First simple Cannon

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.
TollBooth
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Thu Feb 26, 2009 9:23 pm

Alright, i used the plans found on this site, for simple cannon. I only changed a few parts. Any ideas or suggestions are welcomed.

3' chamber 15"
54" of 1 1/2' for the barrel
changeable barrel concept
Internal ignition via modified kitchen lighter
Internal computer fan. runs off six AA batteries with on/off switch

Whole cannon put together
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Chamber
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Taken part
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mark.f
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Thu Feb 26, 2009 9:29 pm

Very nice!

I like the little igniter/battery cover you cut out of pipe there. A good touch.

How come you didn't make the barrel breech loading? It would have been easy to do with that 2" adapter.
TollBooth
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Thu Feb 26, 2009 9:37 pm

That would have been a good idea, i had not thought of doing so. i have only launched one spud out of her so far. ran into trouble after the first shot. but since then i have shot many socks as a test subject out. She works well with hair spray, having trouble getting car starter fluid to light inside her.
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mark.f
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Thu Feb 26, 2009 9:53 pm

It's probably because you're using a tad too much. With starter fluid, a quick little tap on the aerosol valve is enough in larger chambers than this. For that chamber, I would try a quick shot, like mentioned before, and then blow a little air into the chamber. A little experimentation should get it working...
TollBooth
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Thu Feb 26, 2009 10:06 pm

i have tried experimenting with the starter fluid only a hand full of times, has only worked once or twice. i will try various amounts and blow in the chamber and turn the fan on, and no boom :( But eh maybe one of these days i will find the right mixture.
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trigun
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Thu Feb 26, 2009 11:02 pm

Well from what I've seen the only thing I would do is add a propane meter and this gun will last forever minus battery changes.

Is the male adapter on the back for easier turning and venting than an end cap ? If so thats a really good idea and is even capable of being modified to become a latke style vent.

Nice cannon especially for a first.
Note epoxy cure time very important barrels are hard to remove from the wall
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starman
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Thu Feb 26, 2009 11:13 pm

Nice, neat little cannon there. The chamber reminds me a little of a light saber handle...I do realize it's not the same scale though... :wink:

Good job!
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mark.f
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Fri Feb 27, 2009 11:00 am

trigun wrote:Well from what I've seen the only thing I would do is add a propane meter and this gun will last forever minus battery changes.

Is the male adapter on the back for easier turning and venting than an end cap ? If so thats a really good idea and is even capable of being modified to become a latke style vent.

Nice cannon especially for a first.
I've used the idea before. The male adapter has more threads than a normal cleanout plug, so it actually takes a little longer to install and remove tightly, but it does add the additional benefit of safety, being made of (probably) pressure rated components.

The only thing I didn't really like about it was that you had to vent the space in the cap manually when you removed it. Unless you installed a separate fan and vent in it. :roll: You could also fill it with AB foam, as well...
TollBooth
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Fri Feb 27, 2009 5:23 pm

The end i was using was a basic 3" cap. had a bad experience with that, along with having a thread problems. so i re thought my options, and doing so i used a 3" male adapter, bushing down to a 1/2 size plug. i did this to allow a more permanent back end. Since i do all the fueling and loading from the front. i use the small plug when venting after shots.

Pictures to help explain, my madness.

All together
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Taken part
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Even more apart
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Back together how it stays, only with 1/2 plug out for venting.
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trigun
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Fri Feb 27, 2009 6:23 pm

O I guess that would make it easier wouldn't it. Even though it will probaly take a bit more time to vent with a fan.

You did push that 4"-2" reducer all the way in right it looks like it might stick out a little bit.
Note epoxy cure time very important barrels are hard to remove from the wall
TollBooth
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Fri Feb 27, 2009 8:25 pm

Yes, it is pushed in all the way, it was extraordinary long.... can you explain the set-up you thought i had? please.
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trigun
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Fri Feb 27, 2009 8:30 pm

I thought you had the 4" male adapter and inside of that was a 4-2 reducer and a plug to cover that hole then you simply unscrewed the male adapter to vent.

On a side note you could build this Image

Image
Note epoxy cure time very important barrels are hard to remove from the wall
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