15ft steel cannon

[teamsushi]

It took us a few weeks of after hours work but we built a 15ft cannon. We set up some diodes and clocked a lemon at mach .9

there are pics and video here

http://www.teamsushi.com/potato/
http://www.teamsushi.com/Picnic/

[patraccoon]

wow....... how much pressure have you put in that thing, Im assuming it's pnuematic, cause i bet it would hold a poo load, very impressive

[drac]

HOLY F***IN SH*T!

Those welds look perfect!! You must know a pretty skilled welder!

Good job, but if you want even more power, make the barrel longer.

[wesman987]

Wow that thing is amazing.

I must ask, how do you plan on breaking the sound barrier with a cold gas gun? Or are you just trying to get close.

[teamsushi]

Yeah it's helium filled (300 psi) so our hope os that since the speed of sound is much faster in helium that will give us the extra boost to hit the sound barrier.

grrr yeah we were supposed to have a 15ft barrel but McMaster screwed up our order and we could only get a 6ft in time. And I have to admit the welds were done at the company we ordered the part from(sorry to be lame)

I actually work for The Labratory for Optical Physics and Engineering and every year we have a potato gun picnic and this year we decided to try for the speed of sound, but on launch day we broke our phototransistors and just destroyed potatoes at high preassure. So does anyone know if the speed of sound has been done?

[airpress]

Yes,i think Lucky Thirtheen did it with his hybrid.
But i'm not sure.

[wesman987]

Oh ok, I didn't know you were using helium as a propellant. There have been some discussions about heating the regular air in a pneumatic to achieve supersonic velocities, but as I'm sure you know, fluid dynamics really works against you close to the speed of sound. Go here: http://www1.iwvisp.com/thehalls/ggdt/index.html

He has written a fairly accurate cold gas gun simulation program that you could try to tinker around with to get your desired velocities.

A better projectile will definitely improve your results, but I don't know if you would consider that "cheating" or not..haha.

[spudshot]

spudinator and Jspellman both broke the sound barrier, both were with hybrid cannons Joel also believes he did with a gigantic pneumatic using AIR, i dont know where people are finding that L13 did it, i havent read anything about that

[airpress]

I'm wrong spudshot.
It was Jspellman.I could not remember it.

[beebs111]

also i remember some site about a couple of guys who did it with a gb a 10 ft length of steel pipe and some gun cotton(bad idea dont try the gun cotton)


Edit: yup, thats the 1, that was the 2nd taste i got of spudding, first i saw sumthin about it in a boyscout mag, googled it and found that, found xinventions,found spudtech then registered here

[drac]

also i remember some site about a couple of guys who did it with a gb a 10 ft length of steel pipe and some gun cotton(bad idea dont try the gun cotton)

Ahhh, the infamous Powerlabs golfball cannon. Those videos were great, especially with the bang echoing in the distance.
http://www.powerlabs.org/cannons.htm
scroll down to see it.

[Mini Khan]

I think ive broke the speed of sound but i cheated and used gunpowder

[TalonXxX]

First off, that was a lame post. Second, this is an older thread... unless you have something not lame to say, leave it be. Third, talking about shooting any explosive or explosive device out of a cannon is not prohibited on these forums or any other spud gun forums as far as I am aware. Thank you.

[spudshot]

really stupid dude, one guy tried that in steel pipe and blew his dumb ass up.