Hello from Wisconsin

[digitalride]

I just started launching rockets with my kids, it was snowing last week for our first launch. We made a pvc launcher and are now working on some 2 bottle rockets. We got started using info on the us water rockets site but the bottles we bought seem really flimsy compared to other curvy bottles that are less suitable for joining, and the #94 o-ring over 1/2" copper in the launch tube is really tight to get the bottles onto. I'm hoping to find some more detailed information on this forum.

[DanInvents]

Hi!

Have you considered using a Robinson coupling for building a bigger rocket? By using this technique you can build bigger rockets regardless of the curvature of the bottle walls. Here is a tutorial:
https://rocket-fun.com/PDF%20Files/Thre ... Joiner.pdf

An alternative to the full-bore launcher that you are describing is building a gardena launcher. You can find more information here:
http://www.aircommandrockets.com/construction_4.htm

Regards,

Daniel