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PMC- Multi chambers

Built a combustion cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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PMC- Multi chambers

Unread postAuthor: Petitlu » Tue Nov 06, 2012 4:30 pm

I thought the concept of multi chambers to double the acceleration of the projectile, I do not know if this is true but hey I suggested the idea anyway ...
I have not yet seen a PAL operating with this principle.
So here is the pattern that speaks better than me!

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Well, I did a test this afternoon and misery, no boom!
I think this is because the spark plug that is too withdrawn from the chamber, the mixture should not be up to it.

So I did another system in order to position my eletrodes where I want in the chamber :

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With the electrode
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Unread postAuthor: jackssmirkingrevenge » Tue Nov 06, 2012 4:42 pm

Unfortunately history suggests this is not a good idea :(

http://html2.free.fr/canons/v3.htm

If the Germans had focused on theK5 Glatt instead of pissing about with this multi-chambered gun, London would have suffered considerably.

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It was discussed here several times, here's one thread: http://www.spudfiles.com/forums/second- ... t7286.html
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Unread postAuthor: Petitlu » Tue Nov 06, 2012 4:46 pm

Thin!
I stopped the project then?

:( :(
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Unread postAuthor: jackssmirkingrevenge » Tue Nov 06, 2012 4:53 pm

When Saddam wanted to make a supergun, under the supervision of the brilliant Gerald Bull, they ignored the multi chamber design: http://www.astronautix.com/lvs/babongun.htm

In my opinion, you will not get better performance than simply using a bigger single chamber.
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Unread postAuthor: Petitlu » Tue Nov 06, 2012 4:56 pm

ok...
I'll do a test anyway because I worked on this project ...
But I know that the result will be negative ...
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Unread postAuthor: jackssmirkingrevenge » Tue Nov 06, 2012 5:14 pm

Do it for science! No experiment is wasted ;)
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Unread postAuthor: Petitlu » Tue Nov 06, 2012 5:21 pm

Yes for science!:lol:
I also built another PAC, a little special... :wink:
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Unread postAuthor: jackssmirkingrevenge » Thu Nov 15, 2012 1:47 am

A note about this:

http://www.utroninc.com/

Utron is a pretty advanced R&D firm, and they apparently gave the multi chambered gun a go:

Side-injection Gun. The side injector is, as the name implies, the accelerating energy coming in from chambers distributed along the barrel. Germany built and fired a side-injection gun named the Millipede during WWII. UTRON personnel have designed, built, and test fired several different versions of the side-injected gun using ET and ELGG technologies. The side-injected gun demonstrated velocities of 7.2 km/sec and, after much experimental work, it was learned that velocities no higher than a breech-feed gun could be reached.


Again, it's an attractive idea on paper, but of no practical benefit.
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Unread postAuthor: Technician1002 » Thu Nov 15, 2012 10:59 am

If you watch some of the flame propagation videos on this site for testing mixes, it would appear that multi chamber may have too slow of a burn rate.

As for lack of ignition due to the distance to the spark plug, that can be fixed by adding a marble or BB to the chamber so it can be shaken like a spray paint rattle can to mix and distribute the contents.

Multi chamber designs would work best with larger heavier slower projectiles.
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Unread postAuthor: mobile chernobyl » Thu Nov 15, 2012 11:13 am

Multi-chambers, while they may not reach a higher velocity, allow for a more controlled acceleration curve for sensitive projectiles. On a combustion basis that is about all you'll get that you can't with a larger chamber.
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Unread postAuthor: jackssmirkingrevenge » Fri Nov 16, 2012 12:36 am

mobile chernobyl wrote:Multi-chambers, while they may not reach a higher velocity, allow for a more controlled acceleration curve for sensitive projectiles. On a combustion basis that is about all you'll get that you can't with a larger chamber.


In this case however it's probably easier and cheaper to just use a rocket.
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