Concise Guide To Spitfire Wing Types

Spitfire Site

An overview of the basic wing types of the Spitfire and the differences between them. With drawings.
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The original wing structure of Supermarine Type 300 Spitfire Mk. I, later referred to as the Type A wing.
Click to enlarge image
[Crown Copyright]

No discussion about the various Spitfire marks can be complete without referring to the different wing types. 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
[Crown Copyright]

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.
Click to enlarge image
[Crown Copyright]

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24 Comments | Add New

By Chris Ashley  |  2010-08-05 at 07:21  |  permalink

Great info on the Spitfire. The wing shape picture is just what I needed to use for a project this week with my Cubs. Cheers

St. George for England

By ferret_64  |  2010-08-08 at 15:15  |  permalink

Chris,
do you want to make a flying model of the Spitfire? Post it on the Spitfire forum.
And good luck with finding the right center of gravity, I find the Spitfire to be quite tricky when it comes to this.

Cheers, Martin

By Martin Overy  |  2011-01-01 at 17:21  |  permalink

Chris

Thanks for a great article: I am currently building every mark of Spitfire and Seafire in 1:48 scale, and it has been really helpful.

However I assume from your article that the Mk.VII and Mk.VIII did not have the downward identification lights under each wing (as the XIV and XVII did), but retained the central light under the fuselage, similar to the Mk.IX and Mk.XVI. Am I correct?

Also the On Target Profile for PR Spitfires show the identification light under the starboard wing only for Mk.XIVe and Mk.XVIII; whereas the Mk.XIX has no identification lights at – do you know if this is correct?

Many thanks, Martin.

By James  |  2011-04-27 at 06:59  |  permalink

The wing was the thing! Destinctive shape which caused a sheet of trailing edge voticies and as a result a smaller wing tip vortex. This led to an overall reduced drag co-efficient. I understand the wing had a beefy “D” box structure leading edge which allowed for at the time, a very thin wing, but strong. There are very few records of a breakup in flight. In Alfred Price’s very good book, Spitfire a Complete Fighting History, Eric Newton MBE CEng FRAeS, who investigated many Spitfire accidents mentions an ultimate loaf factor of +10g, pretty impressive for a wing as thin as that! He also mentions a lot of airframe failures being caused by aileron distortion at high speeds. One surviving pilot reported that in a high speed dive he saw both ailerons suddenly flip up, causing a violent pitch up and resultant airframe failure. The later metal cladding went a long way to curing this. Has anyone got any data on the ailerons? They are quite unusual on the Spitfire, “Frise” type having a sharp leading edge which protrudes noticably below the lower wing surface when deflected upwards. I have seen Frise type ailerons before but not with that sharp leading edge? My understanding is the protrusion of the aileron leading edge below the wing surface was to counter adverse aileron yaw.

By Barry Gillingwater  |  2011-04-28 at 08:49  |  permalink

James,

Frise ailerons were (are) quite common in aileron design. The idea of having the leading edge of the ‘up-going’ aileron protruding down into the airflow underneath the rear of the wing is to counteract the drag effect of the ‘down-going’ aileron on the other wing.

If your aircraft were fitted with ‘simple’ ailerons you would always get more drag from the wing where the down-going aileron was applied. The effect of this ‘aileron drag’ was for the pilot to see a yawing movement in the opposite direction to the roll you had initiated by applying aileron.

This phenomenom is called ‘adverse yaw’ and is something that trainee pilots are taught to counteract by appropriate use of rudder to keep the aircraft balanced as the turn is initiated. The trainee in a Tiger Moth had to learn to really co-ordinate his feet as he rolled into turns as the nose of the aircraft would swing quite noticeably in the opposite direction of the turn, which made the Tiger an excellent trainer.

One of the lovely design characteristics that Mitchell incorporated into the Spitfire was the Frise ailerons which had the effect of balancing the yawing moment as you entered into a turn, which effectively negated the adverse yaw and required minimal input from the pilot to keep the aircraft properly balanced. Nicely harmonised controls.

Another design method of reducing adverse yaw and aileron drag is to fit your aircraft with differential ailerons. These were geared so that the ‘up-going’ aileron travelled further upwards than the ‘down-going’ aileron travelled downwards. An example of differential ailerons was on the Piper Cherokee (non-Warrior) wing. These had the same effect as the Frise.

By James  |  2011-05-02 at 01:39  |  permalink

Hello Barry, thanks very good explanation and absolutely right, however whilst I do understand the principles behind adverse aileron yaw, to make it clear, what I’m curious about is, to my mind, the unusual shape of the spitfire aileron leading edge, being very a sharp wedge shape, something I’ve not seen on other Frise aileron designs, it’s almost as if the intent was to “scoop” air up over the upwards deflected aileron, the down going aileron, would almost seal the gap between wing and aileron, due to the sharp edge. This is actually desirable as it causes max pressure differential, without high pressure air “leaking” up into the low pressure area on the wing top surface. This will aid/improve roll rate. If again this was Mitchell’s intent, he really was an aerodynamacist of exceptional ability, for that era?

By David Bailey  |  2011-04-27 at 12:05  |  permalink

Informative article, but as an experienced naturalist what I would really love to see is a ‘Field Guide to Spitfires’, done in the same style as birding guides. Simple pictures from various angles, with information pointing out the various visible differences (‘field marks’ to birders) among the types. There would be things on a variant that positively identify it as that type and no other, which would be very helpful to have ready for a quick glance.

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