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Full Auto 50

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Re: Full Auto 50

Unread postAuthor: Brian the brain » Thu May 29, 2014 1:10 pm

Offical??

:D

What caliber is that launcher?
"Offi-cal"

:shock:


Anyway..
I just showed the above video to my son....he now wants me to make a similar drum magazine for the Pnushnikov project....
Not gonna happen any time soon..
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Re: Full Auto 50

Unread postAuthor: jackssmirkingrevenge » Fri May 30, 2014 5:06 am

Brian the brain wrote:Not gonna happen any time soon..


Oh come on!

Somehow I imagine you breaking into a Dutch Natural History museum and stealing a Nautilus shell to adapt it :D

By the way, the name is already sort of taken...
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Re: Full Auto 50

Unread postAuthor: Brian the brain » Fri May 30, 2014 3:02 pm

If I had to I'd rather break into a Austrian museum and steal a genuine Girandoni...

About the mag: How is the ammo held in, before it is placed inside the launcher?
Do you wind up the spring after it's in or lock it prior to inserting it or what??
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Re: Full Auto 50

Unread postAuthor: kustomkb » Sat Jun 07, 2014 10:22 pm

Thanks very much for the compliments and encouragement. It is greatly appreciated.

So proud this is happening on the same land mass


Jack, if we can keep the air compressed, we'll be able to ward off the zombie apocalypse, mongrel hoards or those who will come after our fresh water supply.

you should machine the lid from transparent polycarbonate


Thanks Matti, I looked for a piece of polycarbonate, because I too love the look of transparent parts and enjoy being able to see the mechanicalness of everything. PC would have been very expensive, and I had a chunk of AL sitting around for years. A cover could be made but would clash with everything else, which I plan on anodizing, as you suggested. A window is a good idea, I'll give it a shot, as long as I can keep it flush.

Wouldn't "Nautilus" sound a bit cooler than snail??


Thanks BtB, how about "Logarithmic Spiral Guided, Spring Propelled, Projectile Advancing, Encapsulator"?

It is 0.610" caliber. It can be wound up, locked, and then filled with rounds with the cover off. Or rounds can be pressed in one at a time through the "exit hole?" holding the winder between round insertions...


Still swamped with household/family duties, so please be patient with the next installment.
I picked up one of those black, Chinese QEV's but it didn't behave properly during bench testing. When I get a chance I'll reassemble everything for a drum mag test and report back with a video.

Cheers!

KB
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Re: Full Auto 50

Unread postAuthor: jackssmirkingrevenge » Wed Jun 11, 2014 8:02 am

kustomkb wrote:Jack, if we can keep the air compressed, we'll be able to ward off the zombie apocalypse, mongrel hoards or those who will come after our fresh water supply.


Bill Burr summed it up pretty nicely talking about "prepping":

Start reading up on sh;t, get some powdered food, plant some zucchini, get a windmill, right? And that’s all well and good, but if you don’t how to fight, all you are doing is gathering supplies for the toughest guy in the block, right? Just thinking about that, what am I going to do when some dude turns me upside down, start shaking the gold coins out of my pockets, I got to get a gun.


:D
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Re: Full Auto 50

Unread postAuthor: RedAsh » Tue Jun 17, 2014 11:33 pm

The machining work on this is amazing not to mention the design that you have put into it all the while juggling home life, you are amazing.
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Re: Full Auto 50

Unread postAuthor: Dig_Gil » Fri Jul 11, 2014 3:16 pm

I hope I'm not late for the discussion! I feel like some holidays from my lurking job :P and right on time to see the Automatic fire craze catch up. I almost thought I was the only one.

First: I didn't know that youtube name's "ukiliheal" was posting around here! I guess I need to lurk archives some more...
Second: I've been analysing and experimenting with his design for a time now. I guess I must come out of the closet about that or something...
Third: Your machined parts are really nice-looking. But I recommend you to use lighter materials for pistons (less inertia, less impact, less noise, ect.). I.E. Plastics. I've been using Nylon on my builds.

Now the real replies:

kustomkb wrote:I will need a stronger spring and probably change the piston to Delrin or something, because the bronze piston makes it feel like a bloody jack-hammer! -Very realistic for sure.

Better get more lubricant. I guess that's obvious, but I'm not seeing it in your pictures. You could also try floating o-rings (also not sure if you're using them). And, again, lighter parts will make for less "stuckiness" due inertia.
POLAND_SPUD wrote:Seriously why waste time trying to tweak it when you can provide pulsed air supply for it with a solenoid valve. The added advantage is that you can have adjustable ROF and no compromises are needed

I hate it when people put batteries on things that would very well work just mechanically (pneumatically, in this case).
This ties to my next point:
kustomkb wrote:Mr Smith has a PVC tank in between the air supply and the valve. Is there any need for this if you are running from an air compressor. A bit of a reservoir charging up while the gun is firing?

I bet you already know the answers about this, but I'll elaborate my thoughts so that it might give you some insight.
If I understand this question properly, you wonder why there is a secondary air chamber (I call it chamber to distinguish from the "reservoir", I.E. the air source). It is aparent that you don't really understand the function of a regular spud gun. All spudgun with QEV action (or similar, like the sprinkler valves) have a chamber which fills from a reservoir before shooting with a desired amount of volume to be dumped into the barrel. In Mr. Smith's design, it works as the following:

Valve closed->reservoir fills chamber.-> chamber pressure reaches the pilot release valve's trip levels.->this valve releases pilot volume, therefore triggering the main valve.->chamber pressure flows into the barrel.->because pressure is too low in the chamber now, both valves close.->risen->repeat.
In this design, the larger the chamber volume, the slower the rate of fire (it takes more time to reach tripping pressure). This is why using electronics is redundant (please take notes POLAND_SPUD). The higher the reservoir pressure the faster the chamber fills=higher ROF. Obviously, lowering the release valve's trip pressure, the higher the ROF although it costs muzzle velocity. It is my personal liking to have a very low ROF (I like my shooters manageable). But just increasing the chamber volume makes the launcher inefficient (wasted air from the reservoir which doesn't really propel the projectile) as in any pneumatic gun (although this is a debatable matter; think of this as fine-tuning a guitar). There are trade-offs, but then there are lots of options. It is advisable to use a pressure regulator if you wish. It makes the fine-tuning easier and can only add efficiency.

I could now throw up the maths I've come up about this, but better keep the post shorter until further needs.
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Re: Full Auto 50

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Re: Full Auto 50

Unread postAuthor: POLAND_SPUD » Sat Jul 12, 2014 6:33 am

I hate it when people put batteries on things that would very well work just mechanically (pneumatically, in this case).
So do I but experience has thought me that getting something to work by using just pneumatics or mechanically is a bit of a pain in the ass. If you can prove me wrong with a working model then go for it - I would be happy for ya

But as I said earlier using electronics makes things easier - especially for people who don't have access to machining
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Re: Full Auto 50

Unread postAuthor: Dig_Gil » Sat Jul 12, 2014 8:23 am

Okay, you've got a point there. One just ought to remain sober about the subject for when some serious project arises.

Actually, I'm finishing a novel valve I've been cooking up which acts like the QEV/Safety Valve/Regulator in a monolithic fashion. I admit, my first attempt at it was too naive (the one I posted about in this forum), but then I got a better understanding after that. I've been taking quite the effort to make sure it was feasible and possible this time. applying mathematical models and comparing with various designs. Maybe I should have been discussing my progress with you guys, but I'm wary that it might not work. Specially after the various revisions I went through with it, I thought it would be better when I finally settle with a design. Indeed, I feel I've reached a proper design. I'm still saving details to when I see it working.

I've made it totally mechanical and actually without pilot air losses. If it works as I think it will, it is also possible to control the output pressure (think as regulated pressure) just by modifying one piston.
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