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GB Cannon

Built a pneumatic 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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GB Cannon

Unread postAuthor: PCGUY » Sat Feb 05, 2005 4:17 pm

<div align="center">GB Cannon

Provided By Boogieman - <a href="http://www.advancedspuds.com">http://www.advancedspuds.com</a>

Ebay is to blame for this one! I saw some Goyen quick exhaust valves on Ebay. They were going at a ridiculously low price, only $9.99 for 3 valves! After shipping they were only $15 for 3! I got the valves, which I thought were only 1/4-1/2" valves. It turns out they were much bigger!

Armed with 3 new valves and a dream I set out to fulfill my destiny. (LOL, just kidding) I found that the valves had a flange on the inlet side and an unknown size on the outlet. I researched various pipe sizes with no luck. I ended up taking a piece of 2" sch80 with 1.5" sdr 21 sleeved inside of it, boring the sdr 21 out slightly, and securing it to the valve with JB Weld. I fabricated a flange to fit onto the valve's flange out of a 1.5" sch80 PVC flange. The rubber gasket between the flanges was freakishly found on the ground outside of a metal scrap yard. I couldn't have asked for a more perfect fit on the gasket!

The valve is triggered by a Gregory high flow blowgun, which I purchased from spudtech.com. The gun is filled through a male quick connect fitting. If you have ever played with quick connect fittings, you know that the males are not air tight. If I were to release the hose, the gun would trigger. To avoid this, I followed the quick connect fitting with a 1/4" inline check valve. These can be found at mcmaster.com.

The chamber is made of 4" clear pvc. I had planned on using it for a combustion, but couldn't resist the coolness of a clear pneumatic. When fired, the chamber becomes filled with vapor from depressurization.

Overall, I am amazed with the power of this gun. The Goyen valves are much more powerful than a sprinkler valve of the same size. Its hard to explain, but a sprinkler valve, even a pneumatic modded one shoots kind of "squishy." Sort of a whoosh-bang sound. The Goyens dump very crisply, with a sharp retort. They remind me more of a piston valve than a diaphragm valve.
The day after initial testing, my stomach was really sore. I had rested the gun on my stomach and legs so I could hold the barrel shut with my hands while firing. The recoil gave me some nice bruises and made me feel like someone had gave me a good butt kickin'!

"Bolt Action" Loading Mechanism

I decided to try a new method of loading with this launcher. It has a golf ball "bolt action" mechanism. The mechanism consists of a 2" repair coupling (sliding type). It is attached to a 2" sch80 barrel, which has 1.5" sdr 21 sleeved inside of it. When pushed forward, the loading hole is exposed. You drop a golf ball in, and pull the repair coupling back. The repair coupling is airtight via o-rings but slides easily. The golf ball is sandwiched between the short gold screws and the inner barrel. As you push the barrel/coupler back the golf ball is loaded into the inner barrel.

There is a slight problem on the barrel. When fired the bolt/ barrel flies forward, letting air escape from the loading hole. This reminds me of a gas blowback system, which could in some cases be useful. A semi automatic design would be one of these uses. I will be fixing the barrel so it will not slide forward when firing.

Future plans for this gun include multiple barrels, Chrony testing in conjunction to GGDT simulation to determine the CV of the valves, and much more.

Provided By Boogieman - <a href="http://www.advancedspuds.com">http://www.advancedspuds.com</a></div>
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Attachments
gbcannon.jpg
gbcannonback.jpg
gbcannonvalve.jpg
gbcannonside.jpg
gbbreechopen.jpg
Breech Open
gbbreechopen.jpg (12.75 KiB) Viewed 6711 times
gbbreechmidway.jpg
Breech Midway
gbbreechmidway.jpg (11.54 KiB) Viewed 6711 times
gbbreechclosed.jpg
Breech Closed
gbbreechclosed.jpg (10.35 KiB) Viewed 6711 times
Last edited by PCGUY on Fri Mar 10, 2006 2:26 am, edited 3 times in total.
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Unread postAuthor: ƒlying$pud » Fri Nov 04, 2005 12:25 am

nice as gun, i'd love a breechloading spudgun.
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Unread postAuthor: mr.potatohead » Thu Jan 12, 2006 9:17 pm

i like the see through air chamber! :D were do you get those
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Unread postAuthor: beebs111 » Sat Jan 14, 2006 3:13 pm

joel at spudtech :wink:
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Unread postAuthor: hannibal21 » Tue Mar 07, 2006 11:37 pm

I don't know but you could possibly have the golf balls in a chute above it, and then have the bolt on a spring, so that when it is puched forward, the spring will press it back, after the pressure stopped. This would give the golfball time to drop in from the chute above. Then the bolt is slid back and you can fire again. I don't know if this would work or not, hope I explained that well.
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Unread postAuthor: LynyrdSkynyrd » Wed Aug 30, 2006 10:43 pm

that breechloader is pretty cool... on ours we just undo the cam lock to breach load it... it works... lol
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Unread postAuthor: frankrede » Tue Oct 10, 2006 6:43 am

Why do you have a clear chamber?
Its pneumatic right?
Whats the purpose?
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Unread postAuthor: Jolly Roger » Tue Oct 10, 2006 6:56 am

Because he can..
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Unread postAuthor: s18022 » Tue Oct 10, 2006 6:56 pm

Does the breach loader whistle when you fire it because i have heard they often do.
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Unread postAuthor: frankrede » Sat Oct 14, 2006 12:43 pm

Jolly Roger wrote:Because he can..
I see no real purpose. Its more expensive.
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Unread postAuthor: ProfessorAmadeus » Sat Oct 14, 2006 3:15 pm

and rated for like 110 psi.
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Unread postAuthor: beebs111 » Sat Oct 14, 2006 10:01 pm

because it fills with vapor and looks cool
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Unread postAuthor: frankrede » Sat Oct 14, 2006 10:07 pm

Seems like a waste of clear pipe.
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Unread postAuthor: killagorrila99 » Sat Oct 14, 2006 10:10 pm

Dude, its his cannon and he can do what he wants. Did you join this forum only to critisize, Or for the post count? Plus boogie is a spudgun legend, Leave him be, OK?
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Unread postAuthor: kyle1292 » Sat Nov 04, 2006 10:43 am

my breech never whistles and i dont even have it tightly sealed
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