question about valves

[Backspace]

hello everyone

i'm going through my first built of a spudgun, and i'm gathering the parts and doing research. I'm gonna use a 75mm barrel, but the valve i found is 1/2" in diameter. Will this difference in diameter impact my pressure/firing distance?

[jackssmirkingrevenge]

You must think in terms of cross-sectional area.

In this case, 75mm is almost 6 times greater than 12.7mm, but in terms of area it is a whopping 35 times greater.

This is not a recipe for good performance.

The effects of the Square-cube law are quite pervasive in this hobby.

Finding a bigger valve commercially is going to cost you, so consider building your own or using something simple but effective like a burst disk.

[farcticox1]

127mm or 12.7mm

[jackssmirkingrevenge]

127mm or 12.7mm

Good catch, edited.