A theory/plan for an "undesirable"

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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Mateo
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Tue Nov 27, 2007 9:26 pm

well how big do you plan on making it? because you might be able to use less barrels (5 instead of 8 or whatever) then you wouldnt need as big of a motor to keep it spinning.
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Fnord
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Tue Nov 27, 2007 10:09 pm

I just got a good idea for this design;
If you look at a real gat, the action of rotating the barrels pulls a (or multiple) firing pin back to hit the shell.
What you can take from this design is to use the same idea to tap a hammer valve as each barrel passes by. Loading shouldn't be too hard to do if you stay true to the original design, but you can expect occasional misfires (blank shots).

Edit: You can also use 1lb propane tanks as a gas source. I'll bet they'll last a good while for such a design.

The more I think about it, the more reasonable this whole idea seems. Hope you can get it working.
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LeprechaunIV
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Tue Nov 27, 2007 10:30 pm

http://www.lowes.com/lowes/lkn?action=p ... lpage=none Try one or two of these. They're fairly portable.
Mad_Max0290
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Tue Nov 27, 2007 10:51 pm

Thanks for the help everyone

and as for size I'm going to use the standard .68 caliber paintballs so I'm not too sure of how many barrels to go with..what do ya'll think?
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Hubb
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Tue Nov 27, 2007 11:02 pm

The problem with using a gas source on such a design is this: Having the barrels rotate means that there has to be rotation on the interior to cause this. This means that there has to be some way of connecting the air source to the chamber (or chambers). All this rotating is going to tangle up some stuff on the interior, causing it to malfunction.

Here is a solution: spring piston.
I know spring pistons have already been discussed with negative results but think about this; being used for paintball, the spring does not have to be that tight (i.e. the paintball should leave the barrel at no more than 300fps, less if shooting full-auto).

Now imagine a real gatling gun (this should help). When it rotates, a pin pulls the plunger in the spring piston back. Once it gets to the firing position, the pin is released, causing the spring piston to do what it does best.

As far as increasing velocity from the spring piston, think about the Bernoulli Principal. Air in a larger chamber travels slower but has higher pressure. When it is choked, or the chamber is reduced, the speed of the air increases (which means velocity increase). Thus, having a larger spring piston chamber than the barrel should increase the velocity of the round, but by how much, I don't know.

This whole theory solves two problems; (1) making the gun fire, and (2) eliminating the need for an air source. This leaves only one problem and that is synchronizing the rounds to be placed in the barrel for each shot.

That, you will have to figure out. I've said too much already.
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jackssmirkingrevenge
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Tue Nov 27, 2007 11:20 pm

I think the simplest way to make a gatling would be to build what is essentially a cloud strafer with rotating barrels. The idea had been put forward on spudtech but I can't be arsed looking it up.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Mateo
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Tue Nov 27, 2007 11:52 pm

i agree with jack but still getting the barrels to rotate is hard. maybe if you do a cloud strafer but use a motor to rotate the barrels? or you could split the air line and have one line go to a fan to push the barrels around but that would probably reduce the air preassure to much. just throwing ideas out there.
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Hubb
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Tue Nov 27, 2007 11:56 pm

jackssmirkingrevenge wrote:I think the simplest way to make a gatling would be to build what is essentially a cloud strafer with rotating barrels. The idea had been put forward on spudtech but I can't be arsed looking it up.
Are you referring to this one by choam8?
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jackssmirkingrevenge
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Wed Nov 28, 2007 12:01 am

not quite, that one had spinning barrels purely of aesthetic effect, the heart was that of a simple strafer:
6xBarrels are fake. They just spin and make some noise. For visual and sound effect only.

Single firing barrel is in the center of 6xbarrels block. Barrels spin around it.
It painted black, so hard to see.
edit: have a look here - as I mentioned earlier, it's essentually a normal cloud design, but instead of a single barrel, the cloud chamber feed through a port that feeds into the individual barrels as they spin.

Image
maybe if you do a cloud strafer but use a motor to rotate the barrels? or you could split the air line and have one line go to a fan to push the barrels around but that would probably reduce the air preassure to much. just throwing ideas out there.
DR's design above uses an air motor to rotate the barrels, if you're feeding from a compressor or a regulated HPA or CO2 supply this would be practical, however to conserve air a separate electric motor would be a better idea.
hectmarr wrote:You have to make many weapons, because this field is long and short life
LeprechaunIV
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Thu Nov 29, 2007 4:34 pm

As far as increasing velocity from the spring piston, think about the Bernoulli Principal. Air in a larger chamber travels slower but has higher pressure. When it is choked, or the chamber is reduced, the speed of the air increases (which means velocity increase). Thus, having a larger spring piston chamber than the barrel should increase the velocity of the round, but by how much, I don't know.

Bernoulli Principle.
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TwitchTheAussie
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Sat Dec 01, 2007 7:02 am

What about a quick design my friend n I came up with? Basically its just a belt fed inline with multiple barrels. Pressure in the chamber builds by a rubber ring connected to the holder of the barrels. A small dc motor outside the chamber with the wiring through the chambers, sealed up, powers the rotating assembly.

I kinda lost my design for all this but I'll try and explain my belt feeder. Basically its just a cog which feeds the tubes holding paintballs/marbles/whatever, into the airstream. The cog rotates with the barrel assembly so its pretty much simple inline rotation.

Fed from co2 it wouldnt be too bad. Anybody whos clever with paint I dare ya to try n follow my inline assembly :P
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