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A little something I'm working on...Shhhhh


NightHawkInLight

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I'm in the process of editing a new video, but it will still be a week or more before it's likely to be finished. In the meantime I really couldn't wait to show off my latest project, which I've really been having a lot of fun with:

http://www.youtube.com/watch?v=EUx95ZS5xVs

 

Hopefully the full tutorial will come sooner than later. The above is just a roughed out intro, and a private video than can only be viewed through the provided link.

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oh yeah! That design is just begging for an electrically operated air valve. ;)
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oh yeah! That design is just begging for an electrically operated air valve. ;)

Electrically opened isn't so great, but a modified sprinkler valve with with a blowgun release works wonders. Not really necessary on a piston cannon though. I tend to think it's overkill just to more quickly release back pressure but quite a few people do it so who am I to argue. For now, my $1.50 1/2" PVC ball valve works great.

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the difference in power is amazing, if you exhaust the pilot quickly, the piston does not wait around, as im sure you know, dumping the air as quick as possible into the barrel allows more muzzle velocity/projectile acceleration, with an ideal c/b ratio

For my old qev cannon the difference in penetrating 3mm al to just denting it.

 

Dan.

 

Im so gutted i cant see the video yet.

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the difference in power is amazing, if you exhaust the pilot quickly, the piston does not wait around, as im sure you know, dumping the air as quick as possible into the barrel allows more muzzle velocity/projectile acceleration, with an ideal c/b ratio

For my old qev cannon the difference in penetrating 3mm al to just denting it.

 

Dan.

 

Im so gutted i cant see the video yet.

I'll have to do a comparison for myself sometime in that case. It does seem reasonable that it would release the piston faster.

 

How does it work? Anyone have a schematic of the internals?

Yes, I do. The concept is the same as the third one shown in the animations on this thread: http://www.spudfiles.com/forums/piston-valves-explained-visually-t8157.html

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minimizing the pilot volume also works wonders paired with fast venting, mine is under 10cc and most of that is the valve housing. The air in the pilot has to escape before the piston moves, you want it to slam back in order for the projectile to stay in situ until its time to move, any early moving means the barrel gets shorter so does the accelaration time.

After the alu incidents modding stopped and dismantling started, small bore piston or qev cannons can be crazy powerful, very suprising what a couple hundred psi can do, and its still not optimised to its full potential.

 

Dan.

 

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Interesting design. I never was much a fan of pneumatic cannons though. I have a advanced combustion cannon with a combustion chamber of 4" ID x 2 1/2'. It shoots pretty decently on propane, still have yet to try it on MAP gas. Maybe I'll upload some videos/pics or something sometime.
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if you ever fired a pneubmatic qev launcher at 300 psi youd change your mind, the first few cannons i built were advanced combustions, fan, fuel meter etc, nice to work with pvc but it has its limits although i think they are more fun.

Mapp burns slightly hotter and will be more powerfull (slightly) but unless you go hybrid the power will be under a good pneumatic its easily possible to get 1000ftlb from off the shelf parts.

I have made many spudders and should really rebuild and post some aswell, thing is gun law in uk.

 

Dan.

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  • 2 weeks later...
Ha, saw you posted it secs after released earlier on the tube. The guy who came to a few club shoots needs to see the vid. He would be a bit safer if he altered his...it was 2-3x larger than yours and I remember it scaring folks since he was nearby the audience.
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I do remember a cannon being brought to a few shoots and having it moved further away from the crowd. I never did take a close look to see what sort of cannon it was.
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  • 2 years later...
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