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need help building potato canon to beat my uncle

Posted: Tue Jul 16, 2013 8:32 pm
by dart guy
i want to win the bet with my uncle that i can build a potato canon that can beat his i need ideas
ideas and explanations that i would want would be
  • best burst disk
    best fuel
    how to inject fuel/air mix
    also what is (1-7)x mixture
    how to mount burst disk
    recomended presure rating
    ignition source
    chamber size
i am up against a standard combution but 2 inch diamiter barrel 8-12inch wide chamber by 1-1 1/2 foot long ignited by a tazer and crincled aluminum foil please help
ps i will input new ideas after get them and i draw them

Posted: Tue Jul 16, 2013 9:26 pm
by jsefcik
12 wide chamber??? Thats huge lol


Be simple nd use pneumatic !!! Blow his cannon out of the water!

Posted: Tue Jul 16, 2013 10:31 pm
by dart guy
no it needs to be combustion or hybrid to win

Posted: Wed Jul 17, 2013 1:16 am
by Technician1002
PVC in your area may be hard to find in larger diameters. To beat your Uncle if building a combustion, avoid DWV non pressure rated PVC. Most larger PVC you can find is NOT pressure rated.. Bummer. In personal testing, I have found Cellular Core ABS works very well in the Schedule 40 thickness. It is less brittle so it is less likely to be dangerous if it does fail. For more info on the subject, see my test cannon in my sig.

A 4 inch chamber is better than a 2 inch chamber.

There is some threads already regarding DWV pipe.
http://www.spudfiles.com/forums/the-tru ... 18058.html
http://www.spudfiles.com/forums/dwv-t21573.html

Posted: Wed Jul 17, 2013 7:43 am
by Gun Freak
dart guy wrote:no it needs to be combustion or hybrid to win
Negative Batman! You could easily blow him away with a pneumatic.

Posted: Wed Jul 17, 2013 8:08 am
by jackssmirkingrevenge
Gun Freak wrote:Negative Batman! You could easily blow him away with a pneumatic to which a stoichiometric amount of fuel has been added that has some form of overpressure opening valve or burst disk and ignition system.
True :)

Posted: Wed Jul 17, 2013 9:45 am
by dart guy
i mean that my canon wont count unless it uses combutible gasses and i must have screwed up i meant that the barrel is 2 inches

Posted: Wed Jul 17, 2013 10:08 am
by Gun Freak
jackssmirkingrevenge wrote:
Gun Freak wrote:Negative Batman! You could easily blow him away with a pneumatic to which a stoichiometric amount of fuel has been added that has some form of overpressure opening valve or burst disk and ignition system.
False, a purely pneumatic system would be ideal in this case as they are always without fail the best type of propulsion system.
Ah, vous avez raison, monsieur :wink: How could I ever make such a silly and naive suggestion?

Posted: Wed Jul 17, 2013 2:42 pm
by dart guy
oh no wonder i cant win with you gunfreak your anti hybrid you dont like hybrids but i cant understand whatever language you are typing but i want a cannon to win against a canon that shoots potatos through steel barrels

Posted: Wed Jul 17, 2013 3:32 pm
by MrCrowley
Dart guy, I appreciate your interest in building a hybrid but you do realise that your questions essentially ask us how to build a hybrid?

Hybrids can be dangerous, but I wouldn't say that's the main problem with spoonfeeding. I think troubleshooting is the issue. Whether you go manometric or volumetric metering, burst disk or piston, you're going to run in to a few niggling problems. To overcome these small problems, you really need to understand what you are doing.

If we can see that you've actually dedicated some time and effort in to researching hybrids, most of us (including me) are more than happy to help you with any questions you may have. You can ask about burst disks, but be more specific as it shows you've actually thought about what you're doing, e.g. "should I use plastic cut from milk bottle or metal from soda cans"?


best burst disk - No such thing as 'best' burst disk, but we have many topics where we discuss ideal burst disks. Search for them.

best fuel - Same as above, people usually trade off between cost and availability; stick with propane. This is also discussed often in this section.

how to inject fuel/air mix - Go to the showcase section. If you don't know how to build a hybrid, and can't be bothered researching, don't build a hybrid.

also what is (1-7)x mixture - do research and you'll find out.

how to mount burst disk - same way everyone else does

recomended presure rating - 'high' (vague questions receive vague answers).

ignition source - discussed frequently on this forum, use your head and the search tool.

chamber size - as large as you need.

Re: need help building potato canon to beat my uncle

Posted: Thu Jul 18, 2013 4:18 pm
by jrrdw
dart guy wrote:i want to win the bet with my uncle that i can build a potato canon that can beat his i need ideas
ideas and explanations that i would want would be
  • best burst disk
    best fuel
    how to inject fuel/air mix
    also what is (1-7)x mixture
    how to mount burst disk
    recomended presure rating
    ignition source
    chamber size
i am up against a standard combution but 2 inch diamiter barrel 8-12inch wide chamber by 1-1 1/2 foot long ignited by a tazer and crincled aluminum foil please help
ps i will input new ideas after get them and i draw them
You ask for a lot of spoonfeeding here on the forums. Unless I missed it, show us something you have built, learned or even vagly picked up on from all the information you ask of us.

Please know that I'm not picking on you, sometimes we have to know members are understanding the danger and risk that comes with our hobby. This risk is minimized by the way we build our cannons.

I really want to see something from you that prooves you know what your doing and have learned from all the information here. You can post completed cannons YOU have build in the 'Showcase' sections or build plans YOU have devised in the 'Discussion' sections.

If PCGUY or any other moderator thinks this thread should be unlocked, feel free...