Air Chamber Pressure

[bambam]

Hello All,

Does anyone know a way or have something up their sleeves for checking the pressure in the AIR chamber???

In detail, the pressure AFTER its been regulated down from an input pressure of, for example 800psi.

This is the area between the powertube and the regular.

The Mag Air valve is very similar to the Air America regulator (UniReg, Violator,etc) in design which the output pressure can be measured.

Iwas just tHiNkInG :rolleyes:

Thanks.

[Smokee_2_7]

ok, here's what I can rememebr. First off, I dont think there' gonna be an easy way for you to measure it.

That being said, I believe AGD said that the reg. drops the pressure to somewhere around 400. Afterward, the pressure gets lowered even more, due to the fact that when the on/off opens, the air must now fill a space that over 2 times the size of where it was confined to previously. Not sure on this, but i want to say that the actual air pressure behind the bolt when the gun is fired is somewhere below 100 psi. The easiest way to get the facts would be to find out from AGD directly. I know tom has determined these values for various points in the gun's firing system.

Hope this helps.

Carl

[nippinout]

The pressure after the valve is around 400psi, as stated earlier.

Before you fire, the on/off is open and both in front and behind the on/off is 400psi. As the on/off is closed, the air in front and behind it is still 400psi. When the sear drops, the 400 psi pushes the bolt and fires the ball.

Bolt returns, on/off opens, and air comes from the reg and the pressure is raised to 400psi again.

To actually know the exact pressure, you'd have to modify the gun. The powertube might be difficult to access with the bolt over it. I say, take Tom's word- it's 400psi.

Any reason you ask?

[bambam]

Nippinout,

Are you saying the pressure in the chamber is 400psi and that is what the mag needs to move the bolt foward with enough adequate fps???

Can anyone else confirm this???

Assuming the 800psi input pressure and a chrono reading of 290fps, doesn't 400psi seems alot to propel a paintball??

Of course there is substantial loss with the spring counter effect or is there??

[Smokee_2_7]

here ya go, read through this thread. http://www.automags.org/forums/showthread.php?s=&threadid=44110&highlight=bolt+pressure

400psi right behind the ball when the gun is fired kinda seems like alot to me, too.

[Havoc_online]

as the air is regulated it's lowered to about 375psi. actual air pressure on the ball when fired is between 60-80psi(depending on settings) which is more "low pressure" than most markers, the rest that gets the ball outta the barrel at 300FPS is bolt speed.

[bambam]

Havoc,

Bolt Speed??

Wouldn't that depend on the air chamber pressure to move the bolt foward??

375psi minus (lets say) 60-80psi = 295-315psi

Is all 295-315psi used to move the bolt forward??

Now couple that with the ~60-80psi, it is still using alot to propel a paintball IMO

Bottomline is regardless if it takes 60-80psi to move a ball down the barrel, it takes 375-400psi every trigger pull to move @300fps

That's hardly "low pressure"

[hitech]

Originally posted by bambam
Bottomline is regardless if it takes 60-80psi to move a ball down the barrel, it takes 375-400psi every trigger pull to move @300fps

That's hardly "low pressure"

That depends on what pressure you are referring to. It's one of the lowest "pressure behind the ball". It doesn't matter, since none of it matters anyway...

If you really want to measure the pressure in the air chamber without modifying the air chamber you need to tap a power tube tip to accept a pressure gauge. You will probably need to attach a hose first, then a quick connect. After replacing the valve (minus the bolt) into the body you can attach the gauge. Gas it up and read the pressure. Hope that helps. :D

[SlartyBartFast]

The pressure experienced by the ball is indeed in the 80 psi range. Check some of Tom Kaye's figures and graphs in the Deep Blue area.

http://www.automags.org/forums/showthread.php?s=&threadid=34429

But the only speed the bolt imparts to the ball is the initial 3/4 in of movement. The gas in the chamber escapes past the bolt and expands to accelerate the paintball to 300fps.

Actually by the graphs, it would seem that Mags are the guns that are the easiest on paint as far as gas pressure on ball is concered.

As far as "low pressure" is concerned, that's one of the rediculous paintball marketing terms that is thrown around without much expalaination. Mags are low pressure behind the ball.

What actually matters is pressure experienced by the ball, the total energy used to fire the ball, and the efficiency of the system.

[fuzzyolary]

AMEN !!

Oooooh, I think I'm going to like it here!

:D

[bambam]

Smokee_2_7 & SlartyBartFast - Thanks for the links. Will definately read thru for more info.

Hitech - Are you serious or what??? It does sound like a good idea. Might have to try a "hose&gauge onto the powertube" contraption.... :cool:

[hitech]

Originally posted by bambam
Hitech - Are you serious or what???

Yes I am. :D However, be forewarned, I have never tried this. If you break something, don't blame me. ;) If it works, let us know what you find out. I'd be curious, esp. a level 10 setup.

[SlartyBartFast]

You don't have to access the powertube to measure chamber pressure. You just have to put a hole through the valve body forward of the ON/OFF.

But, still. Why do you want to? The important pressure is the pressure that the paintball experiences in the breech and as it accelerates down the barrel.

[2xFast]

AGH....much easier than drilling holes...

Simply disable the regulator so that it can't regulate pressure down anymore, hookup an adjustable air source, and turn the pressure down till you're shooting at the same FPS as you were before you disabled your AIR valve....

I believe to disable the air valve all that is required is the removal of the reg pin...but definetly double check me on that...and I'm not sure if its changed on the RT valve...but I know several people have disabbled standard AIR reg so that they could run the gun directly off an aftermarket reg...

As for the pressure, it varies, but its around 400 psi...I know this becuase back in the day I had a Smart mag, which sucked, so I chopped of the magic box and filled the resulting hole with a gauge suprise suprise, it read ~400psi day in and day out...

Hope this helps...

2xFast

[hitech]

Originally posted by 2xFast
Simply disable the regulator so that it can't regulate pressure down anymore, hookup an adjustable air source, and turn the pressure down till you're shooting at the same FPS as you were before you disabled your AIR valve....to disable the air valve all that is required is the removal of the reg pin...

That will work also. And that is all that is required to disable a classic valve (and I assume the RT also). I would also back off on the AIR reg. :D

[bambam]

2xFast - Best idea I ever heard... Will have to try that one as well....

:cool:

[SlartyBartFast]

Good thinking about measuring at the input of a disabled Regulator.

Now why didn't I think of that?:(

[bambam]

AOG: If anyone has tried 2xFast's idea, please post your air chamber pressure to compare to what others have with different markers shooting @290fps.

I'll post mine as soon as I get a chance...:)