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by jimmy101
Fri Apr 03, 2020 1:10 pm
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Re: Pnuematic Cannon Making Very Loud Noise....!

You can search these forums for "honking" for a number of posts about the problem.
There is also a brief page on the wiki at spud_wiki/index.php?title=Honking and spud_wiki/index.php?title=Sprinkler_valve_modification
by jimmy101
Thu Jun 04, 2020 10:29 pm
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Re: Calculations related to pneumatic cannon.

The teacher isn't a "professor", it is a high school teacher so expertise in this area is probably limited. :) Mark.f gave a reasonable answer. Don't need much of a "computer", you can do it an Excel spread sheet. Wont be super accurate but were talking a high school project, not a DARPA project. Ju...
by jimmy101
Thu Jun 04, 2020 11:04 pm
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Re: Potato Howitzer

Looks outstanding. But the coax design is killing the performance. I would expect a gun that size to be firing something like a spud at about 150-200 MPH. From the video I would guesstimate about 50 MPH or less. Any idea what the chamber and barrel volumes are?

But it does looks sweet.
by jimmy101
Mon Jun 15, 2020 4:58 pm
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Re: I was hoping for some feedback on my oxy-propane combustion cannon.

The biggest I usually see is 150 ml. That's big enough for 1x in a 3.75 liter (229 in^3) chamber, which is a pretty big chamber. https://www.amazon.com/Syringes-Scientific-Measuring-Watering-Refilling/dp/B07C71C1LH/ref=sxin_7_ac_d_rm?ac_md=2-2-bGFyZ2Ugc3lyaW5nZQ%3D%3D-ac_d_rm&cv_ct_cx=syringe&dchild...
by jimmy101
Mon Jun 15, 2020 4:53 pm
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Re: I bring you some cannon performance data

Moonbogg wrote:
Sat Jun 06, 2020 2:07 pm
jackssmirkingrevenge wrote:
Sat Jun 06, 2020 6:05 am
jimmy101 wrote:
Thu Jun 04, 2020 10:31 pm
Caliper in the fruit isle? Just take a little length of barrel!
"Security? Yeah it's that weirdo putting limes through a pipe again..."

Yeah, that wouldn't look good.
Meh. Put a cut in the 1/2" long piece of pipe and wear it into the store as an ear ring.