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Cad drawing project (PCP airgun)

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: Brian the brain » Tue Oct 09, 2007 2:05 pm

and CO2 turns liquid at between 50 and 60 bar...not 5!!!
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Unread postAuthor: Pete Zaria » Tue Oct 09, 2007 3:08 pm

As mentioned already, your twist rate on the barrel's rifling is far too tight - in fact, rifling that tight could cause a dangerous barrel blockage situation. Rifling more like 1 full twist in 10" will provide much better velocity and still yield good accuracy.

My question is, if you're designing a high-pressure, rifled barrel pneumatic, why not use a barrel from a "real" black powder gun, such as a .44 cal muzzle loader barrel? You could probably find one inexpensively on an auction site or gun show, and modify that to use with your pneumatic setup.

The "reducer valve" you mentioned to knock down the pressure of your HPA tanks down to a more reasonable pressure is called a regulator, not a reducer valve, and you're going to need a pretty hefty regulator for this project.

What kind of (main) valve are you going to use? For pressures this high a metal piston valve seems like the obvious choice.

Good luck.

Peace,
Pete Zaria.
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Unread postAuthor: jackssmirkingrevenge » Tue Oct 09, 2007 5:00 pm

Brian the brain wrote:and CO2 turns liquid at between 50 and 60 bar...not 5!!!


According to wikipedia:

Liquid carbon dioxide forms only at pressures above 5.1 atm
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Unread postAuthor: clide » Wed Oct 10, 2007 12:25 am

Jack, that just means the pressure where it can turn to liquid at all, and that would be at a very low temperature (−56.6°C) for CO2 to be liquid at 5 bar. At room temperature it liquefies at over 50 bar.
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Unread postAuthor: jackssmirkingrevenge » Wed Oct 10, 2007 1:12 am

Ah, you meant room temperature :roll: :D
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Unread postAuthor: Necrosis » Wed Oct 10, 2007 8:10 am

Yay, the valve stress tested at 200 bars.
Well virtually anyway.

*edit* and a cross section render
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Unread postAuthor: Necrosis » Thu Oct 11, 2007 11:02 am

Hmm, I've been wondering... What would be the best way to trigger the valve? I was thinking about using a strong magnet and an electro magnet..and a capacitor, But I do not know if this will work.

Does anyone know?

*edit* and a spring to push it back of course
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Unread postAuthor: jackssmirkingrevenge » Thu Oct 11, 2007 2:16 pm

Necrosis wrote:I was thinking about using a strong magnet and an electro magnet..and a capacitor, But I do not know if this will work.

Does anyone know?

*edit* and a spring to push it back of course


have a read through here ;)
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Unread postAuthor: Necrosis » Thu Oct 11, 2007 3:06 pm

That's indeed where I got this idea from. :D
Not from that particular document, but from the stuff people at my favorite airgun forum have been telling me.
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Unread postAuthor: Necrosis » Mon Oct 15, 2007 8:14 am

Bumpedy bump, Exactly how would I get the air into the chamber? with a schrader valve?

And if so, does anyone have the dimensions to such an apparatus?

*edit* New piston valve assembly thingy! whoo!
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