First Pneumatic: P.A.P.A.

Just build a cannon and want to show it off? Post it in here.

Postby Drew Rowland » Mon Mar 21, 2005 6:27 pm

This is my first pneumatic, and a bit of an upgrade from my old super-ghetto combustion (it didn't even have a BBQ lighter, it had a touch-hole[:p]) The name stands for Pneumatically Actuated Potato Accelorator, and as a plus is spanish for potato (right?)
<img src="http://www.spudfiles.com/uploader/uploadFiles/IMG_0762.JPG">
As you can probably tell, this is a piston coaxial, with a 6" chamber. It is exausted by a modded sprinkler valve. Here's the back end:
<img src="http://www.spudfiles.com/uploader/uploadFiles/IMG_0758.JPG">
I'm not sure if this has been done before, but I put the sprinkler valve inside the cannon both to protect it and to prevent leaks: there isn't any pressure diffrential. Here's the inside of the back plug:
<img src="http://www.spudfiles.com/uploader/uploadFiles/IMG_0760.JPG">
I had turned a step into the female coupler so that there was more than just the glue holding it in there, and it was extremly lucky that the fittings I used allowed it to sit even with the edge of the sprinkler valve.
Its got a spudtech 5'x1.5" rifled barrel and yes I know the C:B is all out of whack but thats b/c I intend to add barrel extentions later.
It's only been a few hours since I finished gluing it so I've only taken it to about 40psi, but its still plenty powerful, I get 13 second hang-times for a vertical shot at 40psi. The piston I'm using is a nylon disc from a cutting board turned to the correct diameter bolted to a 3"x1.5" reducer which fits almost perfectly in the 4" pipe that the piston travels in. (It took some sanding)
Here's another pic of the plug:
<img src="http://www.spudfiles.com/uploader/uploadFiles/IMG_0761.JPG">
Let me know what you think, and PCGUY you can put it on spudfiles if you like.
Drew Rowland
 
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Postby utcpyro » Mon Mar 21, 2005 6:35 pm

That thing is crazy... And this is your first pnumatic gun?!

Woah..
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Postby Drew Rowland » Mon Mar 21, 2005 6:38 pm

Well I decided I'd like to start big and get bigger, but I'm affraid my next cannon won't come any time soon: I blew all my money on parts for this gun.
Drew Rowland
 
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Postby Longshot » Mon Mar 21, 2005 6:47 pm

looks well thought out. Pretty sweet. To hone performance i'd fell in the dead area around the sprinkler valve with some expanding foam, or something to reduce exhausting volume.
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Postby buzzboy » Mon Mar 21, 2005 7:12 pm

Is that sch. 80 or conduit(sp)
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Postby Drew Rowland » Mon Mar 21, 2005 7:19 pm

Everything is SCH40 except for the plug, which is SCH80. USplatics sells SCH40 pipe in both grey and white.
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Postby SMOMW » Mon Mar 21, 2005 8:43 pm

is that a pressure gauge I see on the back coupling of the chamber in the first pic?

sweet cannon. Nicely planned out. i'm getting a real itching to build a piston cannon.....
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Postby Drew Rowland » Mon Mar 21, 2005 8:51 pm

Yeah that's a 0-160 psi gauge mounted in the double-thick plastic in the back. It makes it much easier to shoot consistantly and not run the compessor obssesively long.
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Postby OJHSPyro89 » Mon Mar 21, 2005 9:17 pm

This is something you dont see too often...
<img src="http://www.spudfiles.com/uploader/uploadFiles/IMG_0760.JPG">

Very nice work. I love the whole hidden fittings things. At first i thought you where exhausting froma blowgun. Nice work man. I wanna see some more of ur stuff.
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Postby Longshot » Mon Mar 21, 2005 9:21 pm

it sure makes that 1.5" barrel look tiny as all get out. I love this gun. I hope you have a video camera.
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