Supermarine Valiant
| Industry | Aerospace engineering, aircraft engines |
|---|---|
| Founder | Henry Royce, Charles Rolls |
| Headquarters | United Kingdom |
| Products | Aircraft engines (including Griffon engine) |
The Rolls-Royce Griffon engine was developed in response to the Royal Navy’s demand for a powerplant delivering strong performance at low altitudes. Plans to modify the Supermarine Spitfire to accommodate this engine began as early as October 1939. Joseph Smith, the chief designer, believed that "The good big 'un will eventually beat the good little 'un," while Ernest Hives of Rolls-Royce Limited regarded the Griffon as "a second power string for the Spitfire". The initial flight of a Griffon-powered Spitfire took place on 27 November 1941.
Although Griffon-powered Spitfires were not produced in quantities comparable to the Merlin-engine models, they represented a significant evolution within the Spitfire lineage. Their advanced versions ensured the Spitfire remained a leading piston-engine fighter throughout its service life. This article focuses on the variations of the Spitfire equipped with Griffon engines.
Wing types
From the Mk VIII onward, most Spitfires featured C, D, and E wing configurations. Unless specified otherwise, all Griffon-powered Spitfire variants were fitted with reinforced Dunlop AH10019 "four spoke" mainwheels. Following the increased use of hard runways after the war, many Spitfires were either built with or retrofitted to larger "three spoke" mainwheels. These wheels were mounted on modified undercarriage legs featuring decreased axle "toe-in," which helped reduce tyre wear during operations.
C type
Frequently referred to as the "Universal wing," this design became the standard on most Spitfires produced from mid-1942 onwards. The wing underwent structural modifications aimed at simplifying production and reducing assembly time. It was engineered to support various armament configurations, including the A type, B type, or a set of four 20 mm Hispano cannon.
The landing gear mountings were reengineered, and the undercarriage doors were shaped with a curved cross section to allow the legs to retract lower within the wells. This change eliminated the upper-wing bulges previously positioned over the wheel wells and landing gear pivot areas. The reinforced landing gear struts were angled 2 inches (5.08 cm) forward, enhancing ground stability and decreasing the chance of the aircraft tipping onto its nose. During the production run of the Mk VIII and Mk IX models, a new undercarriage leg design featuring external v-shaped "scissor-links" at the front was introduced; this modification also resulted in subtle adjustments to the undercarriage bay and leg fairing contours. Several Spitfire variants, including the Mk XIV and Mk XVIII, incorporated additional 13-gallon integral fuel tanks located in the leading edges of the wings between the wing root and the inboard cannon bay.
The Hispano Mk.II cannons utilized a belt-fed system supplied from box magazines, allowing for 120 rounds per gun (rpg) via the Châtellerault mechanism. The fairings over the cannon barrels were shortened, often accompanied by a small rubber cap covering the outer cannon port. Redesigned upper wing gun bay doors featured "teardrop"-shaped blisters to accommodate the cannon feed motors, while heating vents previously present on the lower wing gun bays outside of these compartments were removed. To accommodate the belt feed system, inner machine gun bays were repositioned outward between ribs 13 and 14. Since these Spitfires were no longer intended for night fighter roles, retractable landing lights were omitted.
D Type
These wings were specifically developed for Photo-Reconnaissance Spitfires, such as the PR XIX variant. They were unarmed and featured D-shaped leading edges ahead of the main spar that served as integral fuel tanks, each holding 66 gallons. To prevent damage from fuel expansion during hot weather, pressure relief valves with small external vent pipes were installed near the wingtips.
E type
While maintaining structural similarity to the C wing, this version eliminated outer machine gun ports; however, outer machine gun bays remained intact with access doors that no longer had empty cartridge case ports or deflectors. The inner gun bays supported two possible armament setups:
- Two 20 mm Hispano Mk II cannons with 120 rounds per gun in the outer bays paired with two 0.5-inch (12.7 mm) Browning M2 machine guns carrying 250 rounds per gun in the inner bays. Relocating the Hispano cannons to outer bays shifted their feed motor blisters outward on the gun bay doors.
or
- Four 20 mm Hispano cannons with 120 rounds per gun, though this configuration was seldom employed.
The 20 mm Hispano cannons were moved outward while a more powerful .50-inch Browning M2/AN heavy machine gun replaced outer Browning .303s in the inner gun bay, carrying 250 rounds per gun. The initial trial of this armament arrangement (modification 1029) was conducted on BS118, a Mark XI aircraft in November 1943. This enhanced weaponry later became standard on all Spitfire Mk XIVs operated by the RAF 2nd Tactical Air Force as fighters. The upgraded firepower proved more effective in both aerial combat and ground attack missions.
The operational Mk XII featured clipped wingtips replacing previous rounded tips with shorter squared-off fairings; equipped with Griffon II or IV engines fitted with single-stage superchargers, these aircraft were optimized as low-altitude fighters and did not carry the LF prefix used by Merlin-powered Spitfires. Starting in early 1945, most Spitfire Mk XIVs also adopted clipped wingtips primarily to minimize wing skin wrinkling; similarly, these aircraft did not receive an LF designation.
Reengineered Late Wing
With the Spitfire's increasing engine power and higher achievable speeds, the likelihood of aileron reversal became a growing concern. To address this, the Supermarine engineering team undertook a comprehensive wing redesign. Initially, the wing's theoretical aileron-reversal velocity was 580 mph (930 km/h), which was somewhat inferior to that of several contemporary fighter aircraft. The improved wing, introduced on the Spitfire F Mk 21 and subsequent models, featured a 47 percent enhancement in stiffness. Additionally, it incorporated a novel aileron design with piano hinges and geared trim tabs, raising the theoretical aileron-reversal speed to 825 mph (1,328 km/h). This upgraded wing configuration debuted on the Spitfire XXI. The standard weapons loadout was updated to four 20mm Hispano II cannons or alternatively, the lighter and more compact Hispano V cannons, each supplied with 150 rounds.
Variants
The Mark numbers assigned in the aircraft designation system did not always reflect sequential development; for instance, the Mk IX was introduced as an interim solution prior to the production of Mks VII and VIII. Numerous Spitfires were converted from one mark or variant to another; for example, several early Mk Vbs originated as Mk Ibs, and initial Mk IXs were converted from Mk Vcs.
Until late 1942, the Royal Air Force consistently utilized Roman numerals for mark designations. From 1943 through 1948, newly introduced aircraft received Arabic numerals for their marks while older models retained their Roman numerals. After 1948, Arabic numerals became standard exclusively. Consequently, the Spitfire PR Mk XIX was redesignated PR 19 post-1948. This article follows the convention of using Roman numerals for Marks I through XX and Arabic numerals for Marks 21 through 24. The type numbers (e.g., "Type 361") refer to Supermarine's internal design reference numbers.
Mk IV / XX (Type 337)
On December 4, 1939, Supermarine's design team released a proposal exploring the adaptation of the Spitfire airframe to accommodate the Rolls-Royce Griffon engine. Predicted performance included a maximum speed of 423 mph (681 km/h) at an altitude of 18,500 ft (5,639 m). However, persistent developmental challenges with the Griffon engine delayed actual implementation until 1942 when successful flight tests of the Mk IV were conducted.
The Mk IV was powered by the Griffon IIB engine—a single-stage supercharged unit delivering 1,735 hp (1,293 kW). To support the increased weight of this powerplant, reinforced main longerons were installed. It also necessitated larger radiator and oil cooler assemblies while retaining the asymmetric under-wing radiator arrangement characteristic of single-stage Merlin engines. The Griffon's thrust line sat lower than that of the Merlin and was set with a 2-degree downthrust. Due to its reduced thrust line and increased dimensions, the engine cowling was extensively reshaped: notable features included enlarged blisters over cylinder heads, an additional tear-drop shaped blister on the upper forward cowling housing the magneto, and a more pronounced curve leading down to a significantly lengthened spinner compared to earlier versions. The lower cowling lost its distinctive "pigeon-chested" contour by adopting a gentler curve up to the spinner. A four-bladed Rotol propeller measuring 10 ft 5 in (3.1 m) in diameter was fitted. Aside from these modifications, the Mk IV airframe closely resembled that of the Merlin-powered Mk III. A notable operational difference was that the Griffon's propeller rotated counterclockwise from the pilot's viewpoint—opposite to that of Merlin engines—resulting in a strong rightward torque during ground runs and requiring left rudder input during takeoff.
The prototype Mk IV DP845 completed its maiden flight on November 27, 1941. It featured a full-span C wing combined with a smaller tailplane and retractable tailwheel. External bracket hinges beneath the wings indicated braking flap installation; however, these flaps were soon removed. A mock-up six-cannon armament configuration—three cannons per wing—was also trialed. To avoid confusion with a renamed photo-reconnaissance variant designated PR Mk IV, this aircraft was renamed Mk XX before finally being designated as Mk XII.
Supermarine's chief test pilot Jeffrey Quill conducted initial flights of prototype DP845 (Mk IV/Mk XII) and remarked:
Mk XII (type 366)
The Mk XII marked the introduction of the Griffon engine in Spitfires entering operational service. Production began in October 1942 with 100 units constructed by Supermarine, and only two RAF squadrons were outfitted with this variant. Early Mk XIIs were built using Mk Vc and Mk VIII airframes: initial models retained fixed tailwheels, Dunlop AH2061 "five spoke" main wheels, and small elevator balances. They featured a single 85-gallon main fuel tank, limiting their internal fuel range to just over 380 miles (610 km). All Mk XIIs were equipped with an enlarged rudder featuring pointed tips. The final approximately 45 aircraft were based on Mk VIII airframes and incorporated two wing fuel tanks, each holding up to 14 gallons, along with larger horn balances, retractable tailwheels, undercarriage legs fitted with torque-links, "dished" leg fairings, and reinforced Dunlop AH10019 four-spoke wheels. Occasionally, these wheels were fitted with disc-style covers. A later version of the Identification Friend or Foe (IFF) system replaced the tailplane tip aerials with a rod aerial mounted beneath the starboard wing. Another significant advancement in Griffon-powered Spitfires was the adoption of a fully flush-riveted exterior finish, which was gradually applied throughout the Spitfire range.
Powered by a single-stage Griffon engine (either II or IV), the Mk XII excelled at low to medium altitudes but experienced diminished performance at higher elevations; consequently, all production models featured clipped wings. Comparative evaluations against the Mk IX revealed that the Mk XII was approximately 14 mph (23 km/h) faster at sea level but slower above 20,000 ft (6,100 m). Pilots noted improved handling characteristics compared to earlier Spitfire versions, with clipped wings enhancing maneuverability through better aileron responsiveness.
At low altitudes, it ranked among the fastest aircraft globally. During a speed trial at Farnborough in July 1942, DP485—now recognized as the Mk XII—piloted by Jeffrey Quill outpaced both a Hawker Typhoon and a captured Focke-Wulf Fw 190, defying expectations.
Despite its speed advantage, pilots found it challenging to capitalize on this in combat since German aviators generally avoided dogfights with any Spitfire variant below 20,000 feet (6,100 m) altitude. When engaged effectively, however, the Mk XII proved to be a formidable adversary, successfully downing multiple Fw 190s and Bf 109G fighters.[1] Later in its frontline tenure during summer 1944, this low-altitude speed remained valuable as its pilots achieved 82.5 confirmed kills against V-1 Flying Bombs. The Mk XII was withdrawn from active service by September 1944.
Mk XIV (type 379)
Early Griffon-powered Spitfires exhibited subpar high-altitude capabilities because they were equipped with only a single-stage supercharged engine. By 1943, Rolls-Royce engineers introduced the Griffon 61 series engine featuring a two-stage supercharger. Ultimately, a slightly revised version, the Griffon 65 series, was selected for use in the Mk XIV. This model demonstrated a significant performance enhancement compared to the Mk IX. Although initially derived from the Mk VIII airframe, subsequent production incorporated common upgrades such as a shortened fuselage with tear-drop canopies and the E-Type wing outfitted with enhanced weaponry.
The Mk XIV differed from the Mk XII primarily by housing the longer Griffon 65 engine, equipped with a two-stage supercharger and delivering 2,050 hp (1,528 kW), positioned 10 inches (25.4 cm) further forward. The upper part of the engine bulkhead was angled forward, creating a distinctive contour change along the upper cowling’s rear edge. A new five-bladed Rotol propeller with a diameter of 10 ft 5 in (3.18 m) was introduced; however, one prototype, JF321, featured an experimental six-bladed contra-rotating propeller assembly. The previous "fishtail" ejector exhausts were replaced by circular-section exhaust stubs. Due to increased cooling demands of the Griffon engine, all radiators were enlarged substantially, and underwing radiator housings were made deeper than those on earlier variants.
New flush-fitting "Amal" type cowling fasteners were installed in greater numbers. The oil tank, relocated from beneath the lower cowling (as on Merlin-engine variants) to a position ahead of the fuselage fuel tanks, was expanded in capacity from 6 to 10 gallons.
To counterbalance the heavier engine, radio equipment was shifted further aft within the rear fuselage, and the access hatch was moved from the left side to the right side of the fuselage. Upgraded VHF radio gear permitted removal of the aerial mast in favor of a "whip" antenna positioned further back along the fuselage spine. The extended nose and stronger slipstream generated by the large five-blade propeller necessitated adoption of a new tail assembly featuring a taller and wider fin along with an enlarged rudder.[2][3]
The initial aircraft fitted with Griffon 60 series engines were six modified Mk VIIIs (serials JF316 to JF321), designated Mk VIIIG. Jeffrey Quill piloted the first of these on 20 January 1943:
One prototype, JF321, underwent testing with a six-bladed contra-rotating Rotol propeller unit intended to eliminate takeoff torque effects caused by propeller slipstream; however, reliability issues arose due to pitch control mechanisms:
A similar contra-rotating propeller configuration was later implemented on production Seafire models 46 and 47.
Upon entering service with 610 Squadron in December 1943, this fighter marked a significant advancement in Spitfire development. Jeffrey Quill flew the first production Mk XIV aircraft (RB140) in October 1943:
The Mk XIV could reach 20,000 ft (6,100 m) altitude in just over five minutes and achieved its maximum speed of 446 mph (718 km/h) at 25,400 ft (7,700 m).[4][5]
Operationally, many pilots initially found handling challenging compared to earlier Spitfire variants. Don Healy of 17 Squadron, stationed at Madura, described flying the Mk XIV as:
...a demanding aircraft requiring acclimatization; personally I preferred flying older Mk Vs... Even applying full control inputs on ailerons, elevators and rudder resulted in takeoffs that veered slightly sideways.[6]
Despite these handling challenges, pilots valued its superior performance capabilities. Wing Commander Peter Brothers, Officer Commanding Culmhead Wing during 1944–1945 and veteran of the Battle of Britain, remarked:
The aircraft was truly impressive—capable of near-vertical climbs—which surprised many Luftwaffe pilots who expected an easy kill from superior altitude but found themselves confronted head-on by an aggressively climbing Mk XIV at full throttle![7]
F Mk XIVs carried a total fuel capacity of 109.5 gallons: two main tanks holding 84 gallons combined plus two leading-edge wing tanks each containing 12.5 imperial gallons; additional drop tanks ranging from 30 to 90 gallons could be mounted as required. However, due to higher fuel consumption of the Griffon engine compared with earlier Merlin-powered variants, maximum range on internal fuel alone was just over 460 miles (740 km). By late 1944, an auxiliary rear fuselage fuel tank holding an extra 33 gallons was added to Spitfire XIVs, extending internal fuel range to approximately 850 miles (1,370 km) when combined with a standard 90-gallon drop tank.[8] Models equipped with "tear-drop" canopies had reduced fuel capacity at about 64 gallons internally; nevertheless F and FR Mk XIV variants attained ranges exceeding 610 miles (980 km), or up to 960 miles (1,540 km) when fitted with a large drop tank.[8]
The initial operational use involved intercepting V1 flying bombs where the Mk XIV proved more effective than any other Spitfire variant in this role. Introduction of 150 octane fuel during mid-1944 enabled increasing engine boost pressure by +25 lbs (80.7"), enhancing top speed by roughly 30 mph (26 kn; 48 km/h) to reach approximately 400 mph (350 kn; 640 km/h) at 2,000 ft (610 m).[9]
Within northern Europe’s theatre under 2nd Tactical Air Force, six squadrons operated Mk XIVs as their principal high-altitude air superiority fighters by December 1944.[10]
A service issue emerged involving localized skin wrinkling on wings and fuselage near load-bearing attachment points; although Supermarine assured no critical structural weakening or imminent failure risk existed, RAF directives issued early in 1945 mandated refitting all F and FR Mk XIVs with clipped wings.[11]
Spitfire XIVs began arriving in the South-East Asian Theatre from June 1945 but arrived too late for combat against Japanese forces.[1][12] Postwar reports suggest several Mk XIVs may have been buried at an airfield in Burma following hostilities.
FR Mk XIV
In late 1944, several high-backed, full-span Mk XIV aircraft underwent modifications by the Forward Repair Unit (FRU) to incorporate a single camera mounted either to port or starboard. This alteration mirrored the conversion applied to FRU-modified FR Mk IXc models. To facilitate this, a new hatch resembling the radio hatch on the port side was added on the starboard side, with both hatches equipped with camera ports enclosed in streamlined blisters. Apart from these changes, this FR Mk XIVe variant remained largely consistent with the original design. These field-modified aircraft were assigned to 430 Squadron RCAF.[13] Subsequently, factory-built conversions—also designated as FR Mk XIVe—featured a redesigned cut-down rear fuselage topped with a tear-drop canopy, camera ports on port and/or starboard sides without blister housings, and an auxiliary 34-gallon rear fuel tank that extended operational range to approximately 610 miles (980 km) on internal fuel alone. Since these production models were primarily deployed at low altitudes, they were fitted with clipped wingtips.
A total of 957 Mk XIVs were manufactured, with over 430 produced as FR Mk XIVs.[14] Postwar, numerous surplus Mk XIVs were distributed internationally; among them, 132 units were transferred to the Royal Belgian Air Force, 70 to the Royal Indian Air Force, and 30 reconnaissance-configured examples to the Royal Thai Air Force.
Mk XV and Mk XVII
The designations XV (15) and XVII (17) were reserved for naval adaptations of the Spitfire, known as the Seafire, aligning their numbering system with that of the land-based Spitfires.
Mk XVIII (Mk 18) (type 394)
Media related to Lua error in Module:Commons_link at line 62: attempt to index field 'wikibase' (a nil value). at Wikimedia Commons
The Mk 18 represented an evolution of the Mk XIV, sharing most characteristics including the Griffon 65 engine and cockpit improvements. It incorporated additional fuel capacity and featured a reinforced wing structure. Its flight characteristics closely matched those of its predecessor, thus formal performance testing was deemed unnecessary. Both fighter and fighter-reconnaissance versions were produced.
Although developed during wartime, the Mk 18 did not enter service before hostilities ended. Production continued until early 1946; however, it was not until January 1947 that 60 Squadron, based at RAF Seletar in Singapore, re-equipped with this variant. Subsequently, other units stationed in the Far East and Middle East also received these aircraft. Approximately 300 F Mk 18s and FR Mk 18s were constructed before manufacturing ceased in early 1946.[15] Operational use was limited mainly to counterinsurgency efforts during the Malayan Emergency. Additionally, the Royal Indian Air Force acquired 20 former RAF Mk 18s in 1947.
Mk XIX (Mk 19) (types 389 and 390)
The Mk XIX represented the final and most accomplished photographic reconnaissance Spitfire model. It merged the characteristics of the Mk XI with the Griffon engine found in the Mk XIV. The initial batch of 25 aircraft (type 389) was followed by later versions equipped with the pressurised cockpit from the Mk X and an enlarged fuel capacity of 256 gallons—approximately three and a half times greater than that of the original Spitfire. These later models were designated as type 390.
Entering service in May 1944, the Mk XIX quickly supplanted the earlier Mk XI by war’s end. A total of 225 units were produced before manufacturing ended in early 1946, yet they remained active in frontline RAF roles until April 1954.
In 1951, RAF Spitfire PR Mk 19s based at Kai Tak Airport in Hong Kong conducted reconnaissance flights over Hainan Island, China, under orders from US Naval Intelligence. The final operational mission involving a Mk 19 occurred in 1963 during combat trials against an English Electric Lightning, aimed at developing tactics for engaging piston-engine fighters such as North American P-51 Mustangs during contemporary Indonesian conflicts.
Mk XX (type 366)
The designation Mark XX was assigned to the original Mk IV Griffon engine prototype DP845 to prevent confusion with the renamed Spitfire PR Mk IVs.
The second aircraft labeled Mk XX, DP851, initially flew in August 1942 powered by a Griffon II engine. In December of that year, it was re-equipped with a Griffon 61 engine and redesignated as the initial prototype for the Mk 21.
Mk 21 (type 356)
By early 1942, it became clear that Spitfires fitted with the new two-stage supercharged Griffon 61 engine required a significantly reinforced airframe and wing structure. This led to the development of the Mk 21, which initially suffered from unsatisfactory flight characteristics that somewhat tarnished the Spitfire’s renowned reputation. The wings were redesigned with a sturdier internal framework and thicker light alloy skinning, resulting in a torsional stiffness increase of 47 percent. This enhancement allowed an elevated theoretical aileron reversal speed up to 825 mph (1,328 km/h). The ailerons were enlarged by five percent, and the previously used Frise-type balanced ailerons were replaced by continuous piano-hinged versions extended by eight inches. Consequently, with a straighter trailing edge, these wings departed from the classic elliptical shape of earlier Spitfires. Armament for the Mk 21 was standardized to four 20mm Hispano II cannons carrying 150 rounds each, eliminating machine guns.
The Griffon engine powered an 11 ft (3.4 m)-diameter five-bladed propeller, which was approximately 7 in (18 cm) larger than that used on the Mk XIV. To accommodate this larger propeller, undercarriage legs were extended by 4.5 in (11 cm) to maintain sufficient ground clearance. Additionally, the landing gear track was widened by 7.75 in (19.7 cm) to enhance ground handling stability. A system of levers was implemented to shorten the undercarriage legs by about 8 in (20 cm) during retraction due to space constraints; these levers also extended the legs upon deployment. The main wheels featured larger four-spoke rims reinforced for increased loads; post-war modifications replaced these with wider three-spoke wheels suited for operations on paved runways. When retracted, triangular doors hinged at the outer edges fully enclosed the wheels within their wells.
The first production examples of the Mk 21 retained the Mk XIV airframe design. The initial true Mk 21 prototype PP139 had its maiden flight in July 1943, followed by production commencing with LA187 on 15 March 1944. However, modifications introduced over the Mk XIV made this model sensitive to trim adjustments. During late-1944 and early-1945 trials, LA201 exhibited poor flight control qualities prompting a critical report from the Air Fighting Development Unit (AFDU):
Supermarine expressed serious concern since Castle Bromwich had shifted production entirely to Mk 21s with increasing output daily. Test pilot Jeffrey Quill noted:
Following extensive testing, critical issues were addressed through adjustments such as re-gearing trim tabs and other refined control changes. By March 1945 trials on LA215 confirmed that these modifications significantly enhanced handling qualities:
General Handling Improvements have been achieved across all altitudes ... Conclusions Prior critical trim issues have been largely resolved; handling is improved accordingly making it suitable for both instrument and low-level flight operations. Overall, it is now considered an effective combat aircraft for average pilots.
Operational deployment began with No. 91 Squadron RAF in January 1945. Although combat opportunities against Luftwaffe forces were limited before war’s end, on April 26th two Mk 21s reportedly damaged and sank a German midget submarine caught on surface patrol. Post-war cancellations reduced total production to only 120 units completed. In 1946, forty aircraft were delivered to Shoeburyness where their leading edges were removed for live-fire lethality testing; some had accumulated less than five hours flight time.
Mk 22 (type 356)
The Mk 22 closely resembled the Mk 21 but featured a shortened rear fuselage topped with a tear-drop canopy and upgraded from a twelve-volt to a more powerful twenty-four-volt electrical system found in earlier models. Most units incorporated enlarged tail surfaces similar to those used on the Supermarine Spiteful design. Production totaled 287 aircraft: with Castle Bromwich manufacturing approximately 260 and Supermarine’s South Marston facility producing another 27.
Only one regular RAF squadron—No. 73 Squadron stationed on Malta—operated the Mk 22 extensively; however, twelve Royal Auxiliary Air Force squadrons also flew this variant until March 1951. The type was additionally employed at flying refresher schools. By May 1955, all remaining F.22s were declared obsolete within RAF service; many were sold back to Vickers-Armstrongs for refurbishment before being transferred to air forces in Southern Rhodesia, Egypt, and Syria.
Mk 23 (type 372)
The intended Mk 23 aimed to enhance upon the Mk 22 by incorporating revised wings featuring an increased angle of incidence that raised the leading edge by approximately 2 inches (51 mm) to improve forward visibility and boost high-speed dive performance. This specially hand-built wing was first trialed on a modified Mk VIII JG204 starting July 1944 but yielded disappointing results. Subsequently, Supermarine decided to develop a new prototype based on Mk 21's PP139, designated F Mk 23 and intended to be renamed Supermarine Valiant. However, handling deficiencies persisted with this wing design; consequently, no production followed using this configuration derived from the Mk 22 airframe.
Mk 24 (type 356)
The final iteration of the Spitfire series—the Mk 24—shared many similarities with its predecessor but featured increased fuel capacity through two additional rear fuselage tanks holding thirty-three gallons each. Underwing zero-point fittings allowed attachment of rocket projectiles as standard equipment. All models incorporated larger tail units derived from the Supermarine Spiteful design along with refined trim tab gearing that enhanced handling characteristics.
The F Mk 24 attained top speeds near 454 mph (731 km/h) and could climb to 30,000 ft (9,100 m) within eight minutes—performance comparable with contemporary high-end piston fighters.
Though primarily designed as an interceptor fighter armed with four powerful twenty-millimeter Hispano cannons—reflecting operational experience favoring heavier armament against increasingly armored enemy aircraft—the aircraft also fulfilled fighter-bomber roles carrying one 500 lb (230 kg) bomb plus two 250 lb (110 kg) bombs alongside rocket rails fitted beneath its wings. Late production examples utilized lighter electrically-fired short-barrelled Hispano Mark V cannons.
Eighty-one units were completed overall; twenty-seven resulted from conversions of existing Mk 22s. Deliveries concluded in February 1948 with continued use until around1952 by No. 80 Squadron RAF; some aircraft later transferred to Hong Kong Auxiliary Air Force service until circa1955.
Introduced late in World War II’s aftermath, this version marked significant evolution from early models such as prototype K5054—it weighed twice as much yet nearly doubled power output while improving climb rate by roughly eighty percent thanks mainly to adoption of Rolls-Royce’s Griffon engine rated at approximately 2,050 hp (1,530 kW), featuring advanced two-stage supercharging that delivered exceptional high-altitude performance previously lacking in earlier Merlin-powered variants.
Production
Following heavy damage inflicted upon Supermarine’s primary Itchen and Woolston facilities during Luftwaffe raids in September 1940, production was dispersed across various "British shadow factories". By war’s end there existed ten principal factories alongside numerous smaller workshops responsible for component manufacture; Castle Bromwich served as a major assembly site supported by these shadow plants.
Production figures below are sourced from Air International (1985), supplemented by serial number data from Morgan and Shacklady (2000). Note that initial XIV models were conversions from existing Mk VIII airframes; thus first true production serial numbers are listed accordingly. Due to protracted development delays, operational introduction of the Mk 21 did not occur until January 1945.
| Mark | Manufacturer(s) | Quantity built | Notes |
|---|---|---|---|
| F Mk XII | Supermarine | 100 | First unit flew on October 13, 1942 |
| F Mk XIV / FR Mk XIV | Supermarine | 957 | Initial production serial RB142 dated October 28, 1943 |
| F Mk XVIII | Supermarine | 300 | First example flown June 1945 |
| PR Mk XIX | Supermarine | 224 | First unit RM626 entered service May 1944 |
| F Mk 21 | Castle Bromwich | 120 | Initial production LA187 flown January 27, 1944 |
| F Mk 22 | Supermarine & Castle Bromwich | 287 (27 +260) | First unit flown March 1945 |
| F Mk 24 | Supermarine | 54 | First delivery March 1946 |
Videography
External links
- The Spitfire Site Archived 17 August 2020 at the Wayback Machine
- Alan Le Marinel’s Supermarine Spitfire Resource
- Performance Evaluation of the Spitfire
- Warbird Alley – Details on Spitfires Currently Airworthy
- K5054 – History of the Supermarine Type 300 Prototype and Production Models
- National Heritage Warbird Foundation
Template:Supermarine Spitfire Template:Supermarine aircraft
- ↑ 1.0 1.1 Thomas 2008
- ↑ Cooke October 1978, pp.489, 491–492.
- ↑ Price 2002, pp. 204–216.
- ↑ Price 1999, p. 217.
- ↑ Performance data refers to JF319, one of six initial Mk XIVs converted from Mk VIIIs tested at Boscombe Down; production variants had modified supercharger gearing.
- ↑ McKinstry 2007, p. 355.
- ↑ McKinstry 2007, p. 357.
- ↑ 8.0 8.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedMorgan and Shacklady 2000, p.420. - ↑ Price 2002, p. 205.
- ↑ Shores and Thomas 2005, p. 297.
- ↑ Morgan and Shacklady 2000, pp. 411–412.
- ↑ Price 1999, pp. 205–206.
- ↑ Aviaeology decals AOD72009.
- ↑ Caygill 2004, p. 92.
- ↑ Price 1999, p. 211.