Does any one have any experance with supd guns (the bigger the better).
I'm thinkin' of building one and was wondering if people who have built them thort is was a worth while project.

cheers ears


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give me 15 mins and i'll have it in bits

yeah theyre fun.

i made one that was only 3 feet long. 1 foot chamber, 2 foot long barrel. the chamber was 3 inch pvc, and the barrel 1.5 inch. despite its apparently dinky size, it shot just as far as some people cannons that were 7 feet long, sometimes farther. so the bigger is not the better. the proportions of the lengths and widths are what matter.

also, i dont recommend a typical bbq grill ignitor. the piezoelectric ones, that is. i found one in menards that was a little box with some electrical components in it, with a battery. then it had two wires and at the end of the wires were little steel electrodes, perfect. i put it on, and when you press the button (its not piezo electric, so no little foce is required), the two electrodes spark about twice a second, and keep sparking till you let go of the button. so it ignites it pretty much every time.

anyway, my seemingly dinky cannon shot about 600 feet, and with good accuracy.

im planning on building a pneumatic one similar to the PC2 on xinventions. im gonna use a rifled barrel that im gonna order from the spudgun technology center.

I agree that with unstable that the size doens't matter. Well, maybe the chamber size to hold more kablooey juice...

Mine's only i'd say, bout 4 foot long. Same as unstables only my cannon's longer. Which, of course, took away some velocity. But i can still shoot 450-500 yards flat with accuracy, and 500 to god knows how far with an angled launched...

So i'd stay with a 2 foot cannon or so, and the one foot chamber is plenty enough....

Oh by the way, what do you all think is the best fuel? ether's what i've heard the most, jus curious....

Have fun.... and be careful, haha....


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Cheers with Cordiality,
Deakon

Me and my friend Buildt one that used one of those portable stove propane tanks and rigged it up to one and it shoot like a mutherfucker ive never seen anything better!

Do you mean like a 17.5 lbs tank for a grill, or one of those smaller tanks like for portable Coleman like stoves and lanterns?

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Cheers with Cordiality,
Deakon

[This message has been edited by Deakon (edited 07-16-2001).]

any good sources of complete plans?

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give me 15 mins and i'll have it in bits

m
my last cannon was PVC and it was a 1.5in id. barrel it was about 5ft tall with a foot long 4in id. blasting chamber. I only used aquanet for fuel and a lantern lighter drilled in the cap for ignition. A lot of people use grill sparkers but i haven't had good luck with them. It was spray painted flat black with some yellow tape around the end of the barrel. It looks really fucking cool.

Anyway as far as barrel length is concerned you want to experiment. The longer the barrel the longer expanding gas will accelerate you projectile. Too long you'll lose distance because of barrel friction. Too short you wont get maximum acceleration. I heard that you want to get the barrel long and slowly cut it down until the blast is the loudest, i don't know if this is true.

Make sure to file the end of the barrel so that is sharp and slants inward a little as to squeeze the projectile a bit to get a nice seal. Another cool thing about a 1.5in id. is that milk caps fit snugly into the barrel. They you can fill your cannon with water, which is funny.

I have a protractor attachment on the front of my cannon with a string tied to it so i know what angle my cannon is at. After you shoot the cannon straight up and get the initial velocity you can then use use ((Vi^2) sin(Angle))/gravity to get a ball park figure of your range to make it easy to hit stuff. Doesn't math suck the fun out of anything

use PVC get PVC cleaner and good glue replace you cannons after a while. Becareful what you use for fuel as it may eat the PVC.
http://www.geocities.com/ResearchTriangle/Lab/4772/spudindex.html
http://members.aol.com/TimJC513/Links.htm


[This message has been edited by biot (edited 07-17-2001).]