Supermarine Spitfire (Griffon powered variants)

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...

engine was designed in answer to Royal Naval

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

specifications which required an engine capable of generating good power at low altitudes. The concepts for adapting the Spitfire to take the new engine had begun as far back as October 1939; 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...

felt that "The good big 'un will eventually beat the good little 'un." and Ernest Hives of Rolls-Royce

Rolls-Royce Limited

Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....

thought that the Griffon would be "a second power string for the Spitfire." The first of the Griffon-engined Spitfires flew on 27 November 1941.

Although the Griffon-engined Spitfires were never produced in the large numbers of the Merlin-engined variants they were an important part of the Spitfire family and, in their later versions, kept the Spifire at the forefront of piston-engined fighter development.

This article describes the Griffon-powered Spitfire variants.

Wing types

The majority of Spitfires, from the Mk VIII on, used three basic wing types — the C through to the E types. Unless otherwise noted all Griffon-engined Spitfire variants used the strengthened 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:...

AH10019 "four spoke" pattern mainwheels. With the increasing use of hard-surfaced runways in the post-war years many Spitfires were either manufactured, or retro-fitted with, larger mainwheels which were of a "three spoke" pattern. These were used on modified undercarriage legs which had reduced "toe-in' for the axles, which reduced tyre scrub.

C type

Also known as the "Universal wing" the new design was standard on the majority of Spitfires built from mid 1942. This wing was structurally modified to reduce labour and manufacturing time plus it was designed to allow 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. 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. During production of the Mk VIII and Mk IX a new undercarriage leg was introduced which had external v-shaped "scissor-links" fitted to the front of the leg; this also led to small changes in the shape of the undercarriage bay and leg fairings. Several versions of the Spitfire, including Mk XIV and Mk XVIIIs had extra 13 gallon integral fuel tanks in the wing leading edges between the wing-root and the inboard cannon bay.

The Hispano Mk IIs were now belt fed from box magazines allowing for 120 rpg (the "Chattellerault" system). The fairings over the Hispano barrels were shorter and there was usually a short rubber stub covering the outer cannon port. Redesigned upper wing gun bay doors incorporated "teardrop" shaped blisters to clear the cannon feed motors, and the lower wings no longer had the gun bay heating vents outboard of the gunbays. In order to provide room for the belt feed system of the cannon the inner machine gun bays were moved outboard to between ribs 13 and 14. As the Spitfire was no longer to be used as a night fighter

Night fighter

A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility...

, the retractable landing lights were no longer fitted.

D Type

These were specifically made for the Photo-Reconnaissance Spitfires, including the PR XIX; no armament was fitted and the "D" shaped leading edges of the wings, ahead of the main spar, were converted into integral fuel tanks, each carrying 66 gallons. To avoid the expansion of fuel in hot weather damaging the wing, pressure relief valves, incorporating small external vent pipes, were fitted near the wing tips.

E type

Structurally unchanged from the C wing. The outer machine gun ports were eliminated, although the outer machine gun bays were retained and their access doors were devoid of empty cartridge case ports and cartridge case deflectors. The inner gun bays allowed for two weapon fits;

2 × 20 mm Hispano Mk II cannon with 120 rounds-per-gun (rpg) in the outer bays.
2 × .50 cal Browning M2 machine guns, with 250 rpg in the inner bays. With of the relocation of the Hispano to the outer gun bay the blisters covering the feed motors were moved outboard on the gun bay doors.

4 × 20 mm Hispano cannon with 120 rpg (this configuration was rarely fitted.)

The 20 mm Hispano cannon

Cannon

A cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...

were moved outboard and a more effective .50 calibre Browning .50 cal M2/AN heavy machine gun

Heavy machine gun

The heavy machine gun or HMG is a larger class of machine gun generally recognized to refer to two separate stages of machine gun development. The term was originally used to refer to the early generation of machine guns which came into widespread use in World War I...

with 250 rpg was added to the inner gun-bay replacing the outer Browning .303s. The first trial installation of the installation (modification 1029) was made in BS118, a Mark XI in November 1943. This armament later became standard for all Spitfire Mk XIVs used by 2 TAF as fighters. The improved armament was more effective for both air-to-air engagements and air-to-ground attacks.

The Mk XII flew operationally with their rounded wingtips replaced by shorter, squared off fairings; the single-stage supercharger of the Griffon II or IV used in the Mk XIIs meant that it was rated and used as a low altitude fighter, and the LF prefix used by Merlin-powered Spitfires was never applied.
Starting in early 1945 most Spitfire Mk XIVs also used clipped wingtips, mainly in an effort to reduce wrinkling of the wing's skin; again the LF prefix was not applied to these aircraft.

Redesigned late wing

As the Spitfire gained more power and was able to fly at greater speeds the possibility was that pilots would encounter aileron reversal

Control reversal

Control reversal is an adverse effect on the controllability of aircraft. The flight controls reverse themselves in a way that is not intuitive, so pilots may not be aware of the situation and therefore provide the wrong inputs; in order to roll to the left, for instance, they have to push the...

so the Supermarine design team set about redesigning the wings to counter this possibility. The original wing design had a theoretical aileron reversal speed of 580 mph (933.4 km/h), which was somewhat lower than that of some contemporary fighters. The new wing of the Spitfire F Mk 21 and its successors was designed to help alleviate this problem; the wing's stiffness was increased by 47%, and a new design of aileron using piano hinges

Hinge

A hinge is a type of bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation. Hinges may be made of flexible material or of moving components...

and geared trim tabs

Trim tabs

Trim tabs are small surfaces connected to the trailing edge of a larger control surface on a boat or aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aero-dynamic forces and stabilise the boat or aircraft in a particular desired attitude without the need for the...

meant that the theoretical aileron reversal speed was increased to 825 mph (1,327.7 km/h).

The standard armament was now four 20mm Hispano IIs or the shorter, lighter Hispano V cannons each with 150 rounds per gun.

Mk IV/XX (type 337)

On 4 December 1939, the Supermarine design staff produced a brochure which mooted the idea of converting the Spitfire to use the 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...

engine. A top speed of 423 mph (681 km/h) at 18,500 ft (5,639 m) was predicted. However, constant problems with the development of the Griffon meant that the decision to proceed with building a Spitfire with this engine didn't come to fruition until 1942, with the successful flight trials of the Mk IV.

The Griffon IIB which powered the Mk IV was a single-stage supercharged engine of 1,735 hp (1,293 kW). Stronger main longerons were needed to cope with the weight of the Griffon and it required a bigger radiator and oil cooler, although it kept the asymmetric under-wing radiator layout of the single stage Merlin marks. The new engine had a lower thrust-line than the Merlin and was set with a minus ½ degree of downthrust

Incidence

Incidence may refer to:* Incidence , a measure of the risk of developing some new condition within a specified period of time* Incidence , the binary relations describing how subsets meet...

. The lower thrust line and larger capacity of the new engine meant that the contours of the engine cowling were completely changed, with more prominent blisters over the cylinder heads, plus a third tear-drop shaped blister on the upper forward cowling to clear the magneto, and a deeper curve down to the spinner, which was much longer than previous types. The lower cowling lost its "pigeon-chested" appearance, with a shallower curve up to the spinner. A four blade Rotol

Dowty Rotol

Dowty Rotol is a British engineering company based in Cheltenham specialised in the manufacture of propellers and propeller components. It is owned by General Electric, forming part of its GE Aviation Systems division.-History:...

propeller of 10 ft 5 in (3.1 m) was used. Apart from these differences the Mk IV airframe was closely related to that of the Merlin-powered Mk III. One feature of the Griffon engine which was to catch a lot of pilots out was that the propeller rotated in the opposite direction to that of the Merlin; i.e.,: to the right, from the pilot's perspective, rather than to the left. This meant that the powerful slipstream swung the Spitfire to the right on the ground, requiring the rudder to be deflected to the left during takeoff.

The Mark IV DP845 first flew on 27 November 1941. It had the full-span C wing combined with a small tail unit and retractable tailwheel, and also had external bracket hinges under the wings, denoting the installation of braking flaps. These were soon removed and a mock up of a proposed six-cannon armament was fitted, three in each wing. The aircraft was soon renamed Mk XX, to avoid confusion with a renamed PR type, then it became the Mk XII.

Jeffrey Quill

Jeffrey Quill

Jeffrey Kindersley Quill OBE AFC FRAeS was a British Royal Air Force officer, RNVR officer and Test pilot and the second man to fly the Supermarine Spitfire after Vickers' chief test pilot, Joseph "Mutt" Summers. After succeeding Summers as Vickers' chief test pilot, Quill test-flew every mark of...

, Supermarine's chief test pilot, was the first to fly the Mk IV/Mk XII prototype DP845; "...there was somewhat less ground clearance, resulting in a slight reduction in propeller diameter; the power available for take-off was much greater; and the engine RPM were lower than in the Merlin. All this meant that the throttle needed to be handled judiciously on take-off but, once in the air, the aeroplane had a great feeling of power about it; it seemed to be the airborne equivalent of a very powerful sports car and was great fun to fly. Changes of trim with changes of power were much more in evidence, both directionally and longitudinally, and the aeroplane sheared about a bit during tight manoeuvres and simulated dog-fights. I realised at once that we should have to correct its directional characteristics and probably its longitudinal stability also, both of which in due time we achieved. Indeed, DP485 eventually went through many phases of development throughout and I, and others, flew in it a great deal; it became one of our favourite aeroplanes."

Mk XII (type 366)

The Mk XII was the first Spitfire powered by a Griffon engine to go into service. The first of 100 Supermarine-built production aircraft started appearing in October 1942; two RAF squadrons in total were equipped with the XII. Mk XIIs were manufactured from Mk VC and Mk VIII airframes: early production aircraft had the fixed tail wheels, Dunlop

Dunlop Rubber

AH2061 pattern "five spoke" mainwheels and small elevator balances. They had a single 85 gal main fuel tank, giving a short range of little over 380 miles (611.5 km) on internal fuel. All were fitted with the larger, pointed tip rudder. The last 45 or so Mk XIIs, were based on Mk VIIIs with two wing fuel tanks, each containing a maximum fuel load of 14 gal, and featured the larger horn balances, retractable tailwheel and undercarriage legs with torque-links, "dished" leg fairings and the stronger Dunlop AH10019 four spoke wheels. The wheels were occasionally fitted with disc-style covers. A later model 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...

was fitted, replacing the aerials from the tailplane tip to fuselage with a rod aerial under the starboard wing. Another important feature of the Griffon-engine Spitfires was the entirely flush-riveted finish which was progressively introduced on all Spitfires.

The single-stage Griffon engine (II or IV) gave the aircraft superb low and medium level performance, although the Mk XII's performance declined at higher altitudes: because of this all production aircraft had "clipped" wings. In comparative tests with a Mk IX it was 14 mi/h faster at sea level, but above 20000 ft (6,096 m) it had become slower. Handling, however, was considered to be better than previous Spitfire marks, and the clipped wings conferred excellent manoeuvrability through enhanced aileron response.

At low altitude it was one of the fastest aircraft in the world; in one speed trial, held at Farnborough in July 1942 DP845 (now referred to as the Mk XII) piloted by Jeffrey Quill raced ahead of a Hawker Typhoon

Hawker Typhoon

The Hawker Typhoon was a British single-seat fighter-bomber, produced by Hawker Aircraft. While the Typhoon was designed to be a medium-high altitude interceptor, and a direct replacement for the Hawker Hurricane, several design problems were encountered, and the Typhoon never completely satisfied...

and a captured Focke-Wulf Fw 190

Focke-Wulf Fw 190

The Focke-Wulf Fw 190 Würger was a German Second World War single-seat, single-engine fighter aircraft designed by Kurt Tank in the late 1930s. Powered by a radial engine, the 190 had ample power and was able to lift larger loads than its well-known counterpart, the Messerschmitt Bf 109...

, to the amazement of the dignitaries present.
However pilots found it difficult to exploit this advantage in combat as German pilots were reluctant to be drawn into dogfights with Spitfires of any type below 20000 feet (6,096 m). When the Mk XII was able to engage in combat it was a formidable fighter and several Fw 190s and Bf 109-Gs

Messerschmitt Bf 109

The Messerschmitt Bf 109, often called Me 109, was a German World War II fighter aircraft designed by Willy Messerschmitt and Robert Lusser during the early to mid 1930s...

fell victim to it.
The Mk XII's speed advantage at lower altitudes again became useful near the end of its front line service in Summer 1944, in which it shot down a respectable number of V-1 Flying Bomb

V-1 flying bomb

The V-1 flying bomb, also known as the Buzz Bomb or Doodlebug, was an early pulse-jet-powered predecessor of the cruise missile....

s, 82.5 The Mk XII variant was retired in September 1944.

Mk XIV (type 379)

The first Griffon-powered Spitfires suffered from poor high altitude performance due to having only a single stage supercharged

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,...

engine. By 1943, Rolls-Royce engineers had developed a new Griffon engine, the 61 series, with a two-stage supercharger. In the end it was a slightly modified engine, the 65 series, which was used in the Mk XIV. The resulting aircraft provided a substantial performance increase over the Mk IX. Although initially based on the Mk VIII airframe, common improvements made in aircraft produced later included the cut-back fuselage and tear-drop canopies

Bubble canopy

A bubble canopy is a canopy made like a soap bubble, which attempts to provide 360° vision to the pilot.-History:Bubble canopies have been in use since World War II. The British had already developed the "Malcolm hood", which was a bulged canopy, but the British Miles M.20 was one of the first...

, and the E-Type wing with improved armament.

The Mk XIV differed from the Mk XII in that the longer, two-stage supercharged Griffon 65, producing 2,050 hp (1,528 kW), was mounted 10 inches (25.4 cm) further forward: the top section of the engine bulkhead was angled forward, creating a distinctive change of angle to the upper cowling's rear edge. A new five bladed Rotol propeller of 10 in 5 in (3.18 m) in diameter was used, although one prototype JF321 was fitted with a six bladed contra rotating

Contra-rotating propellers

Aircraft equipped with contra-rotating propellers, also referred to as coaxial contra-rotating propellers, apply the maximum power of usually a single piston or turboprop engine to drive two propellers in contra-rotation...

unit. The "fishtail" design of ejector exhaust stub gave way to ones of circular section. The increased cooling requirements of the Griffon engine meant that all radiators were much bigger and the underwing housings were deeper than previous versions.

The cowling fasteners were new, flush fitting "Amal" type, and there were more of them. The oil tank (which had been moved from the lower cowling location of the Merlin engine variants to forward of the fuselage fuel tanks) was increased in capacity from 6 to 10 gal.

To help balance the new engine the radio equipment was moved further back in the rear fuselage and the access hatch was moved from the left fuselage side to the right. Improved VHF radio equipment allowed for the aerial mast to be removed and replaced by a "whip" aerial further aft on the fuselage spine. Because the longer nose and the increased slipstream of the big five-bladed propeller a new tail unit, with a taller, broader fin and a rudder of increased area was adopted.

The first batch of aircraft to fly with the Griffon 60 series engines were six converted Mk VIIIs JF316 to JF321 which were designated Mk VIIIG. The first one of these was flown by Jeffrey Quill on 20 January 1943:
One prototype, JF321, was fitted and tested with a Rotol six-bladed contra-rotating propeller unit; although this promised to eliminate the characteristic swing on take-off (caused by the propeller slipstream) the propeller unit was prone to failure. The pitch control mechanism controlled the pitch on the front propeller;
A similar contra-rotating propeller unit was later used on production Seafire 46 and 47s

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:...

.

When the new fighter entered service with 610 Squadron

No. 610 Squadron RAF

No. 610 Squadron of the Royal Air Force was as a Squadron of the Auxiliary Air Force, its pilots were initially part timers who would spend their weekends and spare time flying and practicing combat maneuvers. The squadron was named the "County of Chester" and adopted the motto "Alifero tollitur...

in January 1944 it signified a new leap forward in the evolution of the Spitfire. Jeffrey Quill flew the first production aircraft, RB140 in October 1943:
It could climb to 20000 ft (6,096 m) in just over five minutes and its top speed, which was achieved at 25400 ft (7,741.9 m), was 446 mi/h.
In operational service many pilots initially found that the new fighter could be difficult to handle, particularly if they were used to earlier Spitfire marks. Don Healy of 17 Squadron, based at Madura, India recalled that the Mk XIV was;

a hairy beast to fly and took some getting used to. I personally preferred the old Mk Vs from a flying standpoint...Even with full aileron, elevator and rudder, this brute of a fighter took off slightly sideways.

In spite of the difficulties pilots appreciated the performance increases. Wing Commander Peter Brothers

Peter Malam Brothers

Air Commodore Peter Malam 'Pete' Brothers, CBE, DSO, DFC & Bar was a famed World War II Royal Air Force fighter pilot during the Battle of Britain...

, O/C Culmhead Wing in 1944-1945 and a 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...

veteran;

It was truly an impressive machine, being able to climb almost vertically - it gave many Luftwaffe pilots the shock of their lives when, having thought they had bounced you from a superior height, they were astonished to find the Mk XIV climbing up to tackle them head-on, throttle wide open!

F Mk XIVs had a total of 109.5 gal of fuel consisting of 84 gal in two main tanks and a 12.5 imp gal fuel tank in each leading edge wing tank. In addition, 30, 45, 50 or 90 gal drop tanks could be carried. The fighter's maximum range was just a little over 460 miles (740.3 km) on internal fuel since the new Griffon engine consumed much more fuel per hour than the original Merlin engine of earlier variants;. By late 1944, Spitfire XIVs were fitted with an extra 33 gal in a rear fuselage fuel tank, extending the fighter's range to about 850 miles (1,367.9 km) on internal fuel and a 90 gal drop tank. Mk XIVs with "tear-drop" canopies had 64 gal. As a result, F and FR Mk XIVEs had a range that was increased to over 610 miles (981.7 km), or 960 miles (1,545 km) with a 90 gal drop tank.

The first test of the aircraft was in intercepting V1 flying bombs, and the Mk XIV was the most successful of all Spitfire marks in this role. When 150 octane fuel was introduced in mid-1944 the "boost" of the Griffon engine was able to be increased to +25 lbs, allowing the top speed to be increased by about 30 mph (24.6 kn; 48.3 km/h) to 400 mph (328.5 kn; 643.7 km/h) at 2000 ft (609.6 m).

The Mk XIV was used by the 2nd Tactical Air Force

RAF Second Tactical Air Force

The former RAF Second Tactical Air Force was one of three tactical air forces within the Royal Air Force during and after the Second World War...

as their main high-altitude air superiority fighter in northern Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

with six squadrons operational by December 1944.

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

Spitfire XVIs also began to arrive in the CBI theatre in June 1945, too late to operate against the Japanese.

FR Mk XIV

Late in 1944 a number of Mk XIVs were converted to have a single camera fitted, facing to port or starboard. To achieve this a new hatch, similar to the radio hatch on Merlin-engine Spitfires, was installed. Otherwise this version of the FR Mk XIV was essentially the same as the standard aircraft. Later, purpose built conversions, also known as the FR Mk XIV, had the cut down rear fuselage with its tear drop–shaped canopy, and a port facing fuselage camera, with an additional rear fuel tank of 34 gallons which extended the Spitfire's range to about 610 miles (981.7 km) on internal fuel. Because it was used mainly at low altitudes the FR Mk XIV had clipped wingtips.

In total, 957 Mk XIVs were built, over 430 of which were FR Mk XIVs. After the war, second hand Mk XIVs were exported to a number of foreign air forces; 132 went to the Royal Belgian Air Force

Belgian Air Force

The Air Component, formerly the Belgian Air Force, is the air arm of the Belgian Armed Forces. Originally founded in 1909, it is one of the world's first air forces, and was a pioneer in aerial combat during the First World War...

, 70 went to the Royal Indian Air Force and 30 of its reconnaissance variant went to the Royal Thai Air Force

Royal Thai Air Force

The Royal Thai Air Force or RTAF is the air force of the Kingdom of Thailand. Since its establishment in 1913, as one of the earliest air forces of Asia, the Royal Thai Air Force had engaged in many major and minor battles. During the Vietnam war era, the air force has been developed with USAF-aid...

Mk XV and Mk XVII

The mark numbers XV and XVII (15 and 17) were reserved for the naval version, the Seafire

Supermarine Seafire

, in an effort to reconcile the Spitfire numbering scheme with that of the Seafire.

Mk XVIII (Mk 18) (type 394)

The Mk 18 was a refinement of the Mk XIV. It was identical in most respects including engine (the Griffon 65) and cockpit enhancements, but it carried extra fuel and had a revised, stronger wing structure. Its handling was also nearly identical and so it was not put through any performance tests. Like the Mk XIV there were fighter and fighter reconnaissance variants built.

The Mk 18 missed the war. It was built up until early 1946 but it was not until January 1947, that an RAF squadron, 60 Squadron

No. 60 Squadron RAF

No. 60 Squadron of the Royal Air Force was formed in 1916 at Gosport. It is currently part of the Defence Helicopter Flying School based at RAF Shawbury in Shropshire....

which operated from RAF Seletar, Singapore

Singapore

Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...

, was re-equipped with the variant. Later, other squadrons in the Far East and Middle East would receive them. Some 300 F Mk 18s and FR Mk 18s were built, before production ended in early 1946.. The Mk 18s saw little action apart from some involvement against guerrillas in the Malayan Emergency

Malayan Emergency

The Malayan Emergency was a guerrilla war fought between Commonwealth armed forces and the Malayan National Liberation Army , the military arm of the Malayan Communist Party, from 1948 to 1960....

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

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

The Mk XIX was the last and most successful photographic reconnaissance variant of the Spitfire. It combined features of the Mk XI with the Griffon engine of the Mk XIV. After the first 25 (type 389s) were produced, later aircraft were also fitted with the pressurised cabin of the Mk X and the fuel capacity was increased to 256 gallons, three-and-a-half times that of the original Spitfire This version was the type 390.

The first Mk XIXs entered service in May 1944, and, by the end of the war, the type had virtually replaced the earlier Mk XI. A total of 225 were built with production ceasing in early 1946, but they were used in front line RAF service until April 1954.

In 1951, Hainan Island (People's Republic of China

People's Republic of China

China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

) was targeted at the behest of U.S. Naval Intelligence for RAF overflights, using Spitfire PR Mk 19s based at Kai Tak Airport

Kai Tak Airport

Kai Tak Airport was the international airport of Hong Kong from 1925 until 1998. It was officially known as the Hong Kong International Airport from 1954 to 6 July 1998, when it was closed and replaced by the new Hong Kong International Airport at Chek Lap Kok, 30 km to the west...

in Hong Kong. The last operational sortie by a Mk 19 was in 1963 when one was used in battle trials against an English Electric Lightning

English Electric Lightning

The English Electric Lightning is a supersonic jet fighter aircraft of the Cold War era, noted for its great speed and unpainted natural metal exterior finish. It is the only all-British Mach 2 fighter aircraft. The aircraft was renowned for its capabilities as an interceptor; Royal Air Force ...

to determine how best a Lightning should engage piston-engined aircraft. This information was needed in case RAF Lightnings might have to engage P-51 Mustang

P-51 Mustang

The North American Aviation P-51 Mustang was an American long-range, single-seat fighter and fighter-bomber used during World War II, the Korean War and in several other conflicts...

s in the Indonesia

Indonesia

Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

n conflict of the time.

Mk XX (type 366)

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

The second Mk XX, DP851, initially had a Griffon II engine and made its first flight in August 1942. In December, it was refitted with a Griffon 61 and re-designated as a Mk 21 initial prototype.

Mk 21 (type 356)

By early 1942, it was evident that Spitfires powered by the new two-stage supercharged Griffon 61 engine would need a much stronger airframe and wings. The proposed new design was designated the Mk 21. At first the Mk 21 displayed poor flight qualities that damaged the otherwise excellent Spitfire reputation.

The wings were completely redesigned with a new structure and using thicker-gauge light alloy skinning. The new wing was torsionally 47% stiffer, allowing an increased theoretical aileron reversal speed of 825 mi/h. The ailerons were 5% larger, and were no longer of the Frise balanced type, instead being attached by continuous piano-hinges. They were extended by eight inches, meaning that with a straighter trailing edge, the wings were not the same elliptical shape as in previous Spitfires. The Mk 21 armament was standardised as four 20mm Hispano II cannon with 150 rpg and no machine guns.

The Griffon engine drove an 11 ft (3.35 m) diameter five-bladed propeller, some 7 inches (17.8 cm) larger than that fitted to the Mk XIV. To ensure sufficient ground clearance for the new propeller, the undercarriage legs were lengthened by 4.5". The undercarriage legs also had a 7.75 inch (19.7 cm) wider track to help improve ground handling. The designers then devised a system of levers to shorten the undercarriage legs by about eight inches as they retracted, because the longer legs did not have enough space in which to retract. These same levers extended the legs as they came down. The larger diameter four spoke mainwheels were strengthened to cope with the greater weights; post-war these were replaced by wider, reinforced three spoke wheels to allow Spitfires to operate from hard concrete or asphalt runways. When retracted the wheels were now fully enclosed by triangular doors which were hinged to the outer edge of the wheelwells.

In other respects, the first production Mk 21s used the same basic airframe as the Mk XIV. The first true Mk 21 prototype, PP139 first flew in July 1943, with the first production aircraft LA187 flying on 15 March 1944. However the modifications over the Mk XIV made the Mk 21 sensitive to trim changes. LA201s poor flight control qualities, during trials in late 1944 and early 1945, led to a damning report from the Air Fighting Development Unit

Air Fighting Development Unit

The Air Fighting Development Unit was an air technical intelligence part of the Royal Air Force which developed operational tactics and tested captured enemy aircraft. It was based at Royal Air Force Stations at Northolt, Duxford and Wittering....

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

Supermarine were seriously concerned because 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,...

had been converted to produce Mk 21s, and more were coming off the production lines daily. Jeffrey Quill commented that "The AFDU were quite right to criticise the handling of the Mark 21...Where they went terribly wrong was to recommend that all further development of the Spitfire family should cease. They were quite unqualified to make such a judgement and later events would prove them totally wrong."
After intensive test flying the most serious problems were solved by changing the gearing to the trim tabs and other subtle control modifications, such that the Mk 21 was cleared for instrument flying and low level flight during trials in March 1945. An AFDU report on LA215 issued that month noted that the Spitfire 21 was now much easier to fly;

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

Spitfire 21s finally became operational on 91 Squadron

No. 91 Squadron RAF

No 91 Squadron was a squadron of the Royal Air Force but is no longer operational. The name acknowledges the contribution made by Nigeria to the cost of the squadron's aeroplanes.-World War I:...

in January 1945. 91 Squadron had little opportunity to engage the enemy before the war ended, but scored a rare success on 26 April 1945, when two Spitfire Mk 21s shot up and claimed sunk a German midget submarine

Midget submarine

A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to 6 or 8, with little or no on-board living accommodation...

which they caught on the surface. With the end of the war most orders for the Mk 21 were cancelled and only 120 were completed. In 1946 40 Spitfire 21s were delivered to Shoeburyness

Shoeburyness

Shoeburyness is a town in southeast Essex, England, situated at the mouth of the river Thames Estuary. It is within the borough of Southend-on-Sea, and is situated at the far east of the borough, around east of Southend town centre...

; once there their leading edges were removed and destroyed in "lethality" tests. Some aircraft had less than five hours flying time.

Mk 22 (type 356)

The Mk 22 was identical to the Mk 21 in all respects except for the fitting of a cut-back rear fuselage and tear-drop canopy and a more powerful 24 volt electrical system in place of the 12 volt system of all earlier Spitfires. Most of the Mk 22s were built with further enlarged tail surfaces, similar to those of the Supermarine Spiteful

Supermarine Spiteful

The Supermarine Spiteful was a British Rolls-Royce Griffon-engined fighter aircraft designed by Supermarine to Air Ministry specification F.1/43 during the Second World War as a successor to the Spitfire.-Design and development:...

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

The Mk 22 was used by only one regular RAF unit, 73 Squadron

No. 73 Squadron RAF

-World War I:It was initially a unit of the Royal Flying Corps and was formed out of the Central Flying School, based at Upavon, Wiltshire. Eight days after, the new unit moved to Lilbourne, near Rugby....

in Malta. However 12 squadrons of the Royal Auxiliary Air Force

Royal Auxiliary Air Force

The Royal Auxiliary Air Force , originally the Auxiliary Air Force , is the voluntary active duty reserve element of the Royal Air Force, providing a primary reinforcement capability for the regular service...

used the variant and continued to do so until March 1951 and the aircraft was also used at Flying refresher schools. May 1955 the remaining F.22s were declared obsolete from all RAF units. Many were sold back to Vickers-Armstrongs for re-furbishment and sale to the Southern Rhodesia Air Force, Egyptian Air Force and Syrian Air Force.

Mk 23 (type 372)

The Mk 23 was to be a Mk 22 incorporating a revised wing design which featured an increase in incidence, lifting the leading edge by 2 inches (50.8 mm). It was hoped that this would improve the pilot's view over the nose in flight and increase the high speed and dive performance of the aircraft. The modified, handbuilt wing was first fitted to a Mk VIII JG204 which was tested from July 1944. However the tests were disappointing and after discussions at Supermarine it was decided to build a new prototype using the Mk 21 prototype PP139; the aircraft was designated F Mk 23 to be renamed the Supermarine Valiant. However once again the new wing gave less than perfect handling characteristics and so the Mk 23 was never built from the Mk 22 airframe as intended.

Mk 24 (type 356)

The final Spitfire variant, the Mk 24, was similar to the Mk 22 except that it had an increased fuel capacity over its predecessors, with two fuel tanks of 33 gal (150 l) each installed in the rear fuselage. There were also zero-point fittings for rocket projectiles under the wings. All had the larger "Spiteful

Supermarine Spiteful

" tail units: modifications were also made to the trim tab gearings in order to perfect the F Mk 24's handling characteristics.
Late production aircraft were built with the lighter, short-barrelled, electrically fired Mark V Hispano cannon.

Performance was impressive – the F Mk 24 achieved a maximum speed of 454 mi/h, and could reach an altitude of 30000 ft (9,144 m) in eight minutes, putting it on a par with the most advanced piston-engined fighters of the era.

Although designed primarily as a fighter-interceptor aircraft, the Spitfire proved its versatility in several different roles. In fighter configuration the F Mk 24's armament consisted of 4 × short-barrelled 20 mm Hispano cannon – operational experience had proved that the hitting power of these larger weapons was necessary to overcome the thicker armoured plating encountered on enemy aircraft as the war progressed. The aircraft also served successfully in the fighter-bomber role, being capable of carrying 1 × 500 lb (226.8 kg) and 2 × 250 lb (113.4 kg) bombs, with rocket-projectile launch rails fitted as standard.

A total of 81 Mk 24s were completed, 27 of which were conversions from Mk 22s. The last Mk 24 to be built was delivered in February 1948. They were used by only one RAF squadron, 80 Squadron

No. 80 Squadron RAF

No. 80 Squadron RAF was a Royal Flying Corps and Royal Air Force squadron active from 1917 until 1969. It was operative during both World War I and World War II.-Establishment and early service:...

, until 1952. Some of the squadron's aircraft went to the Hong Kong Auxiliary Air Force where they were operated until 1955.

Introduced into service in 1946, the F Mk 24 differed greatly from the original Spitfire Mk I in many respects and undoubtedly brought the design to the peak of perfection, being twice as heavy, more than twice as powerful and exhibiting an increase in climb rate of 80% over the prototype aircraft, 'K5054'. These remarkable increases in performance arose chiefly from the introduction of the Rolls-Royce Griffon engine in place of the famous Merlin of earlier variants. Rated at 2050 hp, the 12-cylinder Vee liquid cooled Griffon 61 engine featured a two-stage supercharger, giving the Spitfire the exceptional performance at high altitude that had been sometimes lacking in early marks.

Production

After the destruction of the main Itchen and Woolston works by the Luftwaffe in September 1940, all Supermarine manufactured Spitfires were built in a number of "Shadow Factories"; by the end of the war there were ten main factories and several smaller workshops which built many of the components. A fuller explanation can be found in Supermarine Spitfire

Supermarine Spitfire

The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s...

. The main Castle Bromwich factory was also aided by a smaller number of the shadow factories.
The breakdown of production figures is taken from Air International 1985, p. 187. Information as to when the first production aircraft emerged is from the serial number lists provided in Morgan and Shacklady 2000. Because the first XIVs were converted from existing Mk VIII airframes the first true production serial No. is listed. Protracted development of the Mk 21 meant that this variant did not reach operational service until January 1945.

Production by Mark
Mark	Built by	Numbers Built	Notes
F Mk XII	Supermarine	100	First Mk XII 13 October 1942
F Mk XIV, FR Mk XIV	Supermarine	957	First Mk XIV RB142 28 October 1943
F Mk XVIII	Supermarine	300	First Mk XVIII June 1945
PR Mk XIX	Supermarine	224	First Mk XIX RM626 May 1944
F Mk 21	Castle Bromwich	120	First Mk 21 LA187 27 January 1944
F Mk 22	Supermarine, Castle Bromwich	(27) + (260); 287	First Mk 22 March 1945
F Mk 24	Supermarine	54	First Mk 24 March 1946

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
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

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