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Weird pneumatic

Posted: Wed Nov 24, 2010 9:52 am
by drunpal
Hey i am new here and (sorry bad English) i am going to show you my lastest pneumatic gun that i have made. It uses valve that i havent seen here, there is a piston connected to the barrel and when you pull the barrel backwards, the air goes to the barrel from holes in that are in the barrel.

Shooting vid here.

[youtube][/youtube]
[youtube][/youtube]


Edited by jrrdw, double post, embedded video.

Update....................................................................................

Now i added stock in the gun, painted the gun and did some more shooting. It can shoot a nail trough both sides of cardboard box.

Posted: Wed Nov 24, 2010 10:05 am
by SpudFarm
This kind of reminds me of Tech's QDV..

The first thing that fell to my mind though is a external magazine for BBs that fall in when you push the barrel forward. Then they are fired when the barrel is pulled backwards, repeat and you have a rough semi..

Pretty clever IMO.

Posted: Wed Nov 24, 2010 10:16 am
by Technician1002
It looks like it has to push against the chamber pressure to open like a poppet valve. It would be impossible to use in larger sizes at high pressure.

I wonder if it blows off o rings at high pressure. Due to the chamber, I doubt it is used at very high pressure.

It does provide a large valve seat for a smaller barrel so it's rate of opening is very high and would open a gap with more area than the cross section of the barrel in very little time. It would be an extremely fast opening valve due to that.

Posted: Wed Nov 24, 2010 10:18 am
by drunpal
Another vid here, very low psi in both videos because of my handpump... ... i guess under 25 psi because i could push the side of the bottle down with my finger.

[youtube][/youtube]


Yes i am sure it would not work with high pressure, it pushes back even with as small pressure as that. Still good enough for me

Edited by jrrdw, double post, embedded video.

Posted: Wed Nov 24, 2010 10:56 am
by jackssmirkingrevenge
Add an electric motor driving an eccentric cam and you have the potential for full auto ;)

Image

Posted: Wed Nov 24, 2010 5:35 pm
by matti
welcome to the forum and for the cannon.. well, at least it works :D
the idea is good but the implementation is a bit poor.

Posted: Wed Nov 24, 2010 6:38 pm
by SpudFarm
but the implementation is a bit poor.
How do you test a concept you haven't seen working before then? I would certainly end up with a prototype much like this if I planned to do a bigger build upon the same concept later.

Posted: Thu Nov 25, 2010 11:55 am
by matti
SpudFarm wrote:
but the implementation is a bit poor.
How do you test a concept you haven't seen working before then? I would certainly end up with a prototype much like this if I planned to do a bigger build upon the same concept later.
He didnt say that it was a prototype and with just a little work it could be much better.
if thats a prototype, then its ok :D

Posted: Thu Nov 25, 2010 2:10 pm
by Selador
matti wrote:He didnt say that it was a prototype and with just a little work it could be much better.
if thats a prototype, then its ok :D
It's -more- than ok, even if it is not a prototype.

Go back and look again, and think about it before you make a judgement.

It was obviously built almost completely from things found about the house.

The builder obviously actually THOUGHT about what they were doing.

They didn't just stick things together because it looked like they would work. They had to actually think about how, and maybe more importantly, WHY that valve works. And then build that valve with what was available.

Putting something like this together, (and have it actually work)... With all the "right" materials... Because one has access to, and can afford them... Is difficult enough.

To have put it together and gotten it working, with what the builder used, is very impressive.

:D

Posted: Thu Nov 25, 2010 4:57 pm
by wyz2285
nice work :) i like it, the power looks good 8) .Try use a blowgun