-------------------------------------------- Okay, I finished my piston valved pneumatic a few days ago, but today was the first testing, so I figured I couldn't really call it finished until I did.
And boy does she shoot.
The cannon itself is rather simple. The main thing here was me working on the valve. It is a barrel sealing tee valve based in a two inch tee with 1-1/2" porting for ALMOST unrestricted flow for a golfball. Even with the tenth of an inch or so on the choked diameter, they still go out of sight.
The chamber is about 36 to 48", (I didn't really measure it), of 2" SCH-40. I was gonna use 3" but for simplicity's sake I just used 2".
The barrel is 2" SCH-40 with 1-1/2" SDR-26 sleeved inside of it with spacers. The barrel, while it is not SDR-21... works beautifully! It's only .03" larger in bore than SDR-21 anyways...
The piston is actuated by a 1/4" Q.E.V. bought off McMaster. The valve itself is piloted and filled from the same ball valve with a male quick disconnect end. This works great, even though it's not as "realistic" as piloting with a blowgun.
The piston is nothing special... just some 1-7/8" PVC rod sealed into the 2" pipe it rides in with duct tape an lubricated with gun oil.
The performance is more than I can ask for. The piston is not bouncing, (due to the quick and full opening and recoil felt), and the golf balls are going faster than in any combustion I've made.
I am going to take some pictures of the actual piston later on tonight when I ask my stepdad where he put the damn strap wrench, (to take it all apart).
Here are some pictures. I plan on more as you guys ask for them, (these are just the basic pictures).
The barrel support is just cardboard tubing painted black and a belt, (
), until I find something a little more permanent.
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