Concise Guide To
Spitfire Wing Types
Part 2
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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The revised 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 ailerons were deemed necessary to increase the agility of the aircraft in the rolling plane. To accommodate them, the wing planform was enlarged with wider chord towards the wingtips, and its internal structure revised to strengthen the wing in torsion and thus increase the useful diving speed and raise the speed limit for aileron reversal. The wingtips 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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