type configuration.

D type

Unarmed long-range wing for reconnaissance versions with the D shaped wing structure ahead of the main spar converted to integral fuel tanks capable of carrying 66½ Imperial gallons (300 l). The filler caps were well outboard, between ribs 19 and 20 on the leading edge and an expansion and overflow vent was fitted further outboard, between ribs 20 and 21.

Mark numbers, type numbers

The Mark numbers did not necessarily indicate a chronological order; for example, the Mk IX was a stopgap measure brought into production before the Mks VII and VIII. In addition, some Spitfires of one mark or variant may have been modified to another; for example, several of the first Mk VBs were converted from Mk IBs; the first Mk IXs were originally Mk VCs, converted, in some instances, by Rolls-Royce at their Hucknall

Hucknall

Hucknall, formerly known as Hucknall Torkard, is a town in Greater Nottingham, Nottinghamshire, England, in the district of Ashfield. The town was historically a centre for framework knitting and then for mining but is now a focus for other industries as well providing housing for workers in...

facility.

Up until the end of 1942, the RAF always used Roman numerals for mark numbers. 1943-1948 was a transition period during which new aircraft entering service were given Arabic numerals for mark numbers but older aircraft retained their Roman numerals. From 1948 onwards, Arabic numerals were used exclusively. This article adopts the convention of using Roman numerals for the Mks I-XVI and Arabic numerals for the Mks 17-24. Type numbers e.g.; (type 361) are the drawing board design numbers allocated by Supermarine.

Prototype K5054 (Supermarine Type 300)

Construction on K5054 started in December 1934, although several modifications were to be incorporated into the prototype as construction continued. The most obvious change was to the Merlin engine's cooling system, which was now to use pure ethylene glycol

Ethylene glycol

Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...

rather than water, and the incorporation of a ducted radiator designed using the results of research conducted by Frederick Meredith of the Royal Aircraft Establishment

Royal Aircraft Establishment

The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...

at Farnborough

Farnborough, Hampshire

-History:Name changes: Ferneberga ; Farnburghe, Farenberg ; Farnborowe, Fremborough, Fameborough .Tower Hill, Cove: There is substantial evidence...

. At the time of her first flight on 5 March 1936 , K5054 was unpainted and the undercarriage had no fairings fitted and was fixed down. The first engine was a prototype Merlin C engine of 990 hp (738 kW), with six flush-fitting exhaust ports each side, driving an Aero-Products "Watts" two-bladed, wooden fixed-pitch

Blade pitch

Blade pitch or simply pitch refers to turning the angle of attack of the blades of a propeller or helicopter rotor into or out of the wind to control the production or absorption of power. Wind turbines use this to adjust the rotation speed and the generated power...

propeller

Propeller (aircraft)

Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...

. The carburettor air intake was shorter and flatter than that of the Mk Is, and was recessed into the centre-section.

The rudder mass balance was larger than that of production aircraft, with an angled lower edge cutting further into the top of the fin. Although the basic wing plan was to stay the same for most production Spitfires, the prototype wing was structurally different: No weapons were fitted and the alclad

Alclad

Alclad is a trademark of Alcoa used as a generic term to describe corrosion resistant aluminium sheet formed from high-purity aluminium surface layers metallurgically bonded to high strength aluminium alloy core material. These sheets are commonly used by the aircraft industry...

skinning was laid out in spanwise strips; underneath the port wing the radiator bath started immediately behind the starboard undercarriage bay, with the opening conforming to the angle of the bay. Unlike production aircraft the wingtips were an integral part of the structure and, for the first series of tests a long pitot tube

Pitot tube

A pitot tube is a pressure measurement instrument used to measure fluid flow velocity. The pitot tube was invented by the French engineer Henri Pitot Ulo in the early 18th century and was modified to its modern form in the mid-19th century by French scientist Henry Darcy...

projected from near the port wingtip.

After the first few flights K5054 was returned to the factory, reappearing about 10 days later with an overall pale blue-grey finish, using a high-gloss automotive nitrocellulose

Nitrocellulose

Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...

-lacquer

Lacquer

In a general sense, lacquer is a somewhat imprecise term for a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required...

applied by people from the Rolls-Royce car plant (there is still some uncertainty over the actual colour). The tailskid originally fitted had been replaced by a Dowty manufactured, fully castoring tail-wheel unit. This tailwheel was to be modified several times on the prototype, including using twin tailwheels each smaller than the single wheel which was later standardised. The engine cowlings had been altered slightly and the angled fin tip had become straight topped - the rudder balance was correspondingly reduced in size. Undercarriage fairings had now been fitted to the legs. Although the propeller was still the fixed-pitch, wooden bladed unit the pitch had been changed in an attempt to increase the top speed. Several different types of propeller unit were to be fitted to the prototype. Later in 1936, the wings were replaced with a set which, for the first time, incorporated the famous eight .303" Browning machine-gun armament.

The Spitfire was to fly in this form until 22 March 1937, when a major oil pressure failure led to a "forced-landing" with the undercarriage up. When K5054 re-emerged from the factory the pale blue finish, which had deteriorated badly, was replaced by the RAF's standard "Dark Earth"/"Dark Green" camouflage on the top surfaces with a silver dope finish underneath; this was worn for the remainder of the airframe's life. On 19 September 1938 the Spitfire was flown for the first time with ejector exhausts, developed for the Merlin by Rolls-Royce. With these it was found that the exhausts developed 70 pounds of thrust, equivalent to about 70 hp at 300 mph.

K5405 came to the end of its flying life on 4 September 1939 while being tested at Farnborough

Farnborough Airfield

Farnborough Airport or TAG London Farnborough Airport is an airport situated in Farnborough, Rushmoor, Hampshire, England...

. After a misjudged landing K5404 bounced and then tipped over on its back, trapping the pilot Flt Lt. White. White died four days later because of serious neck injuries which were caused by the design of the anchor point to the Sutton harness; this accident lead to the system being redesigned. Parts of the prototype went to the Photographic Department at Farnborough where they were used to test camera installations in the wings and fuselage of reconnaissance Spitfires.

Mk I (Type 300)

In 1936, before the first flight of the prototype, the Air Ministry

Air Ministry

The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...

placed an order for 310 Spitfires. However, in spite of the promises made by the Chairman of Vickers-Armstrongs (the parent company of Supermarine

Supermarine

Supermarine was a British aircraft manufacturer that became famous for producing a range of sea planes and the Supermarine Spitfire fighter. The name now belongs to an English motorboat manufacturer.-History:...

) that the company would be able to deliver Spitfire at a rate of five a week, it soon became clear that this would not happen. In 1936 the Supermarine company employed 500 people and was already engaged in fulfilling orders for 48 Walrus

Supermarine Walrus

The Supermarine Walrus was a British single-engine amphibious biplane reconnaissance aircraft designed by R. J. Mitchell and operated by the Fleet Air Arm . It also served with the Royal Air Force , Royal Australian Air Force , Royal Canadian Air Force , Royal New Zealand Navy and Royal New...

amphibian reconnaissance aircraft and 17 Stranraer

Supermarine Stranraer

|-Surviving aircraft:A single intact Stranraer, 920/CF-BXO, survives in the collection of the Royal Air Force Museum London. This aircraft was built in 1940, one of 40 built by Canadian Vickers. In service with the Royal Canadian Air Force, it flew with several squadrons, on anti-submarine patrols,...

patrol flying boats. In addition the small design staff, which would have to draught the blueprints for the production aircraft, was already working at full stretch. Although it was obvious that most of the work would have to be sub-contracted to outside sources, the Vickers-Armstrongs board was reluctant to allow this to happen. When other companies were able to start building Spitfire components there were continual delays because either parts provided to them would not fit, or the blueprints were inadequate; the sub-contractors themselves faced numerous problems building components which in many cases were more advanced and complicated than anything they had faced before.

As a result of these problems the first production Spitfire K9788 was not delivered to the RAF until July 1938 with front line service starting in August 1938. For a time the future of the Spitfire was in serious doubt, with the Air Ministry suggesting that the programme be abandoned and that Supermarine change over to building the Bristol Beaufighter

Bristol Beaufighter

The Bristol Type 156 Beaufighter, often referred to as simply the Beau, was a British long-range heavy fighter modification of the Bristol Aeroplane Company's earlier Beaufort torpedo bomber design...

under licence. The managements of Supermarine and Vickers were eventually able to convince the Air Ministry that production would be sorted out and, in 1938, an order was placed with the Morris Motor Company

Morris Motor Company

The Morris Motor Company was a British car manufacturing company. After the incorporation of the company into larger corporations, the Morris name remained in use as a marque until 1984 when British Leyland's Austin Rover Group decided to concentrate on the more popular Austin marque...

for an additional 1,000 Spitfires to be built at huge new factory which was to be built at Castle Bromwich

Castle Bromwich

Castle Bromwich is a suburb situated within the northern part of the Metropolitan Borough of Solihull in the English county of West Midlands. It is bordered by the rest of the borough to the south east, North Warwickshire to the east and north east; also Shard End to the south west, Castle Vale,...

. This was followed in 1939 by an order for another 200 from Woolston and, only a few months later, another 450. This brought the total to 2,160, making it one of the largest orders in RAF history. Over the next three years a large number of modifications were made, most as a result of wartime experience.

Early in the Spitfire's operational life a major problem became apparent; at altitudes above about 15,000 ft (4,572 m), any condensation could freeze in the guns. Because of this the system of gun heating first fitted to K5054 was introduced on the 61st production Mk I. At the outset of World War II, the flash-hiders on the gun muzzles were removed and the practice of sealing the gun ports with fabric patches was instituted. The patches kept the gun barrels free of dirt and debris and allowed the hot air to heat the guns more efficiently. Early production aircraft were fitted with a ring and bead gunsight, although provision had been made for a reflector sight

Reflector sight

A reflector or reflex sight is a generally non-magnifying optical device that allows the user to look through a partially reflecting glass element and see an illuminated projection of an aiming point or some other image superimposed on the field of view...

to be fitted once one had been selected. In July 1938, the Barr and Stroud

Barr and Stroud

Barr & Stroud Limited was a pioneering Scottish optical engineering firm, based in Glasgow, that played a leading role in the development of modern optics, including rangefinders, for the Royal Navy and for other branches of British Armed Forces during the 20th century...

GM 2 was selected as the standard RAF reflector gunsight and was fitted to the Spitfire from late 1938. These first production Mk Is were able to reach a maximum speed of 362 mi/h at 18500 ft (5,638.8 m), with a maximum rate of climb of 2,490 ft/min at 10000 ft (3,048 m). The service ceiling (where the climb rate drops to 100 ft/min) was 31900 ft (9,723.1 m).

All Merlin I to III series engines relied on external electric power to start; a well known sight on RAF fighter airfields was the "trolley acc" (trolley accumulator) which was a set of powerful batteries which could be wheeled up to aircraft. The lead from the "Trolley Acc" was plugged into a small recess on the starboard side cowling of the Spitfire. On Supermarine-built aircraft a small brass instruction plate was secured to the side cowling, just beneath the starboard exhausts.

The early Mk Is were powered by the 1,030 hp (768 kW) Merlin Mk II engine driving an Aero-Products "Watts" 10 ft 8 in (3.3 m) diameter two-blade wooden fixed-pitch propeller, weighing 83 lb (38 kg). From the 78th production airframe, the Aero Products propeller was replaced by a 350 lb (183 kg) de Havilland

De Havilland

The de Havilland Aircraft Company was a British aviation manufacturer founded in 1920 when Airco, of which Geoffrey de Havilland had been chief designer, was sold to BSA by the owner George Holt Thomas. De Havilland then set up a company under his name in September of that year at Stag Lane...

9 ft 8 in (2.97 m) diameter, three-bladed, two-position, metal propeller, which greatly improved take-off performance, maximum speed and the service ceiling

Service ceiling

With respect to aircraft, a ceiling is the maximum density altitude an aircraft can reach under a set of conditions.The word ceiling can also refer to the height of the lowest obscuring cloud layer above the ground.-Service ceiling:...

. From the 175th production aircraft, the Merlin Mk III, with a "universal" propeller shaft able to take a de Havilland or Rotol propeller, was fitted. Following complaints from pilots a new form of "blown" canopy was manufactured and started replacing the original "flat" version in early 1939. This canopy improved headroom and enabled better vision laterally, and to the rear.
At the same time the manual hand-pump for operating the undercarriage was replaced by a hydraulic system driven by a pump mounted in the engine bay. Spitfire Is incorporating these modifications were able to achieve a maximum speed of 367 mi/h at 18600 ft (5,669.3 m), with a maximum rate of climb of 2,150 ft/min at 10000 ft (3,048 m). The service ceiling was 34400 ft (10,485.1 m).

A voltage regulator

Voltage regulator

A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components...

under a black, cylindrical cover was mounted low on the back of frame 11, directly behind the pilot's seat:starting in the N30xx series this was repositioned higher, appearing low in the rear transparency. From N32xx the regulator was mounted directly behind the pilot's headrest on frame 11. Other changes were made later in 1939 when a simplified design of pitot tube

Pitot tube

was introduced and the "rod" aerial mast was replaced by a streamlined, tapered design. To improve protection for the pilot and fuel tanks a thick laminated glass bulletproof plate was fitted to the curved, one piece windscreen and a 3 mm thick cover of light alloy, capable of deflecting small calibre rounds, was fitted over the top of the two fuel tanks. From about mid-1940, 73 pounds (33 kg) of armoured steel plating was provided in the form of head and back protection on the seat bulkhead and covering the forward face of the glycol header tank. In addition, the lower petrol tank was fitted with a fire resistant covering called "Linatex", which was later replaced with a layer of self-sealing rubber.

In June 1940 de Havilland began manufacturing a kit to convert their two pitch propeller unit to a constant speed propeller

Constant speed propeller

A constant speed propeller is a type of propeller that can change its blade pitch to take better advantage of the power supplied by an engine in much the same way that a transmission in a car takes better advantage of its power source...

. Although this propeller was a great deal heavier than the earlier types (500 lb (227 kg) compared with 350 lb (183 kg)) it provided another substantial improvement in take-off distance and climb rate. Starting on 24 June de Havilland engineers began fitting all Spitfires with these units and by 16 August every Spitfire and Hurricane

Hawker Hurricane

The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...

had been modified. "Two step" rudder pedals were fitted to all frontline Spitfires; these allowed the pilot to lift his feet and legs higher during combat, improving his "blackout

G-LOC

G-LOC, pronounced 'GEE-lock', is the abbreviation of G-force induced Loss Of Consciousness, a term generally used in aerospace physiology to describe a loss of consciousness occurring from excessive and sustained g-forces draining blood away from the brain causing cerebral hypoxia...

" threshold and allowing him to pull tighter sustained turns. Another modification was the small rear view mirror which was added to the top of the windscreen: an early "shrouded" style was later replaced by a simplified, rectangular, adjustable type.

Starting in September 1940, IFF

Identification friend or foe

In telecommunications, identification, friend or foe is an identification system designed for command and control. It is a system that enables military and national interrogation systems to identify aircraft, vehicles, or forces as friendly and to determine their bearing and range from the...

equipment was installed. This weighed about 40 lb (18 kg) and could be identified by wire aerials strung between the tailplane tips and rear fuselage. Although the added weight and the aerials reduced maximum speed by about two mph (three km/h), it allowed the aircraft to be identified as "friendly" on radar: lack of such equipment was a factor leading to the Battle of Barking Creek

Battle of Barking Creek

The Battle of Barking Creek was a friendly fire incident that happened on 6 September 1939, resulting in the first death of a British fighter pilot in the Second World War.-Incident:...

. At about the same time new VHF

Very high frequency

Very high frequency is the radio frequency range from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted High frequency , and the next higher frequencies are known as Ultra high frequency...

T/R Type 1133 radios started replacing the HF

High frequency

High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...

TR9 sets. These had first been fitted to Spitfires of 54 and 66 Squadron

No. 66 Squadron RAF

No. 66 Squadron was a Royal Flying Corps and eventually Royal Air Force aircraft squadron.-In World War I:It was first formed at Filton on 30 June 1916 as a Training Squadron equipped with BE2c,d & e, BE12 and Avroe 504A machines. The squadron received its first Sopwith Pup on 3 February 1917,...

s in May 1940, but ensuing production delays meant the bulk of Spitfires and Hurricanes were not fitted for another five months. The pilots enjoyed a much clearer reception which was a big advantage with the adoption of Wing formations throughout the RAF in 1941. The new installation meant that the wire running between the aerial mast and rudder could be removed, as could the triangular "prong" on the mast.

Weight increases and aerodynamic changes led to later Spitfire Is having a lower maximum speed than the early production versions. This was more than offset by the improvements in take-off distance and rate of climb brought about by the constant speed propeller units. During the Battle of Britain

Battle of Britain

The Battle of Britain is the name given to the World War II air campaign waged by the German Air Force against the United Kingdom during the summer and autumn of 1940...

Spitfire Is equipped with constant-speed propellers had a maximum speed of 353 mi/h at
20000 ft (6,096 m), with a maximum rate of climb of 2,895 ft/min at 10000 ft (3,048 m).

Although the Merlin III engine of Spitfire Is had a power rating of 1,030 hp (768 kW), supplies of 100 octane

Octane rating

Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...

fuel from the United States started reaching Britain in early 1940. This meant that an "emergency boost

Supercharger

" of +12 pounds per square inch was available for five minutes, with pilots able to call on 1,310 hp (977 kW) at 3,000 rpm at 9,000 feet (2,743 m). This boosted the maximum speed by 25 mi/h at sea level and 34 mi/h at 10000 ft (3,048 m) and improved the climbing performance between sea level and full throttle height. The extra boost wasn't damaging as long as the limitations set forth in the pilot's notes were followed. As a precaution if the pilot had resorted to emergency boost, he had to report this on landing and it had to be noted in the engine log book. There was a wire 'gate' fitted, which the pilot had to break to set the engine to emergency power, this acted as an indicator that emergency power had been used and would be replaced by mechanics on the ground. The extra boost was also available for the Merlin XII fitted to the Spitfire II.

Late in 1940, a Martin-Baker

Martin-Baker

Martin-Baker Aircraft Co. Ltd. is a manufacturer of ejection seats and safety related equipment for aviation. The company origins were as an aircraft manufacturer before becoming a pioneer in the field of ejection seats...

designed quick-release mechanism began to be retroactively fitted to all Spitfires. The system employed unlocking pins, actuated by cables operated by the pilot pulling a small, red rubber ball mounted on the canopy arch. When freed, the canopy was taken away by the slipstream. One of the most important modifications to the Spitfire was to replace the machine gun armament with wing mounted Hispano 20 mm cannon

Hispano-Suiza HS.404

The Hispano-Suiza HS.404 was an autocannon widely used as both an aircraft and land weapon in the 20th century by British, American, French, and numerous other military services. The cannon is also referred to as Birkigt type 404, after its designer. Firing a 20 mm caliber projectile, it delivered...

. In December 1938, Joseph Smith was instructed to prepare a scheme to equip a Spitfire with a single Hispano mounted under each wing. Smith objected to the idea and designed an installation in which the cannon were mounted on their sides within the wing, with only small external blisters on the upper and lower wing surfaces covering the 60 round drum magazine. The first Spitfire armed with a single Hispano in each wing was L1007 which was posted to Drem

Drem

Drem is a small village in East Lothian, Scotland. It is approximately 20 miles east of Edinburgh and is close to Haddington , North Berwick , Dirleton and Gullane ....

in January 1940 for squadron trials. On 13 January, this aircraft, piloted by Plt Off

Pilot Officer

Pilot officer is the lowest commissioned rank in the Royal Air Force and the air forces of many other Commonwealth countries. It ranks immediately below flying officer...

Proudman of 602 Squadron

No. 602 Squadron RAF

No 602 Squadron is a Royal Auxiliary Air Force squadron. Originally formed in 1925 as a light bomber squadron, its role changed in 1938 to army co-operation and in 1939 to that of a fighter squadron....

took part in an engagement when a Heinkel He 111

Heinkel He 111

The Heinkel He 111 was a German aircraft designed by Siegfried and Walter Günter in the early 1930s in violation of the Treaty of Versailles. Often described as a "Wolf in sheep's clothing", it masqueraded as a transport aircraft, but its purpose was to provide the Luftwaffe with a fast medium...

was shot down. Soon after this Supermarine was contracted to convert 30 Spitfires to take the cannon armed wing; 19 Squadron received the first of these in June 1940 and by 16 August, 24 cannon armed Spitfires had been delivered.
These were known as the Mk IB: Mk Is armed with eight Brownings were retrospectively called the Mk Ia. With the early cannon installation, jamming was a serious problem. In one engagement, only two of the 12 aircraft had been able to fire off all of their ammunition. Further cannon-armed Spitfires, with improvements to the cannon mounts, were later issued to 92 Squadron, but due to the limited magazine capacity it was eventually decided the best armament mix was two cannon and four machine guns (most of these were later converted to the first Mk VBs).

From November 1940, a decision was taken that Supermarine would start producing light-alloy covered ailerons which would replace the original fabric covered versions. However, seven months after the decision was taken to install them on all marks, Spitfires were still being delivered with the original fabric covered ailerons. From May 1941 metal ailerons were fitted to all Spitfires coming off the production lines.

Foreign orders: Mk Is

The type numbers 332, 335, 336 and 341 were given to versions of the Mk I which were to be modified to meet the requirements of Estonia

Estonia

Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

, Greece

Greece

Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

, Portugal

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

, and Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

respectively. Estonia's order was cancelled when the Soviet Union annexed the country. The Greek and Portuguese orders were refused by the Foreign Office. The 59 aircraft for Turkey were approved, but after delivering two aircraft, the Foreign Office put a halt to that too in May 1940. The 208th production Spitfire I was sold to France and in June 1939 was delivered for evaluation.

In 1941, the British government agreed to supply Portugal with 18 Spitfire Mk 1as. These were refurbished aircraft, drawn from RAF stocks, retrofitted with TR 9 HF radios and no IFF. These arrived from late 1942 and were given the serial numbers 370 to 387, forming the XZ Esquadrilha at Tancos. These were all scrapped by the end of 1947.

Speed Spitfire (Type 323)

In 1937 ideas about modifying a Spitfire to make an attempt on the world landplane speed record were mooted. At the time the record of 352 mi/h was held by Howard Hughes

Howard Hughes

Howard Robard Hughes, Jr. was an American business magnate, investor, aviator, engineer, film producer, director, and philanthropist. He was one of the wealthiest people in the world...

flying a Hughes H-1 racing aircraft. Although an early Spitfire I was capable of 362 mi/h, this was at a full-throttle height of 16800 ft (5,120.6 m); the regulations for the world speed record demanded that the aircraft fly a 1.86 miles (3 km) course at an altitude no greater than 245 ft (74.7 m). The prototype Spitfire, which was the only one flying, was capable of 290 mi/h at very low level. On 11 November 1937 the modified Messerschmitt Bf 109 V-13 (D-IPKY), flown by Herman Wurster, raised the world speed record to 379 mi/h. It was still felt that a modified Spitfire could do better than this and, on the strength of this, the Air Ministry issued a contract to fund this work.

Accordingly a standard Mk I K9834 (the 48th production Spitfire) was taken off the production line and modified for the attempt on the World Speed Record. All military equipment was removed and the hinged gun panels, radio door and flare chute opening were replaced with removable panels. A special "sprint" version of the Merlin II, running on a special "racing fuel" of gasoline

Gasoline

Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

, benzol

Benzol

Benzol may refer to* Benzole* Benzene* Phenol* British Benzol, which was one of the largest independent oil distributors in the UK. It went into administration on 16 August 2005...

and methanol

Methanol

Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

, with a small amount of tetraethyl lead was able to generate 2,100 hp (1,565 kW) for short periods. This drove a Watts coarse pitch, four bladed wood propeller of 10 ft (3 m) in diameter. Cooling the more powerful engine was achieved using a pressurised water system. This required a deeper radiator inside a lengthened duct which extended to the trailing edge of the starboard wing. A larger diameter oil cooler was fitted under the port wing. The wingspan was reduced to 33 ft 8 in (10.29 m) and the wingtips were rounded.

All panel lines were filled and smoothed over, all round headed rivets on the wing surfaces were replaced by flush rivets and an elongated "racing" windscreen was fitted. A tailskid replaced the tailwheel. Finally the "Speed Spitfire" was painted in a highly polished gloss Royal Blue and Silver finish. As it turned out the finished aircraft weighed some 298 lb (135 kg) more than a standard 1938 vintage Spitfire. However, in June 1938 the Heinkel He 100

Heinkel He 100

The Heinkel He 100 was a German pre-World War II fighter aircraft design from Heinkel. Although it proved to be one of the fastest fighter aircraft in the world at the time of its development, the design was not ordered into series production. Approximately 19 prototypes and pre-production machines...

V2 set a new record of 394.6 mi/h, which was very close to the maximum speed the as yet unflown Speed Spitfire was likely to achieve.

The first flight of the modified Spitfire took place on 11 November 1938; from late February 1939 the maximum speed reached was 408 mi/h at 3000 ft (914.4 m). It was obvious that further modifications would be needed; the decision was made to delete the radiator and change the cooling to a "total loss" system. The upper fuel tank was removed and replaced with a combined condensor

Condenser (heat transfer)

In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, typically by cooling it. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant...

and water tank. The water was fed through the engine and back to the tank, where as much as possible would be condensed and the rest was ejected from the base of the engine as a jet of steam. It was calculated that the Speed Spitfire would be able to make the speed runs and land safely before the water and much reduced fuel would run out at about the same time.

However once the World Speed records were twice broken in quick succession by the Heinkel He 100 V8 (463.9 mi/h on 30 March 1939) and Messerschmitt Me 209

Messerschmitt Me 209

|-See also:-Bibliography:* Feist, Uwe. The Fighting Me 109. London: Arms and Armour Press, 1993. ISBN 1-85409-209-X.* Green, William. War Planes of the Second World War, Fighters, vol. I. London: Hanover House, 1960....

(469.22 mi/h on 26 April), it was decided the Speed Spitfire needed a great deal more modification to even come close to the new speed records and the project lapsed.

On the outbreak of War, the Speed Spitfire was modified to a hybrid PR Mk II with the special Merlin II being replaced by a Merlin XII driving a variable pitch de Havilland propeller, and the racing windscreen replaced by a PR wrap-around type. Nothing could be done about the reduced fuel capacity and it could never be used as an operational aircraft. Flown as a liaison aircraft between airfields in Britain during the war, K9834 was scrapped in June 1946.

PR Mk I - Early Reconnaissance Versions

Before the Second World War, the conventional wisdom was to use converted bomber

Bomber

A bomber is a military aircraft designed to attack ground and sea targets, by dropping bombs on them, or – in recent years – by launching cruise missiles at them.-Classifications of bombers:...

types for airborne photo reconnaissance

Reconnaissance

Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

. These bombers retained their defensive armament, which was vital since they were unable to avoid interception. It was soon found that modified Blenheims

Bristol Blenheim

The Bristol Blenheim was a British light bomber aircraft designed and built by the Bristol Aeroplane Company that was used extensively in the early days of the Second World War. It was adapted as an interim long-range and night fighter, pending the availability of the Beaufighter...

and Lysanders

Westland Lysander

The Westland Lysander was a British army co-operation and liaison aircraft produced by Westland Aircraft used immediately before and during the Second World War...

were easy targets for German fighters and heavy losses were being incurred whenever these aircraft ventured over German territory.

In August 1939, Flying Officer Maurice Longbottom, inspired by Sidney Cotton

Sidney Cotton

Frederick Sidney Cotton OBE was an Australian inventor, photographer and aviation and photography pioneer, responsible for developing and promoting an early colour film process, and largely responsible for the development of photographic reconnaissance before and during the Second World War...

, filed a memorandum Photographic Reconnaissance of Enemy Territory in War with RAF Headquarters. In the memorandum Longbottom advocated that airborne reconnaissance would be a task better suited to fast, small aircraft which would use their speed and high service ceiling to avoid detection and interception. He proposed the use of Spitfires with the armament and radios removed and replaced with extra fuel and cameras. As a result of a meeting with Air Chief Marshal

Air Chief Marshal

Air chief marshal is a senior 4-star air-officer rank which originated in and continues to be used by the Royal Air Force...

Hugh Dowding, Air Officer Commanding RAF Fighter Command

RAF Fighter Command

RAF Fighter Command was one of three functional commands of the Royal Air Force. It was formed in 1936 to allow more specialised control of fighter aircraft. It served throughout the Second World War, gaining recognition in the Battle of Britain. The Command continued until 17 November 1943, when...

, two Spitfires N3069 and N3071 were released by RAF Fighter Command

RAF Fighter Command

and sent to the "Heston

Heston Aerodrome

Heston Aerodrome was a 1930s airfield located to the west of London, UK, operational between 1929 and 1947. It was situated on the border of the Heston and Cranford areas of Hounslow, Middlesex...

Flight", a highly secret reconnaissance unit under the command of Acting Wing Commander

Wing Commander (rank)

Wing commander is a commissioned rank in the Royal Air Force and the air forces of many other Commonwealth countries...

Cotton.

These two Spitfires were "Cottonised" by stripping out the armament and radio-transmitter, then, after filling the empty gun ports and all panel lines, the airframe was rubbed down to remove any imperfections. Coats of a special very pale blue-green called Camoutint were applied and polished. Two F.24 cameras with five inch (127 mm) focal length

Focal length

The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus...

lenses, which could photograph a rectangular area below the aircraft, were installed in the wing space vacated by the inboard guns and their ammunition containers as a stop-gap measure. Heating equipment was installed on all PR Spitfires to stop the cameras from freezing and the lenses from frosting over at altitude. These Spitfires, which later officially became the Spitfire Mk I PR Type A, had a maximum speed of 390 mph. Several of the sub-types which followed were conversions of existing fighter airframes, carried out by the Heston Aircraft Company

Heston Aircraft Company

Heston Aircraft Company was a British aircraft manufacturer based at Heston Aerodrome, Middlesex, England.Starting in 1934 the company produced a number of aircraft designs beginning with the Heston Phoenix and the Hordern-Richmond Autoplane. During the Second World War the company transitioned to...

. The Type D, which was the first specialised ultra long-range version, was the first to require that the work be carried out by Supermarine.

In the Mk I PR Type B (also known as Medium Range (MR)) conversions which followed the camera lenses were upgraded to an eight inch (203 mm) focal length, giving images up to a third larger in scale. An extra 29 gal (132 l) fuel tank was installed in the rear fuselage. It had been envisaged that much larger cameras would be installed in the fuselage immediately behind the pilot, but at the time RAF engineers believed this would upset the Spitfire's centre of gravity. Cotton was able to demonstrate that by removing lead weights, which had been installed in the extreme rear fuselage to balance the weight of the constant speed propeller units, it was possible to install cameras with longer focal-length lens in the fuselage. The Type B was the first to dispense with the heavy bullet resistant windscreen. Many of these early PR Spitfires were fitted with the Merlin XII engine and Rotol constant-speed propeller with the early, blunt spinner of the Spitfire Mk II.

The Mk I PR Type C carried a total of 144 gal (655 l) of fuel and was the first photo reconnaissance aircraft to reach as far as Kiel

Kiel

Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...

. The extra fuel was carried in the tank behind the pilot and in a 30 gal (136 l) blister tank under the port wing, which was counterbalanced by a camera installation in a fairing under the starboard wing. A larger oil tank was installed, necessitating the reshaping of the nose to the distinctive PR Spitfire "chin". This version was also known as the Long Range or LR Spitfire.

The Mk I PR Type D (also called the Extra Super Long Range Spitfire) was the first PR variant that was not a conversion of existing fighter airframes. The Type D carried so much fuel that it was nicknamed "the bowser." The D shaped wing leading edges, ahead of the main spar, proved to be an ideal location for an integral tank. Accordingly, in early 1940, work started on converting the leading edges, between rib four through to rib 21, by sealing off the spar, outer ribs and all skin joins allowing 57 gal (259 l) of fuel to be carried in each wing. Because the work was of low priority, and with the urgent need for fighters the first two, hand-built prototypes of the PR Type Ds weren't available until October. In addition to the leading edge tanks these prototypes also had a 29 gal (132 l) tank in the rear fuselage. An additional 14 gal (63 l) oil tank was fitted in the port wing. The cameras, two vertically mounted F.24s with 8 inch (20.3 cm) or 20 inch (50.8 cm) lens or two vertically mounted F.8s with 20 inches (508 mm) lens, were located in the rear fuselage. With the full fuel load the center of gravity was so far back the aircraft was difficult to fly until the rear fuselage tank had been emptied. Despite these difficulties the type quickly proved its worth, photographing such long distance targets as Stettin, Marseilles, Trondheim

Trondheim

Trondheim , historically, Nidaros and Trondhjem, is a city and municipality in Sør-Trøndelag county, Norway. With a population of 173,486, it is the third most populous municipality and city in the country, although the fourth largest metropolitan area. It is the administrative centre of...

and Toulon

Toulon

Toulon is a town in southern France and a large military harbor on the Mediterranean coast, with a major French naval base. Located in the Provence-Alpes-Côte-d'Azur region, Toulon is the capital of the Var department in the former province of Provence....

.

Once the first two Type Ds, P9551 and P9552 had proven the concept the production aircraft, which were soon redesignated PR Mk IV, were modified to increase the leading edge tank capacity to 66.5 gal (302 l) and by omitting the rear fuselage tank. These aircraft were better balanced and had the more powerful Merlin 45 engine as used by the Mk V, along with heated cabins, which were a great comfort to pilots on such long flights. A total of 229 Type Ds were built.

A single Mk I PR Type E N3117 was built to address a requirement for oblique close-ups as opposed to high altitude vertical pictures. This conversion carried an F.24 camera in a fairing under each wing. These faced forward, were splayed outwards slightly and aimed downwards at about 15 degrees below the horizontal. A 29 gal (132 l) fuel tank was fitted in the rear fuselage. N3117 proved most useful as it was able to photograph targets under weather conditions that would make high altitude photography impossible and experience with this aircraft resulted in the development of the Type G.

Mk I PR Type F was an interim "super-long-range" version which entered service in July 1940, pending the Type D. The Type F carried a 30 gal fuel tank under each wing, plus a 29 gal tank in the rear fuselage, as well as having an enlarged oil tank under the nose. It was a useful enough improvement that nearly all existing Type Bs and Type Cs were eventually converted to the Type F standard. Operating from East Anglia

East Anglia

East Anglia is a traditional name for a region of eastern England, named after an ancient Anglo-Saxon kingdom, the Kingdom of the East Angles. The Angles took their name from their homeland Angeln, in northern Germany. East Anglia initially consisted of Norfolk and Suffolk, but upon the marriage of...

it was just able to reach, photograph and return from Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

. 15 of these were based on the Mk V airframe.

The Mk I PR Type G was the first fighter-reconnaissance version and performed a similar low-level tactical role to the Type E. One oblique F.24 camera, with either an eight inch or 14 inch lens, was fitted facing to port, between fuselage frames 13 and 14. Two vertical F.24 cameras were also installed in the fuselage. The forward camera, installed below the oblique, could be fitted with a five inch or an eight inch lens while the rear camera could be fitted with an eight inch or a 14 inch lens. A 29 gal (132 l) fuel tank was fitted just behind the pilot. The first PR Gs were converted from Mk I airframes and their Merlin II engines replaced with Merlin 45s. Late PR Gs were converted from Mk V airframes. The Type G was fully armed with 8 × .303" Brownings and retained the armoured windscreen and gunsight.

A feature of most PR Spitfires were the specially modified "Blown" canopies which incorporated large lateral teardrop shaped blisters, allowing the pilots a much clearer view to the rear and below, vital for sighting the cameras. The lateral cameras were aimed by lining up a tiny +, marked on the side of the blister, with a fine black line painted on the port outer aileron. On all unarmed PR conversions the gunsight was replaced by a small camera control box from which the pilot could turn the cameras on, control the time intervals between photos and set the number of exposures.

In 1941, a new system of mark numbers was introduced, independent of those used for the fighter versions. Also, several PR conversions were re-converted to later PR types.

The Type C became the PR Mk III.
The Type D became the PR Mk IV.
The Type E became the PR Mk V.
The Type F became the PR Mk VI.
The Type G became the PR Mk VII.

In all, 1,567 Mk Is were built (1,517 by Supermarine between May 1938 and March 1941, 50 by Westland, July to September 1941).

Mk II (Type 329)

In the summer of 1939 an early Mk I K9788 was fitted with a new version of the Merlin, the XII. With the success of the trial it was decided to use this version of the Merlin in the Mk II which, it was decided, would be the first version to be produced exclusively by the huge new Lord Nuffield shadow factory at Castle Bromwich

Castle Bromwich Assembly

Castle Bromwich Assembly is a factory owned by Jaguar Cars. It is located on the Chester Road in Castle Vale, Birmingham, England.The facility currently handles body stamping operations, body assembly, paint and trim, and final assembly for the Jaguar XF, Jaguar XJ and Jaguar XK...

.

Chief among the changes was the upgraded 1175 hp Merlin XII engine. This engine included a Coffman engine starter

Coffman engine starter

The Coffman engine starter was a starting system used on many piston engines in aircraft and armored vehicles of the 1930s and 1940s. The Coffman system was one of the most common brands; another was the Breeze cartridge system, which was produced under Coffman patents...

, instead of the electric system of earlier and some later versions of the Merlin, and it required a small "teardrop" blister on the forward starboard cowling.. The Merlin XII was cooled by a 70% to 30% water glycol

Ethylene glycol

Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...

mix, rather than pure glycol used for earlier Merlin versions.

In early 1940 Spitfire Is of 54 and 66 Squadrons

No. 66 Squadron RAF

were fitted with Rotol manufactured wide-bladed propellers of 10 ft 9 in (3.27 m) diameter, which were recognisable by a bigger, more rounded spinner: the decision was made that the new propeller would also be used exclusively by the Mk II. This engine/propeller combination increased top speed over the late Mk I by about 6-7 mph below 17000 feet (5,181.6 m), and improved climb rate. Due to all of the weight increases maximum speed performance was still lower than that of early Mk Is, but combat capability was far better. The Mk II was produced in IIA eight-gun and IIB cannon armed versions. Deliveries were very rapid, and they quickly replaced all remaining Mk Is in service, which were then sent to Operational Training Units. The RAF had re-equipped with the new version by April 1941. The Rotol propeller units were later supplemented by de Havilland constant-speed units similar to those fitted to Mk Is.

A small number of Mk IIs were converted to "Long Range" Spitfires in early 1941. These could be recognised by the fixed 40 gal (182 l) fuel tank which was fitted under the port wing. With a full tank manoeuvrability was reduced, maximum speed was 26 mph (42 km/h) lower and the climb rate and service ceiling were also reduced. Several squadrons used this version to provide long-range bomber escort.
Once the Mk II was taken out of front line service, 50 of them were converted for air-sea rescue work, at first under the designation Mk IIC (type 375) but later referred to as the A.S.R Mk II. The Merlin XII was replaced by the Mark XX, a "rescue pack" was fitted in the flare chute and smoke marker bombs were carried under the port wing.
A total of 921 Mk IIs were built, all by Castle Bromwich. A small number of Mk IIs were converted to Mk Vs.

Mk III (Type 330)

The Mk III was the first attempt to improve the basic Spitfire design and introduced several features which were used on later marks. Powered by a Rolls-Royce RM 2SM, later known as the Merlin XX, developing 1,390 hp (1,036 kW), the wingspan was reduced to 30 ft 6 in (9.3 m) and the area reduced to 220 square feet (20.4 sq m) while the overall length was increased to 30 ft 4 in (9.2 m). The strengthened main undercarriage was raked forward two inches, increasing ground stability and had flaps to fully enclose the wheels when retracted. The tailwheel was also made fully retractable. The windscreen was redesigned, with a built-in, internal laminated glass, bulletproof panel and optically flat, laminated glass quarter panels.

The first Mk III N3297 was first flown on 16 March 1940. In addition to N3297 in early 1941 a Spitfire Mk V, W3237 was converted to a Mk III, although it didn't have the retractable tailwheel. W3237 replaced N3297 when the latter was delivered to Rolls-Royce; W3237 went on to become a test aircraft and was still being used in September 1944.

Although the new Spitfire was developed to replace the earlier marks on the production lines, a decision to allocate the limited supplies of Merlin XX to the Hurricane II series

Hawker Hurricane

The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...

meant that the Mark III lapsed. Priority then focused on the Mark V series. The Mk III with the Merlin XX was capable of a maximum speed of 400 mi/h at 21000 ft (6,400.8 m).

N3297 became the power-plant development airframe, the wings were replaced with standard Type A and the aircraft was delivered to Rolls Royce at Hucknall

Hucknall

. A prototype Merlin 60 was installed, in effect making this aircraft (renumbered the type 348) the prototype Mk IX.

Mk V (Types 331, 349 & 352)

Late in 1940, the RAF predicted that the advent of the pressurised Junkers Ju 86

Junkers Ju 86

The Junkers Ju 86 was a German monoplane bomber and civilian airliner designed in the early 1930s, and employed by both sides during World War II. The civilian model Ju 86B could carry 10 passengers. Two were delivered to Swissair and five to Luft Hansa...

P bomber series over Britain would be the start of a new sustained high altitude bombing offensive by the Luftwaffe

Luftwaffe

Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....

, in which case development was put in hand for a pressurised version of the Spitfire, with a new version of the Merlin (the Mk VI). It would take some time to develop the new fighter and an emergency stop-gap measure was needed as soon as possible: this was the Mk V.

The basic Mk V was a Mk I with the Merlin 45 series engine. This engine delivered 1,440 hp (1,074 kW) at take-off, and incorporated a new single-speed single-stage supercharger

Supercharger

design. Improvements to the carburettor also allowed the Spitfire to use zero gravity manoeuvres without any problems with fuel flow. Several Mk I and Mk II airframes were converted to Mk V standard by Supermarine and started equipping fighter units from early 1941. The majority of the Mk Vs were built at Castle Bromwich.

Three versions of the Mk V were produced, with several sub-series:

Mk VA (Type 331)

The VA continued to use the Type A wing with 8 × .303" Brownings. This version could reach a top speed of 375 mph (603 km/h) at 20800 ft (6,339.8 m), and could climb to 20000 ft (6,096 m) in 7.1 minutes. A total of 94 were built. One well known VA was W3185 D-B flown by Douglas Bader

Douglas Bader

Group Captain Sir Douglas Robert Steuart Bader CBE, DSO & Bar, DFC & Bar, FRAeS, DL was a Royal Air Force fighter ace during the Second World War. He was credited with 20 aerial victories, four shared victories, six probables, one shared probable and 11 enemy aircraft damaged.Bader joined the...

when commanding the Tangmere

RAF Tangmere

RAF Tangmere was a Royal Air Force station famous for its role in the Battle of Britain, located at Tangmere village about 3 miles east of Chichester in West Sussex, England. American RAF pilot Billy Fiske died at Tangmere and was the first American aviator to die during World War II...

Wing in 1941. He was shot down in this aircraft (possibly by friendly fire) during a "Circus" (a wing of fighters escorting a small number of bombers) over Northern France on 9 August 1941 and spent the rest of the war as a POW. In April 1941 two Spitfire VAs R7347 and W3119 were sent to Wright Field

Wright Field

Wright Field was an airfield of the United States Army Air Corps and Air Forces near Riverside, Ohio. From 1927 to 1947 it was the research and development center for the Air Corps, and during World War II a flight test center....

, Dayton, Ohio

Dayton, Ohio

Dayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...

USA as sample aircraft. Both Spitfires were tested by NACA

NACA

- Organizations :* National Advisory Committee for Aeronautics, the forerunner of the U.S. federal agency NASA* National Association for Campus Activities, an organization for programmers of university and college activities...

; one series of tests included the fitting of special NACA "jet-propulsion" exhaust stacks.

Mk VB and VB(trop) (Type 349 and 352)

The VB became the main production version of the Mark Vs. Along with the new Merlin 45 series the B wing was fitted as standard. As production progressed changes were incorporated, some of which became standard on all later Spitfires. Production started with several Mk IBs which were converted to Mk VBs by Supermarine. Starting in early 1941 the round section exhaust stacks were changed to a "fishtail" type, marginally increasing exhaust thrust. Some late production VBs and VCs were fitted with six shorter exhaust stacks per side, similar to those of Spitfire IXs and Seafire IIIs

Supermarine Seafire

The Supermarine Seafire was a naval version of the Supermarine Spitfire specially adapted for operation from aircraft carriers. The name Seafire was arrived at by collapsing the longer name Sea Spitfire.-Origins of the Seafire:...

; this was originally stipulated as applying specifically to VB(trop)s. After some initial problems with the original Mk I size oil coolers, a bigger oil cooler was fitted under the port wing; this could be recognised by a deeper housing with a circular entry. From mid-1941 alloy covered ailerons became a universal fitting.

Large numbers of modifications were made as production progressed. Two new types of "blown" cockpit canopies were introduced in an effort to further increase the pilot's head-room and visibility. In addition, a large number of Spitfire Vbs were fitted with "gun heater intensifier" systems on the exhaust stacks. These piped additional heated air into the gun bays. There was a short tubular intake on the front of the first stack and a narrow pipe led into the engine cowling from the rear exhaust.

The VB series were the first Spitfires able to carry a range of specially designed "slipper" drop tanks which were fitted underneath the wing centre-section. Small hooks were fitted, just forward of the inboard flaps: when the tank was released these hooks caught the trailing edge of the tank, swinging it clear of the fuselage. A wide bladed Rotol constant speed propeller of 10 ft 10 in (3.29 m) diameter was able to be fitted, resulting in a modest speed increase over 20000 ft (6,096 m) and an increase in the service ceiling

Service ceiling

. The blades were either "Jablo" (made out of compressed wood) or metal and the spinner was longer and more pointed.

With the advent of the superb Focke Wulf Fw 190 in August 1941 the Spitfire was for the first time truly outclassed , hastening the development of the "interim" Mk IX. In an effort to counter this threat, especially at lower altitudes, the VB was the first production version of the Spitfire to use "clipped" wingtips as an option, reducing the wingspan to 32 ft 2 in (9.8 m).The clipped wings increased the roll rate and airspeed at lower altitudes. Several different versions of the Merlin 45/50 family were used, including the Merlin 45M which had a smaller "cropped" supercharger

Supercharger

impeller and boost increased to +18 lb. This engine produced 1,585 hp (1,182 kW) at 2,750 ft (838 m), increasing the L.F VB's maximum rate of climb to 4720 ft/min (21.6 m/s) at 2000 ft (609.6 m).

The Mk VB(trop) (or type 352) could be identified by the large Vokes air filter fitted under the nose; the reduced speed of the air to the supercharger had a detrimental effect on the performance of the aircraft, but the decreased performance was considered acceptable. This variant was also fitted with a larger oil tank and desert survival gear behind the pilot's seat. A new "desert" camouflage scheme was applied. Many VB(trop)s were modified by 103 MU (Maintenance Unit-RAF depots in which factory fresh aircraft were brought up to service standards before being delivered to squadrons) at Aboukir, Egypt

Egypt

Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

by replacing the Vokes filter with locally manufactured "Aboukir" filters, which were lighter and more streamlined. Two designs of these filters can be identified in photos: one had a bulky, squared off filter housing while the other was more streamlined. These aircraft were usually fitted with the wide blade Rotol propeller and clipped wings.

Mk VC and VC(trop) (types 349 and 352/6)

As well as having most of the standard Mk V features this version had several important changes over the earlier Mk Vs, most of which were first tested on the Mk III. These included the re-stressed and strengthened fuselage structure and the new windscreen design, which was also used by some VBs. The VC also introduced the Type C or "Universal" wing along with the revised main undercarriage; the tops of these wings featured large, bulged fairings to provide clearance for the ammunition feed motors of two Hispano cannon. Later, because two cannon were seldom fitted, these fairings were later reduced in size to more streamlined shapes. A deeper radiator fairing was fitted under the starboard wing and a larger oil cooler with a deeper, kinked air outlet was fitted underneath the port wing. In addition more armour plating was added, protecting the bottom of the pilot's seat and the wing ammunition boxes.

The first Spitfire modified to carry bombs was a Malta

Malta

Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

based VC, EP201, which was able to carry one 250 lb (113.4 kg) bomb under each wing. In a note to the Air Ministry Air Vice Marshal Keith Park

Keith Park

Air Chief Marshal Sir Keith Rodney Park GCB, KBE, MC & Bar, DFC, RAF was a New Zealand soldier, First World War flying ace and Second World War Royal Air Force commander...

wrote "[w]e designed the bomb gear so that there was no loss of performance when the bombs were dropped. Unlike the Hurricane

Hawker Hurricane

The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...

bomb gear our Spitfire throws away all external fittings with the exception of a steel rib which protrudes less than one inch from the wing."

One VC(trop) BP985 was modified by 103 MU as a high altitude fighter capable of intercepting the Ju 86P

Junkers Ju 86

photo reconnaissance aircraft which were overflying Allied naval bases in Egypt. This aircraft was stripped of all unnecessary weight, including all armour plating and the Hispano cannon, while the compression ratio

Compression ratio

The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...

of the Merlin 46 was increased by modifying the cylinder block. A four bladed de Havilland propeller was fitted along with an "Aboukir" filter, a larger 9.5 gallon oil tank and extended wingtips.

The first Spitfires to be sent overseas in large numbers were Mk VCs; many of these were built as VC(trop)s. With the advent of the Mk IX to RAF service few of the Mk VC saw combat over Europe, with the majority of them being used either in North Africa and the Mediterranean or in the Far East.

Spitfire V production and overseas shipments

A total of 300 Mk VC(trop)s were shipped to Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

for the RAAF

Royal Australian Air Force

The Royal Australian Air Force is the air force branch of the Australian Defence Force. The RAAF was formed in March 1921. It continues the traditions of the Australian Flying Corps , which was formed on 22 October 1912. The RAAF has taken part in many of the 20th century's major conflicts...

; the first of these arrived in late 1942. A total of 143 Spitfire VB (including Mk II conversions) were supplied to Soviet Union. Portugal was the recipient of two lots of Spitfire VBs; 33 refurbished ex-RAF aircraft started arriving in early 1944 and a further and final shipment of 60 mainly clipped wing L.F Mk VBs arrived in 1947. All were retrofitted with TR 9 HF radios and had no IFF. The last of these Spitfires were taken out of service in 1952. Twelve were delivered to Royal Egyptian Air Force.

In 1944 enough Spitfire VB (trop)s to equip one squadron were supplied to Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

. Some were later fitted with the larger, pointed rudder developed for later Merlin-powered Spitfires. These flew alongside of the Focke-Wulf FW 190A-3s which had been supplied to Turkey by Germany.

In total, production was 6,479, consisting of 94 Mk VA, built by Supermarine, 3,911 Mk VB, (776 by Supermarine, 2,995 Castle Bromwich and 140 Westland) and 2,467 Mk VC, (478 Supermarine, 1,494 Castle Bromwich, 495 Westland) plus 15 PR Type F by Castle Bromwich.

German Daimler Benz powered Spitfire VB

In November 1942 a Spitfire VB EN830 NX-X of 131 Squadron

No. 131 Squadron RAF

No. 131 Squadron RAF was a Royal Air Force Squadron formed to be a night bomber unit in World War I and reformed as a fighter unit in World War II.-Formation and World War I:No...

made a forced landing

Forced landing

A forced landing is a landing by an aircraft made under factors outside the pilot's control, such as the failure of engines, systems, components or weather which makes continued flight impossible. For a full description of these, see article on Emergency landing...

in a turnip field at Dielament Manor, Trinity, Jersey

Jersey

Jersey, officially the Bailiwick of Jersey is a British Crown Dependency off the coast of Normandy, France. As well as the island of Jersey itself, the bailiwick includes two groups of small islands that are no longer permanently inhabited, the Minquiers and Écréhous, and the Pierres de Lecq and...

, under German occupation

Occupation of the Channel Islands

The Channel Islands were occupied by Nazi Germany for much of World War II, from 30 June 1940 until the liberation on 9 May 1945. The Channel Islands are two British Crown dependencies and include the bailiwicks of Guernsey and Jersey as well as the smaller islands of Alderney and Sark...

at the time. This aircraft was repairable and started being test flown in German markings and colours at the Luftwaffe research facilities at Rechlin

Rechlin

Rechlin is a municipality in Mecklenburg-Western Pomerania, Germany. The town's airport has a long history and was the Luftwaffe's main testing ground for new aircraft designs during the Third Reich....

. There it was proposed that the Spitfire's Merlin engine should be replaced by a Daimler-Benz DB 605

Daimler-Benz DB 605

|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7...

A inverted Vee-12 engine; the Spitfire was sent to Echterdingen, south of Stuttgart

Stuttgart

Stuttgart is the capital of the state of Baden-Württemberg in southern Germany. The sixth-largest city in Germany, Stuttgart has a population of 600,038 while the metropolitan area has a population of 5.3 million ....

, where Daimler-Benz operated a flight testing division.

When the Merlin engine was removed it was discovered that the fuselage cross section was virtually identical to that of the engine nacelle of a Messerschmitt Bf-110G. Consequently a new engine support structure was built onto the Spitfire's fuselage and the DB 605 engine and cowling panels added. A propeller unit and supercharger air intake from a Bf 109 G completed the installation.

Other changes made were to replace the Spitfire instruments with German types, and to change the 12-volt electrical system to the German 24-volt type. In this form the Daimler-Benz Spitfire started flying in early 1944. It was popular with German pilots and was flown regularly until destroyed in a USAAF bombing raid on 14 August 1944.

Mk VI (Type 350)

At the time that the Mk V was placed in production there were growing fears that the Luftwaffe were about to start mass producing very high flying bombers such as the Junkers Ju 86

Junkers Ju 86

, which could fly above the reach of most fighters of the time. It was decided that a new Spitfire variant would be required with improved high altitude performance. During a meeting held at the RAE

Royal Aircraft Establishment

at Farnborough

Farnborough, Hampshire

-History:Name changes: Ferneberga ; Farnburghe, Farenberg ; Farnborowe, Fremborough, Fameborough .Tower Hill, Cove: There is substantial evidence...

on 17 February 1941 the Air Ministry asked "that a Spitfire should be provided with a pressure cabin capable of maintaining a pressure differential of 1 lb per square inch at 40,000 feet." A Marshall

Marshall Aerospace

The Marshall companies have been internationally associated with aerospace engineering for nearly a century. The company employs over 1,800 people and is based on an site with of covered hangar space...

-manufactured compressor was to be used, and it was agreed that the sliding canopy could be replaced by one which could not be slid open, as long as it could be jettisoned by the pilot.

The pressurised cabin was used to counter the physiological problems encountered by pilots at high altitudes. The cabin was not like the fully pressurised cabin of a modern airliner; the pressure differential provided by the modified cockpit of the VI was only two pounds per square inch (which was double the Air Ministry requirement). To achieve this, the forward and rear cockpit bulkheads were completely enclosed, with all control and electrical cables exiting though special rubber sealing grommets. In addition, the side cockpit door was replaced with alloy skin and the canopy was no longer a sliding unit: externally there were no slide rails. Once the pilot was in, the canopy was locked in place with four toggles and sealed with an inflatable rubber tube. It could be jettisoned by the pilot in an emergency. The windscreen of production Mk VIs was the same as the type fitted to the Mark III and some Mk Vs although it was fitted with an inward opening clear-view panel on the port quarter pane. The effect was to make 37000 ft (11,277.6 m) seem like 28000 ft (8,534.4 m) to the pilot, who would still have to wear an oxygen mask. Pressurisation was achieved by a Marshall-manufactured compressor located on the starboard side of the engine, fed by a long intake below the starboard exhaust stubs. Mk VIs were built with the Coffman cartridge starter, with a small teardrop fairing just ahead of the compressor intake.

The engine was a Rolls-Royce Merlin 47 driving a four-bladed Rotol propeller of 10 ft 9 in (3.27 m) diameter; the new propeller provided increased power at high altitudes, where the atmosphere

Earth's atmosphere

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...

is much thinner. To help smooth out airflow around the wingtips the standard rounded types were replaced by extended, pointed versions extending the wingspan to 40 ft 2 in (12.2 m). Otherwise the wings were Type B.

The maximum speed of the Mk VI was 356 mi/h at 21800 ft (6,644.6 m). However, because of the limitations of the single stage supercharger, at 38000 ft (11,582.4 m) the maximum speed had fallen away to 264 mi/h. The service ceiling was 39200 ft (11,948.2 m).

The threat of a sustained high altitude campaign by the Luftwaffe did not materialise and only 100 of the Mk VIs were built by Supermarine. Only two units, 124 Squadron

No. 124 Squadron RAF

No. 124 Squadron RAF was a Royal Air Force Squadron formed to be a light bomber unit in World War I and reformed as a fighter unit in World War II.-Formation and World War I:...

and 616 Squadron

No. 616 Squadron RAF

No. 616 Squadron was a unit of the British Auxiliary Air Force and later the Royal Auxiliary Air Force between 1938 and 1957.-Formation:...

, were fully equipped with this version, although several other units used them in small numbers as a stop-gap. More often than not, the Spitfire VIs were used at lower altitudes where it was outperformed by conventional Spitfires. At high altitudes it was discovered that modified Spitfire Vs could perform almost as well as the Mk VI. At low levels, especially, pilots were often forced to fly with the canopy removed because the cockpit would get uncomfortably hot and they were not confident it would be possible to jettison the canopy in case of an emergency.

In 1943 five Spitfire VIs (BS106

United Kingdom military aircraft serials

In the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry , and its successor the Ministry of Defence , is used for aircraft operated by the Royal Air Force , Fleet...

, BS124, BS133, BS134 and BS149) were converted to improvised PR Mk VIs by 680 Squadron

No. 680 Squadron RAF

No. 680 Squadron RAF was a photo-reconnaissance squadron of the Royal Air Force, active during the Second World War.-History:No. 680 Squadron RAF was formed in February 1943 from 'A' Flight of No. 2 Photographic Reconnaissance Unit , equipped with a variety of aircraft including Supermarine...

in Egypt. These aircraft had been "tropicalised" using the same bulky Vokes filter and other equipment used by Spitfire VB Trops, as well as being painted in a "desert" camouflage scheme.

By the time these aircraft arrived they were no longer required to intercept high-flying Junkers Ju 86P

Junkers Ju 86

reconnaissance aircraft although there was a need for a pressurised RAF photo reconnaissance aircraft to carry out missions over Crete

Crete

Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...

and the rest of Greece

Greece

Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

. 103 MU at Aboukir carried out the modifications by removing the armament and installing vertical F8 cameras in the rear fuselage. These Spitfires were used a few times in April and May 1943 but were withdrawn from service by August. They were the first pressurised PR Spitfires.

PR Mk XIII (Type 367)

The PR Mk XIII was an improvement on the earlier PR Type G with the same camera system but a new engine, the Merlin 32, which was specially rated for low-altitude flight. It carried a light armament of 4 × .303" Browning machine guns. The first prototype Mk XIII was tested in March 1943.

Twenty-six Mk XIIIs were converted from either PR Type G, Mk II or Mk Vs. They were used for low level reconnaissance in preparation for the Normandy landings.

Production

The breakdown of production figures is taken from "Spitfire: Simply Superb part three" 1985, p. 187. Information as to when the first production aircraft emerged is from the serial number lists provided in Morgan and Shacklady 2000. The majority of the early P.R Spitfires were converted from existing airframes and are not listed separately . Because the first Mk Vs were converted from Mk I and some Mk II airframes the first true production Spitfire V is listed.

Production by Mark
Mark	Built by	Numbers Built	Notes
Prototype	Supermarine	1	K5054. First flight 5 May 1936.
IA, IB	Supermarine, Westland Westland Aircraft Westland Aircraft was a British aircraft manufacturer located in Yeovil in Somerset. Formed as a separate company by separation from Petters Ltd just before the start of the Second World War, Westland had been building aircraft since 1915...	1,567	First production Spitfire K9787 first flew 14 May 1938.
IIA, IIB	Castle Bromwich	921	First CB built Spitfire P7280, June 1940.
III	Supermarine	2	N3297 converted from Mk I, W3237 converted from Mk V.
VA, VB, VC	Supermarine, Castle Bromwich, Westland	6,487	First Mk V; P8532 (VB) June 1941.
VI	Supermarine	100	First Mk VI AB136 December 1941.

External links

The Spitfire Site
The Spitfire Society
Alan Le Marinel hosts Supermarine Spitfire
Spitfire Performance Testing
Spitfire/Seafire Serial Numbers, production contracts and aircraft histories
Warbird Alley: Spitfire page - Information about Spitfires still flying today
K5054 - Supermarine Type 300 prototype Spitfire & production aircraft history
The Spitfire: Seventy Years On - Includes images of the factory
Spitfire Mk. VIII and Mk. XVI - Temora Aviation Museum
Temora Aviation Museum
The Temora Aviation Museum is an Australian aerospace museum located in Temora, New South Wales. The Museum was established in late 1999, based on the collection of warbird aircraft owned by David Lowy...

page
National Heritage Warbird Foundation
NACA reports on Spitfire Mk VA W3119 :
Spitfire VA flight qualities
Spitfire VA stall characteristics
Jet propulsion exhaust stacks Retrieved: 29 January 2009.

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