Spitfire B Wing vs C Wing question

Just to help understand where the designation Mk IXB may have came from I have a quote from Dr Alfred Price who suggests that the Mk IXB is in fact the LF IX and coincides with the introduction of the Merlin 66 with its lower rated altitude engine. It appears that the RAF may have used the unofficial designations Mk IXa to describe Mk IXs with Merlin 61 or 63 engines, and the Mk IXb with the Merlin 66. The Merlin 66 was first introduced in the spring of 43 with the Biggin Hill wing.

This situation caused confusion in the field as previously the a,b,c suffix had been used to describe the armament fit. Long after the unofficial designations had become commonplace the Ministry of Aircraft Destruction issued the following designations

LF IXC for the Mk IX b
F IXC for the Mk IX a
HF IXC for the Mk IX fitted with Merlin70 and extended wing tips. (not sure if any of these were produced)

The C designation was dropped soon after it was introduced as all Mk IXs had the Universal wing, (that is until the e wing arrived about the summer of 44)

Some of the early MK IXs were conversions of MkVs and could have had the genuine B wing, but I believe they were never designated MkIXBs.

Hope this helps, but my vote goes to all MK IXs having the Universal wing until the arrival of the e wing. As to the chimneys being present or not I have to leave that to those who are lucky enough to examine at close hand those surviving aircraft.

Not to get this going again, but while looking at my copy of Bruce Robertson’s book on the Spitfire, I came across an interesting paragraph:

“A suffix to mark numbers indicated armament. Not until early 1941, when cannons came into general use, did it become necessary to qualify the then standard 8 x 303 machine guns as “A” type armament and the new 2 x 20mm cannons and 4 x 303 machine guns as “B” type armament. When later Universal wings were introduced, origially designed for the Mk. III, that could accomodate 4 x 20mm cannons or “B” type according to arrangement, these were designated “C” type. Later still wing sets to accomodate 2 x 20mm cannon and 2 x .5 machine guns were introduced and these were known as “E” type. The redesigned wings for the Mk 21 onwards accomodated 4 x 20mm cannon with no alternative fitting and no classification was used.

Thus ‘A’. ‘B’, ‘C’, or ‘E’ armament depended on the types of wing fitted, and wings it should be noted were interchangable. WIth the Mk. V where Va Vb or Vc could apply, it was usual to use the appropriate suffix in every case, but with for example the Mk XII where the Universal wings invariably appl;ies, it was not usual to apply the suffix…..

With e.g. Mks. IX, XIV and XVI, it was usual to apply the suffix ‘E’ where appropriate, but not to qualify the alternative ‘C’ armament.”

I guess Mark12 had it figured when he suggested that there was no ‘C’ designations for IX’s

Dan

Mark,
I am not sure where this discussion is going to right now, so it is my turn to say I do not understand 100%.
Are you saying that the Mk IX manual contains two similar diagrams of the cannon arrangment, of which one shows the two “chimney pot” layout, and the other shows the single “chimney pot” layout?
I think there is only one diagram, and it seems to me we have no doubt now that both layouts were in use, so one of them is not shown in the diagram, anyway.

‘Not drawn because not needed’ is high risk in any manual and unlikely in my view be it V.S. Spifire or Triumph Spitfire for that matter.

I believe every diagram in every manual omits some unimportant items for simple clarity. It is just a question of deciding which components are unimportant.
To make myself clear: I believe the only difference between the single “chimney pot” and the twin “chimney pot” wing a Mk IX is the presence or absence of the second stub. Otherwise they are identical. Therefore, for the diagram in the manual, it is immaterial whether the outer stub is shown or not, as it does not affect the way the cannon is mounted, harmonised, etc. If it did affect these questions, there would have to be two diagrams, two sets of instructions in the manual text, etc.
I think the second “chimney pot” was omitted in the Mk IX manual diagram, because the two wing layouts were in use. If this item was shown, the drawing could confuse armourers when working on those Mk IXs that did not feature the outer stub.
Yes, the Mk XIV manual diagram shows the outer redundant stub, perhaps owing to the fact that there was no other wing layout in this Spitfire variant.

Voy Tech,

Quote:-

“Well, not quite. We have a diagram that shows one casting, because with no second cannon there was no point putting the other casting in the diagram (I believe there is no separate drawing set for the two “chimney pot” layout, even though there is no doubt there were Spitfires with such wing design).”

The drawing referred above and posted is dated December 1945!

In the same manual it shows a pictorial drawing with the twin aperture casting, the stub cap and gunheating ducting passing through and consuming the spare bay.

In the parallel Mk XIV manual for November 1944 for the equivalent drawing/diagram of the single 20mm Hispano cannon and the pair of .303 Brownings, it shows the spare bay, twin aperture casting and the cap.

‘Not drawn because not needed’ is high risk in any manual and unlikely in my view be it V.S. Spifire or Triumph Spitfire for that matter. 🙂

Mark

Originally posted by Mark12

Are you saying that there were no single aperture castings fitted to Mk IX at production?

I am saying that many of those without the outer stub may have been modified the way the Americans did in the 52nd FG.

We have the single aperture casting armament layout diagram in the Mk IX manual and that has been posted.

Well, not quite. We have a diagram that shows one casting, because with no second cannon there was no point putting the other casting in the diagram (I believe there is no separate drawing set for the two “chimney pot” layout, even though there is no doubt there were Spitfires with such wing design).

We have a number of Mk IX photographs from non US loaned stock with no second stub visible.

Which may be either from production, or from local modification.

I believe they were produced at a sub contractors factory like this. There may be mixed aperture batches within serial bands but I think a subcontractor using up available stock of castings and leading edge skins could account for this.

Yes, I believe so, either.
You have always assumed (or so it seems from your input in this discussion) that the single “chimney pot” Mk IX wings were manufactured as such.
I have always assumed otherwise: that they were all modified this way after delivery.
The conclusion now is, I suppose, that there were both kinds: production ones and modified ones.

I suppose you know a lot more than we all here about Spitfire production organisation, subcontractors etc. What is interesting for me now is to establish which batches of Mk IXs were built with these wings. I thought the MA800-MH434 serial range looked a good starting point for this kind of research.
So any addition to my list of identified no-stub Spitfire IXs would be welcome. Of those I listed:
the photo of BS340 I have was taken some months after the Spitfire was repaired (cat. AC damage), and the wing may be altered (or a new wing fitted as a replacement)
BS342 and the apparent BS354 are both Mk IXs modified in the Med for high altitude interceptor duties, so the outer chimney pots may have been removed in the general effort to make the airframes lighter
BS546 is a mystery (the Mov Card mentiones ‘modifications’ during late 1942, but this would rather be fitting the camera gun)
MA706 is a late 1944 photo in Italy – with the gaps in ME Mov Cards there is no way to tell what happened to this Spitfire between delivery and the time of the photo.
That is what makes them all doubtful. All the other ones are shown not long after delivery and in Britain, where Mov Cards are much more specific about repairs, modifications, etc.

Mark

Read the last few paragraphs again – at the end he said:

“At some point it was decided to discard the second 20 mm cannon in Mk IX (this was decided quite early in trials of the variant and was beacuse of CoG problems, not heating, as far as I remember). For this reason designers altered the wing structure to do away with the second ‘chimney pot’. But then the (e) weapon fit was devised, so the second ‘chimney pot’ became useful once again, and went back in production.”

Interesting stuff, chaps!

Ed

Voy Tech,

I am not sure if I have understood 100% correctly.

Are you saying that there were no single aperture castings fitted to Mk IX at production?

We have the single aperture casting armament layout diagram in the Mk IX manual and that has been posted.

We have a number of Mk IX photographs from non US loaned stock with no second stub visible.

I believe they were produced at a sub contractors factory like this. There may be mixed aperture batches within serial bands but I think a subcontractor using up available stock of castings and leading edge skins could account for this.

Even with the Mk IXe wing, the gun bay panels and basic structure for the .303 outer machine guns are still there.

As to the US aircraft I am sure you are correct. With every fraction of a mile per hour being perhaps the difference between living or dying I am sure some US field engineer said “flush ’em off like those other aircraft”. A ‘messy’ job in engineering terms and probably done by drilling and tapping the casting with half a dozen 6BA countersinks to hold down a local piece of 10swg cover and a generous splodge of filler, or ‘bondo’ as the yanks call it, to smooth it over.

Mark

Again, of the aircraft of which I have experience.

AR614 – Vc had the 2 castings – although these had been cut off at some time in the past in a very poor manner. We reinstated them.

In other words, they were not readily removable, as they are a casting around which the leading edge skin fits. That doesnt mean they could not be removed in service, and then faired over as suggested above.

Now, some conjecture:

There has been a mention of the 2 cannon positions not being used due to inadequate heating on the Mk 5 – this is logical, as the Mk5 relied on heating ducts from the coolant radiator, across (on one side) the fuselage, through the wing, and into the cannon bay – not very efficient.

With the advent of the Mk9, the cannon bays were fed from each radiator, and hence the heating must have been more efficient.

So in theory, there should be no reason why the Mk9 could not carry the 2 guns if required.

Thoughts??

Bruce

Hello everyone,

Away from my computer for the weekend, I was doing my home work, anyway. I am much pleased to say I reached most of the same conclusions that you did.

In case you thought the matter was all explained and clear now, a few more comments.

As per fitting 4 0.303 Brownings in a C wing: the Mk V manual (the one reprinted and sold in bookshops) actually includes a drawing of how this is to be done.

About the universal (C) wing without the outer stub:
Close look into Ventura’s “American Spitfire Camouflage and Markings. Part 2” reveals that many Mk VC and Mk IX Spitfires of the 52nd FG had these outer stubs removed and the openings faired over in a not too careful way (photos on pp. 19, 23, 24, 27, 29, 38, 43). Curiously, none of the Mk VC and Mk IX Spitfires of the sister 31st FG (shown in “Part 1” of the same publication) lacked these stubs. This seems to prove that the outer stubs could be removed when required, and that at least in the USAAF it was a matter of unit policy rather than production.

I have also checked my library and photographic archive for any identifiable Mk IXs with these stubless wings.
I found four early F.IXs of Supermarine proper:
BS340,
BS342,
possibly BS354
BS546
But there are photos of other Mk IXs in the same serial range that feature the stubs very prominently, so it seems unlikely this was a production standard – to me their stubs were removed in service.

But I also found at least seven (possibly eight) CBAF built Mk IXs:
MA706,
MA807,
possibly MA834,
MA843,
MH314,
MH353,
MH378,
(Mark, do you have early photos of MH415?),
MH434.
Clearly, the latter sequence is noteworthy – they were all delivered by Castle Bromwich Aircraft Factory in the summer 1943. MA706 served in the Mediterranean, so may have passed through the butcherous hands of the 52nd FG (MA743, MA747 and MA791 in Britain had their outer stubs in place). In any case, I found no photo of a Mk IX in the MA800-MH434 serial range with these stubs on! Therefore I now have little doubt that such a variation existed in production. So, I come back to my earlier hypothesis:
At some point it was decided to discard the second 20 mm cannon in Mk IX (this was decided quite early in trials of the variant and was beacuse of CoG problems, not heating, as far as I remember). For this reason designers altered the wing structure to do away with the second ‘chimney pot’. But then the (e) weapon fit was devised, so the second ‘chimney pot’ became useful once again, and went back in production.

One last thing. Have you noticed that all the official reference to Mk V wing variants is in capitals: Mk VA, VB, VC. But the weapon fit in Mk IX/XVI is invariably ‘(e)’, not ‘E’? Would that be insignificant?

I do believe we’ve reached a consensus.

Thanks Mark and all. I very much enjoyed the mutual detective work, opinions that went into this discussion.

Gotta love learning something new too 🙂

Dan

It just got much heavier

Dan,

I just re-read a chunk of the Mk V manual.

The wing as fitted to the Mk Vc is capable of being configured in three dispositions per wing

2) Single Hispano and two .303 Browning.

3) Twin Hispano (With no .303 Browning)

AND

1) Four Browning .303 with the two inboard guns mounted in the same position as the two Hispanos and close together, unlike, and totally different positioning to, the Va.

Totally ‘Universal’.

So we have two set ups for four .303 Browning. I believe you have alluded to this in your postings and I had not picked it up. I can’t believe however that this 4x.303 in the Vc was ever implemented in service.

So ‘Mr Project Engineer’ you are sitting at you drawing board at CBAF or Supermarine.

We want a wing for this new Mk IX Spitfire. It has a more powerful engine and an intercooled supercharger. Right, lets take the Mk. Vc Universal wing as a starting point. A bit of extra strength here, a bit of extra strength there. Upgrade the u/c and it’s mountings. Dump the cylindical oil cooler fixing there and replace with a symetrical set. Mount the twin symetrical main radiators and the intercooler radiator and its matching volume intercooler radiator. We have a problem with the twin Hispano per wing installation you say? We can’t keep the oil warm – it jams. Fine, for the time being then we will just fit this single aperture ‘chimney pot’ that we used on the Mk Vb. until you get it sorted as it is lighter and cheaper than the twin and we have an excess of the Vb leading edge skins in production. Ah! Now that we have twin main radiators, as opposed to the single main radiator in the Mk V, we will be able to get more heat ducted over that second Hispano. Tell me when you have developed and fixed it and we will change the casting to the twin. We will probably be changing it anyway in the near future as we are going to dump the two outer .303 Brownings and replace them with a single .5 Browning adjacent to the cannon. We will call this single Hispano and single .5 Browning per wing the ‘e’ armament and then we better refer to them as ‘early’ and ‘late’ Mk IX aircraft to differentiate them in the manual. Oh and while you are at it, tell Organisation and Statistics Branch we want them to put ‘e’ on the Movement Cards of these later aircraft so that we can move and place them in squadrons with tactical and logistical commonality.

We better talk to the Mk XII design guys. They have got a similar problem to us but they haven’t got a second main radiator. Oh well, they are only going to build a few of them for low altitude Home Defence, as a stop gap measure, and they will be replaced by the Mk XIV Griffon anyway.

Well something like that. 🙂

Mark

Just another tidbit that might explain the lack of a second chimney pot, at least for a while on the MK IX.

I was trying to figure out why the XII was ‘restricted” to the 2 cannon, 4 303 machine gun set up.

A comment by Jeffry Quill seems to explain it in his book “Spitfire”.

“Although the Spitfire VC(with the Universal wing) had provision for 4 cannon, it was normally possible to fit only two, because heating for the outboard cannon was inadequate.”

Two things from that comment. Once again the use of “Universal wing” vs C Wing, along with the reference to the Spitfire Vc.

Second is the reference to the inadequate heating for the outboard cannon. I would assume that early IXs like the XII were restricted to home use as they would not have been tropicalized like the VIII. Knowing this would have made it initially pointless to have that second chimney pot as it wasn’t going to carry a second cannon anyway. Yet both the XII and IX used the universal wing.

It also seems to clearly support the notion that what we have been calling a C wing, was in fact the Universal wing, that happened to be connected to the Spitfire VC, leading to the mistaken reference that it is a C Wing.

Dan
Managing to bump this back up at the same time 🙂

Originally posted by Mark12
Dan, Voy Tech, Bruce et al,

So far as I can tell, Bruce, it seems to me, the XIV and XVIII are referred to ‘e’ armament, not ‘e’ wing. That is provision to carry the .5 Browning adjacent to the 20mm Hispano cannon.

Yet another trawl through the books is enlightening. The mammoth combined Spares Schedule for Mk V & IX has clear sections for Va, V b & Vc but only one section for Mk IX. Ditto the Pilots Notes as already mentioned.

The more I dig into this the more I am inclined to think there never was a Mk IX a, b, or c. Just Mk IX. With the introduction latterly of the .5 Browning installation we see reference to the Mk IXe and from thence on they are referred to and distinguished as ‘early and late Mk IX aircraft’.

From the Mk IX manual diagrams, which are not full engineering drawings, the basic construction and layout for both single and twin cannon aperture ‘chimney pot’ types are effectively the same. In all probability the twin is an iteration of the single aperture design to provide provision for twin Hispanos per wing for potential tactical requirement. As we now know, for the RAF in WWII, they were not needed on the MK IX and were blanked off, and the reason clearly is that the later installation and hitting power of the massive .5 Browning compared to the .303 was the optimum combination for tactical superiority for the Merlin Spitfire.

I suspect it us latter day ‘historians’ who have quite logically transferred the clear designators of ‘b’ and ‘c’ armament from the Mk V over to the Mk IX and I suspect we were wrong.

The challange:-

Who can find or locate any official document of any type were there is reference to a Mk IXb or Mk IXc Spitfire?

Mark

I think you are on to something Mark.

I can only go back to the Mk XII manual as I don’t have one for the IX, but I would suspect the introduction for the Mark IX is similar.

“1.The Spitfire F. Mk. XII(NOTE NOT XIIC) is a single seat fighter, low-wing monoplane powered by a Griffon III or IV engine, driving a Rotal four blade, 35 degree pitch range, constant Speed propeller.

2.The aircraft is fitted with the universal wing type main plane as fitted to the Spitfire VC…….”

That may be the key. No mention of XIIC, just XII, fitted with a Univeral wing, not C wing, but referencing the Spitfire VC

I’d just about bet the house the IX manual says the same and us historian types did exactly what Mark12 suggests by making the connection to the VC even though it isn’t offically called an IXC or XIIC for that matter.

SO MH434 for example was just an LFIX that had a universal wing that had a single aperture ‘chimney pot”

Does this mean we now have to send all the books back to the printers to correct this? 🙂

Dan

Sadly, I have scant original documents on the Spitfire. I have to keep it all in my head, which is getting rather cluttered these days.

I remember the parts manual – in fact the Mk9 section was published as an addendum to the Mk5, so perhaps thats where the confusion arose – ie if there was Mk5 a,b,c, it must transfer over.

Dan, Voy Tech, Bruce et al,

So far as I can tell, Bruce, it seems to me, the XIV and XVIII are referred to ‘e’ armament, not ‘e’ wing. That is provision to carry the .5 Browning adjacent to the 20mm Hispano cannon.

Yet another trawl through the books is enlightening. The mammoth combined Spares Schedule for Mk V & IX has clear sections for Va, V b & Vc but only one section for Mk IX. Ditto the Pilots Notes as already mentioned.

The more I dig into this the more I am inclined to think there never was a Mk IX a, b, or c. Just Mk IX. With the introduction latterly of the .5 Browning installation we see reference to the Mk IXe and from thence on they are referred to and distinguished as ‘early and late Mk IX aircraft’.

From the Mk IX manual diagrams, which are not full engineering drawings, the basic construction and layout for both single and twin cannon aperture ‘chimney pot’ types are effectively the same. In all probability the twin is an iteration of the single aperture design to provide provision for twin Hispanos per wing for potential tactical requirement. As we now know, for the RAF in WWII, they were not needed on the MK IX and were blanked off, and the reason clearly is that the later installation and hitting power of the massive .5 Browning compared to the .303 was the optimum combination for tactical superiority for the Merlin Spitfire.

I suspect it us latter day ‘historians’ who have quite logically transferred the clear designators of ‘b’ and ‘c’ armament from the Mk V over to the Mk IX and I suspect we were wrong.

The challange:-

Who can find or locate any official document of any type were there is reference to a Mk IXb or Mk IXc Spitfire?

Mark

As I understood it, the ‘E’ wing was the Universal one, although it is similar in many respects to the ‘C’ wing.

The major difference would be the provision of oil cooler on one side for the Mk 5, which is a very different structure to the radiator housing structure.

Perhaps the ‘E’ designation was born with the Mk9??

Mind you, to further complicate matters, the XIV and XVIII had somewhat different wings, in terms of spar design and some internal structure, but they too are referred to as E wings. I have also seen a XIV with holes in the l/e for .303 in the outboard positions.

Bruce

Re: Is ‘e’ or nothing?

Originally posted by Mark12
Ok let’s try this.

In the armament section when discussing ‘early Mk IX aircraft’ it does not mention a suffix. When discussing’ later Mk IX aircaft’ it mentions (e) armament .

Here is the first para. of the ‘Introduction’ of the Mk IX manual at level March 1945 when all aircraft have been built.

Note that : – ‘and suffix letters indicating special armament’ .

So the suffix refers to armament and not to the wing.

Whilst this may have been precise in the Mk V manual with designations ‘a’, ‘b’, & ‘c’ it is not so defined on the Mk IX or indeed the MK XIV.

Just looking at a random selection of Movement cards of IXs and XIVs, ‘e’ appears in the designation with later aircraft but in those I have studied there is no ‘b’ or ‘c’ designator

Indeed it may just be that it was ‘e’ or nothing officially and that we have carried over the generic from the V.

For some they have carried over the perception of wing structure for others the pure armament fit capability.

They key to this discussion will be a study of the early and mid period Air Publications for the Mk IX.

Mark

Would we agree that the internal structure of the early Spit IX wing was the “Universal” wing? This then was what was referred to as the “C” wing on the Spitfire V but may not have been called specifically that with the IX as your latest info may indicate?

It makes sense that for production reasons they would not have gone back to producing the wing that was the “B” wing for the Spit V, due to the different internal design. In particular as the “Universal” wing allowed for twice the ammo load per cannon.

Dan

If I recall correctly, this to is how they are described in the IX & XVI Pilots Notes.

Cheers

Paul

Is ‘e’ or nothing?

Ok let’s try this.

In the armament section when discussing ‘early Mk IX aircraft’ it does not mention a suffix. When discussing’ later Mk IX aircaft’ it mentions (e) armament .

Here is the first para. of the ‘Introduction’ of the Mk IX manual at level March 1945 when all aircraft have been built.

Note that : – ‘and suffix letters indicating special armament’ .

So the suffix refers to armament and not to the wing.

Whilst this may have been precise in the Mk V manual with designations ‘a’, ‘b’, & ‘c’ it is not so defined on the Mk IX or indeed the MK XIV.

Just looking at a random selection of Movement cards of IXs and XIVs, ‘e’ appears in the designation with later aircraft but in those I have studied there is no ‘b’ or ‘c’ designator

Indeed it may just be that it was ‘e’ or nothing officially and that we have carried over the generic from the V.

For some they have carried over the perception of wing structure for others the pure armament fit capability.

The key to this discussion will be a study of the early and mid period Air Publications for the Mk IX prior to the introduction of the single .5 Browning.

Mark

Another thing

Changing the castings on the leading edge would be one thing.

But the gun bays on the B and C wings are very very different.

Outboard of rib 5 behind the spar is completely different on the B and C wings, and so you could not very well convert one sub type to another.

Cheers

Bruce