First advanced combustion launcher

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.
Spud Bud
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Thu Feb 18, 2010 6:27 pm

Okay guys this is my First attempt at an advanced combustion. The specs are:
4'' dia,24'' long chamber(30in. with all fittings included)
374 ci chamber
metered propane
7ft 4in golfball barrel
chamber fan
piezo igniter :cry:
Attachments
1/2 plywood
1/2 plywood
spud4.jpeg (2.08 KiB) Viewed 2835 times
spud3.jpeg
spud3.jpeg (3.11 KiB) Viewed 2835 times
spud.jpeg
spud.jpeg (3.23 KiB) Viewed 2835 times
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deathbyDWV
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Thu Feb 18, 2010 7:42 pm

Looks good. Nice damage too. If you can buy mapp gas and use that instead of propane you'd get a little better preformance. Also (if) you can get a stun gun and make multiple spark gaps that would increase preformance... and everyone wants moar power... :twisted:
Life's too short to mark off the items on your wish list...
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mark.f
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Thu Feb 18, 2010 8:13 pm

Well, I can't really see much from the pictures. Any chance of getting some better ones?

As for as for what you said, multiple sparks can be accomplished with a simple piezo igniter. Simply wire them in series. The width of all of your gaps shouldn't exceed the maximum distance your piezo igniter can easily jump.
Spud Bud
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Fri Feb 19, 2010 6:07 pm

mark.f wrote:Well, I can't really see much from the pictures. Any chance of getting some better ones?

As for as for what you said, multiple sparks can be accomplished with a simple piezo igniter. Simply wire them in series. The width of all of your gaps shouldn't exceed the maximum distance your piezo igniter can easily jump.
How many sparks can a piezo generate? I have heard people said only 2 but if i can can away with more it would be great.Also, as of right now my spark is located in the front of the chamber towards the breach where there is a double layer of pvc. Is it safe to screw in screws for another spark in the middle of the chamber despite only one layer of pvc?
Here are some more pics....
Attachments
brick.jpeg
brick.jpeg (2.24 KiB) Viewed 2777 times
jug.jpeg
jug.jpeg (3.09 KiB) Viewed 2777 times
spud2.jpeg
spud2.jpeg (3.47 KiB) Viewed 2777 times
spud close up.jpeg
spud close up.jpeg (2.99 KiB) Viewed 2777 times
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mark.f
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Fri Feb 19, 2010 7:34 pm

It depends on how large the individual spark gaps are. Also, I would opt for a spark strip instead of drilling screws into the chamber. This will allow only two screws to operate multiple spark gaps.
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starman
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Fri Feb 19, 2010 11:24 pm

Spud Bud, You are posting almost thumbnail size photos here. I'm sure Mark.f was suggesting larger pictures as well as closer shots.

Can you replace those with larger pictures?
Spud Bud
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Sat Feb 20, 2010 11:38 am

starman wrote:Spud Bud, You are posting almost thumbnail size photos here. I'm sure Mark.f was suggesting larger pictures as well as closer shots.

Can you replace those with larger pictures?
Well i only have a camera phone right now but i will try to get hold of my sisters digital camera
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