firing more than once before re-pumping

[knappengineering]

My friend and I want to figure out how to get multiple launches without having to re-pressurize our chamber. First we thought of having multiple chambers that are pressurized and just putting a pressurized one in, firing, taking it out, and putting in a pressurized one. We are thinking of using the quick connects that are used on compressors. Does any1 have any suggestions so that we can shoot more than once before we have to refill the chamber?

[us sniper]

Use co2 and a regulator. Then once youu fire the co2 fills up your cannon again, or look at clides golf ball semi.

[dongfang]

Hi,

I thought of this as well....

One way is to have a primary (tank) and a secondary (firing) chamber. Before each shot, the secondary chamber is refilled from the primary. That could be done by a more or less automated valve system. I think Clide´s GB semi is a 2-chamber design.

One basically has these (maybe more) choices for how to refill:
- Pressure divider. First, the primary chamber is connected to a fixed volume (third) chamber. Then, the primary is disconnected, and the third chamber is connected to the secondary (firing) chamber.
- Just fill the firing chamber directly from the tank chamber
- Put a pressure regulator between the 2. That should also give you constant performance until the tank goes too low on pressure. This could be really nice for a hybrid.

Regards
Soren

[singularity]

if you plan on using quick disconnects to connect the cartridges it would only work on the small scale (bb guns and other small diameter cannons) becuase they don't have the greatest flow rate. i would suggest a shell type gun where both the ammo and air are stored in a shell, all that would be in the gun itself them would be the pilot vale and the barrel. it would be easy to make a bunch of 2" coaxial shell, you could make like a sweet artillery piece.

[DYI]

I think what he means is that the firing chamber could be refilled with the precharged cartridges, and then he would open the valve. If you need better flow, you can always get 1" quick connects (could be expensive though. You could make loads of pressure cartridges, then just attach them with quick connects. A more practical method would be to have a large, high pressure secondary chamber which is regulated down to your intended working pressure.

[windshrike]

The quick connects are a bad idea unless you can connect them VERY quickly or else they will leak a lot while you put them on. Just divide it with a ball valve.

[Infernal Maveric]

If you are using quick connects, why not just keep the compressor turned on, and let it refill your chamber in between each shot. That way it saves you messing about with extra chambers and such.

Another way to get about 2-3 shots from 1 pressurized chamber is to make a barrel sealing piston inside a T. Have a powerful spring behind the piston and a re-sealing exhaust valves (Think blowgun, rather than ball valve). That way, after say 1/3 of the chamber has been cleared, the spring re-seals the barrel ready for the next shot.

[DYI]

I think the point of this is to be portable, and lugging around a compressor (which needs a power source), isn't exactly portable.

Obviously you wouldn't use quick connects in this application unless they had ball valves on the air source side to prevent leaking, i.e.; close BV on pressure cartridge, attach cartridge with quick connects, open BV.

Something along the lines of a CO2 tank would be the most practical in this application, but cartridges would look cooler.

[dongfang]

Hi, DYI

OK, what I call a primary chamber (tank) is what you call a secondary chamber. This could get confusing if we aren´t careful...

Regards
Soren

[knappengineering]

Thanks for all the help guys, I'll probably end up having two chambers, a filling chamber and a firing chamber. I still have one questions though, what would i use for a regulator between the two chambers, keep in mind i want to keep this a compact, portable gun. It is going to be like a pistol size with a 1/2 inch barrel. I also want to stay away from co2 cartridges just because i don't want to buy them and I wanted to make this myself and be able to just refill the chambers w/ the compressor. thx again.

[singularity]

well you could just put a gauge in the firing chamber and slowly open the ball valve between the chambers and turn it off once it gets to the right pressure.

[jrrdw]

Thanks for all the help guys, I'll probably end up having two chambers, a filling chamber and a firing chamber. I still have one questions though, what would i use for a regulator between the two chambers, keep in mind i want to keep this a compact, portable gun. It is going to be like a pistol size with a 1/2 inch barrel. thx again.

You could plumb in a regulater for a air compressor. You can get them from hardware stores/on line, basicly just about anywhere. Scrap one from any old out of use air compressor.

[knappengineering]

I think I found the perfect regulator for this project all i need to do is find the fittings to connect it to pvc but that shouldn't be too hard. thx again for the help. here is the link:

http://www.lowes.com/lowes/lkn?action=p ... lpage=none

[666lucky693]

another idea since u want it to be like a pistol you could have a hose going from your gun to a pressure tank made out of pvc and have 2 of them and a valve to turn each on and off so when one runs out just turn off one valve and turn on another

[knappengineering]

@ 666lucky693 That could also be helpful if i had tanks like that on my back or something similar and then i would get a lot more shots. thx