Piece of @#$% Canteloupe Cannon!

Post questions and info about pneumatic (compressed gas) powered launchers here. This includes discussion about valves, ratios, compressors, and anything else relevant to launchers powered by compressed gas.

Postby buzzboy » Sun Jun 05, 2005 3:54 pm

That thing will rock when it is finished. Also you should try a ball valve on the actuator and the blow gun. Because it is on such a large scale it should show the difference between the two. Overall this thing is sick. I can't wait to see the damage pics.

On an off topic note where in Utah do you live. My family goes out for a month every winter and stays in Midvale.
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Postby ybott » Sun Jun 05, 2005 6:32 pm

Wouldn't it be fun to build this exact cannon, but without sprinkler valves.....burst disk (union) instead ?..at the tee where the chambers meet the barrel.
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Postby airpress » Mon Jun 06, 2005 12:33 pm

Whend do you think the cannon will be finished DR?
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Postby tim jones » Mon Jun 06, 2005 2:15 pm

I'll be interested to see how you control the recoil from that bruiser. I ended up building a massive thrust block that conforms to the rear half of the receiver tee on the P5, but that launcher only had 4" chambers and a pair of puny little 2" valves. Do you have a plan yet?

Also, you won't be able to mount 8" or 10" barrels (for pumpkins, basketballs and bowling balls, of course!) if the launcher is bolted directly to a flat surface, as pictured. Were you planning on living with that limitation, or will you build a more versatile mount later?

I hope this doesn't sound critical. I'm just wondering if you have concocted some brilliant new approach to these issues.
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Postby buzzboy » Mon Jun 06, 2005 3:58 pm

I just thought of something.............Golf ball shot gun:twisted:
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Postby BewareOfDog » Mon Jun 06, 2005 11:51 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><b><u>airpress</u></b>
Whend do you think the cannon will be finished DR?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><b><u>tim jones</u></b>
I'll be interested to see how you control the recoil from that bruiser...Do you have a plan yet?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
I took off the ratchet-straps, and the wood on the sides of the chamber (looked like crap!), and
installed some custom-made U-bolts. I did the same thing on a combustion cannon, and they
handled the recoil very well.

The U-bolts are made from 1/4-20 allthread. After eye-balling a length of 1/4" I.D. hose around the pipe,
each piece of hose was cut at an 18" length. I had to put a small dab of white Lithium Grease on one
end of the allthread, and chuck the other end in a variable speed electric hand drill.

The allthread was 36" in length, so I marked 9" from one end with a permanent marker, and spun the
allthread into the hose. After stopping at the 9' mark, I marked the center of the hose, and bent it
around a piece of scrap 6" pipe...Voila! - ghetto hold-down clamps!
<A HREF="http://img.villagephotos.com/p/2003-9/398596/Phase3bsmall.JPG">TEE CLAMPS</A HREF>
<A HREF="http://img.villagephotos.com/p/2003-9/398596/Phase3csmall.JPG">CHAMBER / BARREL CLAMPS</A HREF>

I was able to do a little more cosmetic work today, and was thinking of installing a pressure gauge flush with the panel.
Maybe I can also install some eye-hooks so that I can hook up a "lanyard" to the handle on the ball valve. And possibly
a remote switch so that the solenoids on the 3" valves can be remote-activated as well if desired.

<A HREF="http://img.villagephotos.com/p/2003-9/398596/Phase3asmall.JPG">PANEL</A HREF>
<A HREF="http://img.villagephotos.com/p/2003-9/398596/Phase3esmall.JPG">PANEL SIDE</A HREF>

I dry-fired it again today at 125psig, and it actually hurt my ears a little...I'm gettin' old! :evil: One of the shops that I use to work for
has an industrial compressor that's set @ <b>175psig</b>...Hopefully they'll let me destroy something <b>there</b> as well!
It's getting pretty hot out here in the afternoon, so any firings over 100psig will be done in the early morning hours. I'm almost
done with the damn thing, so hopefully I can start posting damage pics soon, and possibly a video.

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><b><u>tim jones</u></b>
Also, you won't be able to mount 8" or 10" barrels (for pumpkins, basketballs and bowling balls, of course!) if the launcher is bolted directly to a flat surface, as pictured. Were you planning on living with that limitation, or will you build a more versatile mount later?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
To tell you the truth, I haven't given it the slightest thought. There
are many times during the summer months that I can get canteloupes for $1 a piece, so I'll settle for that. -In the fall, I <b>guess</b> I can just hunt for small pumpkins.:)


buzzboy: I though along the same lines... but with a whole 10lb. bag of potatoes!;)
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Postby tim jones » Tue Jun 07, 2005 12:42 pm

In this area (notheast Indiana) 6" baking pumpkins go for about $1.00 in late Fall. I'll bring a load down, if you decide to host a Fall field day.

Round bleach bottles and windshield washer fluid bottles, either 1-gallon or 1/2-gallon size, are also a perfect fit in 6" Sch 40 PVC pipe. These are nice because they can be filled with water or concrete, and are available year-round.
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Postby ishallstabyouwithabluntsp » Tue Jun 07, 2005 1:17 pm

for a remote switch can't you just screw in a hose barb with long hose and blowgun to the ball valve?
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Postby BewareOfDog » Mon Jun 20, 2005 6:03 pm

For some reason, this project is cursed.

I can get the cannon to work for one shot, but then to get it to work again, I've got to take both of the 3" valve's tops off, and then reinstall them.[:(!]

Every time I disassembled the valve, the diaphragm was unseated from the groove in the valve body: <a href="http://img.villagephotos.com/p/2003-9/398596/3Vgask.GIF">Diaphragm</a href>

I though that maybe the spring was not strong enough to reseat the diaphragm, so I began modifying the diphragm. At first, I took off the small piece of screen on the bottom, along with the <a href="http://img.villagephotos.com/p/2003-9/398596/3Vsansscreen.GIF">pilot tube/guide-rod thingy</a href>

Then, it STILL would not work...So I modified the pilot by removing the 1" modded valves, and installing 3/8" compression fittings. Then I
<a href="http://img.villagephotos.com/p/2003-9/398596/3Vplugged.GIF">plugged</a href> the hole at the bottom of the diaphragm, and reassembled the valves. If I pre-charge the top of the diaphragms with 100psi, then immediately after -charge the chambers, then it'll work every time.

I cannot figure out how to modify these valves to make them consistent! The assembly worked GREAT in my garage through more than a dozen firings, but now it's suddenly a tempermantal POS. - And it's not because ther's any foreign material keeping the valve's diaphragm from reseating.

I was able to shoot a 2 Liter bottle at a dumpster today (ONE time), and then it started giving me problems. oes anyone have any suggestions on how to PROPERLY modify this damn valve?
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Postby pbmann123 » Mon Jun 20, 2005 6:39 pm

well what about hooking a line from the chamber to above the diaphrams. the only was i can see to restrick flow would be to pack the tube extreemly tightly with steel wool. then hafe it so your piolot valve dumpos more than it can provide, or mabe do it the opposite way round, fill the valve, then it goes through the hose and into the chamber.. have it packed, slightly to create a pressur differential and havce a bal;l valve to shut it off. it seems like a lot of work though. i bet the asnwer is going to be something simple... best of luck with your project(s)
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