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chamber volume

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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chamber volume

Unread postAuthor: urgle the danish cow » Wed Jul 27, 2011 10:27 am

for a new project i need to know what size chamber volume would be best
it will shoot .22 pellets
uses a 1/2 qev
filled by a schreader
piloted by a blowgun
aair chamber is copper and will have a street elbow so the chamber is horizontal

so what length of tube should i use?
and what pressure? (my pump only goes to around 200psi

thank you
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Unread postAuthor: jackssmirkingrevenge » Wed Jul 27, 2011 10:38 am

How long is the barrel?

Which of these do you want the most?

- power

- noise

- ease of pumping

What sort of power do you want?

Is this single shot?
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Unread postAuthor: DYI » Wed Jul 27, 2011 8:37 pm

If you want the highest achievable muzzle energy, the tube should be sufficiently long that (c<sub>chamber</sub> * (t<sub>projectile clears muzzle</sub> - t<sub>valve opens</sub>)) < L<sub>chamber</sub><sup>+</sup>. This is slightly more than needed, but the chamber size would be absurdly large anyway. You would, of course, use as much pressure as possible.

+: where c is used to indicate sound speed, not light speed, in the medium


If you want supreme ease of pumping and low noise, the chamber should be just large enough to get the round out the barrel while using some pressure low enough so as to not exert yourself unnecessarily.

If, on the other hand, you want something worthwhile, you'll have to define what your criteria for worthwhile is, and stop being so damned ambiguous. Either that, or take what appears to be the conventional route and hire me to write a request for proposal for you. You probably won't get what you want, but I'll eat well next semester :P

Or, you know, you could design your own toys like the rest of us do...
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Unread postAuthor: Crna Legija » Thu Jul 28, 2011 3:24 am

GGDT use it
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Unread postAuthor: urgle the danish cow » Thu Jul 28, 2011 10:05 am

Crna Legija wrote:GGDT use it


danke
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