Pnematic Potato Cannon

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The cannon:-Dual air chamber 800cubic inches total (4"x4"x25")-Dual 1" sprinkler valves-2" 304grade stainless pipe, 60 inches long-Tig welded-And the rest is magic.According to the calculations its supposed to shoot around 600fps with a 1100 ftlbs muzzle engergy. According to the feel of my pants it goes woosh and i like it. I like it alot. Spuds dissapear from sight.
Reply:Gotta luv it. Need that out in the desert so you can see where you're hitting. I saw on TV  a long time ago where they were launching pumpkins with air. pretty impressive.
Reply:holy (something)!!! now i have to make oneStangnetShop Full Of Stuff. Joey
Reply:Originally Posted by vipermanzholy (something)!!! now i have to make one
Reply:Some people work towards world peace some people heal the sick and some people build high powered potato cannons. My kinda people.
Reply:Originally Posted by 12,000 DoorsSome people work towards world peace some people heal the sick and some people build high powered potato cannons. My kinda people.
Reply:I have made from PVC before and used good old hair spray for ignition and they flew like mad, but that gun is taking it up a notch.  I am going to shoot a spud for you as a salute right now.  Nice job!
Reply:Sweet God Almighty...You just got my brain all stormin with ideas... see what you did, if i get in trouble, its your fault.
Reply:If you outlaw potato cannons, only outlaws will have potato cannons...that's what I always say...well, you can actually say that about pretty much anything, right?This is the same principle as the tee shirt cannons used at ball games.  Seems like you could make it really portable if you used...like...liquid co2 or something like that.  Use that for crowd control and provide important nutrients at the same time.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I have been selling mine on e-bay for a while now. I sell them as t-shirt and confetti launchers. I use C02 and a ball valve. I tried the sprinkler valves and the C02 pressure blows the valve apart this is why I keep it manual. Mine are TIG welded 6061. They will launch a potato over 600 feet or so.T.J.
Reply:Yeah, but can they make julian frys???I have to say this beats the holy crap out of a $10 dollar wrist rocket sling shot.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I have a half-inch, servo-actuated ball-valve that's good up to about 600psi or so.  I also have a 3000psi solenoid valve, but the flow probably isn't that great.  I am so tempted to make one of these.  If I get into trouble, I'm going to blame all of you!-Heath
Reply:Ball valves just don't open fast enough. We use diaphram sprinkler valves which are good up to 130 psi I think.
Reply:Ball valves do the job. The pressure of C02 is around 1100psi, when the tank is in warm weather the pressure goes up to 1300+psi. Here is a vid of the prototype I made. I have beat others with the hairspray ones hands down.That is not me in the video. I am the one filming. Please right click and save-as.http://www.tjsperformance.com/media/shoot.avi
Reply:hair spray combustion guns are easy to beat. They only produce 20psi or so in the chamber... Just saying.
Reply:Next step...ICBPInter-Continental Ballistic PotatoSmithboy...if it ain't broke, you ain't tryin'.
Reply:I'd have to do some math to determine the Cv of the ball valve and the solenoid valve that I have to see which will develop the most pressure more quickly.  I believe the ball valve has a .500" diameter opening and a 1.5 second time to full open, but can only handle 600PSI or so.  With high pressure gas, I'd wager that it will develop a good deal of pressure quickly.  The solenoid valve that I have has a much smaller opening, I believe it's .250", but it'll handle 3000PSI and opens almost instantly.  It might make for a pretty exciting cannon.If I were going to use a high pressure gas (~3000PSI), which would be cheaper, nitrogen or CO2?-Heath
Reply:Originally Posted by halbrittI'd have to do some math to determine the Cv of the ball valve and the solenoid valve that I have to see which will develop the most pressure more quickly.  I believe the ball valve has a .500" diameter opening and a 1.5 second time to full open, but can only handle 600PSI or so.  With high pressure gas, I'd wager that it will develop a good deal of pressure quickly.  The solenoid valve that I have has a much smaller opening, I believe it's .250", but it'll handle 3000PSI and opens almost instantly.  It might make for a pretty exciting cannon.If I were going to use a high pressure gas (~3000PSI), which would be cheaper, nitrogen or CO2?
Reply:WEll i paintball and co2 and nitrogen (compressed air) are the two things we use.Generally, Nitrogen is cheaper and can be compressed anywere from 1 psi - 9000 psi (thats the highest tank ive seen) and anywere inbetween.. a scuba shop will fill a 4800 psi (45 cubic inch tank) tank for about 3 bucks Co2 on the other hand is around 850 psi and thats that.  Its 4.50 to fill a 20 oz tank here at the local sport shop.  Co2 on the other hand can ruin electronics in PB guns, so im going to vote on it can ruin the ignitier on your spud cannons.  also, Co2 is very inconsistant on its output PSI.. depending on wether u got all gas or liquid co2.Hope that helps
Reply:Originally Posted by DirtWEll i paintball and co2 and nitrogen (compressed air) are the two things we use.Generally, Nitrogen is cheaper and can be compressed anywere from 1 psi - 9000 psi (thats the highest tank ive seen) and anywere inbetween.. a scuba shop will fill a 4800 psi (45 cubic inch tank) tank for about 3 bucks Co2 on the other hand is around 850 psi and thats that.  Its 4.50 to fill a 20 oz tank here at the local sport shop.  Co2 on the other hand can ruin electronics in PB guns, so im going to vote on it can ruin the ignitier on your spud cannons.  also, Co2 is very inconsistant on its output PSI.. depending on wether u got all gas or liquid co2.Hope that helps
Reply:I believe co2 raises psi 11 lbs per degree (temp)
Reply:Nitrogen can be had in any of the same cylinders used for inert gas and O2.  Around here, a 125CF cylinder runs about $150 and the price is going up.-Heath
Reply:Originally Posted by DirtWEll i paintball and co2 and nitrogen (compressed air) are the two things we use.Generally, Nitrogen is cheaper and can be compressed anywere from 1 psi - 9000 psi (thats the highest tank ive seen) and anywere inbetween.. a scuba shop will fill a 4800 psi (45 cubic inch tank) tank for about 3 bucks
Reply:Originally Posted by ctardiYea, but that isn't nitrogen, that is either atmosphere, or nitrox.
Reply:Cool video. I was always kinds afraid to show my face when I get into something. Out of fear that the authoritied run out of felons and real law breakers to harass.I'm not a Engineer, I just play one on the weekend.ctardi, its been a while since I've done any painballin' but I believe Dirt is correct on  the use of nitrogen in paint markers.
Reply:you cant beat the good hairspray "frruuump" it makes either
Reply:Originally Posted by TEKctardi, its been a while since I've done any painballin' but I believe Dirt is correct on  the use of nitrogen in paint markers.
Reply:Originally Posted by FearcityINCyou cant beat the good hairspray "frruuump" it makes either
Reply:Well seeing this thread, I couldn't resist, I just had to post a picture of my combustion cannon. This unit utilizes propane as the combustion fuel. When I have it mounted in the trailer as shown, you can, from the front seat of the cart adjust the cannon remotely, which can traverse about 330° while the elevation range is from -20° to +75°, and yes you can fire it from the front also.
Reply:Ok, now I have to tell my story...I built the potato cannon from spudzooka.net (they have free plans online).  The cannon is made from schedule 40 pvc and I designed a mobile quick exhust valve to fire.I smash in the spud, fill tank to 100 PSI and fire.  We did some calculations on a verticle shot at about 85 deg. upward and it went almost 1200' striaght up.As for the distance shot at a 45 deg. angle, they are out of site in 1 second.  I would estimate 350 yards... not sure, all I can say is it clears the lake in the back of my house.  Mike
Reply:weldbyear, that thing is bad!!!   Is it magazine fed?  or maybe(gasp) belt-feed??
Reply:No, it's still a muzzleloader. Perhaps if I find myself with spare time (  ) I'll get around to devising an autofeed for it. Most likely I'll build a new one from scratch and make it either a pneumatic or hybrid system. I had set up a crony on this one, and the results were between 315-345 fps depending on the fuel pressure. The next one I want to at least double that.
Reply:Originally Posted by GYROBall valves just don't open fast enough.
Reply:Originally Posted by 12,000 DoorsEver see the "chicken thrower" episode on Mythbusters. That had a big giant ball valve capable of tossing a chicken through an airplane. As long as the ball valve is big enough it will do the job.
Reply:Originally Posted by 12,000 DoorsMythbusters.
Reply:Originally Posted by 12,000 DoorsEver see the "chicken thrower" episode on Mythbusters. That had a big giant ball valve capable of tossing a chicken through an airplane. As long as the ball valve is big enough it will do the job.
Reply:Once, after my first spudzooka lost it's luster, I took one of those tire bead expanders- you know the air tank with the big ball valve- and changed the tube configuration to fit golf balls. Talk about out of sight...this thing was unimaginable. You barely got a glimpse of the ball if at all.
Reply:I have to get my pics of the one I built in college.  Complete with an ajustable angle of attck base.   I used a 40 gallon halon fire suppresion tank, 2" ball valve and 2 1/2" pipe.  We had to make an tennis ball launcher.  The teacher said we could used compressed air.  You should have seen the look on his face when he saw me bring in this tank.  Because he though it was a "tank" (just missing the tracks)  The other two teams used PVC.  HAHAHa yea right.  They spent all that money to built theirs.  Mine was built from scrap around the shop in 2 hours.  My other 4 team members just sat there and watched me work.Lincoln 300 Vantage 2008300 Commander 1999SA250 1999SA200 1968Miller Syncrowave 200XMT350MPA/S-52E/xr-15Xtreme 12vs Millermatic 251 w/30A  Millermatic 251 Dialarc 250 Hypertherm 1250 GEKA & Bantom Ironwokers