With a good fan and a good mix, that should produce a good (and loud) shot.
My combustion is considerably smaller than those specs (2"dia X 10" chamber, 1"dia X 30" barrel). One thing I do is leave the fan ON while I fire. I don't know what kind of effects it will have on your larger cannon but with mine, I can tell a difference in the shots with it on and off.
Questions for my semi advanced combustion.
thats almost exactly the same size as mine. i have a 3x24'' chamber and a 72 inch 1.5'' barrel. mine is inline.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote
you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
Hope thats it for now.(probably add to this in another couple of days with more stupid questions 
).
Really for a combustion it's not going to matter if you use PVC or ABS. Even most "advanced" combustions don't generate enough pressure to cause problems for PVC or ABS. ABS is lighter and usually easier to find fittings for. They both have their pros and cons and everyone here has their own preference for the materials they use, but I wouldn't say one is "better" than the other. I personally use PVC.
Your face is going to freeze like that. http://iplaaz.freehostia.com/
my father is industrial engineer and he toldme to use hidraulick pvc is better (for higth persure water) i ued it is a litle expensiver than common pvc but i havent any problem whits this and i use a piezo ignither too
other thing ..if youi use two 9 volts(18 volt) for a 12v you probably wil burn it ina few time for overhaeting
use a 9v+2 of 1.5 v in serial conecion (9+3=12)
have fun
other thing ..if youi use two 9 volts(18 volt) for a 12v you probably wil burn it ina few time for overhaeting
use a 9v+2 of 1.5 v in serial conecion (9+3=12)
have fun
