How powerfull can a combustion cannon be?

[Cool]

I'm wondering of how powerfull a combustion cannon can be. How long its posible to get it to shoot? And is bigger chamber more powerfull than a small one?

I think the guns look so small and boring with a 3-4 inch chamber.

I'v build 2 guns now, one with 4x16 Inch chamer, it was ok, but nothing to get excited over. Then i build a 6x22 Inch chamber, and thats 3 times as powerfull as the old one.

Anybody got a sugestion what i can do to make it more powerfull?

[spudshot]

add a fan to mix the fuel and air, add multiple spark gaps, use a stungun ignition for a more powerful spark, use propane injection for consistant launches every time instead of fooling with fuel amounts

[v3ngence]

ditto, but I emphasize the stronger spark, with me it makes a world of differance.

[Cool]

I have a fan installed. I cant get stunguns here, they are not alowed

I'm currently fooling around trying to make a camera ignition with coil, i'm hoping it will be better.