What may seem a silly question about HPA tank size/pressure

[punkncat]

This seems really simple, and a silly question to ask, but just wanted to be sure that I am thinking correctly.

Between a 4.5K and 3K tank, it would take a 33% larger 3K tank to hold the same air as a smaller 4.5, correct?

In other words, as far as volume of air a hypothetical 60/3000 would hold the same amount of air as a 45/4500 right?

What I am getting at, is that an 88/3K holds just barely less air than a 68/45 and would hold almost half again as much air as a 45/45?

[cmoses]

Your thoughts seem sound to me. I think it's Boyle's Law that you are using, P1V1=P2V2. Take your current tank size(45cu) multiplied by its pressure capacity(4500psi), and then divide that by the alternative pressure(3000psi) and it should tell you what size tank you would need to be equivalent(68cu).

[Spider-TW]

Which means you would need a 50% larger 3k tank.

[factoid]

Spider's got it right...the way the math works out a 4.5k tank holds 50% more air than a 3k tank.

if you look at it in the other direction, though....a 3k tank holds 33% LESS air than a 4.5k tank. It just depends on which tank is your frame of reference.

If you get 500 shots from a 45/3000 you should get 750 shots from a 45/4500.

[cockerpunk]

internal energy is pressure times volume. this neglects entropy or expansion losses, but its a pretty good approximation.

[Spider-TW]

internal energy is pressure times volume. this neglects entropy or expansion losses, but its a pretty good approximation.
Have you ever compared the total internal energy in a 68/45 to the kinetic energy of some number of shots? I've done it twice and I keep loosing the file. As a theoretical limit, it appeared that 100% conversion would give you ~3000 shots, and a 70% conversion would give you ~2000 shots.

Besides ignoring the irreversible losses, it seems a little too simple. I guess it's just comparing the two different forms of energy that bugs me.
***
Found a file. That's with 280 fps and 3.185 gram paintballs (that was an average from somewhere).

[punkncat]

Which means you would need a 50% larger 3k tank.


This was what I was messing up in my thought process, and why I asked. Thanks.