SpudFiles

<div align="center">MCPAC

Provided By Fiebig - <a href="http://www.geocities.com/fiebigspudguns ... udguns/</a>

This is the MCPAC. Its a coaxial piston cannon. Meaning that the barrel runs through the chamber where it meets a piston on a spring which stops air from entering the barrel. You pressurize the chamber as well as behind the piston then release the air behind the piston very quickly which creates a relative vacuum and the piston moves back and allows all the air to enter the barrel to shoot... stuff... far. The MCPAC has gone through a few design changes to increase performance, or even just to get it to work at all. The original design is below. I had a blowgun as the trigger valve. I laugh at this now because blowguns have horrible airflow, that plus I had 1/4" pipe leading to it, this is all way too constricting to let the air vent properly. Also I used this cheap plumbers epoxy stick junk to seal around the barrel because Sears didn't have JB Weld. This crap was crap. It leaked horribly. Needless to say I had a lot of work to do...

Provided By Fiebig - <a href="http://www.geocities.com/fiebigspudguns ... /</a></div>

wait, is that a metal plug screwed into the end of the sprinkler valve? why would you do that? now I understand why your sprinkler valve was constricting the flow, besides, sprinkler valves open up faster and more then ball valves ever will!!!!!, you should take that plug out of the sprinkler valve and use it instead of the ball valve, trust me it will work so much better.

OHHHH, so that is how pistons work, lol,
STOP MAKING FUN OF ME...
I make combustions, but that is awsome, I like how it is made of metal

Wait could someone describe a piston a bit further, i might want to make one eventualy...

...with the ball valve he can go with highr pressure than if he use a sprinkler valve wich is rated 125 psi......

syko that looks as though it is a copper male adapter, perhaps he screwed it in and had trouble getting it out, so he left it in, it wouldnt bother the flow that much

interesting, thanks to the detailed pictures i understand pistons a whole lot more, if i can manage to get my hands on some pressure rated 4" pvc i think ill start constructing a tenis ball coaxial...

I like the look of that gun, and the way you painted MCPAC along the chamber, it makes it look kind of (idk whats the word for it?) artillery. Looks like a pretty sweet coaxial, good job. I wish there was a place around where I live that sold that steel pipe cause you just sparked a wicked idea in my head.

yo dont bring back old posts...

Yo spudthug!

Rather than just adding a pointless and badly spelled post on as well, why didn't you just ignore it?
Often, the "Don't kick up dead topics" posts are more annoying than the posts that kicked up the dead topic - at least shud_b_rite's post was grammatically correct.

After your ranting and flaming in the other thread - I think you really don't realise that you are walking on eggshells, and you need to think carefully before each post.

Now, I'm not going to allow myself to get angry at you, but I can't guarantee that other forum members will do the same. I suggest that you don't give them the chance - clean your act up.