Hello from China

[noarrogance]

Hi, everyone. I'm a middle school student in china. In the last term, my school held a water rocket launch competition. I fist tried to make a 2-stage water rocket, but I failed. I'm glad to be here and I hope we can help each other.

[WRA2]

Hi, everyone. I'm a middle school student in china. In the last term, my school held a water rocket launch competition. I fist tried to make a 2-stage water rocket, but I failed. I'm glad to be here and I hope we can help each other.

Welcome to the forum

Can you describe what went wrong with your two stage rocket so we can help you improve it?

[noarrogance]

The two bottles separate too early.

[Spaceman Spiff]

The two bottles separate too early.

That may not necessarily be a bad thing. As long as they don't separate while on the launch pad then you're probably on the right track. The first stage bottle should have a big wide mouth and when released it will get going up to full speed within milliseconds of launch. At the exact moment of top speed you want to have the bottles come apart from on another and the top stage will then fly powered by a smaller nozzle opening so that it thrusts for a very prolonged time. The theory is that the first stage makes the rocket accelerate very fast and the second stage (called a "sustainer") provides enough thrust to maintain (sustain) that speed for as long as possible without slowing down. The sustainer works much better when it has less drag and weight to carry so the booster first stage should fall away as soon as the booster runs out of water and has made maximum speed.

I hope this is helpful in your question!

[ninja_iga]

hi!
glad to know i'm not one of the rare chinese WRocketeer around, lol

i'm from Malaysia btw.