Help!

[Margarita]

HOLA! every one I'm from Ca. I have been recruited by my nephew to coach his water rocket teams for the science olympiads this year. I have been researching this subject and would like try to keep it simple. But I don't see that happening. We need to use a 2l bottle, 75 psi, no metal or store bought gizmos. We only get together 2 hrs. a week due to I'm an hr away. As of now we are trying out different fins and today adding different size parachutes, still figuring out the proper amount of water. Ya we still are at the beginning stages. Any suggestions would greatly be appreciated. These kids are 3rd thru 6th grade. And I must say I never heard of such an event, but I must say this is cool. I'll try to put some pictures up but I'm somewhat computer illiterate. What n neat website!!!

[WRA2]

HOLA! every one I'm from Ca. I have been recruited by my nephew to coach his water rocket teams for the science olympiads this year. I have been researching this subject and would like try to keep it simple. But I don't see that happening. We need to use a 2l bottle, 75 psi, no metal or store bought gizmos. We only get together 2 hrs. a week due to I'm an hr away. As of now we are trying out different fins and today adding different size parachutes, still figuring out the proper amount of water. Ya we still are at the beginning stages. Any suggestions would greatly be appreciated. These kids are 3rd thru 6th grade. And I must say I never heard of such an event, but I must say this is cool. I'll try to put some pictures up but I'm somewhat computer illiterate. What n neat website!!!

Hi,

Welcome to the forum,

To answer your fist question, 1/3 full is the best amount of water so start there and fine tune.

As for fins go there are several different types ranging from the "standard" triangular shape to circular "ring fins" . They all work well and usually it is up to the person designing the rocket, with personal preference or competition rules (restricting use of certain materials). You could just start with something simple like the waxed cardboard (milk carton" and cut triangular fins and tape them to the rocket.

What kind of launcher are you using? Do you need to make your own or is the launcher provided? Type of launcher may also dictate the type of fins you use (you might me limited to using certain fin types based on fitting it to the launcher).

Thanks for the complement on our website design.