And thanks for all your reply. I'm more understand on how to build a better water rocket launcher. I'll try it and posts my successes.

OK, I'm not so well in English, maybe I dont know what is bottle rocket before that. Thank for your information. Not bottle rocket, but water rocket.

But that is OK, not dangerous game.... and thanks for your remind, I'll keep in eye on the rules for the next time.

No, a bottle rocket which is filled with water (pressurize the air space inside the bottle which will force the water to spill out at high speed as soon as it is released)
http://ourworld.compuserve.com/homepages/pagrosse/h2oRocketindex.htm

Anyway, u means use the aerosol and the combustion ...

Pressurize the aerosol and burn it as the bottle rocket is released? Don't the water bottle will burst?

Oh, you means directly use the pressurized gas to propel the bottle without using the traditional heavy duty air pump?

If so, I will add a launch tube at the nozzle of the combustion cannon and launch the rocket (with water inside) as normal. The only differences is the pressure and no release ...

Hi, everyone.
I am taking part in [water] bottle rocket launcher recently. Other than water as the propellant, I have no other replacement. I think if I launch the bottle rocket in other way, like the potato cannon, this will be more creative and more fun.

My idea is like these:
When the aerosol ...