Propane Semi-auto <--real idea

interesting...

Ok, so I found out that I am going to have access to a machine shop at my school.

Im going to use roughly the design above. Except for a change in the bolt latch, and I am going to move the air mixture valve to to beside the bolt.

The chamber should end up being roughly 4.5 cubic inches. on further review I can make the chamber 3.5 cubic inches. As this will lower the profile of the chamber.

Ill start a new thread when I begin the actuall work on it. This should be freakin sweet.


Edited by Monk - 05 August 2006 at 9:21pm

With an increase to the size of the rear valve body, and a change to the bolt.

I put in a spring that when fired the piston pushes the spring back and latches it. The piston will then return to the original position. The spring on the exhaust piston will push it forward with the bolt. The bolt will hit the latch causeing the spring to release and push the bolt forward along with the exaust.

Im not real sure this will work. It probably wont. But Im about ready to give up. lol.

Enos Shenk wrote: You need to look at any design from a practicality point of view. Most of those parts would be extremely difficult if not impossible to actually make.

Actually, in the last drawing i tried to make everything manufactuable using only a drill press and lathe. mcmaster part numbers are listed. No real milling. Everything is circular. The chamber would have to be made from scratch, or possibly a modified co2 tank(?). A cocker 3 way with a volume chamber on the input would be the obvious choice for the valve, that is the way my valve works.

Enos Shenk wrote: Or what draws the propane out of the injector valve. Or how you would get an adequate fuel mix when the injector valve closes before the system mixes, so the only propane available to be mixed is contained in the small hose.

Small hose + adjustable volume chamber in valve should be adequate. Combustion ratio for propane is 2.37 – 9.5%. So small volume @160psi will equalize to acceptable amount when the path to the chamber is open.

Enos Shenk wrote: Doesnt make any sense on what is moving what.

It probably makes sense to me only cause I drew it.

1: At rest the breech is open, the ball drops in. The main (blue) spring is holding the valve open to the chamber, and holding the plunger back.

2: When fired the huge chamber pressure blows the bolt out of the powertube, overpowering the main spring, and when the bolt exits the powertube the feed neck has been sealed off so the paintball will shoot. The valve is now free to recharge w/ fresh propane. The bolt will lock in the forwards position thanks to the small spring clip that latches in the powertube.

3: When chamber pressure reaches zero, the plunger spring (green) will be able to push the plunger and flush the chamber. At the plunger's forward point it disengages the spring clip holding the bolt forwards, and the more powerful main (blue) spring will return the bolt and plunger together, and at the same time it will discharge the valve contents into the fresh chamber. Back to rest position. Ball will drop into the open breech.

Dang, thats hard to explain in words.


Edited by pattison - 17 September 2006 at 1:13pm

if it bothers you then don't read it.
i haven't had the patience or time to respond to es's post coherently. this weekend i do.

Thats kind of an outragious price estimation. When they switched from pump to semi on regular guns noone expected a price hike like that. lol.

I think this is a great idea... to keep the chamber from being too wide try making it an elipptical shape and back in the middle of the back and forward grips....also with cooling im sure u could incase it in water or a computer heatsink.  The heatsinks on computers are made to cool ofvery hot objects to room tempurature and i think would work very well!!!