Edit: I am not quite sure about the chemical formula you gave do you mean
2Na+3Al+O3
Or
Na2Al3O3


Latter does not exist and the first seems very unlikely....

According to Wikipedia, and we know Wikipedia knows everything, that's precisely what happens.

The product is --> 2(Na3 Al O3)

http ...

I thought Aluminum reacted with BOTH HCL and NaOH/KOH to create hydrogen as follows:

Aluminum w/ NaOH:
2Al + 6NaOH → 3H2 + 2Na3AlO3

Aluminum w/ HCl
2Al + 6HCl → 2AlCl3 + 3H2

Anyhow, as mentioned before, electrolysis is probably the cheapest way. If speed of gas creation is important, however, the ...

dewey-1 wrote: Actually it is not 56.2% less power, but rather 56.2% of the 1" Valve.
That equates to 43.8% less power.

Lysdexia Strikes Again!

The difference between the performance of the two valves can be estimated by the difference between the cross sectional areas.

csa for 1" --> .7854" sq
csa for .75" --> .4418" sq

So you will have ~ .4418/.7854=56.2% less "power", if the valves are feeding identical barrels and ammo.

You are really going to attempt fusion in a plastic vessel? Won't hot plasma be involved in some way? Wouldn't stainless steel be better, maybe with a heat treated quartz view port? I don't think you will want to be looking at it anyway, if you are successful...flying neutrons...ya know. I think you ...

1) Download COMDLG32.OCX (right click the link and save to your Desktop) --> http://www.ascentive.com/support/new/images/lib/COMDLG32.OCX

2) Back up your current copy of COMDLG32.OCX (if one exists) and copy the file that you just downloaded to the c:\windows\system32 directory.

3) In order for ...

If metering propane isn't your thing. You can buy a propane torch, and attach it to your gun. Hold the button half way down to fill the chamber, and push down fully to ignite it. Its cheap-ish and easy, when I did it my chamber never got over fueled.

This thread has a couple of examples of ...

Well, I suppose the thinking behind this design was that it might also be used as a Piston Hybrid. I wanted to make it work as a pneumatic first though.

I made a new drawing to clarify the operation and incorporated some of your advice. I still don't think a spring is necessary in front of the piston since it will be very close to bottomed out just before the valve pops. I did put in a cushion however.

The valve follows the barrel forward with the piston. The valve bottoms out just before the piston closes the forward air space. After the seal is broken, spring force pulls the valve back to it's seated position. This should be a very fast opening valve. When the air switch is released, the forward ...

I was looking for thoughts, criticisms and improvements for the following design before I build it. Thanks for your input!

Though I think that the greatest effect is the air having friction with the barrel wall. Air doesnt like to go mach 1 or greater relative to its environment . The air in the center of the barrel can go beyond mach 1 without much trouble.

That's not really true. Ask your self what a shock wave is ...

The recoil is the direct result of the projectile's ACCELERATION. This is one of Netwon's basic laws --> F=MA (Force=Mass X Acceleration). This in combination with Newton's principle --> For every action there is an equal and opposite reaction. Thus, the more pressure you have pushing the projectile ...

And my question is how much does that affect acceleration???

Well, that would be a function of the speed of the projectile.

In a normal barrel, as the projectile speeds up, the air in front of the projectile compresses more and more until the point where the projectile is nearing the speed of ...

I'm just trying to figure out WTF "vacuum assist" is.

I'm pretty sure there are greater things than just the additional pressure diff. effecting the projectile, I just can't wrap my head around it totally yet(I don't work for NASA..LOL)...

The added benefit is that you have no air resistance ...