a 3,000 psi cannon

[grumpy]

i am planning on building a new launcher that will operate at 3000 to 4000 psi ( no this is not a typo ) , the presure chamber will built out of a 2' 6"x 2" sch 160 carbon steel pipe, the barrel will be of same pipe except 1" in diameter ( length still to be determined ) . the valve i'm going to use is a 2 ball valve rated for upto 6,000 psi, will most likely put a spring on the ball valve to help open it faster , i'm hoping to get some very high fps with thi setup, so what do think ?

[Hotwired]

I think you'd better have access to a HPA or nitrogen tank.

Also that you shouldn't hold it. Such a large volume of 3-4kpsi gas and a 1" barrel would be fairly likely to dislocate or break whatever was behind it.

You will get high fps though if it all works out.

[jackssmirkingrevenge]

Most modern precharged pneumatic rifles operate at that presssure, but never seen one at 1" calibre I hope you have your ear protection sorted

[Fnord]

Eh.. you can take it. Be a man

ok, just kidding. Depending on the projectile weight, it'll probably feel like a 4-bore shotgun.
If you do decide to hold it, think big stock+padding.

Make a pneumatic cylinder with a small low pressure tank to open the ball valve. It'll probably work better than a spring and shouldn't be hard to rig up either.

[jackssmirkingrevenge]

Eh.. you can take it. Be a man

Without ear protection, you'll only have to "take it" once. Subsequent firings will be easy

[ALIHISGREAT]

i reckon you should make it a smaller bore so you could shoot marbles at insane velocitys.

however i thought that you can't propel something past the speed of sound with a normal pnuematic so i don't think there would be much point making it such high pressure unless you want to fire heavy things fast.

also have you thought about using helium?

[jackssmirkingrevenge]

however i thought that you can't propel something past the speed of sound with a normal pnuematic

yes you can

[ALIHISGREAT]

i saw that somewhere before, can't remember where though, but don't you get dieseling in some air rifles which allows them to go supersonic.

[jackssmirkingrevenge]

that's true of springer rifles, but the Condor linked to above is a pure pneumatic that goes supersonic by virtue of it's high pressure chamber (over 3,000 psi) and extremely efficient inline hammer valve.

[ALIHISGREAT]

hmm can;t remeber who i heard it off them must be wrong.

[Killjoy]

Depending on the projectile weight, it'll probably feel like a 4-bore shotgun.
If you do decide to hold it, think big stock+padding.

It might also help to have a recoil absorbing stock + the padding.

As I recal the mythbusters built a cannon somewhat similar to the one your planning (except smaller) for a car grappling hook, and the recoil was unbeliavble. So a heavy duty, extremely solid stand would also be a requirment.

[ALIHISGREAT]

it would have to be one hell of a recoil absorbing stock for the amount of recoil.

[SpudUke5]

Make a pneumatic cylinder with a small low pressure tank to open the ball valve. It'll probably work better than a spring and shouldn't be hard to rig up either.

If you decide to do this, which i think would increase your performance, then you will need another seperate air chamber for powering the pneumatic cylinder. If you need help with using a pneumatic cylinder or mounting it or anything, just contact the user name idiotfactory and he will help you with this. Mention me and he will know what you are talking about.

[psycix]

Why not make a custom piston valve?


Nah a ball valve will do.
But take one hell of a long barrel though and maybe use lighter gasses (helium!)
I cant wait to see it!

But how do you wanna reach 3000 psi? A normal compressor cant do that.

[ALIHISGREAT]

also have you thought about using helium?

and it would have to be a very strong piston with a very strong housing with a very strong bumper etc.