my first cannon- propane fueled w/ spark plug ignition

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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WOW!!
Corporal 4
Corporal 4
Posts: 891
Joined: Thu Mar 16, 2006 9:47 pm
Location: New jersey

Wed Jan 02, 2008 12:27 pm

It looks great! I like the idea of the couplings in the chamber, don't really need it, but as it was said before if your happy then your money!

Only thing I would suggest is the barrel/chamber support. Just keep doing what your doing with the propane and later on change it if you want.

Keep up the good work!
turbocoop
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Joined: Tue Jan 01, 2008 8:15 pm

Wed Jan 02, 2008 6:52 pm

any idea how big the cap and resistor should be? I understand the idea but I dont know enough about electronics to figure out how big they should be, can I get the stuff at radio shack or something? What would be the best switch to use, just a heavy duty momentary on/off push button???

Ill cement the barrel in and make some supports this weekend and take some more pics. Ill try to get a a video or some pics of me shooting it too if I can
bigbadbrad
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Joined: Tue Dec 18, 2007 3:06 pm

Wed Jan 23, 2008 10:55 am

wow great start. that looks close to ours. you dont need any of that resistor crap. and you can run it off an 6v camping battery just fine. We started with tapping the bare wires on a 6v battery to get the plug to spark. and that worked great last yeat. this year we went to a launch button and an arming switch 20 feet way. it sparks the plug continuously when you hold the button down. it's works GREAT!! we found a flasher module from a police car that flashes 4 times a second. it cost about $11 on ebay. and its what lets us hold the button down and spark the plug. if you're using propane the spark will be just fine off that ignition coil charging the coil is not necessary. we've made two of these now with the spark plug and ignition coil. if you have any questions please feel free to contact me. here are some pics of our parts. http://www.mrduffy.com/hpc/ and a tool for optimizing the propane based on chamber size. there are no pics of the new full cannon yet. our latest is 10' long and shoots 3" plaster of paris cannon balls. you can see in the pics the launcher switch we're using. and here is the link to the police flashers on ebay. they are actually $9 and two come in the order. http://cgi.ebay.com/ebaymotors/2-FLASHE ... 0201286618 If you're building a launch mechanism for an ignition coil this is the way to go. seriously if you have any questions please feel free to contact me and my team.
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