# Got an Idea

So, I got this idea last night, but I need to know if it works. Now, I can’t tell you what it is, but I can say that there is a solenoid that is directly related to opening and closing the valve. I need to know how long the valve needs to be open for the gun to fire at about 290 FPS. How can I figure this out?

Find out how long the paintballs would take to travel their diameter once (and the width of the valve) at 290 FPS.

290ft/sec = 7366mm/sec

(paintball width + valve width)/(time the valve should be open) = 7366

So the time the valve should be open would be the paintball’s diameter plus the valve’s width, divided by 7366.

Ah. How the heck did you find that out, and how the heck did the first person find this out? Thanks, BTW.

I’d guess he took a high school course in physics.

No, I’m taking that next year.

Really, it’s quite simple math. >.>

But it requires a lot more than you gave me. I need things like air pressure, and ball velocity. BTW, I took High school physics and I didn’t learn anything about this kind of stuff. Otherwise, I wouldn’t be asking.

You gave me a velocity so I worked with that. I assumed that 290FPS was the velocity of the ball while leaving the barrel.

And if that’s not true, then put the ball’s velocity (in mm/sec) in place of 7366.

No, that’s true, but what about air pressure?

Then you calculate the speed of the paintball based on differences in air pressure and put its speed in mm/sec in place of 7366 in the formula I gave you. Or better yet, you could ensure that there is never a difference in air pressure between the gun’s chamber and the environment by having various tubes between the inside of the gun and the environment that can be opened without the gun being fired. Though I’m not sure how the would affect the gun’s mechanism.

WTF?!? I have no idea what you mean. The chamber is the same pressure as the enviroment.

Nevermind then. I’m not really sure how exactly a paintball gun works, and I thought that there would always be a paintball in the chamber, keeping high pressures from escaping.

But anyways once you have the speed of the paintball (which I am no longer sure how to calculate) then you can figure out how long the vlave would need to be open:

(width of paintball in mm) + (width of valve in mm) = time valve needs to be open in seconds
(speed of paintball in mm/sec)

A paintball is .68 cal.