Collapsable Travel Combustion

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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sgort87
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Wed Feb 14, 2007 12:38 am

I was inspired by DR's chain of little theme launchers that he's got to come up with something new and kinda useful. I thought it would be cool to have a simple combustion that was fairly light and compact. Collapsibility was the answer. I don't know when I'll use it but, well, I can.

It's got a 24" 1.5" SDR 21 barrel for golf balls and I lathed the tip for spud cutting. The ratio comes to about 1.6:1. The gun's got a lantern sparker ignition and I plan to use butane but I still have to figure out how to use the damn stuff. [:D]

It collapses by threading and unthreading the barrel. I lathed out some 1.5x2" thread x thread PVC bushings to slide over 1.5" pipe and cemented them on. The tip of the chamber has two female adapters facing opposite lathed to fit. The barrel also has a slip cap for storing the fuel and some golf balls in it.

So here's a few pictures and a video of the collapsing.

<a href="http://www.spudfiles.com/uploader/uploa ... .JPG"><img src="http://www.spudfiles.com/uploader/uploa ... s.JPG"></a>
<a href="http://www.spudfiles.com/uploader/uploa ... .JPG"><img src="http://www.spudfiles.com/uploader/uploa ... PG"></a><a href="http://www.spudfiles.com/uploader/uploa ... .JPG"><img src="http://www.spudfiles.com/uploader/uploa ... s.JPG"></a>

<a href="http://media.putfile.com/TravelGun"><b>Video</b></a>
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Wed Feb 14, 2007 12:46 am

simple, compact, its great. You not planning on any midnight adventures with the law with that golfball barrel are ya?
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sgort87
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Wed Feb 14, 2007 1:30 am

I'd be more inclined to do that with something powerful, fast, and reliable.
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noname
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Wed Feb 14, 2007 4:06 pm

Very nice job on that. I should make something small with threaded parts for transportation, but I haven't yet.
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sgort87
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Wed Feb 14, 2007 4:35 pm

Here's a diagram. The blue section is two opposite facing female cleanout adapters. The male "threaded rings" I made thread into those. There's also another picture showing the male ring on the inside of the chamber.

<a href="http://www.spudfiles.com/uploader/uploa ... .JPG"><img src="http://www.spudfiles.com/uploader/uploa ... s.JPG"></a> <a href="http://www.spudfiles.com/uploader/uploa ... .JPG"><img src="http://www.spudfiles.com/uploader/uploa ... s.JPG"></a>

So I figured out how to work butane. It isn't rocket science but I am still working on the ideal spray time. Here's a video of the launcher firing a golf ball.

<a href="http://media.putfile.com/TravelGunShot">Launch Video</a>

Also, I forgot to mention that the barrel cap is used for a mixing device. :D
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Wed Feb 14, 2007 6:37 pm

Really cool idea for a cannon. Wish i could watch the video!!!
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medievalman
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Wed Feb 14, 2007 7:46 pm

Nice! you have some great ideas. just one question: when you put the lid into the chamber in the "launch" video, is it for mixing the fuel?
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sgort87
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Wed Feb 14, 2007 7:58 pm

Yep. You got it. It works like a charm.
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