strange ideà

[SpudFarm]

hello!
this is a ideà that fell in my head 10 minutes ago. absolute no time used to think through it.

the picture pretty much explains it all. the screw on the end of the chamber is screwed in and pushes the piston towards the valve and compresses the air in front of it. then you simply open the valve (burst disk mabe) and watch the ting fly (?)

any suggest?

[subterranean]

That would increase the pressure but only by a factor of 2. So the pressure will be low and the volume will also have decreased significantly. It would be the same as pumping a bike pump one time.

[SpudFarm]

it can work on a mini cannon if you make the piston housing bigger than the camber in diam. lets say a 1" chamber and 2" "pump" and the pump little longer then the chamber as well.

the potential is there but pretty little.

another thing to get it working can be a small diameter barrel and large chamber.

it is not to be a good way to charge but to make something new.

[MaxuS the 2nd]

Indeed, it would only be worth while if your chamber was absolutely gigantic.

[SpudFarm]

i am not sure if i know what you mean maxuS

[Velocity]

Hmm... what if you pressurized the chamber to say 100 PSI, and then used this method? I am not sure about the ability of the materials to get the job done, but in theory, P1V1 = P2V2 tells me there is definitely some potential.

[subterranean]

There you go, now its maybe worth while But you would still need a large initial volume.

[jackssmirkingrevenge]

Single stroke pneumatics use a similar system (though compressing the air through a lever instead of a screw thread) and generate enough pressure for one small calibre shot at a decent (say up to 600 fps in 0.22) power level.

[SpudFarm]

i think i make someting like that on my marble gun. i pump in 150psi then compresses it t 250 or so ;- )

or i can make a copy of the marble gun just for testing stuff on it?

[Hubb]

This is kind of like that hybrid idea that FeLeX (I think) posted.

[FeLeX]

Yea I had a similar idea only it was to eliminate the need to measure the fuel and air pressure bla bla bla I got discouraged. I think this is a lot better idea though but I think it would only work having a long thin chamber and having a small caliber barrel.

[psycix]

It should work if you could make a good piston.
But its not very effective.
You can better build a pump for this.
Multi-stroke causes a way more compact design.

[schmanman]

you could modify one of these /w/ o-rings and/or a rubber face on the front to do this for you.....

[Hotwired]

That would increase the pressure but only by a factor of 2. So the pressure will be low and the volume will also have decreased significantly. It would be the same as pumping a bike pump one time.

Eh?

Ramming a piston to the bottom of a sealed shaft doesn't just double the pressure. We're not talking about a bike pump pumping a large chamber either.

This is the whole chamber of air being squeezed. Push the piston halfway down and the pressure doubles. Halve that volume again and the pressure doubles again.

So lets say you had a chamber piston which could compress the volume to 1/8th of its original. Starting with 15psi atmospheric pressure that goes up to 120psi or 105psi on the gauge.

You wouldn't get performance value for size out of such a cannon since it could be matched (and out performed) by a smaller cannon that used a normal multi-stroke fill system instead of a long compression chamber.

[Spitfire]

ITs like a syringe. Block the end and squeeze the pressure increases