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QEV + PopOff Airsoft Machine Gun.

Posted: Thu Apr 02, 2009 5:59 pm
by Davidvaini
Now realize this was a quick drawing and I have changed a few things around...

Image

The propane tank would actually get replaced with a separate chamber that propane or co2 can get injected into.

It works in the same way that THISworks.

My design would incorporate a metal hopup chamber and would use Airsoft Magazines. There might also be a flow control valve between the tank and the pressure washer handle.

The popoff that I would use would operate at a lower psi so I can use propane without any problems (100psi popoff.)

What do you guys think?

Posted: Thu Apr 02, 2009 7:25 pm
by sputnick
I am not sure if this is an April fools joke or not...

In case this is serious, Yea, sure, why not. Do not think you need to use a pressure washer handle though, and you will definitely need to put a BFV or something on the ammo feed, and some form of non-sh*tty cover on it, so it didn't look like an assortment of pipes with an AK mag on them :wink:

Why not just make that, then pour an epoxy shell around it, it would make it solid and good looking, just make sure you figure out how to keep a magazine well open.

Posted: Thu Apr 02, 2009 8:02 pm
by SpudsMcGee
sputnick wrote:Why not just make that, then pour an epoxy shell around it, it would make it solid and good looking, just make sure you figure out how to keep a magazine well open.
Thats a good idea, but then if a leak is created there is no way he would be able to fix it. If I understand right...

Edit: And to answer your question David, yeah it sounds great (like everything you make). I can't wait until it is done.

Posted: Thu Apr 02, 2009 8:07 pm
by sputnick
SpudsMcGee wrote: but then if a leak is created there is no way he would be able to fix it. If I understand right...
Yes I suppose that would be true, However I also suspect by the time you get to that point, he would have already sealed and tested and done all he could to make sure it was perfect BEFORE taking the final step and making it into a full blown air soft gun. Which he can never use. Because he would kill someone.

It's thinks like this that really make me appreciate the vacuum forming machine, then you could make a perfect mold out of an existing airsoft gun, only about 300 times more likely to seriously injure.

Posted: Thu Apr 02, 2009 8:48 pm
by dudeman508
Thats a good idea, but then if a leak is created there is no way he would be able to fix it. If I understand right...

Edit: And to answer your question David, yeah it sounds great (like everything you make). I can't wait until it is done.[/quote]

Their wont be leaks, its covered in epoxy[/quote]

Posted: Thu Apr 02, 2009 8:58 pm
by sputnick
How do you propose a leak would "form" with steel parts, (of good quality) within a solid block of hard epoxy, after being well threaded and sealed, It honestly seems like it would not be to much risk, considering he probably would have another gun finished in a few weeks,

Not saying he would never use it, But in total honesty, it is much more likely that he gets bored of it before he wears the internals down to the point of destruction.

And if he really was worried about it, he could just make the epoxt cast in 2 parts, then just bolt them together.

Posted: Thu Apr 02, 2009 10:34 pm
by Lentamentalisk
You are not going to get that to work at all with a 100psi popoff... it doesn't reach 100psi till the liquid is at 65f, which it will quickly drop below if you use it at all.
Image
I would suggest something like 75psi or so, and have a large expansion chamber somewhere.

My other suggestion, is maybe rather than having that long chamber, you could have a short 1" chamber or something like that, to make it more compact.

I am excited to see how this turns out!

Posted: Thu Apr 02, 2009 10:50 pm
by jackssmirkingrevenge
I think this will work nicely.
There might also be a flow control valve between the tank and the pressure washer handle.
I would definitely incorporate it for fixing rates of fire. Also, why pressure washer handle? Blowgun should be perfectly fine.
The popoff that I would use would operate at a lower psi so I can use propane without any problems (100psi popoff.)


I would get an adjustable one if I were you in order to get optimum performance.

Good luck if you go through with this, definitely has potential. Sure if you made a large pop-off and used it as a direct valve you'd waste less air, ah well...

This setup gave me 360 fps with 0.25g 6mm airsoft BBs at 100 psi, not enough for my purposes but maybe good enough for airsoft.

Posted: Fri Apr 03, 2009 3:36 am
by SPG
I can see why he's using a pressure washer handle, cos it LOOKS GOOD. As for pouring an epoxy body, you're kidding right? It'd weigh a feckin ton. Also if you've gone to all the trouble of sculpting a female mold then you may as well just sculpt a male body for it which'd be a lot easier, for preference do it in two halves so that you can then carve the interior to match the pipes and voila, a nice body, and one you can open up to fix/mod things.

Simplest material to sculpt from would be closed-cell foam insulation (usually blue or pink sheets) It cuts easily, will sand, and then you just lay a couple of layers of glass fibre over the top. It's quick, cheap, easy and I've used it for springer airguns so I'm sure it can take the shock.

I'd personally sling the tank out the back so you could use it as a shoulder stock like the GunPower Stealth.

Image

Posted: Fri Apr 03, 2009 8:17 am
by POLAND_SPUD
I like the overal concept... any bolt is a pain in the ass to implement and casues flow restictions so I like ideas that are simple and aim at eleiminating any restictions at the same time...

I'd like to try something similar myself but I am not quite sure about hop ups... I've read that they spill bbs as soon as you connect the magazine becasue in airsoft guns there is some sort of a bolt.. is this really true ??

I see that propane has some potential... I wonder how much would you have to heat it to get 30 bar ??

EDIT
to get 30 bar you'd have to heat the tank to 80 deg C
100 deg C would result in 40bar

it seems a bit tricky to heat the tank but one way or another you would have to find some way to heat it and/or avoid temperature (and pressure) drop casued by evaporation

ohh I've got an idea - you could burn propane from a pop off valve to heat the tank... yeah I know it sounds scarry

Posted: Fri Apr 03, 2009 9:33 am
by jackssmirkingrevenge
POLAND_SPUD wrote:I've read that they spill bbs as soon as you connect the magazine becasue in airsoft guns there is some sort of a bolt.. is this really true ?
[youtube][/youtube]

A bit like the blow-forward bolt ;)

Posted: Fri Apr 03, 2009 10:02 am
by POLAND_SPUD
yeah I know how they work - but david suggested that they'll work without it just like the drozd...
so the question is whether the bolt is really needed ?

Posted: Fri Apr 03, 2009 10:23 am
by Davidvaini
actually the hopup on the airsoft gun keeps the BBS from falling out of the barrel because it has a rubber bucking that holds the BB's back until enough force is used to push it through.

An airsoft gun typically has a nozzle that moves forward and shoots air which results in the force, but as seen with my other BBMG prototype, straight up air can be enough force to get it through as well.

Posted: Wed May 06, 2009 3:16 pm
by thedeathofall
Why dont you build it into an airsoft gun body like your P90? You can use a m16 body and use m16 magazines, but cut the handle to accapt a 1/8 inch push button valve instead of a pressure washer handle and ya. here's a pic to explain a little better...