Full-auto

[CpTn_lAw]

Hey there evryone, so I dug up an old topic I posted, about a full-auto valve prototype:
linky

In parallel, I took apart a nerf vortex gun... It has the exact same valve, though it doesn't work exactly the same, it is the same model.... kinda takes credit away .
Still, it proves that the design works perfectly, i took the valve assembly out of the plastic gun, and dry-fired it. It's very fast opening, creates a nice puff of air, but like my ghetto design, it actuates a little higher than 1 bar.
I don't have acces to machining tools, and therefore cannot make a very clean working valve.
The nerf one is all plastic, and the only thing rising pressure does, is increasing the rate of fire (to i must say, a very very very high ROF... )
This valve is to me the simplest way to have a full-auto mechanism, without all the check valves, pop-off's etc...
If anyone want's to try a prototype, I would really love to see something like that actuate a 400 psi, running on a scuba tank to give it nice autonomy and ROF... I'm going to post some videos of the workings as soon as I can.
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[velocity3x]

I'm going to post some videos of the workings as soon as I can.

I would be interested in seeing the design....Maybe recreate it in high pressure materials with high flow volume.

[CpTn_lAw]

I'm gonna do tests as soon as I set my soundcard problem right! Exams are finished and I succesfully validated each one ^^, so I have more time in my hands ! I'll try to film the mechanism in high speed, since it's clear plastic.

[CpTn_lAw]

[youtube][/youtube]

[qwerty]

Cool! i guess you could make a full auto blowback pistol with that.
I'm still a bit confused about the valve though, i'll look at it some more.

[jackssmirkingrevenge]

Isn't it essentially like one of my first piston designs?

[chinnerz]

what ever it is, its nice

[Skywalker]

Slick! You just need to find some really big-&$$ springs to make that work @ high pressure. That is pretty simple, should have constant shot power, and it has the advantage over jack's rattlesnake in that the porting to the barrel is straight with no dead space. (That's the valve from that huge nerf revolver, isn't it? I saw it once but I couldn't take it apart b/c it belonged to a friend.)

[velocity3x]

JSR,
I find your valve design to be quite interesting. Did you ever make it .....or a variant?

[jackssmirkingrevenge]

I find your valve design to be quite interesting. Did you ever make it .....or a variant?

I had made a prototype here, sadly built somewhat hurriedly with epoxy and I couldn't get it to seal properly, I moved on to the pop-off valve idea that works on vaguely similar concepts and had much more success.

I think this one is a better idea though:

[CpTn_lAw]

The blowgun was pumped at 300 psi, very small volume, and allowed for 4-5 shots.
The high speed is 1200 fps, so you can imagine the ROF.
It was indeed from the big nerf revolver !

I think there is some potential to it, and yes Jack, it seems it has something in commom with your piston design. Imagine a hybrid with a pieton that way? would be cool i guess...

[Brian the brain]

Wouldn't changing surface area make for a higher pressure valve??
Without the use of big donkey springs?

Edit:

JSR..don't you have a Monsoon???
Appearently they can be turned full auto too:

[youtube][/youtube]