air calculations? (volume and how much is needed to shoot)

[ramenjames]

ok i know volume
(pi x radius sq x lenth (in inches))
but what is the calculation that will tell me how much air is needed to fire some thing?
also is it possabel to calcultae the fps of something with out chrononing? (based on the weight of the shot and the volume/presure of the air?)
please help

also how many grams are in an ounce?


(btw this is for a paintcannon)

[Redkey]

there is another current thread discussing the amount of air required to fire a paintball, it should help to shed some light on what you are asking about.

there are roughly 454 grams in a pound and 16 ounces in a pound. 454/16 = grams per ounce.

can you calculate the velocity knowing the weight and pressure/volume of air? In theory yes. In reality there are so many variables that will impact the velocity an accurate calculation will be very difficult. Things like barrel friction, flow dynamics through the valve, any leaks either in the valve or past the projectile would have to b included in the calculation.

However, with experience, you should be able to figure out roughly how far your paintcannon will fire a certain shape and weight when charged to a certain pressure level.

I would be more concerned about building something that won't explode when pressurized.