SpudFiles

I'm new to pneumatic guns and just built a very simple before, so this time i where gonna go a bit further and build a semi auto rifle, I don't have a air compressor and i wouldn't like to use one as well since i would like to be able to shoot with my rifle in the forest. But i have some questions about the tank and the rifle itself. Will my rifle be semi or have i totally miscalculated it? its not in the right measurement but how small/big will my secondary tank have to be so i could get at least 5-10 shots(with partly the same speed) of before having to re-pump it?

Also feel free to comment anything you like


The rifles schematic:

you used pneumatic symbols... I wanna hug you (jk)

Will my rifle be semi

yeah, though you need a loading mechanism... I found that air cylinders work great when coupled with a 3 way valve

its not in the right measurement but how small/big will my secondary tank have to be so i could get at least 5-10 shots

I'd say that its volume has to be about 25 times larger than the chamber volume

You could also use a tank pressure higher than the pressure you want to use your cannon at. A simple air tool regulator would then take it down to some pressure, and velocity would be the same until the tank dipped below that set pressure. You do loose out on peak power( first shot) , though.

Have you considered a CO2 tank? ready made regulators for use with air tools are about $90.

POLAND_SPUD wrote:you used pneumatic symbols... I wanna hug you (jk)

No you're not, you genuinely want to hug him, I'm sure

According to fluidsim this should work.

I've been thinking about loading the rifle with 2 disposable CO2 cylinder and make some hot cover for them in the handle to make it look more realistic, do you guys know how i would calculate the size of my external tank for that? i also thought about making the external tank in a changeable size so i can either shoot a hole in a road sign with one shoot or use it in a paint-ball war and shoot 100 shots if u know what i mean, will that work like that? I find it hard to test since my only pneumatic spud gun is kind of simple and parts are expensive so id like to hear ideas from the pros before i waste my salary.

Thanks for the help everyone and Poland_spud I've seen your rifles, there way hot and i would hug you if i gotten the chance as well, but with "loading mechanism" do you mean something to load the air with or the bullets? I'm working on a bolt action with magazine and working ejector, hopefully it will work quite good, I will post more blueprints as soon as i can

According to fluidsim

I wanna to hug both of ya

ohh notice that fluidsim has a symbol for QEVs (though you can't connect anything to its barrel port as it has an inbuilt muffler)...no need to use shuttle valve

ohh BTW I did use fluidsim to calculate/model that

its volume has to be about 25 times larger

with "loading mechanism" do you mean something to load the air with or the bullets

http://www.spudfiles.com/forums/files/s ... ii_400.gif

Bullets

i also thought about making the external tank in a changeable size

Just use threaded fittings and pipes

and parts are expensive

Not if you can reuse them (threaded fittings and pipes)

CO2 cylinder and make some hot cover for them in the handle to make it look more realistic, do you guys know how i would calculate the size of my external tank for that

You'd need a co2 calculator for that. IIRC Davidvaini has made one

how y'all like this?






semi auto reloading with mono-stable cylinder

I like the simple air ram connected to chamber with a 3/2 NO valve for piloting. You can use the same magazine behind QEV set up, as long as you make the air ram piston slightly larger than the barrel bore.


Err actually isn't there a slight issue on that last drawing, with the projectile loading and piloting starting at the same instant ?

Err actually isn't there a slight issue on that last drawing, with the projectile loading and piloting starting at the same instant

yes, you're right

I like the simple air ram connected to chamber with a 3/2 NO valve for piloting

me too.. no need to overcomplicate stuff and waste air

I saw some modifications have to be made

Got all, thanks!