SpudFiles

Well ive been working on a combustion that i call equinox and its going well ive added duel ignition (spark in front of chamber and back) and it increased performace ALOT so i luv it but theres something ive noticed when i shoot it i dont get the satisfieing BOOM! my others have made it makes more of the sound of a cork being popped like a vacum behind the projectile wich i think is do to the C:B Ratio i think the explosion has already reached its peak psi and starts cooling before the projectile is out of the barrel creating a suction behind the projectile therefore causeing it to sound like a popping cork rather then a nice BOOM! now i relize the a boom can mean wasted energy because the projectile has left the barrel before the explosion has reached its peak.

Confusing?

Anyway my C:B is .91:1 and i got the following quote from burntlatke "An efficient and powerful C:B ratio is 1.5:1." so should i shorten my barrel to get the 1.5:1 ratio or what i like boom and the cork sound is no fun.

Thanks for any help on this.

Just keep shortening the barrel until u get the 1.5 to 1 cb ratio.

Keep shortening or just shorten it to the 1.5:1 lol is the 1.5:1 a good ratio or should i stick with what i have now.

Stick with what you have now.

Loud Bang = inefficent.

If it makes lots of noise, you should extend the barrel. Inefficency isn't something you should deliberately seek.

But i like boom lol o well i could just make anotherone with like a 5in barrel that would be super loud lol.

i think i found out why it makes the noise my end cap was leaking pretty bad so i cleaned it up and now it sounds like a rifle lol

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does this ratio go by length or volume?, the volume of chamber shud be 1.5 times larger than the barrel?

yes the ratio is by volume formula for a cylinder is....
pi x (radius squared) x height=volume

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that sounds ok to me

also i've found that using hairspray or glade you get that loud boom with just a kleenex in the barrel however with propane...i get this lame-o wooOOMMMM sound thats really dumb i like the boom so im trying to find a way to make CLEAN propane POP like hairspray Im thinging a burst of oxygen (like a tiny burst of it) however DON'T TRY THAT it may be catastrophic so idk idk ill find a way ( or someone else can help PS my cannon has the 1.5:1 ratio and its great but I NEED THE LOUD BOOM

I've also found that the 1.5:1 isn't the best for distance. A 1:1 was the best in my experiment. If you use Hairspray, you get the same loud BANG! no matter the ratio.

1:1 is in my opinion the best compromise - It goes Bang quite well, without too much power loss.

Personally, I prefer quieter cannons, because I live in a sub-urban area, so I keep my C:B ratios low for both combustions and pneumatics to avoid too much noise.

So, if building a combustion, I'd do it with a .7:1 to .8:1 ratio, and my Pneumatics tend to reside in the 1:1 to 1.5:1 ratio.

what are you using for fuel now...? i have a large cannon with 1:1 ratio using propane and it leaves my ears ringing every time i shoot it. perhaps you should try a fan to mix the fuel so it all reacts.

And if anything i think you should using a coupling to expand the chamber so as not to compromise the length and accuracy of your barrel.