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Test Graham

Gunsmoke stains on Spitfire leading edges

57 posts in this topic

Enthusiasts of weathering on WW2 aircraft often add significant staining from the leading edge machine gun positions. It has been pointed out that although staining can be seen from the cartridge ejection slots, the nature of the Browning gun means that such staining would not appear at the leading edge, and is not visible in photos.

I refer you to pages 59 and 60 of Wojtek Matusiak's new Polish Wings 15: Supermarine Spitfire Mk.IX 1944-45. It's a good book if you like Spitfires. If you like late war Spitfires in Polish squadrons, it's a great book. On these pages there are seven photos of MH674, RF.A, which the author describes as "extremely dirty", and shows dark streaks underneath the wing, both from the ejection slots AND from the leading edge openings. The artist of the adjacent profile clearly disapproves of this, for he has left this detail off his artwork!

I feel that the term "extremely dirty" should be qualified "for a UK-based Spitfire": I'd say it was only "somewhat scruffy" and there are photos showing a lot worse on overseas Spitfires. However, in adressing modellers of Spitfires that appear to come out of a coal mine, it'll no longer be possible to claim that stains from the leading edge never happened.

Edited by Graham Boak

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Just a casual look through Osprey's Aircraft of the Aces 12 - Spitfire Mark I/II Aces (Alfred Price) turns up a few instances of stains leading back from the Browning muzzles - eg pages 14,35,77.

So I expect plenty more can be found.

They are in the minority, which suggests that the staining isn't much, and most units would try to clean it off.

In other words, 'significant' staining on leading edges are just as wrong as over done panel lines, they need to be subtle if done at all IMHO.

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Graham, Graham, what are you thinking? "everybody " "knows" that all WWII air craft had great gobs of oily/soot and black powder trails all over the wings and exaust areas (exausts are "always" rust color too). Why, next you'll be trying to have us belive that Sky is/was a real color a2699520.gif tisk, tisk

So, Here you are flying in the face of all the current "wisdom".......

........GOOD CALL getsmileyCA01OWOH.gif

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ncb86w.jpg
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Just a very random thought which literally came to me, but would the level of "gunsmoke" staining around a gun port be subject to the percentage of tracer round in the ammo mix.

I mean, its got pyrotechnic mix in the bullet base so it burns from the back when fired - so the more tracer in your ammo mix - the more "staining" you might get??

Cheers

Jonners

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Just a very random thought which literally came to me, but would the level of "gunsmoke" staining around a gun port be subject to the percentage of tracer round in the ammo mix.

I mean, its got pyrotechnic mix in the bullet base so it burns from the back when fired - so the more tracer in your ammo mix - the more "staining" you might get??

Don't confuse tracer(rarely used, despite what Hollywood would have you believe) with incendiary; tracer contains a material which burns off as the round travels, affecting its trajectory, while incendiary usually has a ball-bearing nose, which is forced into the inner charge, so that it explodes on impact. If a pilot has tracer, and adjusts his aim to allow for its trajectory, it's possible that he would miss with everything else, while incendiary explodes on impact, with a bright flash, which tells him that his aim is correct.

Note this result of a meeting held in 1942, which altered the "care" system for Spitfires, from the end of 1942, especially with regard to paragraph 9, concerning the previous state of affairs:-

Spitfiresmoothpaint19421-Copy.jpgSpitfiresmoothpaint19422-Copy.jpg

This is almost certainly why you will see a huge difference between the condition of Spitfires of the Battle of Britain era, and the less frenetic periods following (with the exception of Malta, the desert and Australia, one suspects.)

Edited by Edgar

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I refer you to pages 59 and 60 of Wojtek Matusiak's new Polish Wings 15: Supermarine Spitfire Mk.IX 1944-45. It's a good book if you like Spitfires. If you like late war Spitfires in Polish squadrons, it's a great book. On these pages there are seven photos of MH674, RF.A, which the author describes as "extremely dirty", and shows dark streaks underneath the wing, both from the ejection slots AND from the leading edge openings. The artist of the adjacent profile clearly disapproves of this, for he has left this detail off his artwork!

Stratus Books, the publisher of this book, provides a few preview pages in PDF including these pictures (in low quality):

Stratus Book preview PDF

The quality is pretty low, but one can estimate, what's going on.

I haven't got this book yet, but I do have 1942-43 Spitfire IX part and it is really great publication.

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I'd assumed it was a given that the airflow around the guns, of every type, would have carried tiny fragments of metal chipped off the projectile during firing. As with engines, this means that over time, this build up of tiny, oxidising and oxidised flakes of metal would become visible. Mixture of browns and greys (maybe very slight green - brass?), I suspect, around the guns, and a more oily (gloss black) mix, but still containing rusting flakes of engine, around the exhausts. I find the muck in the bottom of a well-used pot of white spirit usually works well for other staining, such as around fuel and oil access points, as these areas don't get exposed to flakes of metal...

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It's funny how the subject of gun staining on Spitfires seems to draw some of the most bitchy comments, and also brings in the anti-panel line wash contingent - often from the ones trying to tell everyone what's right and what's not.

What is wrong with someone building the model their way and leaving out the condescending attitude, whichever side of the fence you're on. Would it raise your blood pressure that much to do so? :shrug:

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Nothing at all wrong at all with building your model any way you like: just don't then show it off and leave the less well informed to assume they really were that way. The real problem is the public diffusion of duff information. People really do model from models, not from looking at the real thing. Myths spread and become embedded.

Besides, if something looks crap are we all forced into Trappist silence about it? Are only positive views permitted in the modelling world? Are queries and discussions to be completely banned? It seems some posters would prefer it that way.

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I have to agree, model your build the way you want to, and damn the torpedoes.

What makes my eyes roll though is when someone does over the top weathering a la spanish method, and people leave comments saying how realistic it looks, and it clearly isn't when compared to the real deal.

regards,

Jack

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Nothing at all wrong at all with building your model any way you like: just don't then show it off and leave the less well informed to assume they really were that way. The real problem is the public diffusion of duff information. People really do model from models, not from looking at the real thing. Myths spread and become embedded.

Besides, if something looks crap are we all forced into Trappist silence about it? Are only positive views permitted in the modelling world? Are queries and discussions to be completely banned? It seems some posters would prefer it that way.

As usual, you take the opposing view to the extreme to ridicule it - the oldest trick in the book. At the start of your post you are basically telling people that if they don't model to your standards and using your techniques that they are to stay away from any forums lest you unleash your particular blend of vitriol on them? How conceited is that? What gives you the right to demand that? :mental:

Let's take a rather more rational approach. Let's all be polite to eachother and get along well without the point scoring that seems to be some modellers' raison d'etre. By all means tell someone you think they've done something "wrong", but use some tact and courtesy, instead of the usual belittling that goes on. If that could be done, everyone stands a chance of learning something and possibly even making friends rather than enemies.

Of course, this method is practiced already by the vast majority of people, but there are always a few, a rather less glorious few than THE few, that revel in asserting their "superior" mode of modelling over the rest. To use your trick of taking it to the extreme... the joyless modelling Nazi.

I despair. :fraidnot:

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As usual, you take the opposing view to the extreme to ridicule it - the oldest trick in the book. At the start of your post you are basically telling people that if they don't model to your standards and using your techniques that they are to stay away from any forums lest you unleash your particular blend of vitriol on them? How conceited is that? What gives you the right to demand that? :mental:

Let's take a rather more rational approach. Let's all be polite to eachother and get along well without the point scoring that seems to be some modellers' raison d'etre. By all means tell someone you think they've done something "wrong", but use some tact and courtesy, instead of the usual belittling that goes on. If that could be done, everyone stands a chance of learning something and possibly even making friends rather than enemies.

Of course, this method is practiced already by the vast majority of people, but there are always a few, a rather less glorious few than THE few, that revel in asserting their "superior" mode of modelling over the rest. To use your trick of taking it to the extreme... the joyless modelling Nazi.

I despair. :fraidnot:

Sorry but I just dont get this approach? If you see a film you think is crap you say so, if you see an artwork you think is crap you say so, if you read a book you think is crap you say so, if you listen to music you think is crap you say so, why should models, built (or unbuilt for that matter) be any different? Are we modellers so fragile that we cant take any criticism?

Andy

Edited by andym

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Sorry but I just dont get this approach? If you see a film you think is crap you say so, if you see an artwork you think is crap you say so, if you read a book you think is crap you say so, if you listen to music you think is crap you say so, why should models, built (or unbuilt for that matter) be any different? Are we modellers so fragile that we cant take any criticism?

Andy

Did you even read my post?

By all means tell someone you think they've done something "wrong", but use some tact and courtesy, instead of the usual belittling that goes on.

I rather thought that this sentence says it all. It's not about the criticism, but about the way it's presented. What's difficult to grasp about that? It's called common courtesy.

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Just a very random thought which literally came to me, but would the level of "gunsmoke" staining around a gun port be subject to the percentage of tracer round in the ammo mix.

I mean, its got pyrotechnic mix in the bullet base so it burns from the back when fired - so the more tracer in your ammo mix - the more "staining" you might get??

Cheers

Jonners

Tracer illuminates some distance in front of the muzzle though, so the composition shouldn't be leaving any staining on the aircraft.

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I'd assumed it was a given that the airflow around the guns, of every type, would have carried tiny fragments of metal chipped off the projectile during firing. As with engines, this means that over time, this build up of tiny, oxidising and oxidised flakes of metal would become visible. Mixture of browns and greys (maybe very slight green - brass?), I suspect, around the guns, and a more oily (gloss black) mix, but still containing rusting flakes of engine, around the exhausts.

But the $64,000 question is, how much time? Aircraft had a strict regime of servicing intervals, which started at around 24 hours flying time. In combat mode, a Spitfire's endurance was about 45 minutes, 2 hours at cruise, and they didn't fire their guns on every sortie. Even if they did, it was the armourer's job to "pull through" (i.e. clean and lubricate) every barrel, as well as replenishing the ammunition. Any small fragments, caught in the rifling, would have been removed by the pull-through cloths (2" x 4" if my memory's correct,) and there were usually three per gun, first to clean, second to lubricate, third to remove any excess oil from no.2.

He also had to fit the covers on the guns (or leading edges mid-BoB,) and any attendant residue would not have helped, so should have been wiped away from inside the gun tunnels. According to an ICI inspector it was common practice to wipe surfaces with petrol-soaked cloths, and there isn't much that can stand up to that sort of treatment.

If (big "if") an airframe saw combat, and fired its guns, using up all of its 15 seconds-worth of ammo, it might go in for a "24 hour check" after only 32 sorties, which, at the height of the Battle, could be 8-10 days (assuming that the aircraft suffered no damage, or a frightened pilot didn't pull so many Gs that he wrinkled the wings' surfaces by more 1/10", in which case the wings had to be replaced.) It's very unlikely that an airframe would have left a servicing bay in the same condition in which it entered; "Chiefy" would have had a fit.

Flakes of engine, in the exhaust staining, is something I've never heard of. It was more usual for wear to be confined to items like piston rings, or gudgeon pins, in which case they ended up in the lubricating oil, then the oil filter, which was regularly inspected for "extras." It was just such an eventuality that lead to K5054 needing an engine change very early in its flying programme.

Edgar

Edited by Edgar

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Facts Edgar. These facts obscuring our long held beliefs! :)

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Did you even read my post?

I rather thought that this sentence says it all. It's not about the criticism, but about the way it's presented. What's difficult to grasp about that? It's called common courtesy.

The problem is even if you do put it tactfully you're sure to put someones nose out of joint (and often it's not the modeller himself but someone reading the article). Also dare to criticise a new release kit and your panned.

Andy

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The problem is even if you do put it tactfully you're sure to put someones nose out of joint (and often it's not the modeller himself but someone reading the article). Also dare to criticise a new release kit and your panned.

Andy

Well if you put it tactfully, and they get upset anyway, at least you tried. It's better than not even bothering.

Again - it's how new kits are criticised. I know that kits don't get hurt feelings, although I'm sure their designers do, but the vitriol, histrionics etc. that accompany almost every new release do get tiring. Of course you can't please all of the people all of the time, but adding tact and respect to the mix will certainly improve your percentages :shrug:

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But the $64,000 question is, how much time? Aircraft had a strict regime of servicing intervals, which started at around 24 hours flying time. In combat mode, a Spitfire's endurance was about 45 minutes, 2 hours at cruise, and they didn't fire their guns on every sortie. Even if they did, it was the armourer's job to "pull through" (i.e. clean and lubricate) every barrel, as well as replenishing the ammunition. Any small fragments, caught in the rifling, would have been removed by the pull-through cloths (2" x 4" if my memory's correct,) and there were usually three per gun, first to clean, second to lubricate, third to remove any excess oil from no.2.

He also had to fit the covers on the guns (or leading edges mid-BoB,) and any attendant residue would not have helped, so should have been wiped away from inside the gun tunnels. According to an ICI inspector it was common practice to wipe surfaces with petrol-soaked cloths, and there isn't much that can stand up to that sort of treatment.

If (big "if") an airframe saw combat, and fired its guns, using up all of its 15 seconds-worth of ammo, it might go in for a "24 hour check" after only 32 sorties, which, at the height of the Battle, could be 8-10 days (assuming that the aircraft suffered no damage, or a frightened pilot didn't pull so many Gs that he wrinkled the wings' surfaces by more 1/10", in which case the wings had to be replaced.) It's very unlikely that an airframe would have left a servicing bay in the same condition in which it entered; "Chiefy" would have had a fit.

Flakes of engine, in the exhaust staining, is something I've never heard of. It was more usual for wear to be confined to items like piston rings, or gudgeon pins, in which case they ended up in the lubricating oil, then the oil filter, which was regularly inspected for "extras." It was just such an eventuality that lead to K5054 needing an engine change very early in its flying programme.

Edgar

But that's the point of weathering, isn't it? It's a quick and simple way of suggesting use, and the more use you think your model would have been used, the more staining you apply. Now, as for cleaning the gun barrels - obviously, that had to be done, but my point is that not all the flakes of metal would have stuck in the rifling, most of them would have been ejected along with the bullets, but being light, would have been caught in the airflow and swept over the top and bottom surfaces of the wing, staining it. No doubt this was cleaned off regularly, but the number of pics I've seen (such as the Hurricane? wing in Daniel's post) that show this staining leads me to conclude that it did happen. Some of the staining would be smoke alone, in which case it would contain small quantities of carbon etc from the combustion of the propellant, so would be soot coloured. Some would be flakes of metal, so rust/verdigris coloured. As for engine wear, piston ring wear is in the cylinder, and hence, some of the flakes end up in the sump, others end up in the exhaust and are ejected. Cylinder wall wear takes place entirely in the cylinder, so again, metal particles would be expelled in the exhaust. And there's the exhausts themselves, which rust in part due to the chemical action of the exhaust gasses, and so also contribute rust to the stream of gas. This is clearly visible on railway locomotives, and sometimes on cars, so I see no reason why a v12 Merlin should be exempt from this common cause of staining. Bear in mind I'm talking microscopic flakes here, not large chunks which would actually cause damage to the machinery. But, as always, the key is to model a prototype for which you have a picture, or preferably several, taken at the time you wish to model it. That way, you can see how "worn" it looked, and weather accordingly. In some cases, an older unit might well be cleaner than a brand new one, just because it had been cleaned the day before, whereas the new one hadn't been properly cleaned since leaving the factory a month previously - or you might be using a picture taken the moment the plane landed after seeing action, and it might be more heavily stained at that moment than it would have been a couple of hours later, after the ground crew had rubbed it over. Without knowing every little detail, all you can do is make a best guess, or model what you see in a picture. One of the key compromises in any modelling, surely?

All academic at the moment though, as my kids want their models to look like they just rolled of the production line! Ah well :)

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I think that, in some (many?) cases, what we call "exhaust staining" is actually due to either or both of (1) the temperature effect of hot gases passing over the paint immediately behind the stacks, and (2) a chemical reaction between the gases and the paint pigment, particularly in a case where the engine is tuned to run a lean combustion mixture. I suspect this is more visible than the presence of metal flakes exhausted from the cylinders; it seems to me that the engine would be totally fried well before this became a visible effect. But, to each his own!

John

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You're not wrong - I saw someone on here, I think, had graded the finish on the exhaust stubs to show the effect of heat, it looked excellent, stubs going from rusty coloured near the engine to cream on the ends. And yeah, you will get all sorts of combination effects, that's true, and if allowed, the heat from the engine would fairly rapidly degrade the paint, not just in the exhaust stream, but around the exhausts. I suspect that this would have taken too long to have a really marked effect though, given the limited flying hours between services, and the fact that serious degeneration of the paint finish would have had a noticeable effect on drag. And dirt would have been wiped off regularly - hence my point about the exact point at which you choose to model the subject. I guess that's what I'm getting at, really - I've seen a bit of weathering done on aero models, and it always seems a bit one-dimensional. We've now got about four sources of potential discolouration, i.e. soot, rust, oil and heat. That means, to my mind, three different colours, and probably three different approaches to applying the weathering. And then there's chipped paintwork - a bit harder to apply, though!

As for fried to emit particles of metals? No, far from it - they're emitted from the word go. Particulate emissions from engines are not often discussed, as we tend to more concerned about gaseous emissions, these days, anyway. The metal particles fall to the ground - in fact, there are studies into recovering this metal from the roads, particularly whatever it is that's in catalytic converters - it's rare, and therefore might be worth the expense of hoovering up.

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in fact, there are studies into recovering this metal from the roads, particularly whatever it is that's in catalytic converters - it's rare, and therefore might be worth the expense of hoovering up.

It's platinum... I did read an article that stated the "value" of the roads in terms of platinum deposits once, but I can't recall them now :sleep_1:

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