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u2-piston rifle

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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Unread postAuthor: spud yeti » Wed Aug 01, 2007 2:06 pm

But the paint job reminds me of a paintjob Jack showed me once, I can't find the link back to it. The camo-tigerstriped pistol.


I remember that. I agree this does look similar, but black, not red/orange.
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really good quote/phrase here
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Unread postAuthor: joannaardway » Wed Aug 01, 2007 3:39 pm

spud yeti wrote:...I could possibly critisize is the pilot volume, which is quite big due to your pipe...

I would have said the pilot volume was fine. The dead volume however is a little big.

I mirror everyone else's comments - fabulous cannon.
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Novacastrian: How about use whatever the heck you can get your hands on?
frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.
...I'm sorry, but that made my year.
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Unread postAuthor: mega_swordman » Wed Aug 01, 2007 4:11 pm

A very nice and well constructed gun. It looks fantastic, keep up the good work!
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"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity." George S. Patton
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Unread postAuthor: locksmith » Wed Aug 01, 2007 4:32 pm

Very nice build
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Unread postAuthor: experament-u2 » Thu Aug 02, 2007 1:00 am

spud yeti wrote:Oh, a question ( 8) ): What pressure do you like running it at?


i run it at 100psi

Modderxtrordanare wrote:But the paint job reminds me of a paintjob Jack showed me once, I can't find the link back to it. The camo-tigerstriped pistol.


thats were i got the idea to try it :lol:

mopherman wrote:Wow, very nice. It looks like your barrel port is a little too big for you piston. How did you get it to work?


i have a slightly smaller bit of pipe glue inside my barrel thats what the piston seals againced
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Unread postAuthor: jackssmirkingrevenge » Thu Aug 02, 2007 1:49 am

spud yeti wrote:Or should you rather say logic is spreading :wink:
At last the good word is becoming known to all...*sigh*...


I think it's an attitude thing - many people are content with just coming up with something that works. Personally, I would rather make the slight extra design and construction effort to make something that works as well as it can. Air is not the most efficient medium for propelling stuff at high velocity, compared to solid propellants, so it's my contention that waste should be kept to a minimum.
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Unread postAuthor: Pyro Ninja » Thu Aug 02, 2007 4:18 am

finally got it posted.....great to see the final product :D ...looks awesome
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Unread postAuthor: joannaardway » Thu Aug 02, 2007 3:10 pm

jackssmirkingrevenge wrote:I think it's an attitude thing - many people are content with just coming up with something that works. Personally, I would rather make the slight extra design and construction effort to make something that works as well as it can.

I wholeheartedly agree - just a few small changes can make that difference between a good cannon and a great cannon.
If you're going to shell out the cash, it's worth those few extra coins, and bit of extra effort to make it it's absolute best.
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Novacastrian: How about use whatever the heck you can get your hands on?
frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.
...I'm sorry, but that made my year.
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Unread postAuthor: bassmaster1228 » Thu Aug 02, 2007 3:31 pm

that is an awsome gun... i reely like it
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current project: portable pnuematic sniper rifle

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Unread postAuthor: joannaardway » Thu Aug 02, 2007 3:48 pm

@JSR: Actually, just minutes after my last post, I found this page, which gives a rough idea of the efficency of firearms cartridges:

http://www.loadammo.com/whatisballistics.htm

Taking the figure of 29% efficency (for the Browning machine gun), it's easily possible to surpass ~30% efficency with compressed air.

So, it seems air can be on a par with solid propellants for energy efficency. Not that it's good on volume efficency.
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Novacastrian: How about use whatever the heck you can get your hands on?
frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.
...I'm sorry, but that made my year.
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Unread postAuthor: noob of noobs » Sun Aug 05, 2007 11:41 pm

That's simply amazing! How did you get the cap to fit on the tee in your piston valve? Is that possible with PVC? Also, isn't the ball valve hard to turn with one finger on such little leverage?
Anyway, that's some truly top notch work there. Can't wait to see the damage pics! :D
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Unread postAuthor: MrCrowley » Mon Aug 06, 2007 12:03 am

First of all that is PVC, just painted black.
Second Im guessing he did what i did with my golfball gun piston valve and sleeve the isnide of the tee with 20mm PVC pipe and just bolt a 20mm endcap on it.
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Unread postAuthor: jackssmirkingrevenge » Mon Aug 06, 2007 2:29 am

joannaardway wrote:So, it seems air can be on a par with solid propellants for energy efficency. Not that it's good on volume efficency.


That's the point I was trying to make, for practical purposes (ie at working pressures) volume for volume air lags woefully behind solid propellant, so short of having a ridiculously powerful compressor or ridiculously large chamber an barrel, one has to maximise efficiency in order to glean the most from a spudgun.
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Unread postAuthor: noob of noobs » Mon Aug 06, 2007 8:52 am

Sorry, I thought it was iron :oops: One question though, does bolting things on provide an airtight seal? Do you have to seal it with epoxy or something? :?:
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Unread postAuthor: spud yeti » Mon Aug 06, 2007 8:58 am

noob of noobs wrote:Sorry, I thought it was iron One question though, does bolting things on provide an airtight seal? Do you have to seal it with epoxy or something?


You seal it with an O-ring, then the screws. By expoxying it in, what would be the point of screws :wink:

EDIT: other than safety purposes!

BTW, I agree with what you say entirely JSR.
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really good quote/phrase here
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