Spitfire 'C' wing cannon stubs

[mike romeo]

An easy question for you Spitfire experts (I can't immediately find a previous post answering this, but . . .)

The 'C' wing started with wide cannon bulges - I think - because initially each wing was supposed to mount 2 cannon side by side (and 2 machine guns further outboard, but that's not important right now) and the bulge was necessary to clear the cannon 'gubbins' (breeches?). However, due to the effect on performance of the weight of the second pair of cannon, usually only one cannon was fitted in each wing.

Is this correct so far?

If so, at some point in the future, the wide cannon bulges were thinned down to fit over the 'gubbins' of just the one cannon, which was fitted in the inboard position (for the 'c' wing, remember). I assume this was done to reduce the drag of the wide cannon bulges.

With me so far?

Therefore, the outer cannon position was unused, and a 'stub' was fitted in this position. Mk Vc, MkIXc etc etc. So, why was the outboard cannon 'stub' not faired flush with the leading edge? I accept that the drag reduction in so doing would have probably been minuscule, but if my statement about the bulges being changed to reduce drag is correct, it just seems strange that the stub was not faired flush too for a 'proper job'.

Later on came the E wing with further differences, but this is not pertinent to the above question.

Can anyone enlighten me?

regards,

Martin

[Jon Kunac-Tabinor]

Hi Martin - interesting question , I'd like to know the answer too.

One thing I can say is that some units did remove the outer cannon stub from their C winged Mk Vs and IXs. Its seems to have been a fairly common mod in USAAF units in the Mid East that used these models.

Cheers

Jonners

[Fernando]

Hi,

I guess that, the whole rationale of the "c" wing was its flexibility (remember it was called "universal") and perhpas the existing plans for refitting .5 in guns called for the stubs to remain where they were, to keep the chances open. Interestingly, the so-called "c" wing in Seafires II-III-XV has no stub.

FErnando

[mike romeo]

Fernando,

Thanks for posting. Re 'flexibility', you could well be right. Just hope that some of the Spitfire 'top guns' can tell us for sure.

Re the Seafires, I know. I guess that was one of the things that made me wonder in the first place.

Jon,

Didn't know that about the USAAF squadrons. That gives me another idea for finishing the Airfix Spitfire IXc! Many thanks.

regards,

Martin

[Test Graham]

Yes, it was because of the universality of the wing. There was at least one Mk.VIII fitted with four cannon in Australia.

A limited number of Mk.IXs were built with only the one cannon position, and no stub outboard, and one of these has survived as a current flyer.

If you are interested in the USAAF Mk.IXs, chase up the two Ventura booklets on the subject. There are also recent books dedicated to the individual groups. There are a surprisingly wide range of colour schemes for these aircraft (although some of them were Mk.VIIIs).

[Andrew Jones]

Hi,

I guess that, the whole rationale of the "c" wing was its flexibility (remember it was called "universal") and perhpas the existing plans for refitting .5 in guns called for the stubs to remain where they were, to keep the chances open. Interestingly, the so-called "c" wing in Seafires II-III-XV has no stub.

FErnando

No .5in weapons on a C wing Spitfire, only .303's, the 50 cals only appeared on the E-wing.

[stevehnz]

I'm guessing that it was done this way for simple expediency. It appears that the C wing leading edge was built with a tubular carry through & it was easier to simply cap this rather than remove & finish flush with the wing leading edge surface. Obviously at unit level this may have been done differently. if you haven't already seen it, THIS PAGE has a heap of info re Spitfire wings although it doesn't answer your query directly.

Steve

[Test Graham]

No. There was a very long discussion on this on A N Other site (I'll remember which one soon.....but fear it is no longer running). There is a casting inset into the wing leading edge that has either two stubs or just the one.

Strictly, it is not a c wing, although we are probably stuck with it as a shorthand. It is a universal wing. The c and e are suffixes that define the armament. Strictly, the original version of the Mk.IX was not a Mk.IXc because there was at that time no need for a suffix, as only one armament was offered, although three could be fitted (a, b or 4 cannon). The modification to fit the 0.5 gun meant that the wing was no longer universal (although strictly speaking the modifications could be reversed, it didn't happen in practice). Later production e-wings had solid outboard leading edges so the outer machine guns could not be not fitted, so they were not universal.

The Mk.III Seafire has no armament suffix, because there were no options on that aircraft either.

[Edgar]

There is evidence (of a sort) that it did happen. 23-12-43 modification 683 was implemented "To standardise armament on VC & IX aircraft as 2 cannon and 4 Brownings." At around the same time mod 820 was raised "To remove the outboard cannon front mounting casting," but there is no "cleared" date (which usually signified the date it went onto the production line,) just an enigmatic "P.M.S. issued." Does anyone know (rather than guess) what P.M.S. stands for? The local Ministry committee last discussed it 20-4-43.

One of the clues that it did happen comes with mod 1029 "Install 2 x .5" guns in lieu of 4 x .303" guns (Mod 820 must not be embodied)" which was issued, as a leaflet, in May 1944, a full year later. (This leaflet said that the mod could only be carried out by Vickers personnel, due to the need for removal of some wing plumbing, incidentally, which probably explains Jennings' findings that some Squadrons just fitted a .5" in the outer bays.) There is a photo, in an old Ducimus book, on Merlin Spitfires, which shows early IXs, in the desert, which appear to have "B" wings, but it now seems more likely that the stubs had been removed. Also photos of the floatplane IX show only the cannon fairings, no stubs, but a C wing bulge.

Returning to the bulges, mod 782 "Introduce cannon single blister door called for under mod 683 as retrospective item", for the V & IX, went into production 7-1-44 (that's January, remember.)

Intriguingly, mod 769 "Introduce cannon gun door with two small blisters in place of one large" was introduced on the VIII from 15-12-43, and I've found a memo, dated 12-4-44, in which a W/C Whitworth states that "(i) The final aim is to fit 4 x 20mm Mark V, or alternatively 2 x Mark V plus 2 x .5 (ii) Until such time that (i) is cleared 2 x 20 mm Mark II plus 2 x 20mm Mark V is acceptable, presuming that Mark V guns are available. If Mark V guns are not available 4 x 20mm Mark II will be acceptable. (iii) It is realised that the .5 alternate armament will require modification sets with each aircraft. At present no action should be taken in regard to fitting the 2 x .5 other than the clearing of the T.I. 2. The decision as to whether the 2 x .5 will in fact be required on the Spitfire VIII, will depend on the operational results with this armament in the Mark IX and XIV." That little lot ties in with Graham's finding of a 4-cannon VIII, and we're left with the possibility that there are photos of 4-bulge VIIIs somewhere.

Edgar

[Doug]

Hi All,

So with what's been said already in mind, was there a 'C' wing with twin cannon as depicted in the Airfix 1/72 Mk Vc?

Doug.

[Work In Progress]

So with what's been said already in mind, was there a 'C' wing with twin cannon as depicted in the Airfix 1/72 Mk Vc?

There are photos of four-cannon Vc's on the way to Malta.

[Jon Kunac-Tabinor]

Hi All,

So with what's been said already in mind, was there a 'C' wing with twin cannon as depicted in the Airfix 1/72 Mk Vc?

Doug.

Hi Doug - yes one of the SAAF squadrons in the middle east used Mk Vc with all 4 cannons ( No 4 Sqd if I recall), and there is a pic in the Osprey book of "late Marque Spitfire Aces" of a 4 cannon Mk VIII in Australia with extended wingtips too, supposedly used for anti-Ki-46 Dinah operations ( a model I'd love to build, but this pic is the only one I've ever found and its a frontish on view - so serial nos etc are impossible to see)

The Spit Vcs delivered to Malta arrived with the 4 cannon installation, but were quickly reconfigured back to the 2 cannon fit, however some had the inner cannon removed, rather than the outer weapon, so can see variations on Malta spits whihc are very non-standard.

Jonners

[gingerbob]

Whoo boy, what a lot of loose ends...

I'll work back to front. (and a couple of posts have snuck in while I was working on this!)

Doug: Yes, there were some 4 cannon Spit Vcs (I think that's what you meant?)- best known are the SAAF examples in the Med. Also some at Malta, though I don't think they remained in that config for long.

Edgar (and others): There most certainly IS evidence that 'it' [the flushing-off of the unused stub] happened, but I'm NOT convinced that it ever happened on the production line. That was the position taken by Peter Arnold, as I recall, in the long debate that Graham referred to (which was on AWF), but I haven't seen any compelling evidence to convince me. There are photographs of Vcs and IXs with the stub deleted. If in doubt, the 'c' cannon still has the long cylindrical part of the fairing, whereas the 'b' cannon sat farther back in the wing and had a conical fairing.

As Edgar noted there was a mod discussing it. I seem to recall that it was worth about 2mph, which might explain why not many took the trouble to remove the stub. I don't know, but I assume it would involve a lot of drilling and filing to get that stub off, and then you've got to plug the hole in the leading edge.

I am not familiar with Jennings' 'findings' concerning .5" guns in the outer position. I am skeptical, but would like to be enlightened!

Graham: Strictly speaking it IS a 'c' wing- the 'c' denoted the 'universal' wing, a structural configuration, NOT the armament fitted (so it is convenient but inaccurate shorthand to refer to the 'a' or 'b' options). This satisfied the people who had to keep track of spare parts, but it did not help the people who had to keep track of ammunition supply! As it happens it turned out to be effectively a moot point until the intro of the .5" gun. The 'e' suffix was applied as a compromise to denote the modified aircraft, partly for the benefit of the aforementioned armament supply chaps, but you're right that the "standard" configuration did not have the 'c', and it was not (officially) retroactively added to the Mark number.

Steve: I think you've got it about right.

Fernando: The Seafire IIc did have the stub, at least for some production. The fact of the deleted stub on Seafires is worth following up- there is probably a different part number for the single-tube casting, so that might shed some light. Incidentally, the FAA applied the suffix even though all Seafire I were 'b' and all Seafire II were 'c'. Different strokes for different folks!

Mike: I think on the Vc the limitation was performance (and possibly cannon supply), but on the IX it was more of a structural consideration. The stub was no doubt retained in the early stage (Vc) because of armament uncertainty- that was, after all, the whole idea of the 'universal' wing. I think it was kept on the VII and IX for production expediency- that's the way the 'c' wing was designed, and we don't want to have to introduce a bunch of new parts to delete the stub. It was retained on the VIII and XIV for armament uncertainty, and it is possible that the .5" gun issue eventually had some bearing on its being retained on the IX.

Jon, and all: As you can see there's no simple (or single) answer, and there's still a lot of uncertainty about the general issue.

bob

[Miggers]

Hi,

I guess that, the whole rationale of the "c" wing was its flexibility (remember it was called "universal") and perhpas the existing plans for refitting .5 in guns called for the stubs to remain where they were, to keep the chances open. Interestingly, the so-called "c" wing in Seafires II-III-XV has no stub.

FErnando

AFAIK,there was no such thing as a "C" wing on Seafire III-XV-XVII series.

The folding Seafire wing was supposedly quite different than the standard Spit wing,supposedly designed

from scratch rather than an adaptation.

Remember that there is no fixed-wing equivalent Spit for the III-XV-XVII series Seafires,all designed as a Seafire from the outset.

The closest Spits to those series machines are the V for the Merlin variants and the XII for the Griffon(they were "based"on those aircraft).

Mark

[Test Graham]

The point about the Seafire folding wing is taken, but you can get a little nearer than the generic "Mk.V", which did after all cover a number of variants. The closest would be an LF Mk.Vc - which is obviously nearer a Seafire L.IIc rather than an L.III, for the reasons you describe.

The important reason why the universal wing differs from the earlier (and why you did not get a Mk.IXa or Mk.IXb) is that the earlier wing is weaker, and the undercarriage has less strake.

[Edgar]

I read, somewhere (can't find it now,) that the opportunity was taken to use the redundant compartment, in the Seafire III wing, to improve the wing stiffness. David Brown says that the muzzle tube was deleted, and he and Kev Darling (in Crowood's book) reckon that it had 90% of the original wing's stiffness.

Edgar

[Miggers]

The point about the Seafire folding wing is taken, but you can get a little nearer than the generic "Mk.V", which did after all cover a number of variants. The closest would be an LF Mk.Vc - which is obviously nearer a Seafire L.IIc rather than an L.III, for the reasons you describe.

The important reason why the universal wing differs from the earlier (and why you did not get a Mk.IXa or Mk.IXb) is that the earlier wing is weaker, and the undercarriage has less strake.

I've read that too Edgar.

Have a look photos of SX366,you'll see that there isn't any second cannon stubs(though the outer panels came from two other aircraft),

so I reckon that is correct about the use of the redundant space.

You're right Graham.

The Seafire 1b was pretty much a navalised Vb.

The Seafire II was pretty much a navalised Vc,with the LF or L prefix pertaining to either clipped or standard wing tips.

All great fun to nail down a precise airframe due to the fact that the RN had 'em all re-serialed by who ever converted them

(mainly ASTH and Westland's) from their original factory serials.

I know a lot more about Seafires(being an FAA buff)than Spits,but I'm learning due to the likes of your good self

and Edgar

Mark

Edited November 28, 2009 by Miggers

[gingerbob]

All great fun to nail down a precise airframe due to the fact that the RN had 'em all re-serialed by who ever converted them

(mainly ASTH and Westland's) from their original factory serials.

I know a lot more about Seafires...

Mark

Good, I'm sure we'll be able to draw on that knowledge. Only the Seafire Ib was reserialled, because it was the only true conversion (not counting hooked Spitfires, which were "half Seafires"). I've got a theory about Sea Ib serials and quantities- I'd be happy to argue about it with you in private!

One other point about the 'b' vs 'c'- it appears that the cannon port part on the 'b' was outside of the leading edge skin, while the 'c' piece was internal. I just point this out because: 1) I just noticed that 'fact', and 2) it makes it very unlikely that the "no stub" examples were using up surplus 'b' parts, which was one theory. I personally think it was only a retroactive removal of stubs, though I admit that the very small population of IXs with no stub that I've managed to note are in a pretty tight serial/ production date range.

bob

Edited November 28, 2009 by gingerbob

[mike romeo]

All,

At least it doesn't seem to have been a stupid question . . . .

Many thanks to all for taking the time to post. I've learnt a lot . . . I think!

regards,

Martin

[Jennings Heilig]

I am not familiar with Jennings' 'findings' concerning .5" guns in the outer position. I am skeptical, but would like to be enlightened!

It wasn't my finding. I'm just the messenger. The hired gun.

J

[gingerbob]

It wasn't my finding. I'm just the messenger. The hired gun.

J

Yes, but can you point me to where this is discussed or announced? (I'm pretty new around here).

bob

[Dave Gibson]

The Seafire II was pretty much a navalised Vc,with the LF or L prefix pertaining to either clipped or standard wing tips.

Ayup Mark,

I may be wrong, but I believe the L pertains to thetype of engine optimisation. L's having the cropped blower and optimised for low altitude work.

Dave

[Miggers]

Ayup Mark,

I may be wrong, but I believe the L pertains to thetype of engine optimisation. L's having the cropped blower and optimised for low altitude work.

Dave

You're not far off Dave,the Merlin 45/55M was also part of the II's "package"

Mark

[Fernando]

No .5in weapons on a C wing Spitfire, only .303's, the 50 cals only appeared on the E-wing.

The wing is the same ("universal"). But there is no "c" or "e" wing. The suffixes apply to the armament; in that sense, you are right in that there is no "c" with .5 guns. That said, the conversion is a bit radical, but not more so than the four-Hispanos one. It is also true that the unarmed wing of the PR.XI was called "d" wing (but may also refer to the armament -none- fitted)

FErnando

[Andrew Jones]

The wing is the same ("universal"). But there is no "c" or "e" wing. The suffixes apply to the armament; in that sense, you are right in that there is no "c" with .5 guns. That said, the conversion is a bit radical, but not more so than the four-Hispanos one. It is also true that the unarmed wing of the PR.XI was called "d" wing (but may also refer to the armament -none- fitted)

FErnando

The "universal wing" was designed so that one wing could be fitted with either the A armament [ 4x 303 browning ] ,the B armament [ 1x20mm Hispano + 2x303 browning] or the C armament [ 2x20mm Hispano ]. Although the term C wing is usually applied to the version with the small stubs fitted to the outside of the 20mm cannon, the true C armament was intended to be 2x20mm/wing. [ Spitfire the History page 151]

The E wing was different internally , in that various fitting were omited during manufacture,[ie gun heating and pneumatic feeds ] that meant the outer 303 gun bays were no longer functional, this meant it was no longer an "universal wing" as only the 20mm +.5in weapons could be fitted.