Red leading edge gun tube patches

[bzn20]

The order to paint the stripes was made at the last (well, June 4th., delayed to the 5th) moment, but the plans were laid months before.

Not necessarily, since 85,000 (Imperial) gallons of the necessary paints were ordered in April, for use by all of the Allies, so personnel might have been thin on the ground, but the paint shouldn't have been (didn't stop it happening, in some cases, of course.)

My post was just a brief description of the older thread,not starting all the other stuff on that thread

Obviously an order is issued by and after Supreme Allied Command planned it. They planned everything down to the last mess tin.The planning for late issue of the Order to conceal D Day Ops

Not all the painting was done to the "book", thats a given.Somewhere on that thread (I think, or I've read elsewhere) was mention of pink ish paint instead of white. Then there were aircraft repairs/battle damage carried out and return to the front line but still under Op Overlord and had to repainted anyway they could,some washed off. Some wasn't very good to say the least,some flying with wet paint due to operational necessity. And any other reason you could think of.

[derek burton]

I agree with Simon in post #5, there are really good quality photos of Spitfires that to me show areas around the gun ports to be perfectly square with a perfect circle in the middle no evidence of a ridge on the edge of the red portion and no sign of a fired through patch. There is good photo of this in Sarkar Battle of Britain the photographic kaleidoscope on page 109.

Dek.

[Edgar]

Do not lose sight of the fact that Supermarine did not make provision for fabric patches (and therefore continued to supply the covers) until 24-9-40; the Local Technical Committee didn't even discuss the possibility before July 1940.

[gingerbob]

Didn't they use condoms on protruding barrels??

In an emergency (which seems apt) maybe, but when specially-made rubber covers were tried, in the early stages of cannon development, it was found that the intense cold affected the rubber, which tended to break up, and go down the barrel, jamming the mechanism.

...and don't we all hate it when that happens!

[Graham Boak]

One reason for the use of protective rubber covers (official or unofficial) on cannon and pitot probes was to keep out insect life whilst on the ground. This may or may not have had much effect on the cannon, but would be much more serious for the pitots. These were (obviously enough) removed before flight so the effect of extreme cold was not a problem..

[Edgar]

One reason for the use of protective rubber covers (official or unofficial) on cannon and pitot probes was to keep out insect life whilst on the ground.

It might be the (convenient) reason, now, but it was, at the time, done to stop the cannon mechanism freezing at altitude (it's all in the files.)

These were (obviously enough) removed before flight so the effect of extreme cold was not a problem.

Pitots yes, cannon no; it's all in the files (even discussions on the shape of the protective covers.) The problem was so acute, the IIb & Vb had the facility for recocking the cannon mechanism while in flight.

[Graham Boak]

This applies to official use on the cannon: my posting was to bring out that cannon were not the only concern, or necessarily the most important. From memory, the particular problem arose (or is best recorded) on the Whirlwind. Whether it was ever officially incorporated is another matter.

[Edgar]

And my posting was intended to be in keeping with the original enquiry on this thread; as early as November 1939 the Air Ministry put forward the suggestion of "putting a bung in the barrel," to stop the flow of freezing air through the barrel and out of ejection port. As no mention is made of insects, one could be forgiven for assuming that they considered temperature to be the most important.

[Iain Wyllie]

.

Edited December 27, 2014 by Iain Wyllie

[Graham Boak]

My apologies for adding a small piece of information about the use of condoms on aircraft during WW2. I thought it might have been interesting to the readers.

[Giorgio N]

In any case, what difference would it have made if insects of any size or kind had entered the muzzle of any guns, mg or cannon. I can't imagine any insect, even a beetle with a hard shell, making the slightest difference to the passage of either a bullet or shell along the barrel. Bear in mind that the driving band was compressed by the rifling in order to impart spin and you will see that insects posed no impediment to the the passage of even the lowest calibre bullet, never mind being a danger to the barrel itself.

Insects are not a problem per se, the substances these insects can produce are a different story. Some insects produce sticky substances that can easily occlude a gun barrel. If these substances are inside the barrel when the gun is fired, the bullet may go through in the end but the pressure builds up very differently compared to a clean barrel and the gun may well be destroyed. Small caliber rifles are known to have suffered barrels blown by the simple presence of water ! And on rifles condoms are very often used to prevent dirt and water from entering the barrel

Edited September 29, 2014 by Giorgio N

[bzn20]

My apologies for adding a small piece of information about the use of condoms on aircraft during WW2. I thought it might have been interesting to the readers.

No need to apologise Graham. Its a fact.

[Iain Wyllie]

.

Edited December 27, 2014 by Iain Wyllie

[Mitch K]

http://en.wikipedia.org/wiki/Florida_Commuter_Airlines_crash

Something similar in a cannon barrel could have very unpleasant consequences. Wasps etc can construct stuff at a fair old pace, I can tell you, so it wouldn't necessarily need to be left terribly long. I'm talking about hours, not days/weeks, certainly the sort of interval that might elapse between cleaning/re-arming a weapon post-mission and flying another mission.

[Iain Wyllie]

.

Edited December 27, 2014 by Iain Wyllie

[Edgar]

I'm talking about hours, not days/weeks, certainly the sort of interval that might elapse between cleaning/re-arming a weapon post-mission and flying another mission.

For major cleaning, guns were removed, in fact they were supposed to be removed, after only a few days, even if they hadn't been fired; when guns were refitted, then re-armed, they were also cocked (probably why red patches were used as a warning not to walk in front) and the patches, bungs, condoms, or whatever, were fitted then and there, so an armourer might possibly notice an army of wasps flying down the barrel, as he did so.

[bzn20]

Things are covered/bunged/plugged and blanked for a reason, regardless of the things function. Foreign Object Damage,FOD. If the component/system isn't designed to take foreign objects its prevented by "blanks" in variety of ways,depending on the position and shape of the component. Thats it, not a specific foreign object.

Blanks and covers also protect ground crew from injury and the component itself, padding on aerials for example.

[Mitch K]

For major cleaning, guns were removed, in fact they were supposed to be removed, after only a few days, even if they hadn't been fired; when guns were refitted, then re-armed, they were also cocked (probably why red patches were used as a warning not to walk in front) and the patches, bungs, condoms, or whatever, were fitted then and there, so an armourer might possibly notice an army of wasps flying down the barrel, as he did so.

A horde of wasps, definitely. Half a dozen, though? Anyway, the risk of being blown to little bitty pieces by every loony on the ground firing with anything in range, plus enemy pilots systematically trying to do the same, would have been vastly greater than the risk of damage from a partial barrel blockage.

[gingerbob]

The size of a pitot tube (or static) is also considerably smaller than that of a gun, let alone cannon, barrel, and since it is there to accurately measure air pressure, any "plugging" would be immediately signficant, no trigger-pulling required.

While I understand Graham's tossing in an additional comment, it would be a mistake to treat cannon barrels and pitot tubes as "analogous" things on aircraft, other than being more-or-less tubular.

bob

[bzn20]

These patches were also a "tell tale" for ground crew, an indicator that the gun/cannon had been used.All Blanks.....Painted red and fitted with flags to stand out,all blanks (ok 99.9%) bungs,ground locks,control locks etc. are red,easy to see and therefor not left fitted for flight(ground/control locks/bungs/covers etc) not the patches though. I can't get over how much confusion surrounds simple things like these patches .

In training we were told things are done,what you will do AND why we will do it,end of story. We didn't sit there arguing the reasons why we do things or what about this and that.

I'd still be sat there trying to pass the Phase tests and Final paper or got kicked out for being untrainable.

Blanks is a generic term for locks/bungs/covers etc.

Edited September 30, 2014 by bzn20

[noelh]

The size of a pitot tube (or static) is also considerably smaller than that of a gun, let alone cannon, barrel, and since it is there to accurately measure air pressure, any "plugging" would be immediately signficant, no trigger-pulling required.

While I understand Graham's tossing in an additional comment, it would be a mistake to treat cannon barrels and pitot tubes as "analogous" things on aircraft, other than being more-or-less tubular.

bob

At risk of going completely off topic. I once noticed a very large insect clinging to the top, (fortunately) of my pitot tube during the take off roll. Impressively it hung on right up to about 50 knots, which I was glad to be able to read on the ASI because she might just have laid something in the opening and was protecting for all I knew!

[AndyL]

Nice tidy patches on a 234 Squadron Spitfire...

[Stew Dapple]

Nice tidy patches on a 234 Squadron Spitfire...

Yep, no way is that dog getting into one of those gun barrels

Cheers,

Stew

[Flankerman]

How do you know that the dog is called Patches ???

Ken

[AndyL]

The dog was actually called 'Poopdeck'

Edited October 1, 2014 by AndyL