automated propane mortar problems

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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singularity
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Fri Mar 14, 2008 5:05 pm

after several months of laying low the project can finally be tinkered with again. it was put into hiding before i was able to test it successfully and now i cannot get it to ignite the propane. if this post makes no sense what so ever (which it shouldn't) you should look at <a href="http://www.spudfiles.com/forums/epic-fa ... 0.html">an earlier post</a> requesting for help on the same project.

as of right now the program runs fine. propane is injected, the stungun runs, then the chamber is vented. but for some reason i cannot get it to ignite, i even removed the end cap in an effort to get a slow burn from the propane but nothing worked. i believe i have over looked something very common and simple yet vital to the operation of a combustion cannon. so any and all ideas are welcomed no matter how basic they are
be sure to check out my <a href="http://www.spudfiles.com/forums/ak-styl ... 9.html">AK Styled Vortex Gun</a> and my <a href="http://www.spudfiles.com/forums/at-4-t9627.html">AT-4 Rocket</a>

upcoming projects... finalized clip fed BBMG and ball point pen sniper
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Fri Mar 14, 2008 5:54 pm

Can you show where the spark gap is placed? Also how big is gap.
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Fri Mar 14, 2008 6:00 pm

Funny how it's always the simplest thing you get snagged on :D


I'd say check your fuel mix, other than that...not much help here.
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CS
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Fri Mar 14, 2008 8:35 pm

Being a bit more specific may be necessary to find out your problem.

For starters your propane ratio could be off. Either your meter volume, or meter pressure could be off. Or is the stun gun even firing? Does your projectile provide a sufficent seal against the barrel? (If not your propane mixture could be too lean when propane escapes past the projectile)

Second of all you may want to check your automated valves. (You may have already) However check to make sure the one fully closes before the other opens. Make sure propane is coming out by reaching into the chamber and feeling for it through the inlet. Might be a good idea to disconnect the stungun at this point.

Not sure how I missed your first thread, but this is a awesome project. If you can get this first version hashed out I would be intrested in purchasing a circut from you. Best of luck!
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Sat Mar 15, 2008 11:00 am

Singularity

We need a bit more info ...

Does it spark if you remove the end cap and disconnect the fuel source?

Chamber fan?

Did you "burp" the meter pipe?
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