Page 1 of 3

mythbusters air cannon

Posted: Wed Jan 17, 2007 11:34 pm
by Petrie
I was watching the mythbusters pirite(sp) episode and i was appalled by their gun it had way to long a barrel and used two electronicly acuated valves to dump at least 6 scuba tanks worth of air. they two guys were also complaining about the volocity they were getting . If any body has an account on the mythbusters fan site i would love to see a topic posted for them to redo it with a couple of Suph valves and an accurite(sp) C:B ratio.

thoughts?

~Petrie

Posted: Wed Jan 17, 2007 11:45 pm
by frankrede
Long barrels on pneumatics are usually a good thing. Especially with such a large chamber, I myself haven't seen the episode but it sounds fine. What type of valves did they use, because not all electronically opened valves are bad, such as some butterfly valves.

Posted: Wed Jan 17, 2007 11:50 pm
by squeaks
I'm about to watch that episode so I'll have to look at it but their valves are usually pretty good. I'll tell you what I think in about half an hour.

Posted: Thu Jan 18, 2007 12:34 am
by Insomniac
The barrel was way too long (I assume this is the episode where they try to shoot hay through a coconut tree) It was sooooooooooo long that the air would have reached its top speed (either just under the speed of sound or the speed of sound, can't remember which) in half the length. They also said they may break the sound barrier, which is impossible with room temperature air. Their valves were fine, they were specially designed to dump lots of air quickly (they were some sort of diaphram valve, like a faster version of a sprinkler valve) I didn't like that episode, simply because I knew a lot more about air cannons than they appeared to (most people on this forum would) The problem with their gun was that they could have achieved an identical result using a much smaller, but better designed gun.

Posted: Thu Jan 18, 2007 12:56 am
by squeaks
No, he's talking about the pirate episode that I'm watching right now. I haven't seen their full scale cannon but their small scale one looked ok, just it used an electric diaphrahm instead of a pneumaticly actuated one.

Posted: Thu Jan 18, 2007 1:06 am
by Insomniac
What is the myth????

Damn, my entire post was a waste of time lol

Posted: Thu Jan 18, 2007 1:24 am
by squeaks
The myth is that splinters from the cannon ball hitting the ship can kill more than the cannon ball itself.
I've seen their cannon now, it's basically 2-2" electric diaphrahm valves with 4 scuba tanks. The barrel is long, but by my estimates around the ideal legnth(most people grossly underestimate the max barrel size for pneumatics). It fires a 6lb ball at 500fps. I'd say that is dang good, especially since it's a 6lb ball. If they were to fire something like a potato they would get velocities around 900+.

Posted: Thu Jan 18, 2007 2:20 am
by Insomniac
I hope they screen that episode in Australia soon!

Posted: Thu Jan 18, 2007 3:32 am
by Recruit
What is with Mythbuster any ways I have watched a few of the episodes and really they go about stuff the wrong way.

Posted: Thu Jan 18, 2007 3:41 am
by MrCrowley
On some myths they seem very un-professional but they do have experience, They should re-search more on some myths though. A few they re-vistied they kind of did half-ass.

Though has anyone seen the exploding pants myth yet? All the way from New Zealand :P they alos said it was their favorite.

Posted: Thu Jan 18, 2007 4:44 am
by experament-u2
i saw that it was sick i cant wait till i see the new cannon ball myth

Posted: Thu Jan 18, 2007 4:52 am
by rna_duelers
Exploding pants??!?I must have missed that!NOOO i love mythbusters and I remember the myth about the straw going though a palm tree and that thing was so outa wack!The valve was good but.They only got to 300fps i believe at 150psi and about 10 meters of barrel.

Posted: Thu Jan 18, 2007 5:31 am
by Insomniac
Exploding pants was cool.....I want some of that shiny paint lol

Posted: Thu Jan 18, 2007 2:34 pm
by zeigs spud
lol.....
okay i think they are fine, they are experts and wouldn't do anythin without research. i'm sure they know what they are doing so calm down.

Posted: Thu Jan 18, 2007 3:34 pm
by MrCrowley
Calm Down? Who are you talking to? Its just that on some myths they have no idea what they are doing and just get stuff from their researchers.