Air flow behind paintball at specific PSI

[noahyay]

Does anyone know a way to calculate the air flow needed to fire a paintball at a certain psi?

A lot of this depends on barrel length too. So how about assuming 8 inches of usable barrel.
This would be differnt for different psi I know, but if needed we can assume 100psi in this case.

For example: the MQ valve needs how much flow at 300 psi to accelerate the paintball to 280 fps in eight inches?

[noahyay]

275fps
.0036spf
0.0024seconds per 8 inches
0.0048seconds acceleration time

.68 diameter
.34 radius
.36298 area
2.9 cubic inches for 8 inches acceleration area

1728 cu inches in cu foot

10cfm
17280cubic inches a minute
288cubic inches a second
1.3824 cubic inches per .0048 seconds

so i would need about 20ish cfm to supply constant pressure to a paintball during its acceleration area of 8 inches.

But I still dont know the answer to my question...

[athomas]

In order to calculate the air flow, you need to know the restriction of the valve. The air through a valve with a 1/4" dia opening is going to flow differently than through a valve with a 3/8" dia opening. There are also air line restrictions within the valve. ie; How long is the opening in the bolt? How much of a restriction is at the valve orfice? What is the operating pressure of the valve? Lots of things to consider.

You know the 300psi operating pressure. Now you need to know the restrictions within the valve. Ideally, all 300psi would be available instantly. That would make the most efficient gun. Then we could actually calculate the actual volume of air required for a shot at any desired pressure. Even though its not the way it works in the real world, its still a good starting point.

[noahyay]

100 psi at 22scfm is the flow rate through the valve..