ok all you people out there who think you have the best cannon out there. we (some people from 131) built a 11 feet long, 5 feet wide beast. it uses compresed air and shooots plastic containers full of peanutbutter (or big potatos) a picture will be comming soon, till then what do the rest of you guys have
We just use a slingshot to fire t-shirts up into the stands. A little less dangerous and alot less likely to cause lawsuits. 
5 feet wide! As long as you donât shoot garbage cans or 55 gallon drums of peanut butter out of it. :ahh:
Do you mean ones that can be used at events, or just ones we have?
Me and my friends built a few. Theyâre about 4â long. 3âx2" PVC barrel and a 1âx4"? combustion chamber. Thatâs right combustion. The back screews off, you spray something flammable in the combustion chamber, close it up quick, and pull the trigger (a grill spark lighter). We shot potatoes about 2 football fields, and apples a little farther (theyâre jucier and slide better).
itâs very similar to this one
it is 5 feet wide in the sence that we have 11 feet of barrel, 5 feet of fittings and then 11 feet of acum. it takes the shape of a UâŚi am purly talking about for your own fun. i wouldent want to know the damage caused by one of these in a stadium
Back in 2000 and 2001 my brother and a buddy of mine built one with all the money we could gather. It was pure luck that we didnât blow ourselves up with the thing. It was about 15 ft long and the biggest chamber diameter was about 8 in. Pure flammable propellant and a grill lighter!!! (Got the gas chamber to glow orange more than once, and even blew the threads off one of these.) You should have seen the look on the check out clerks face when she saw 3; 16 year olds buy 4 bottles of diesel engine starter (love the ether).
We did quite a few trials with it and it worked greatâŚheck we actually shook the windows on his back porch once. I wish I had a picture of this beast, but since then my friend has moved to TN and he is now attending Georgia Tech. Infact, I believe itâs still in his grandparents garage.
I know the technokats have an air powered canon this year. Iâve seen it in use a few times and itâs pretty cool. You might keep an eye out for them in Atlanta because I know they had it out in Chicago.
I have a smallish potato cannon, combustion. Doesnât really have the right ratios, made it before I knew how to do it right.
Planning on âborrowingâ a few solenoids from robotics in a few weeks to make me a pneumatic one, if I can. I know all the crazy formulas now, so I should be able to get it to work a lot better.
We have a radish cannon that is about a foot and a half long, and shoots baby carrots real nice. We also have a few 6 foot long 1.5" diameter tube 3" chamber with grill sparker cannons.
I recomend skipping potatos down a stream or across a lake. 
A warning. The PVC will get very brittle when it is cold. If you keep it un heated, take it inside and warm it up before firing it at 30F. We shattered one firing it cold. I was surprised noone got hurt by shrapnel.
Wetzel
A friend of mine made a steel potato cannon that uses old gunpowder as the fuel.
I do not think that you should âborrowâ things without asking your mentors. You should just save up to order your own solenoids. Then you could not be arrested. Muhahahahahhahah
My mentors let me borrow a couple solenoids to make and air cannon, but that project is on hold until the end of build session.
The first one i made is about 7 feet long, and has a total of⌠7 pieces of PVC. And its painted camo.
The second one is under 3â long but you can fire it every 20 seconds as long as you donât run out of crab apples.
How about this?
You, I believe, win. Got any more details on that? dimensions, muzzle velocity, max psi, range, ammunition? (plus any cool exploits with said machine?)
umm Beener, epic win sir, epic win:eek: