GB Semi

[clide]

Wow Brian, I like the way you think. When I initially set out on this project I was trying to make a valve that opened forward like that so the loading mechanism could be linked directly to the valve. But after trying and failing at a few valves I just gave up on the forward moving valve design, and I didn't even consider what would happen if I made this one move forward. I really like the idea of using the dropping chamber pressure as the piston force boost. Thanks for the idea, that just may be worth trying.

But as far as full auto goes, this design works great for full auto, even better than I expected, but it is the loading mechanism that is giving me problems. Anyone have any idea why the rear o-ring on the bolt would be blowing out of its groove <i>towards</i> the loading port? Ugh...writing that down gave me an idea of what it could be and it is not going to be fun to fix.

[iknowmy3tables]

I've been trying to look for a valve powered bolt design as well,

Brain's got a nice Idea but the input is open when firing and its no longer high efficencey, unless is can close really fast

him i think it would have to be inline first, then it the first Idea I get is to attach the blow forward bolt directly to the piston, but then the the bolt wont close until the valve is fully open might waste some air into the mag

my other thought i had earlier was attaching a camshaft system like in the eclipse to the outward pushing piston you got now but I'm not sure if the piston movement is full enough

[cb4289]

sweet man that inspires me to wreak some havoic sob. lol

[clide]

OK updated ROF figures. From the few clips I have of it going full auto and loading a ball each time it seems to be at 6 RPS. Semi-auto I am somewhere between 4 and 5 tops.

The method I am using to calculate this is just counting frames between balls and considering that the camcorder is recording at 30 FPS. Full auto with a ball each time is pretty much dead on 5 frames between balls. A good semi-auto run is 6 or 7 between balls.

Do you guys want a video of what I have so far? It will be pretty choppy because the loading mechanism still isn't perfect and usually the last ball doesn't want to go while rapid firing and is shot separately and 1 or two pop out because of some escaping air at the beginning. This leaves 10 or 11 that get shot which takes ~2 seconds. So the video would just be several very short clips.
I'd like to either add some extra storage tanks inline with mine or see if I can get my hands on a bigger compressor and put a hopper on the gun and maybe get a video of 50 or so rounds going off, but who knows when that will happen.

[cb4289]

would co2 work like a big canaster or some compressed nitrogen with a regulator on the nitrogen tank. 8)

[keep_it_real]

Do you guys want a video of what I have so far?

That's like asking if we want a million dollars...

[clide]

That's like asking if we want a million dollars...

Well that was my next question, but since you want the video.. it was a million dollar production.

Yeah CO2 might work if it doesn't freeze up. Guess that may be what I spend the $100 on if I win.

Anyway here is a new video
http://video.google.com/videoplay?docid ... 1304386326

[frankrede]

would co2 work like a big canaster or some compressed nitrogen with a regulator on the nitrogen tank. 8)

It wouldn't work.
Why? Because the sun sets to the east, causing any pneumatic gun with a piston valve to fail and not actuate correctly due to the earths polarity fluctuating.

ha, I hate when people ask obvious questions.
But seriously, the question is, why wouldn't it work?
There is no reason. Come on use some logic!

[cb4289]

i did not knot i've only had this hobby 1 month 20 days so to me its not so obvious.

[frankrede]

It doesn't take much experience to take 1 thing and another and find a simple result.You understand the basics of pneumatics, so whats stopping you from using common sense?

[jackssmirkingrevenge]

Anyway here is a new video
http://video.google.com/videoplay?docid ... 1304386326

sweet! though you really should cap that mag

[wannabie]

OMFG I WANT ONE

how many shots do you get when its not conected to a compressor?
and do you think that making somthing like that would be possible on a smaller scale say a sprinkeler valve and instead of a compressor a LPG tank or somthing ( LPG because its cheap just dont use neer open flames lol )

[Velocity]

...wow...

That video is amazing! I had no idea that this cannon had such a high rate of fire! I can't imagine how good the "final product" will be, when all of the bugs are worked out...

[clide]

sweet! though you really should cap that mag

Arg, that's what I've been working so hard on the bolt to avoid. The fact that balls are shooting out the top means that it isn't working properly and a cap would merely hide that fact, not fix it. If air is getting into the magazine then it wont feed fast enough for full auto, so it is something that needs to be fixed not bandaged.

[chaos]

cap it and spring load the magazine, i also have a HPA air on the way and am aiming for semi/full auto