First combustion(Bouncy Ball-zooka!)

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.
Boomer58cal
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Mon Apr 07, 2014 9:07 pm

Hello SpudFiles!

This is my third cannon and I'm in about my 5th month of spudding. My other two cannons are pneumatics. The first was a compact single sprinkler valve cannon and the second has three sprinkler valves in parallel. Well I just had to do a combustion next!

I thought I should start somewhat small to get my feet wet. I also added some cosmetic parts for effect. I was going for the bazooka/rocket launcher look. I will likely come up with a better mount for the propane bottle than the zip ties. I just happen to have some that fit.

Specs...
Overall length: 47.5"
Chamber: 10" of 2" sch 40
Barrel: 24" of 1' sch 40
C/B ratio: 1.7/1 ( because I wanted It to be loud :bom: )
Ignition: Electric barbecue igniter
Fuel: Metered propane
Chamber fan: will be added if I can find one that fits 2" sch 40

Well what do you think? Tips? Complaints? Ideas?
Attachments
Sorry for the cell phone photos
Sorry for the cell phone photos
image.jpg
image.jpg
Last edited by Boomer58cal on Fri Apr 11, 2014 1:58 pm, edited 1 time in total.
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jrrdw
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Wed Apr 09, 2014 7:15 am

Looks like a bazooka, I like it! :bigsmurf:
Boomer58cal
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Thu Apr 10, 2014 11:11 pm

Well thanks jrrdw. I just wanted something different than the traditional spud gun fat chamber and skinny barrel silhouette. Not that there's anything wrong with it.

I finely found a brushless motor that would fit inside 2" sch 40. The fan is 1 9/16" so I had to do some clearancing to get the housing to fit. I will be powering the 12v fan with a single 9v battery, but even at half speed the fan should flow the combustion chamber volume every 4 sec. I have no experience with chamber fans, but I think this should be more than adequate. The hardest part is working inside that little bitty chamber. :cry:

After working on this tiny little thing, I think next time I'm building one with a Chamber big enough to stuff my whole arm in. :twisted:

Hopefully a video and working chamber fan in near future.

Edit... Now called "Bouncy Ball-Zooka" by my kids, because I found a source for bouncy balls. 80 for $10 :bounce: 8 for a buck, can't beat that.
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IMG_20140410_212220.jpg
The damaged ball went through a cardboard box and blow in half on impact with the plywood backstop.
The damaged ball went through a cardboard box and blow in half on impact with the plywood backstop.
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jackssmirkingrevenge
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Mon Apr 14, 2014 5:56 am

Not bad, metering and everything! You should be happy with the benefits of the fan.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Boomer58cal
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Wed Apr 16, 2014 9:18 pm

jackssmirkingrevenge wrote:Not bad, metering and everything! You should be happy with the benefits of the fan.
I love the propane meter! The few spud guns I played with when I was a kid were DWV spray and pray death traps! I think the only reason they never blow up was because they didn't work but maybe 50% of the time. Even without the chamber fan installed it already fires over 90% of the time.
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