Tennis Ball Machinegun (New Video pg.2)

Just build a cannon and want to show it off? Post it in here.

Postby BewareOfDog » Sat Sep 17, 2005 3:18 am

My third anniversary as a member is coming up, so I figured what better way to celebrate than by building yet another big POS? ;)

<img src="">

Although it lacks paint and it's stand, this thing kicks ass! The parts were salvaged off of my twin-valved canteloupe cannon. I took it apart because it was just too damn big. The single 3" valve now dumps into a 4" TEE. The air flow was choked down to 2" because a 3" valve dumping out of a <b>2½</b> " opening would not pull the balls out of the chamber...
"Bernoulli's Law"?

I was only able to shoot it three times tonight. I started on it at around 6, and didn't finish till about 9:30. I'm sure that the neighbors were wondering WTF was going on!
Besides, trying to pressurize a 1700 cubic inch reservoir with a 2 gallon compressor sucks.

I was only able to get it up to 110psi, and wish I would break down and get a video camera that has audio as well. The sound that this thing makes is hard to an amplified recording of someone forcefully spitting grapes out of their mouth? I can't wait to get 170psi into this thing at work.

I used a half-round wood file to chamfer the inside edge of the breech end of the barrel.
The chamfer falls back approx. 1/2" or so. I couldn't believe that I never tried that on the muzzle end of any of my previous launchers... the ball practically loads itself.

The "fun balls" that I get at Wal*Mart seem slightly smaller than a regulation? tennis ball. They don't require half as much effort as a quality tennis ball does to load. I'm wondering how far they'll launch, or if each successive ball will have a shorter arc?

For people who like spec.'s:
The barrel is 5 feet long, approx. 282 <sup>3</sup> in.
The entire tennis ball Chamber is approx. 286<sup>3</sup> in.
The reservoir is approx. 1700<sup>3</sup> in.

3:1 ratio (Reservoir to entire Launcher)
6:1 ratio (Reservoir to entire Tennis Ball Chamber)

And here's a cutaway view of the Chamber: <a href="">Cutaway-view</a>
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Postby draculon » Sat Sep 17, 2005 6:58 am

:shock: That thing is friggin huge!!!!! Pretty awesome gun though, I guess you've been really bored ]lately. [:P}
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Postby buzzboy » Sat Sep 17, 2005 7:50 am

Geese DR. How many bps do you think you are getting? Also how many balls does the chamber hold.
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Postby spudshot » Sat Sep 17, 2005 8:18 am

170psi!?!?! holy crap DR thats realy dange.....oh wait its DR
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Postby saladtossser » Sat Sep 17, 2005 9:45 am

wow, thats interesting, but i fail to understand how the balls are loaded into the barrel.
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Postby theexp » Sat Sep 17, 2005 10:43 am

i used to have the drill press you have in the background, 30 bux at lowes. BUt nice cannon, a nice way to celebrate
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Postby Mr.Plow » Sat Sep 17, 2005 12:41 pm

That actually works? Wow!

Pretty sharp, DR. You need to get some vids of it firing.
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Postby jimmy » Sat Sep 17, 2005 3:24 pm

That's pretty clever DR, kind of a cloud tennis ball gun. Does it tend to fire a single or multiple balls?

Do you think it would work if the T was rotated 90° so the magazine was vertical, and the inlet and barrel postions were swapped?

The design also looks similar to the RC warship BB selector guns (without the selector) but on a massive scale.
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Postby SMOMW » Sat Sep 17, 2005 3:37 pm

that is awesome. i also want to know it's rate of fire.
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Postby tim jones » Sat Sep 17, 2005 3:47 pm

Nice cannon, DR. Does it kick much? Looks like it weighs 30 lb or so.
tim jones
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