My first potato cannon. lots of damage pictures!

[schmanman]

this is my first potato gun. I am 14,and built ,designed, and funded this gun entirely on my own. the barrel is 15 feet long,and 2 inches in diameter. the air chambers are both 6 feet long and 4 inches in diameter. The piston valve is 4 inches in,and 2 inches out. the piston is a regular 3 inch schedule 40 endcap,with the injection molding marks sanded off. this fits perfectly into a piece of 4 inch sch40 pipe. it seals against a 2 inch rubber coupler on the end of he barrel inside the tee. IT WORKS GREAT! the foldable stand on the front is a set of folding banquet table legs. The wheels are solid steel and rubber,on an 1/2 inch threaded piece of barstock. I also have a 1 1/2 inch, 3,and 4 inch diameter barrels. they are also 15 feet long, exept the 4 inch. it is 10 feet long.I caculated the volume of the air chambers, elbows, tees, and all, and its bigger than the mega launcher! It was about $220($340 now with the new air chambers and longer barrel) of christmas and birthday money to build.




the GGDT was correct about the distances it shot at 80psi and below, so the estimation about 150psi should be right. It says 1.12 miles!and 550-850 fps! The pictures of the car hood are only a couple of the many holes I put in it. The shot was at 80psi, from 80 feet away. The metal slug I shot, weighing in at 3/4 to 1 pound,went through both layers of metal, then went through the 2x4 and piece of 3/4 inch plywood, no problem. other shots went right through the supportive stamped steel bracing on the car hood, too.anyway, the metal slug finally hit the ground 200 yards into the field next to my house, and bounced about another 100 yards before finally stoping.and it kicked,like,4 feet! in the picture showing the end of the barrel is 6 feet off the ground,you can see the far treeline in the background.I can clear that at 30 psi no problem. In the one picture,a friends average hairspray spud gun is laying on the ground, for comparison.it is ,like 3 to 3 1/2 feet long



the barrel tip is 6 feet off the ground. I was originally going to go a lot smaller for my first potato gun, but I figured,why not build it first, so I don't waste my money on 15 others and then build this one. I also could not afford a supah. this valve rivals, if not outperforms, the quickness and flow of a supah valve.


LET ME KNOW WHAT YOU THINK!














THIS IS HOW I BUILT MY VALVE
to see it better, copy it and then paste it on word or something and enlarge it

[saladtossser]

wwwwwwooooooooooooooooooooooowwwwwwwwwwwww

nice damages!!

[schmanman]

that's a hood from a 80's lincon I found in the woods.I will post more pictures of it somtime. Oh,and sorry the gun is such a mess.It's the winter,nasty out.

[Atlantis]

Your right it is huge and powerful. Paint it to cover all those primer stains and you'll have a lot of fun at parties.

[drac]

Wow. This is your first? You definitely did your homework on this one. My hat's off to you.

[schmanman]

the second from last picture, is of where a 1/2 inch piece of steel pipe tore through the three layers of metal on an oldsmobile like nothing.the last picture is from pipe,too. The lincon hood and oldsmobile door had no holes,ect on them before hand. If you look closely,you can see where I shot a bunch of bb's. It looks like it got hit by a shotgun.

[boilingleadbath]

I don't believe your valve flow numbers... 1 valve with 2" porting (and several internal turns) will not out-flow 2 valves with 2" porting.
...most likely quicker opening, though; it's an inhernt property of barrel-sealing piston valves, and the sprinkler valve certainly helps.

Other than that, nice, large cannon, and nice wright-up. (if a tad difficult to navigate)
I see you'v combined several different configurations; the valve in a tee, the duel tanks in such an arangement, the rubber fitting seal... nice job.

Have you considered getting a 1.25" barrel? With a 2" valve such as yours, it allows the highest speed of any of the barrel with light projectiles... indeed, supersonic velocities are possible with things as heavy as paintballs (and their sabots).

[schmanman]

i'll post a video somtime.you'll see what I mean. And, the fittings are all 4 inch,not much resistance,compared to say, the mega launcher,with 2 or 3 inch fittings and alot more turns.but your probobly right

[DonTheLegend]

Awesome cannon. I wish i could build one with a barrel that long, but there's no place to use or store a 15' barrel in the county

[Shrimphead]

I must say that I am very impressed with this gun. One thing, why not mod the sprinkler valve? Won't that increase performance (not that you need it).[/i]

[)DEMON(]

impressive, it would be nice if you buy a few spraypaints and give that a paintjob, it would look really cool

[jrrdw]

Question: If you are useing a piston valve, why are you useing a sprinkler valve to open it?

[schmanman]

this is how it works.the air is put into the gun from behind the piston. the piston is pushed into the rubber coupler, and it seals so no air can go out the barrel.

but air goes between the piston and pipe,and goesthrough the bottom of the tee,into the chambers.Okay,this is where the sprinkler valve comes in.since there is air pressing on the front and back of the piston,but there is less surface on the front because of the seated barrel,the pressure on the back keeps it seated.

to fire,activate the solonoid,which vents the back of the piston,so there is much,much more pressure pushing it on the front.this causes it to slam backwards,unseating the valve,and dumping huge ammounts of air out the barrel at once.

this all actually happens instantaniously(instantly) at the instant you hit the button.this sprinkler valve vents,and the 1 inch sprinkler valve opens much quicker than,say,the supah,with a 1/4 inch blowgun

[schmanman]

oh,and about the modded sprinkler valve,I tried it once. It ruined the valve,and I had to get this one. but ,if I bought one off spudtech ,that would work.at the moment,I dont really think it needs it

[spud freak]

WOW! awsome damage pics.i lov ur cannon