Early cannon-armed Spitfires

[Edgar]

The wings were built separately, in pairs, and would have been attached to the fuselage during final assembly, when all major parts were brought together.

The armour was attached to the seat, so would have gone in when the seat went in. The seat, when fully armoured, takes three men to handle it, since it can only be removed when it's at the bottom of its travel, and must be lifted straight up (which takes two,) then handed to the third man on the floor.

Years ago, a former "erk," who'd been based at Benson, told me that removing the seat was the one job that they hated most; he, especially, loathed it, because, being only about 5' tall "and considerably slimmer, then," he always got the job of sliding down inside the fuselage, to do any work. One day, his mates quietly replaced the seat, while he was working, and went off to the NAAFI, leaving him, as they thought, trapped. He found, though, that he could slide right down to the end, and wriggle out of the rear hatch, giving his mates a huge surprise when they walked in. He told them how he'd done it, and regretted it, ever afterwards, because they would then feed him up through the hatch, leaving the seat in situ.

Edgar

[johnd]

On 05/10/2012 at 13:09, Edgar said:

This is the drawing, for the underside bulge, and it's dated October, 1940, so seems likely to have been fitted to the IIb & Vb, at least. The legend, in the top l/h corner gives its application as mod 260, which applied to the cannon to be fitted to the Mk.I.

As well as the bulges, top and bottom, there was an extra control fitted on the starboard wall of the cockpit; this consisted of a square box, with pipes running up to, and down from, it, with a turnkey on its face. This enabled the pilot to cock the cannon while in flight.

Edgar

 

Forgive me for resurrecting an old thread but does anyone have a copy of Edgar's photo that I could have a look at by any chance?

I'm at the point where I should be looking to reshape the underwing bulges on my Ib.

 

Thanks,

John.

[Troy Smith]

someone will have the drawing saved, I  may have 'somewhere' ...

but, have you seen this

 

note the bulge shape on this, 

 

 

 

which I believe is the early bulge shape

HTH

T

[brewerjerry]

Hi

    might be something here in the collection of edgar info/notes 

http://www.jonbius.com/edgar-brooks-spitfire-notes/

   cheers

     jerry

[johnd]

Thanks, Troy, the bulge does look thinner than is usual for a Mk.V. I'll model mine on that if the drawing doesn't turn up.

 

Cheers, Jerry, nothing there unfortunately but plenty of other things of interest!

 

John.

[gingerbob]

IF I can get it to work (Photobucket much worse than last time I tried to do this!), I think this is the drawing.  Very poor resolution, unfortunately.

 

[johnd]

Thanks, gingerbob, that's great.

 

John.

[Troy Smith]

19 hours ago, Troy Smith said:

someone will have the drawing saved, I  may have 'somewhere' ...

but, have you seen this

 

note the bulge shape on this, 

 

 

 

which I believe is the early bulge shape

HTH

T

 

2 hours ago, gingerbob said:

IF I can get it to work (Photobucket much worse than last time I tried to do this!), I think this is the drawing.  Very poor resolution, unfortunately.

 

note the shape in the drawing is quite different to the photo I posted, which was a Ib, later converted to a Vb

The drawing looks a lot like the standard underwing B bulge,  as seen on BM597 here

 

any ideas bob?

 

[gingerbob]

Only that I had pretty much the same idea, without looking for an alternate underside view!  Thanks for confirming my suspicion.  There was a second drawing, but it looks even less like either bulge.  The date of that second drawing was also April '41.

 

bob

[Graham Boak]

April 1941 seems very late for a drawing of the early bulge.

 

Also, I rather doubt that the earlier wings were reused on the aircraft once they became Mk.Vs.  Apart from the outer wing gun problem, it would leave a handful of oddball airframes floating around in the system, at the cost of a significant oddball rework programme.  Logically, they changed the wings with the engine.  Fortunately, in RAF service the main fuselage carries the identity.

[gingerbob]

I disagree, Graham.  I recall no mention of the need to re-wing them, first of all, and I suspect that (once all the tweaking was done) there was functionally little difference between these initial aircraft and production 'b' wings.  Furthermore, where did these replacement 'b' wings come from, when they were not yet in production at the time the Merlin 45s were fitted?

 

Just to be clear, it was "the other drawing" that was dated April '41.  I can't read the date on the one I posted, but if it is the right one, then Edgar said October '40.

[Graham Boak]

Which could hinge on just how much work was required to move from the initial wing to the B wing.  If it was genuinely 'only two cannon', that implies more work than some fudge where the majority of the structure and internals was still that of the A wing.  It may have needed no more than a new leading edge and some rewiring.  Then there is the matter of the changes to cope with the differences between a feed that didn't work properly to one that did.  The initial cannon wing wasn't "in production" but were hand-made (or at least modified) examples- why not the same for the early B wing examples?

[viscount806x]

Just to firstly apologise for resurrecting this thread. I'm looking at the two styles of underwing cannon blisters supplied in the current KP Ib/IIb/Vb kits. They are suggesting the 'kidney' shaped fairings for early cannon a/c. I don't have a Vb kit so unsure which pair they suggest for those issues but I'm suspecting the later 'teardrop' for the Vb.Perhaps early production Vbs had the kidney shapes too. If so, any ideas on serial batches etc.?

 

The Edgar drawing has gone but Troy has kindly posted it above again and it certainly has an assymetrical profile but not nearly so 'kidney' shaped as those in the KP kits.

 

Also, at the very start of the thread, the originator talks about a Rotol prop  for his IIb model but the few photos I can turn up all show DH props although I would assume Hydromatic CS versions by this stage. Someone else on BM said this recently too but I can't find it, sorry.

Cheers, N

[Graham Boak]

Given that there was a feed difference between the early unsatisfactory cannon fit and the later successful one, I'd very much doubt that any B wings were made with the early feed, and thus the early bulge.  Yes, the teardrop shape is the right one for the B wing.

 

As the photo of QJ.S shows outer machine guns, I believe that this photo dates with the others of GJ.S to after the reengining with M45s.  If this bulge differs from the standard bulge on the B wing then this would back Bob's point of the original wings being re-used, but not that this shows the original bulge.  This could be a pre-production bulge for these reworked wings.

[gingerbob]

2 hours ago, viscount806x said:

Also, at the very start of the thread, the originator talks about a Rotol prop  for his IIb model but the few photos I can turn up all show DH props although I would assume Hydromatic CS versions by this stage. Someone else on BM said this recently too but I can't find it, sorry.
 

 

Probably me- I seem to bring it up on a regular basis.  I HAVE seen some IIBs with Rotols (memorably shortly after I said something like "I don't think I've seen any..."), but those might have been fitted later.  Certainly the majority of photos I've seen show them with DH (and I'd say "original style" DH) props.

 

Graham, I agree that the photos of QJoS show it as a Mk.V, I think because I've seen a date connected to the photos somewhere along the way.

 

I'll dodge the "underside bulge" question, because I frankly don't have any trustworthy arguments.  Note, however, the small, slim bump that I THINK I see just outboard of the big bulge.  (I've got an idea that I finally recognized the extra bump on a relatively clear version of that photo, and it is easy to imagine the asymmetrical production bulge covering that area.  It may be geometrically impossible, but it's easy to imagine!)  I've never made a very diligent search of b-wing bottom views, looking for shape variation.

[Steve in Ottawa]

Somewhere on a hard drive I have photos of the underside of the wing of the Canadian War Museum's Mk. IIb (P8332) which is on display on an elevated platform here in Ottawa. If I find it I'll post the picture up here. I searched online and found a few ground-level photos but you don't get a good view of the cannon bulge arrangement.

[gingerbob]

I'd love to see that, Steve.  I may even have a similar photo somewhere in MY computer!  My prediction is that any Castle Bromwich 'b' wing will be the "later" (which may in fact be "production standard") shape.  Actually, now that you mention it, that is one Spitfire I have yet to see in person, and I'd really like to.

[Steve in Ottawa]

Okay, I'll dig for it in the home office hard drive later today. Unfortunately the room is adjacent to the bedroom where SWMBO is sleeping for her night shift at the hospital. I fear for my life if I wake her up; I'm sure you understand.🤫

Edited April 11, 2020 by Steve in Ottawa

[viscount806x]

Hello and thanks to all for the interest in my question. Obviously this is a grey area even after all this time. Going back to the KP kits, they seem to know what bulges are to be used on whichever model is depicted. Where did they get their information, one wonders ?   If Steve in Ottawa (lovely city by the way, know it well) can come up with the underside of a IIb and if it is in orginal condition, i.e. not modded, then that at least might open the door to a partial answer anyway

[Graham Boak]

Not really, as the early cannon aircraft were Mk.Is not IIs.

[viscount806x]

50 minutes ago, Graham Boak said:

Not really, as the early cannon aircraft were Mk.Is not IIs.

The 'partial answer' I was referring to would be that the IIb had the early kidney shaped under wing fairing. That would just leave the question mark over whether some early Vbs had same, part of my original open question. I am aware that some Vbs were built up from previously built Ib and IIb airframes, by the way.

[Graham Boak]

But the early faring covers the early feed mechanism, which didn't work.  Only the first handful of Mk.1s had this mechanism.  The later mechanism required the later fairing.  All aircraft with the b suffix had the b wing with the later mechanism and fairing.  The early aircraft were not titled Mk.1b, this is a later and mistaken assumption.

[Steve in Ottawa]

...

Edited April 12, 2020 by Steve in Ottawa
can't figure our how to delete post

[Steve in Ottawa]

Well, a quick search on the other computer didn't turn up the desired Canadian War Museum images I took, so a deeper search is underway as I type this. Here are a couple of shots of P8332 when it was photographed in the 1960's at the then-National Aviation Museum in Ottawa. This is certainly a rebuild/restoration so there are a number of odd features on the aircraft that are "not on" for this variant or even for a Spitfire. However the lower wing bulges are visible, so hopefully they advance the conversation until I can find the desired imagery.

 

DND Canada photo PL-144713

 

DND Canada photo PL-144714

 

And if you're dismayed by the incorrect features seen above, here is the same aircraft prior to the restoration, on display at RCAF Station Borden, Ontario. I don't have a date for the photo, but I'm guessing it's in the 1950's or maybe the early 1960's

 

DND Canada photo PCN-202

 

[gingerbob]

40 minutes ago, Graham Boak said:

But the early faring covers the early feed mechanism, which didn't work.  Only the first handful of Mk.1s had this mechanism.  The later mechanism required the later fairing.  All aircraft with the b suffix had the b wing with the later mechanism and fairing.  The early aircraft were not titled Mk.1b, this is a later and mistaken assumption.

 

I don't know that the explanation has to be so cut-and-dried.  As for the suffix, there's another explanation: by the time the "a/b" suffixes were officially promulgated, the cannon Mk.Is had become the first Mk.Vs.  Thus there was no [perceived] need for a retroactive "Mark IB" designation.  That doesn't stop people from extrapolating, of course.