SpudFiles

Okay I've been through these designs over and over and I haven't fond any flaws in them yet. Basically it is an idea for a semi-semi-auto hybrid. No burst disk, no timely refiliing. And best of all efficient. I have posted the pictures below with a breif description of each stage.

That will certainly work, I think that it is a great idea.

I like it alot. The piston idea is great!

Cheers guys, after a little mucking around with calculations and what not I plan on drawing up the details for it. I plan on using either stainless so at least I can weld wherever I may need to, or carbon steel although that may have to be machined alot for certain parts. Maybe even sculpted from rods.. Dunno.. I thought while I'm at it, may as well make it the best I can. Apart from that there shouldn't be too many hassles with it. Some guy's trying to make a homemade paintball gun from scratch on http://www.gizmology.net/pbm.htm and I hope to use his loading mechanism in mine. (With a couple of mods.) It's quite simple but thats what I like about it.

Anyone see any problems in the design?

nope looks flawless to me. it would be really good if you could get it to work.

seems to waste an awful lot of oxidiser!!!!!

dude from what i can see the oxidiser is the air and i dont think that we are going to run out of that anytime soon. please correct me if im wrong

You have to make sure that the small disk that vents behind the piston is smaller than the barrel, otherwise it won't stay closed. Since adding fuel will raise the pressure on only one side of the piston, you will need to make the vent disk significantly smaller than the barrel, you would need to run the calculations with the actual pressure rise of adding fuel, and I would use an o-ring seal on the barrel to prevent leaking since you probably won't have a large force pushing the piston closed.

Yeah true, I havn't actually thought about about the added pressure of the gas. Maybe if I make it the same as the diagram with the addition of another inlet in the rear chamber. This has a ball valve between the reg and the inlet. This ball valve is connected to the gas ball valve so when I add the gas in the front chamber, it is equalized by adding air in the rear. I believe that should work. I'll put a diagram on. UPDATE: Either that or a piston equalization idea where it involves a piston connected before the check valve and after the ball valve along the gas line. This disperses pressure into the rear chamber without letting combustible gases in. (Top diagram - I tried to get the picture at the bottom but no go

TechnoMancer wrote:seems to waste an awful lot of oxidiser!!!!!

I dont see how it would, the combustion would be almost instantaneous so as soon as the piston hits the bumper, the oxidizer is shut off. And as the spring pushes the piston back foward again, it passes the inlet once again and the pressure will force it closed very quickly. There really should be a very minimal amount of air wasted, as much as a paintball marker 'wastes' in a shot.

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