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Crank Powered Semi Auto Idea

Unread postPosted: Thu Mar 06, 2008 12:25 am
Author: kablooie
I have been toying with the idea of using a revolving wheel/gear to both load and fire a cannon, achieving affect sort of like a Gatling Gun where all you do to fire is crank. This would definitely be a small bore cannon (3/4"?) that shoots uniform ammo, maybe paintballs. I realize there are probably much better and more effective ways to do this, I am just wondering if it would work.
I have a 10lb CO2 tank that the guns would be refilled from. Also, while the diagram is pretty self-explanatory, I do need to explain a few things: I realize I will need some sort of seal for the sliding magazine, something that will slide easily. I know it would be more ergonomic if I had the crank vertical, but that would prevent one side from gravity feeding, and I want to avoid springs and the jams they cause if possible. Also, I am not sure when, if ever I would build this, but I like to put ideas out there anyway.

Unread postPosted: Thu Mar 06, 2008 12:33 am
Author: Novacastrian
I suggest you make a cannon that auto feeds first, then add the complication of a gear and many headaches trying to get it to run in sync. The concept would work i think but is it realllllly worth the hassle?

Unread postPosted: Thu Mar 06, 2008 12:40 am
Author: kablooie
Well, the auto feed is accomplished by turning the crank, so unless I used a different design, auto wouldn't be possible. I do understand what you are saying though, maybe i will make the sliding loader first and then see what happens from there. I know what you mean by hassle too, I have tried a more compact version of semi auto before too, and it worked poorly for about 4 shots before the pvc snapped. I think I am ready to take another stab at it though.

Unread postPosted: Thu Mar 06, 2008 12:44 am
Author: OuchProgramme
Hmm...timing is going to be a pain. I'd say just screw the cogs and have the blow gun's become triggers. Dual wield the dam thing and kick some ass. Lol.

You could build a simple mount onto your back, w/ a backpack or something for the air chamber. Have the two blowguns in your hands and you could become a human turret. ;).

Really. Just take off the cogs, put the design on a mount. Its like a dual wielded M2. browning. Total ownage.

Unread postPosted: Thu Mar 06, 2008 12:50 am
Author: kablooie
If I did take off the gear thing, it would make it so to fire, I would have to cock and then pull the trigger. Also, a 10 pound CO2 tank weighs upwards of 20 pounds so it would be a beast to haul around. It would be cool though, just not quite what I am aiming for.

Unread postPosted: Thu Mar 06, 2008 12:51 am
Author: Novacastrian
OuchProgramme wrote:Hmm...timing is going to be a pain. I'd say just screw the cogs and have the blow gun's become triggers. Dual wield the dam thing and kick some ass. Lol.

Funny you said that, it was my first thought! :D

@Kablooie, i meant semi auto, not auto as i wrote sorry.

Unread postPosted: Thu Mar 06, 2008 1:49 am
Author: mega_swordman
I can understand wanting to do something completely new, which we encourage, however, I don't think this design is practical enough for further research. Keep at it if you wish, but there are certainly much easier ways to make a semi-auto cannon.

Unread postPosted: Thu Mar 06, 2008 2:41 am
Author: Pyro Ninja
You could use a ballvalve with a crank handle to which you could attach a gravity fed magazine to, to achieve semi/full auto (You just have to cut the little stop off).

Unread postPosted: Thu Mar 06, 2008 3:06 am
Author: jackssmirkingrevenge
Pyro Ninja wrote:You could use a ballvalve with a crank handle to which you could attach a gravity fed magazine to, to achieve semi/full auto (You just have to cut the little stop off).


This is a much better way of doing things, especially if you're using spherical ammo.

Unread postPosted: Thu Mar 06, 2008 5:00 am
Author: ghostman01
but i think with your idea JSR is that alot of air is going to be let out if you cant turn it quikly enough, you add a high tourqe/speed motor but then you have to worry bout batteries

Unread postPosted: Thu Mar 06, 2008 5:09 am
Author: jackssmirkingrevenge
If the diameter of the ball valve is the same as your projectiles, they will act as a very effective flow restrictors so that shouldn't be a problem. You just need some sort of mark on the crank so you stop cranking in the right position.

Unread postPosted: Thu Mar 06, 2008 5:14 am
Author: ghostman01
yeah or just have it so its in line with the barrel when you stop its parrallel to the barrel

Unread postPosted: Thu Mar 06, 2008 5:26 am
Author: BigGrib
Instead of using the ball valve as the main firing valve, you could setup a firing peg system or something so that when the crank handle comes around every 180 degrees (when the ball valve is lined up) it trips a blowgun to pilot a sprinkler valve, crank it fast enough with a big enough chamber you could get maybe 3 or 4 shots off without filling it, but if you're hooked to a co2 tank or compressor you'd be good.

Unread postPosted: Thu Mar 06, 2008 5:57 am
Author: jackssmirkingrevenge
You'll need a massive flow in order for the sprinkler valve to reseat in time, besides the projectile will not leave the ball valve until it's 100% open, and that's practically as good a valve as a burst disk so you won't get much better efficiency than that. It would be conceptually similar to this.

You can have your projectiles (again assuming they're spheres) within the pressurised chamber itself to avoid drilling the ball valve, picture this design but with a crank instead of a handle:

Image

Image

Unread postPosted: Thu Mar 06, 2008 7:41 am
Author: psycix
Wouldnt that make a cloud JSR??