Making the process a bit easier

[CS]

Here is a basic layout. If possible I would like it to be shot the same style as BTB's sawed off, but I can't find a nice place to place the handle.

As you see it uses mostly NPT pipe, however most joints are just welded together without using a connecting nipple.

[psycix]

I dont really think the whole piston idea will work!!

Coz when you push out all the air in the chamer, it enters the barrel.
When you suck back the air you suck back the same air you just pushed out.

Okay, ofcourse it will help, but i think having a case fan will be way more effective.

[shiftyguy]

Just thinking off the top of my head.... If this was a dirt bike engine it would have a reid vent to allow for venting and intaking of new air. When an explosion in a chamber happens 2 things happen, there is an explosion (high pressure) and out comes the potatoe/flames. Then there is a a low pressure as everything is propelled out. If there was a reid vent that would seal off the chamber during the high pressure and allow air in during hte low pressure it would ventilate it's self.

Anyone think i am crazzy... I just came up with this now. It could be moulnted to the screw cap...

[Dornep]

The atmosphere contains ~20.9% oxygen, and the atmospheric pressure is ~14.7PSIA. So the venting process could be simplified by injecting ~3.1PSI of pure oxygen. In fact I have easy access to regulated oxygen, however we all know the dangers of handling pure oxygen. Although you could inject ~14.7PSI of compressed air, and get the desired amount of oxygen contained in the ~20.9% of the air. As noted below the chamber would need to be closed, implementing a burst disk, or similar device. That only detracting to the elusive goal of ease.

[note - the chamber would need to be closed for discussed methods to work. as well compensation for spent gasses in the chamber were not made.]

Or after the shot you could emit short *puffs* of air into the chamber in a attempt to blow spent air out the barrel. But in reflection that probably wouldn't work as not all the spent air would be exhausted. That resulting in a unpredictable amount of oxygen in the chamber, which gives you nothing to base your propane calculations on.

Your probably either going to have a bulky external venting setup, a burst disk setup to inject the 14.7PSI of compressed air, or a removable end cap. If your wanting an exact mix every time your probably gonna have to give a little on the design..

[jrrdw]

Sgort, i think was the one who entered a quick venting systemed cannon in the cannon contest. You'll remember that one? He popped off 10 shots in like a minute. I don't think he loaded it every time, but it all happened nicly and quickly. Look that one up Pimpmann22.

[psycix]

Just do chamber fan + huge ball valve on the butt.
Meanwhile have a bolt action reload.

Close valve and go again

[redchigh]

A computer exhaust fan on a 9volt battery works great for me *shrug*

[pyromaniac]

You need your chamber to be sealed off to put the oxygen in right? You could change the way the piston is put in. You could move it to the tee and seal off the barrel put in the oxygen pull it back when your ready to fire, and well fire.