SpudFiles

Hello,

First time builder and i could use some help with calcs. I've tried downloading the GGDT and couldn't open it up.

all PVC...
ID of the barrel is 2.58"
ID of the chamber is 3.04"
1" sprinkler valve to fire it

I plan on using a portable air compressor to pressurize the system. Since i'm going to be shooting tennis balls out of the barrel for my dog they don't need to go 100 yards every time. And since the portable air compressor will take awhile to fill up the chamber i'm looking at creating a primary chamber on the smaller side.

With that being said, sometimes ill want to "show off" and see how far i can shoot something. At that point i could open up the ball valve that leads to the secondary chamber for more capacity. As you can see by the rough sketch attached.

So now i need some experienced builders to help me with sizing the barrel and chambers. Feel free to tell me if I have any major design flaws too! Any time you spend responding is much appreciated.

Thank you

If your budget will allow it, would you consider dropping some cash on a paintball bottle and regulator as a fill system?

What would a rough estimate be for that? Most likely not, my wife said my budget has ran out lol. Maybe i could pick one up used

Not sure if my first response went through...
Most likely that will be outside of my budget. Maybe I can find one used. Why do you suggest it? Is it a big improvement in performance?

Have a look at something like this setup:

another one:

I would then make the launcher with a single chamber, and vary power by varying pressure.

That looks really cool and perfect for the task at hand, but it is way outside of my budget :/

Are you able to make any recommendations on chamber size based off of what I have right now?

Or can anyone offer a general rule of thumb for optimal barrel:chamber ratio?

Ive seen some posts say 1:1 is pretty good, is that correct?

Hey i got the GGDT up and running finally. I'll do my due-diligence and play around with this before i ask anymore questions!

Thank you

Here's a simulation for a launcher with a 1" sprinkler valve (modded for pneumatic actuation), 2 foot barrel and 1 foot chamber. You can see the difference in performance at 50 and 100 psi, to me it makes more sense to have a single chamber and alter the performance by altering the pressure.