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Post by knave on Jan 26, 2020 17:42:30 GMT -5
Can a ping pong ball smash through plywood?? This is the same boy that made the snowman with a window AC. jamesp
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Jan 26, 2020 22:00:22 GMT -5
How'd he do that knave ? I think the mylar was taped to the end with duct tape. Then pipe was pressurized pressurized till Mylar ruptured to release pressure like an instant open full pipe diameter valve then launching ball ? Mystery is why did the plywood stay put and not get blasted across room when air blasted the ball out of the pipe ? I'm stumped. Gotta contemplate this one.
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Post by knave on Jan 26, 2020 22:12:28 GMT -5
jamesp this is definitely on my bucket list. The foil from helium balloons on each end of the pipe. When near perfect vacuum is achieved, break Mylar on ball end. Ball blasts through other end Mylar with power to spare. You prob know this but perfect vacuum is only -15 psi. So packing tape is fine. Key is no air molecules in front of the ball. I would love to know the peak velocity of that ping pong ball. Note how the ball got shredded but not before it blasted a circle through the plywood. He has another one with several beer/soda cans where it blasts through (I think) 2 of them and imbeds in the 3rd. Edit: pipe not pressurized, until 0 psi air rushes into it.
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Post by knave on Jan 27, 2020 17:28:40 GMT -5
They clocked it. It’s fast. 1,729 mph
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Post by aDave on Jan 27, 2020 18:19:41 GMT -5
How'd he do that knave ? I think the mylar was taped to the end with duct tape. Then pipe was pressurized pressurized till Mylar ruptured to release pressure like an instant open full pipe diameter valve then launching ball ? Mystery is why did the plywood stay put and not get blasted across room when air blasted the ball out of the pipe ? I'm stumped. Gotta contemplate this one. James, although knave touched on this being caused by a vacuum in the pipe, here's an earlier demo by the guy which shows him puncturing the mylar on the ball end of the pipe. Air rushes in behind the ball and propels it down range. As far as the plywood not moving, it's braced at the top with the wood, and there are nails wedging at the bottom. Nails are visible in the original vid at about 1:42.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Jan 27, 2020 20:50:43 GMT -5
Must review this in morning knave. Vacuum does make it a game changer. Forgot about those powerful vacuum pumps you guys deal with. Thanks aDave for the extra points. 1700 mph !!
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Post by RickB on Jan 28, 2020 7:13:17 GMT -5
Not a cannon knave but....interesting How to make an Arizona penny can alcohol stove
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