Probably the most well-known World War 2
era airplane fighter
, the Supermarine Spitfire is known for its sleek and appealing design
with the elliptical wing shape, its ballerina
-like agility and performance. And of course its lethality in battle.
Whereas the Hawker Hurricane was the mainstay of the RAF (Royal Air Force) of Great Britain during the period around the Battle of
Britain, the Spitfire was the aircraft bestowed the honor and glamor by the media. The Agile Spitfire was usually commissioned to attack
enemy fighter aircraft, while the sturdier Hurricane would attack the bomber formations.
The concept of the Spitfire emerged in the early 1930s, when Supermarine, Westland and Blackburn aircraft companies submitted competing
designs for an all-metal fighter aircraft, which was to comply to the Air Ministry specification F.7/30. Reginald Mitchell, the chief
designer at Supermarine developed the Type 224. A gull-winged monoplane with fixed landing gear, and powered by the Rolls-Royce Goshawk
engine at a mere 600 horsepower, giving the 224 a top speed of 228 miles per hour. Mitchell was, however, disappointed with the design even
before it few its maiden flight on February 19th, 1934, and began as a private venture designing a new aircraft.
At the time, Sydney Camm, the father of the Hawker Hurricane, was active designing the Hurricane in Weybridge. Reginald Mitchell, of
course, knew about these developments and radically modern designs and set about in designing a completely new aircraft, as opposed to the
old-fashioned Type 224. He, naturally, stuck with the Ministry specifications of F.7/30 - a metal-bodied cantilever type fighter aircraft.
But decided to use fully metal-clad wings as opposed to the Camm designed Hurricane which used fabric, believing the fabric to be a flaw or
weak spot in the design. Retractable wheels and enclosed cockpit, with a large elliptical wing area were super-modern design desicions
Mitchell included. Alterations, such as mounting the radiator air duct under the starboard wing, and the smaller oil cooler air duct under
the port wing, and with the carburetor air intake under the center fuselage. These design decisions caused assymmetry, and can easily be
spotted if one looks at the underside of a Spitfire. The result was the sleek and streamlined "Type 300" wich indeed was yet the most
attractive aircraft ever to be designed.
In 1934, Type 300 was ordered as a prototype. Now fitted with the Rolls-Royce PV12, their modern 12-cylinder liquid cooled engine, also
used in the Hurricane. Armed with eight, as opposed to the four machine guns previously designed the Type 300 was a
powerful machine of war. Official tests were held on March 5th, 1936, and by June the Type 300 name was replaced by the new name Spitfire.
After the contract was won by Supermarine, in 1936, they would for two years prepare and expand their Woolston factory for the large-scale
production demanded by the contract. In fact, this was the largest subcontract scheme ever undertaken in British history. Soon they
realized that fulfilling this contract would be something close to filling a bottomless pit, and had to lay out plans to construct the
Nuffield Group, which would serve as a sister plant at Castle Bromwich (near Birmingham). On April 12th, 1938 the official order was placed
for one thousand Spitfires. When actual construction began the next year, 200 more were ordered, and later that year an additional 450. When
Britain declared war on Germany on September 3rd, 1939, about 2200 Spitfires were on order.
Spitfire Mk.I / Mk.Ib
The Spitfire Mk.I weighed 5,280 lb. had a wing loading of 24 lb./sq. ft. and a fuel capacity of 85 Imperial gallons. Its
maximum speed was 362 mph its maximum diving speed was 450 mph its initial climb rate was 2,500 ft./min. and it took 9.4
minutes to climb to 20,000 feet. Its combat range was 395 miles and its roll rate was 140 deg./sec. The Type 300-Mark I was the first
Spitfire to enter service with the RAF. Between August and December 1938 No. 19 Squadron at Duxford was equipped with the Mk.I. By the end of
1938, the RAF had two fully-equipped Spitfire squadrons with 100 percent reserves. By the outbreak of war on 3 September 1939, Spitfires
equipped nine squadrons - Nos 19, 66 and 611 at Duxford, Nos 54, 65 and 74 at Hornchurch, No 72 at Church Fenton, Nos 41 and 609 at Catterick
and No 602 at Abbotsinch. Additionally, No 603 Squadron was in the process of replacing its Gladiators at Turnhouse. A total of 306 Mk Is
had been delivered of which 36 had been written off in training accidents. In total 1569 Spitfire Mk.I's were built. It housed eight
Browning .303 Machine Guns each with 300 rounds of ammunition (totalling 2400 rounds), a 998 horsepower Rolls-Royce Merlin II engine (the
later productions of the Mk.I used the 953 horsepower Merlin III). The Mk.Ib was a designation for the Spitfire Mk.I, but fitted with two
20mm Hispano Cannons. This design emerged in 1940, but was not very popular with the pilots using them due to the mountings in the Spitfire's
wings which were too flexible causing the guns to jam. Only 30 Spitfire Mk.Ib's were built. And it was the Mk.I which bore the brunt of the
fighting during the Battle of Britain; by July 7th nineteen Fighter Command Squadrons were operational with the type. The performance of
the Spitfire Mk I and the Messerschmit Bf-109E was very similar. The former possessed a better turning radius at any height and was slightly
faster below 15,000 feet, but the Messerschmitt was superior in the climb and marginally faster above 20,000 feet. The Messerschmitt's
Daimler-Benz DB 601A engine had the advantage of fuel injection which enabled the aircraft to bunt (push negative g at the top of a manouvre
or climb) without losing power. The Merlin engine of the Spitfire had a float-type carburettor which necessitated the aircraft performing the
longer stress of rolling inverted before diving to maintain positive G-forces, thus preventing the engine from cutting out as a result of
Spitfire Mk.II / Mk.IIb
In June 1940, the Mk.I gave way to the more faster and powerful Type 329 - Mk.II. Testing and research had evolved the Spitfire into a
superior aircraft. The Merlin II/III engine was replaced with the Merlin XII, which gave the Spitfire a total of 1175 horsepower. The
difference in armament from the Mk.I / Mk.Ib was still in place. The Mk.IIa was the eight .303 BMG version, and the Mk.IIb was the 2x20mm
Hispano Cannon version. A total of 751 Mk.IIa's and 170 Mk.IIb's were built.
The Type 348 - Mark III Spitfire, designed in 1940, incoroprated some severe changes to the design. It was powered by the 1265 horsepower
Rolls-Royce Merlin XX, had a smoothed windscreen and redesigned rear fuselage gave the pilot a better view, retractable tailwheel and clipped
wings for a faster roll rate. The weight had increased to 6350lb. At high speed, the stick force from the ailerons had been very heavy and
this was found to be due to the fabric covering of the ailerons ballooning and causing a thicker trailing edge section. This was remedied
by fitting stiffer, metal-covered ailerons. The Mk.III also included an ammunition counter. In July 1940 it was intended to build 1,000 but
only two Mk.III Spitfires were ever built due to the upcoming Mark V, but the changes in this design were used in future marks.
The Type 353- Mark IV was the Griffon engined variant, later reintroduced as the Mark XII. A Photoreconnaissance aircraft named PRIV was
powered by a Merlin 45 or 46, and 229 were produced. The torsion box in the wing leading edge was modified to provide extra fuel and oil
tanks. The Photographic Reconnaissance Unit was split into four squadrons in October 1942. Nos 541, 542 and 543 were fully equipped with
Spitfire Mk IVs, while 544 Squadron had other types as well as some Mk IVs. Photoreconaissance Spitfires could be easily recognised by
the absence of armament in the wings, a low visibility paint scheme. Later PRU blue, earlier a sort of blue-green called Camotint (the
precise shade of which is still the subject of much debate), or even pink. Although it sounds bizarre, and there is no doubt that pilots felt
rather vulnerable over occupied europe in an unarmed pink aircraft, but against an overcast sky a pink colour scheme provided very
good camouflage. And a deeper "chin" under the nose to allow a larger oil tank. As the oil consumption of a Merlin could be measured in
gallons per hour.
The first squadron to fly the Type 349-Mark V was the No. 92 and in March 1942, it was built to counter the Messerschmitt Bf109F, which
outperformed the older Spitfires especially at high alititudes. Improvements included the introduction of a pressurized cabin (the first
version of the Spitfire equipped was the Mark VI derived directly from the Mark Vb as a result of work on pressure cabins at the Royal
Aircraft Establishment and Supermarine during 1940-41) and the use of an engine suitably rated for higher altitude. They were powered by
the 1185 horsepower Merlin 45 or 46 (although at the combat rated altitude of 9250 feet, the output was 1470 horsepower), and added a
strengthened airframe. The Merlin 45 engine was also installed into the Mk.II airframe and in total 150 of these were made and became known
as Mk.V conversions. Essentially produced as a stop-gap, pending the availability of the Spitfire Mk.VI, the Mk.V was subsequently produced
in greater numbers than any other version of the Spitfire. With the German invasion of Russia in June, the threat of a renewed air
offensive against Britain disappeared and with it the need for the Spitfire Mk.VI. So, the "stop-gap" Mk.V remained in full production. The
Mk.Va was equipped with eigth .303 BMGs, only 94 were built, the Mk.Vb was armed with four .303 BMGs and two 20mm Hispano Cannons, 3911
were built. The Mk.Vc had four 20mm Cannons and four .303 BMGs - these totalled 2467 aircraft. Those airframes intended for desert
conditions acquired a deep "chin" under the engine in the form of an air filter to keep out the desert sand. Many versions of the Mk.V
followed, depending as to which field of conflict the aircraft were assigned to. Some were assigned to low altitude flying and for this many
of the Mk.Vb's had their wing span reduced to 32 feet 2 inches and the Merlin 45 engine was replaced by the Merlin 45M, the Merlin 50M and
the Merlin 55M, all of which performed better at low altitudes. These low altitude versions were designated LF MK VB's. Other versions
included the medium altitude Mk's. These aircraft were designated F Mk.Va, F MK.Vb and F Mk.Vc. The Merlin power plant was configured in a
number of configurations and all these F series Mk.V's has either a Merlin 45, 46, 50, 50A or 56 engine installed. All these Mk.V's became
successful fighter aircraft.
The Type 350 - Mk.VI was introduced to combat the threat of high flying German bombers, and the German fighter Focke Wulf 190, its advantage
due to its powerful BMW engine and its high-rate of roll, which outclassed the Spitfire Mk.V. The Mk.VI was fitted with a Merlin 46 or 47
driving a 4-bladed propeller, and extended, high altitude, wingtips. Some were fitted with injection of liquid oxygen into the air
intake. The most notable change was the addition of a partially pressurized cabin, with a canopy that was fixed in place on the ground except
for emergency jettisoning. The production Spitfire Mk.VI also had an increase in wing area to improve controllability at high altitudes the
wing being of pointed planform with a span of 40 feet and 2 inches. The pressure cabin was contained between the bulkheads fore and aft of
the cockpit and a special non-sliding hood was fitted to simplify the sealing problem. A Marshall blower provided a cabin differential of 2
lb./sq. in. reducing apparent altitude from 40,000 feet to 28,000 feet. In other respects including armament the Mk.VI was similar to the
Mk.Vb.It was not a successful variant, and only 100 were built and outfitted with No 616 Squadron, intended for high-altitude use.
The Spitfire Type 351 - Mark VII was a more extensive re-design for high-altitude work and was the first of the Spitfire series intended to
make use of the two speed Merlin 60 series of engines, which were coupled with a re-designed cooling system which showed itself in the
enlarged air intake under the port wing matching that to starboard. The wing outline remained similar to that of the Spitfire Mk.VI but the
ailerons were reduced in span. The chord and area of the rudder were increased and the elevator horn balance was extended. Structural changes
were made to the fuselage to take the increased engine loads and a double-glaze sliding hood was fitted to the cockpit. The retractable
tail wheel first developed for the Spitfire Mk.III was applied in production for the first time on the Mark VII and the universal C-type wing
was employed. Maximum speed jumped by 44 mph, to 408 mph.
In response to the introduction of the FW-190, another 'interim' mark of Spitfire was proposed, pending full scale development of the Type
360 - Mk.VIII. The result was the Mk.IX. Like the Mk.V, this 'stop-gap' was also an outstanding success, 5665 being built, the second
highest number of any mark. Essentially a low altitude, unpressurized Mk.VII, with a 1565 horsepower Merlin 61 or a 1710 horsepower Merlin 63
driving a 4-bladed airscrew. Furthermore, changes to the carburettor allowed to stress the airplane in negative G-forces. Due to the
upcoming Mk.IX, only 1652 were produced, many modified for tropical climates. A single airframe was converted into the first official 2-seat
Spitfire, the Tr8, but no great interest was shown and it was not followed up.
In June 1942, an Fw-190 landed at Pembrey after its pilot had become lost. When tested against the captured Fw-190, the Type 361 - Mk.IX was
found to compare favorably, and the first Spitfire Mk.IX's went to No 64 Squadron at Hornchurch in July. The Polish pilots attached to No 145
Squadron with Spitfire Mk.IXs shot down more enemy aircraft in the first two months of 1943 than any other Polish unit in the whole year.
In February, No 72 Squadron arrived in North Africa with Mk.IXs. The Mk.IX started life as a strengthened Mk.V airframe with the latest, 60
series, Merlin engines driving a 4-bladed airscrew. It proved so successful that all in total around 7180 were produced. After the war a
limited number of Mark IX Spitfires were bought back by Vickers Armstrongs and converted to the Trainer (Tr) Mk IX. The front cockpit was
moved forwards, and a second cockpit with raised seat and high domed canopy was added behind it, it went under the name Type 509 - Tr 9.
The Type 362 - Mark PRX was a converted Mk.VII airframe, with PRXI wings. 16 were produced.
Basically Type 365-Mk.PRXI was a Mk.IX photoreconnaissance version, but disarmed and integral fuel tanks. 470 were produced.
This Spitfire ( Type 366 ) was equipped with the Griffon engine. A 36 liter volume engine rated at 1720 horsepower (Griffon III and IV). It
also had a reverse-spinning, 4 blade, airscrew. Total of 100 were produced, most were clipped-wing meant for low-altitude use.
Under the designation of Type 373, this was the Mk.VIII airframe fitted with a Griffon 61 (later Griffon 65) engine, with a five-bladed
airscrew. Some were built with a lowered rear fuselage to accomodate a bigger cockpit-dome bubble with enhanced visibility. About 950 were
Type 361 was basically a Mk.IX fitted with a Packard Merlin 266 engine at 1372 horsepower. 1054 of this mark were produced.
300 produced as Type 394 - Mk XVIII was a Mk.VIII fitted with the 2035 horsepower Griffon 65 or 2375 horsepower Griffon 67 engine.
A photoreconnaissance version of the Mk.XIV. It had a pressurized cabin for high-altitude flight. 225 were delivered.
Spitfire Mk.21/22/24 (All Type 356)
The 20 series was a major rebuild of the previous marks. Visually similar to the older marks, they had little in common when it came to their
internal structuring. The engines powering the 20-series Spitfires were the 2050 horsepower Griffon 61, 2120 horsepower Griffon 85, and 2340
horsepower Griffon 64. And also had a wider wing. The Mk.22 Had the big cockpit dome of the Mk.XIV, and 287 were produced. The Mk 24 was
essentially a Mk 22 with an extra short barreled 20mm Hispano Cannon. Only 54 were ever built. The Mk 21 appeared in 120 copies.
The Hurricane and Gladiator was not the only fighter to be equipped with facilities to operate from the Navy's aircraft carriers. The
Spitfire also served from these platforms. In March 1942 this naval version of the Spitfire was given the name of Seafire.
Type 340. The first Spitfire to fly with arrestor hook and folding wings took place in January 1942 when a modified Mk.Vb made tests with
the Navy. A further conversion took place that provided the aircraft with catapult spools and the undercarriage was given additional
strengthening, and an A frame type of arrestor hook was incorporated. 340 were built.
The Type 357 was the first true Seafire. Built off of the Mk.Vc production, strengthened for catapult launches, lenghtened undercarriage, and
the Merlin 32 engine now drove a four bladed propeller which improved low altitude flying. In November of 1942 a Seafire Mk.IIc was altered
so that the wings could be folded for storage on aircraft carriers, this was to be a prototype for the proposed Mk.III. In total, 372
Mk.IIc's were delivered.
Manufacture of the Seafire Type 358 - Mk.III now also boasted a powerful 1470 horsepower Merlin 55 engine. 1263 of these Mk.III were made all
being used by Britain's Navy by June 1943. Many of these Mk.III's also had the Merlin 55M engines that had increased horsepower to 1585.
The Mk.III had a wing that could be manually folded to increase storage space on the aircraft carriers, and a 4-bladed propeller ( the
Mk.III Seafire did not have an enlarged radiator as other 4-blade-propeller equipped Spit/Seafires had). 1218 were produced.
This version (Type 337) was the sea-version of the Spitfire Mk.XII, with two enlarged wing radiators, and a 1750 horsepower Griffon VI engine
fitted with a 4-bladed airscrew, a broad rudder and retractable tail wheel. 450 were produced.
233 produced, and 30 Seafire Mk.XV's were converted into this mark. Type 395 - Mark XVII AKA Mark 41, was a modified Seafire Mk.XV. It had
the lowered rear fuselage and the curved windscreen for enhanced visibility, strengthened undercarriage, and enlarged tail fin and rudders.
The Seafire was during the production of the Mk.XVII renamed to the Mark 40-series to avoid confusion with the Spitfires, which continued
with their roman enumeration.
Naval version of the Spitfire Mk.21. The Type 388 Mk.45 had a new wing, and a Griffon 61 engine. 50 produced.
Type 388 Mk.46 had a counter rotating airscrew, without folding wings. Basically renamed Mk.V Spitfires.
Type 388 Mk.47 was an extremely powerful aircraft. Fitted with the 2200(!) horsepower Griffon 87 engine, had a huge tail section and
folding wings. It was superseded by jet aircraft, and only 90 were built.