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cirvin
Nobel Prize Winner
USA
1542 Posts |
 Posted - Jul 14 2003 : 10:46:03 PM
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I am Currently Building an automatic spudgun. it has a large wheelwith barrel sized holes that line up with the barrel and the combustion chamber. the only problem I am having is having the combustion chamber refilled after every shot. the circut would drive a solenoid valve. it has to be ajstible. i would build a mechanical timer, but digital is juast that easy. any ideas? more gun info, e- mail me
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Jul 14 2003 : 11:54:41 PM
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you could use a simple 555 timer to do that.
How do you plan to bring O2 in, after the first couple of shots, your going to loose a lot of power unless you use an oxidiser or vent the combustion chamber....
This sounds like a neat project...I would like to see some pics when you get it finished
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Jul 15 2003 : 01:41:22 AM
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Ok here is a circuit that you could use, I pulled it out of probibly the best book for a begenner Getting Started in Electronics sold at radio shack...
when you push the button, it closes the relay for a time adjusted by R1 and can further be adjusted by changing the value of C1
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 15 2003 : 11:21:41 AM
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I was just gonna oxidise the gas like a gas grill. you know the part where the tube has holes in it? thanx 4 the schematic BEatonNo1 gets the diagrams. they will come eventually, everybody else, don't worry, the plans that you can get will come less eventually.(next month)
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 15 2003 : 11:23:25 AM
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WAIT A MUNITE!! I HAVE THAT BOOK!!!ARRGH!!!!!!!
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 15 2003 : 11:47:23 AM
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Anybody got any oxidiser plans/ideas?
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Jul 15 2003 : 1:43:43 PM
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Like I said its a really good book
As for the fuel, I would suggest something the other way around...the only time that you arent going to be spraying in the propane is during the ignition (for obvious reasons) that way as the next tube is comming around the chamber will be open and as the new propane is injected, it will help to flush out the spent gases and bring in O2...now when the next round comes in, the gas will only need to be on for a little while then shut off while the chamber is ignited.
There are a few problems that I see at this point. First you should use 2 valves one before the mixer (oxydiser) one after, this way if one sticks you dont have to worry about a huge explosion. even better would be to have a feed back of somesort that would check that both are closed and if not, it would prevent the firing. The second problem that I see is that when the potato is infront of the chamber then the gas will be pouring out of the little holes that are supposed to let the air in, instead of going into the chamber. There would be a signifigant amount of propane in the chamber, enough for a firing, but if you were to solve this problem you would probably be able to get more power. the last problem is the seal between the combustion chamber, potato cardrege and barrel this needs to be as tight as possable so that you dont lose any of the explosion out of the cracks, if it isnt tight then your going to loose a lot of power.
As for the plans, dont worry about it. I'm not in much of a need for an automatic potato gun at the moment
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 15 2003 : 3:50:21 PM
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I will probably just inject compressed air with the fuel into the chamber. all of this will be carefully ajusted so that when i hold down the trigger, it will fire multiple rounds. not fast though, it will probably take 5 seconds or more to reload. mount it on a go-kart and terrorize the neighborhood! HEHEHEHH. thanx
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 15 2003 : 5:03:36 PM
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I will put a compressor in line with the fuel feed tube. i then can controll the mixture by controlling the compressor speed and the duration of time the propane valve is open. as for the reloader seals, maybie i should take thick o-rings and put them at all the joints so they seal up. any ideas?
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 15 2003 : 7:18:15 PM
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Wait a minute, the more i think about a project, the better ideas i have! instead of a wheel with holes that the taters go in, i could make the wheel a sprocket that pulls a belt of tubes with taters in them. more ammo storage, more of a chance to win the battle! HEHEHE Oh the evil....
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 21 2003 : 10:04:38 PM
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ahh screw combustion, ill just use pneumatcs. i will build a diaphragm air gun.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Jul 22 2003 : 11:20:34 AM
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no dont give up on the combustion...try getting ahold of a basic stamp to controll it...as for mixing the propane before hand...thats probibly not nessicary. you could just as easily clean out the combustion chamber while the next barrel is comming around, then spray in some propane when the potato is in.
Another idea would be to have 6 barrels that are capped off on one side...you then spray in some propane and put the potato in front, so that all six barrels are ready to shoot. then you could either a have it spin and shoot or you could have it all done electronically
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jul 22 2003 : 11:49:59 PM
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i barely know how to program basic, i was hoping for an analogical solution. why stick with combustion. pneumatic is faster, easyier, and a little bit cheaper. the cartridged spuds have a bad chamber/barrel ratio, plust the fuel might settle.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Jul 23 2003 : 12:03:51 AM
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you have a point....what do you plan to use as a valve
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Kale
Nobel Prize Winner
Canada
795 Posts |
Posted - Jul 23 2003 : 1:46:32 PM
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Your best bet is to use the good 'ol internal combustion engine as design inspiration. Spuds are soft, so it shouldn't be hard to build a sealed piston (like the pistons in a car engine) to ram the spuds from behind into the barrel. Then you want the piston to come back halfway to the home position, creating a space between the spud and the piston head that you can use as your combustion chamber. Fill the chamber with oxidizer and use a sparkplug to touch it off.
Just use a really sturdy valve for your oxidizer injector. You should be able to get an electrically actuated valve that can handle the pressure but it won't be cheap. Pneumatics might be simpler if you could rig up a compressed air tank to inject compressed air into the firing chamber.
Edited by - kale on Jul 23 2003 1:49:30 PM |
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Jul 24 2003 : 01:36:53 AM
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While digging through some old drawings, I found a design that used a rotating barrel with a notch in it. it rotated slowly enough so that it would a projectile would drop in through the notch, the combutionchamber filled and fired, the gun blowed out and about this time the notch comes back around and another projectile dropped in.
the gun was supposed to shoot ice...its nice and cheap and slippery. but it could also fire the smoke shells we planned as well as the paint ones...bythe way have you read the post i made on the fully automatic tater gun...I cant remember but that might of been how i planned for it to work
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fully Automatic Potato Gun
