Concise Guide To
Spitfire Wing Types
The original wing structure of Supermarine Type 300
Spitfire Mk. I was later referred to as Type A.
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No discussion about the various Spitfire marks can be complete without referring to the different wing types. This article is intended to provide an overview of the basic wing types of the Spitfire and the differences between them.
The Merlin-powered Spitfires used four different wing types, A through to D which had the same dimensions and plan but different internal arrangements of armament and fuel tanks. After introducing the Griffon, Supermarine recognized the need for a completely revised laminar-flow wing to facilitate even higher speeds made possible by this powerful engine. Starting with production Spitfire Mk 21, this wing became standard for post-war variants of this famous fighter.
The majority of the day fighter Spitfires from the Mk I through Mk XVIII used four basic wing types, A, B, C and E.
A type
The original wing design, the basic structure of which was unchanged until the arrival of C type wing in 1942. The only armament able to be carried was eight .303-calibre Browning machine guns with 300 rounds per gun.
The one major alteration made to this wing soon after production started was the incorporation of heating for the gun bays to prevent the guns from freezing at altitude. Open structures around the gun bays were blocked off and ducting, drawing hot air from the back of the radiators, was added to the wings. The heated air was exhausted through underwing vents, covered by streamlined triangular blisters, just inboard of the wingtips.
Towards the end of 1940 the fabric covered ailerons were replaced by ones covered in light-alloy.
General arrangement of the Type A wing
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B type
This was the A type wing modified to carry a 20mm Hispano cannon. One type of armament could be fitted, comprising two 20 mm-calibre Hispano Mk II cannon, fed from drum magazines with the capacity of 60 rounds/gun, and four .303 Browning machine guns with 350 rounds per gun.
The retractable underwing landing lamp was repositioned and the innermost machine gun bays were replaced with a single cannon bay, plus a compartment for the drum magazine outboard of the wheel well.
The upper and lower wing skins incorporated blisters to clear the ammunition drum. Under the wings there were two possible blister shapes.
The alloy covered ailerons were standardised on this wing type.
General arrangement of the Type B wing
[Martin Waligorski]
Internal structure of the Type B wing of the Spitfire Mk.
Vb.
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C type
Called "universal wing", this wing was structurally modified to reduce labour and manufacturing time and allow mixed armament options; A or B type armament or a new, yet heavier combination of four 20 mm Hispano cannon.
The undercarriage mountings were redesigned and the undercarriage doors were bowed in cross section allowing the legs to sit lower in the wells, eliminating the upper-wing blisters over the wheel wells and landing gear pivot points.
The revised, strengthened undercarriage legs were raked 2 inches (5.08 cm) further forward, making the Spitfire more stable on the ground and reducing the likelihood of the aircraft tipping onto its nose.
The Hispano Mk II cannon fitted in all cases were now belt-fed from box magazines (the Chattellerault system) allowing to double the ammunition supply to 120 rounds per gun. The fairings over the Hispano barrels were shorter and there was usually a short rubber stub covering the outer cannon port when not in use.
General arrangement of the Type C wing
[Martin Waligorski]
The redesigned upper wing gun bay doors incorporated blisters to clear the cannon belt feed motors. Initially a single wide blister was incorporated that covered both motors. Initial production Spitfires Mk. Vc, such as those which were transported to Malta were factory-fitted with four cannon. In field conditions, it was often sufficient with two cannon armament and many of the four-cannon Spitfires were converted to fly with either outboard or inboard pair of Hispanos, or else converted to B-standard armament. Later on, production aircraft carried the two 20mm Hispanos and four Brownings. In such circumstances, the very large blister on top of the wing was not required and a new, more streamlined cannon breech cover was provided, with narrow blister fairing over the inboard cannon position and flat surface over the second, unused cannon bay.
The inner machine gun bays in C wing were moved outboard to between ribs 13 and 14. Also, the lower surface of the wing no longer had the gun-bay heating vents outboard of the gun bays and the retractable landing lights were no longer fitted.
The wing structure was stressed for provision of hardpoints outboard of the wheel wells capable of taking a 250 lb (113 kg) bomb under each wing.
Apart from early Spitfires Mk. IX converted from Mk. Vc airframes, the undercarriage indicator pins were not used on this or any of the later Spitfire marks.
Comparison of armament layout between type A (middle) , B
(top) and C (bottom) wings on Spitfire Mk. V.
Note the difference in the placement of inner .303" Browning on C wing.
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Internal structure of the Type C wing as fitted to the
Spitfire Mk. VIII.
The leading edge fuel tank was peculiar to this mark and was not mounted on
Spitfires Mk. V and IX.
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Corresponding structural drawing of the Spitfire Mk. XIVc
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D type
This designation applied to the unarmed long-range wing for reconnaissance versions. Space for substantial amount of additional fuel was provided in the space ahead of the wing spar, which together with the reinforced skin of the wing's leading edge formed a rigid torsion box. Its otherwise empty interior was converted into an integral fuel tank capable of carrying 66 imp gallons. On hot summer days, so large amount of fuel inside the wing would produce a substantial volume of vapour, so relief valves were fitted to the tanks in the outboard rib position.
Internal structure of the Type D wing as used on the
Spitfire PR Mk. IV and XI.
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Clipped wings
Starting with the Mk. V, some Spitfires had their classic elliptical wingtips replaced by shorter, squared-off fairings reducing span to 32 ft 2 in (9.80 m). Shortening the wing span substantially enhanced the roll rate, closing the gap in this respect between the Spitfire and the formidable German Focke-Wulf Fw 190.
The clipped-wing Spitfires are sometimes being referred to as "L.F." versions, e.g.: LF Mk Vb. Formally, this is a misunderstanding as the LF designation referred to the low-altitude version of the Rolls-Royce Merlin engine and while many LF Spitfires had the clipped wings, a number did not.
Extended wingtips
Pointed, triangular wing tips were designed especially for high-altitude versions of the Spitfire, starting with the Mk. VI. The enlarged wing area they provided resulted in better climb rate and slightly improved ceiling at the expense of manoeuvrability in combat on "normal" altitudes. The idea with both clipped and extended wing tips was taken further in Mk. VIII production, when the tips became easily interchangeable and theoretically could be swapped to suit the preferences of an individual pilot or tactical requirement.
Internal structure of the extended Type B wing of the
high-altitude Spitfire Mk. VI.
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Identical in outline, the wing of the Spitfire Mk. VII was
of C type and therefore significantly different from the Mk. VI.
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E type
A new wing was introduced in early 1944 - type E. Structurally unchanged from the C wing, the outer machine gun ports were eliminated. Although the outer machine gun bays were retained, their access doors were devoid of empty shell case ports and shell deflectors.
The inner gun bays allowed for two weapon fits two 20 mm Hispano Mk II cannon with 120 rounds/gun in the outer bays and two American .50 calibre M2 Browning machine guns, with 250 rounds per gun in the inner bays. Alternatively, four 20 mm Hispano cannon with 120 rounds per gun could be carried as per original C-wing production standard.
The cannon in the E wing was slightly relocated, positioned further to the rear in its bay. Consequently, the protruding portion of the barrel was shorter and almost entirely enclosed by a new cigar-shaped fairing. Also, the overwing blister was more narrow and a little deeper than the corresponding feature of the C wing.
An interesting curiosity is that several C-wing Spitfires LF Mk. IX of No. 485 (New Zealand) Squadron were converted to carry the Hispanos and .50 Brownings just before D-Day.
The Type C and E wings were structurally identical,
differing only in armament installation.
This diagram shows the layout of cannon and .5" M2 Browning installation in
the latter.
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Laminar-flow wing
Beginning with the Mk. 21, the Spitfire had a new, restructured wing design. The design work on the new wing started as early as 1942, but it found its way into production only by the very end of the war.
New, larger area aileron were deemed necessary and to accommodate them, the wing planform was enlarged with wider chord towards the wingtips. The tips themselves were gently squared-off making for a noticeable a departure form the perfect elliptical outline of the original Spitfire wing.
The new wing was armed with four 20 mm Hispano Mk II or V cannon. No other armament configurations were incorporated as the RAF standardised on all-cannon armament for its post-war fighters.
The Hispano Mk. V was lighter, had a higher rate of fire and a shorter barrel, leading to the protruding gun fairings being shortened even more. Also, the cannon and their belt were staggered, and consequently, the inner and outer blisters for feed motors were of different shape.
Other changes included widening the undercarriage by 7.25" (19.6 cm), with its wells placed correspondingly further away from the centerline. In order to enable larger propellers to be fitted while providing adequate ground clearance, the undercarriage legs were also longer by 4.5" (11.4 cm). The undercarriage could be also fully enclosed in flight due to the new outer undercarriage covers.
No official designation was ever given to this wing type. It was most often referred to in official letters as the "new wing".
The new wing introduced on the Spitfire Mk. 21 was only
superficially similar to the preceding wing types.
Internally, all aspects of its construction have been revised.
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