New Internal Spring Valve Piston

[sgort87]

Ok, what do you guys think about this? http://www.geocities.com/sgort87/piston This piston works by a spring keeping the valve shut until there's enough pressure on it to open it. This makes it so the air doesn't enter the chamber until the piston is fully locked forward. This should work as long as those equalization holes are not too big. When the pressure behind the piston is released, the spring will push the valve back and then the piston will slide back and the air will exit through the barrel.

[boilingleadbath]

Interesting system; might be usefull if you wanted to make a _very_ fast filling piston gun. Of course, the piston would have to be a larger diameter - it won't work if it's the same size as the barrel (there's a sticky at the SGTC that tells you how a piston valve works, it should explain why).

The only issue I can think of is this: your "checkvalve" holes won't close when you fire, as the pressure has to drop to praticaly nill for them to do so. This concern is easily eliminated by simply being sloppy in the construction of your little grey spring pusher - so that air can leak into the cavity. With the cavity being filled, the spring has a "'little' helper" - the compressed air.

I might replace the complex (and probably heavy) push-rod and internal piston system with a concave (think U-shaped) thing. This moves forwards just like your piston, and uncovers the equilization holes. The second equilization hole (for the insides of the piston) should be moved so that it is filled from the chamber itself. (and of course, should be made as small as you can make it - 1/16" is too big for this, maybe a number 80 or 60 hole would work.)

[sgort87]

Okay, yes I origionally intended to have the barrel a bit smaller but forgot to fix that. Someone actually already caught that mistake on another forum that I posted this on. I see what you are saying about the spring needing to be messy. Maybe a tiny equalization hole in the side wall of the piston up where the spring is so the air can escape and allow the disk to move. But, doing so may cause problems with how it returns to its origional position after the shot. Then again, this whole point may not even be valid because air will be compressed on the left side causing the disk to compress the air on the right. I think the only way to tell is to experiment with it exacltly how it is drawn (except the barrel size problem) and then add small changes if necessary. I encourage you people to experiment with this and please give me feedback.