Re: THe NAC Lots-O-Post Thread
eff ladies then, theyre a waste of time anyway.
x2.
what chamber size / bore? I've got a proud and colorful past consisting of many potato cannons being confiscated from my college apartment by campus police
Ill see if I can find pics of my friends cannon.
MAP gas, built in pc airfan to disperse waste gases, adjustable pressure regulator(depending on ambient temp +or-)and tazer electronics to ignite it.
barrel #1 was limited to the length of his xj due to transportation.
barrel #2 is collapseable and is around 15',iirc
oooooh. :thumbup: I haven't taken mine out in years. I built a pneumatic air cannon; instead of using fire I have a compressed air chamber and ball valve to open it. All that means is that I can shoot water and other loose stuff out of it since the ball valve also keeps the compression chamber and barrel separate until firing.
..that and I can run the compression chamber up to 120PSI (and accurately measure how much pressure I am firing at each time)... a standard aerosol cannon produces a max of maybe 30ish PSI if the air/fuel mixture is perfect.

Best part is I built a huge remote-fire (can fire from 50 ft away) cannon for my highschool science fair and won an honorable mention for my study of effects of increased pressure behind a projectile. I loved science
3" PVC endcap. I built this gun 11 years ago.
That comment was mostly directed towards Adam, as he had the (mis)fortune of standing behind it at Rausch a few weeks ago when the old endcap exploded. I think we had probably cracked it previously trying to unscrew the cap with a gigantic pair of pliers. Dried-up hair spray gunk holds pretty well.
I had also been used to using Aquanet, but apparently Suave extra-hold requires some different stoichiometry for an optimal mixture. Later testing has shown that it's a much more potent fuel.
After that failed, and the subsequent trip to the hardware store in downtown Pine Grove on a sunday night over labor day weekend failed, I still had most of a 5-lb bag of potatos left. We may or may not have removed the cast-iron fill plug from the fuel/oil tank by the office with a big pipe wrench, which might or might not have had the same threads/diameter as the PVC cap. Furthermore, I will neither confirm or deny that a potato fired from close range can go through the windshield of an XJ, as well as put a decent dent in a rear quarter panel.
The gun itself (and the combustion chamber volume vs. barrel length, etc) has a ton of testing & tweaking time. The one in question is Spudnik II; the first one was a really basic test mule; III was a mini gun for shooting chunks of the leftover scraps, and IV has a 10-foot barrel. II, III, and IV are all scale models of each other and the large one has gone over 1000 feet with Aquanet. II will reliably go between 600-700 feet on hairspray, with a muzzle velocity of over 100 MPH, and I've punched holes in 1/2" plywood with it.
II also features electronic ignition (courtesy of Weber), a shoulder rest (taken from a Nintendo Super Scope 6), a scope (the small spotting one from a telescope), and a little thru-bolt right at the bottom of the barrel so that you never have to worry if the potato is in the right spot.
I'll dig up a pic, but here are the technical details:
http://pages.prodigy.net/dmacock/photos/spudnik ii results.doc