SpudFiles

If i want to fill my HPA "T" piston valve by putting the fill valve in the chamber of the gun, not behind the piston, will i need a stronger spring to push the piston? or just the same? do piston valve cannons with springs have worse performance? same? or... ?


I'd also like to know if a burst-disk would have any affect of a HPA piston "T" cannon and how fast has any body gotten a piston cannon to fire (RPM wise) because it would be cool if i could make a semi-auto HPA piston cannon. discuss.

Thanks in advanced.

Assuming you have a well lubricated piston with effective equalisation, you don't need that strong a spring if filling from the chamber side. Naturally a spring will dreuce the velocity with which the piston opens but in practice I doubt you will see a significant drop in performance.

A burst disk in a multi-shot won't really work, what you need is some kind of o-ring or detent that will hold the projectile in the breech until enough pressure builds up to fire it. As to RPM, pretty friggin fast

My biggest problem with springs and piston valves is they tend to destroy the spring. I gave up on trying to use them long ago. I use a puff of air in the pilot to close the valve and provide the initial holding pressure then blast it full in the chamber.

My Mouse Musket was the last functioning traditional piston valve cannon I had. It is now retired. My current line are all QDV cannons. Valve is closed by simply pushing in the knob and filling the chamber.

I do have plans to build one in a T, but I am going to finish my 2.5 inch build first. Now that the weather is nice again, I need to get busy working on it.