A valveless pneumatic?
Posted: Fri Oct 15, 2010 5:30 am
Hey Guys,
I was thinking........ In my 2" gun discussion, we got into CV values and the benefits of fast acting valves versus high flow valves and I got to thinking and came up with a couple ideas;
#1 What about a totally valveless system? Picture a common combustion cannon layout (but not used as a combustion cannon) using an O-ringed projectile similar to the UHMW slugs. This O-ringed slug would be, in effect, the piston of an air valve. The slug would be slid down the barrel and latched in place with some sort of extremely beefy latching system (obviously air tight system) to hold the slug in place. Air up the tank and release the slug. There would be no flow restriction what-so-ever and there would be no valve opening delay at all. The latch could be released by way of a pneumatic ram. Latch release time is really not important because the slug would not start moving untill the latch is completely unlatched. Does this sound crazy?
#2 The other option is to use a pneumatically released ball valve, but, in the interest of delaying slug movement to allow more time for the ball valve to open, the slug could be a very tight fit in the back of the barrel. Perhaps tight enough to withstand maybe 50psi or so. That way the ball valve would begin opening, but the slug would delay its journey just long enough for the valve to open further (all the way?). This would, in effect, decrease barrel length required for a given FPS due to having much more pressure acting on the slug before it begins moving. Either that, or more velocity for a given barrel length. Oh, the slug would only fit tightly into the rear most portion of the barrel. The fit would loosten as the slug moves forward slighly to reduce drag in the barrel.
Thoughts?
Matt
I was thinking........ In my 2" gun discussion, we got into CV values and the benefits of fast acting valves versus high flow valves and I got to thinking and came up with a couple ideas;
#1 What about a totally valveless system? Picture a common combustion cannon layout (but not used as a combustion cannon) using an O-ringed projectile similar to the UHMW slugs. This O-ringed slug would be, in effect, the piston of an air valve. The slug would be slid down the barrel and latched in place with some sort of extremely beefy latching system (obviously air tight system) to hold the slug in place. Air up the tank and release the slug. There would be no flow restriction what-so-ever and there would be no valve opening delay at all. The latch could be released by way of a pneumatic ram. Latch release time is really not important because the slug would not start moving untill the latch is completely unlatched. Does this sound crazy?
#2 The other option is to use a pneumatically released ball valve, but, in the interest of delaying slug movement to allow more time for the ball valve to open, the slug could be a very tight fit in the back of the barrel. Perhaps tight enough to withstand maybe 50psi or so. That way the ball valve would begin opening, but the slug would delay its journey just long enough for the valve to open further (all the way?). This would, in effect, decrease barrel length required for a given FPS due to having much more pressure acting on the slug before it begins moving. Either that, or more velocity for a given barrel length. Oh, the slug would only fit tightly into the rear most portion of the barrel. The fit would loosten as the slug moves forward slighly to reduce drag in the barrel.
Thoughts?
Matt
oh well... great minds think alike i guess. Yes I agree that your mechanical latch idea would be better, however I think that you would be replacing that o-ring that seals the bb quite often, as bbs usually have pits in them that would be rough on that kind of seal.
