This blog covers the day to day progress of water rocket development by the Air Command Water Rockets team. It is also a facility for people to provide feedback and ask questions.

Thursday, March 28, 2013

Materials Challenge and Clark Cable tie launcher

Almost two weeks ago we had a go at one of the 10 challenges we set a while back - the Materials Challenge. Basically you have to build a water rocket using only PET plastic bottles. You are not allowed to use any glue, tape or any other materials! It was a fun challenge and things didn't quite work out as we planned but we'd like to visit it again to improve a couple of things in order to get more performance.

The full report with details of how the rocket was made is here: (video included)

Because we couldn't use our regular nozzles for the challenge (they are not made of PET), we also built a Clark Cable-tie launcher to launch the rocket. We've also put together a tutorial on how to make the launcher. It fits a standard Gardena release head so it can be used it with our regular launchers.

The tutorial is here:


Nathan said...

Very interesting. I never thought of making a rocket entirely out of PET. Is there a way to make the plastic welds stronger. I have always wondered about whether or not plastic could be welded together.

George Katz said...

Certainly it is possible. I think you need to squeeze the joint when doing the weld, a lot like spot welding. We've re-designed the fin attachment method and how it is welded. We flew it again today and the fins stayed attached. :)

Jan said...

Hi Georges,
This weekend I made my PET-Only rocket. Now I still have to adapt my launcher and wait for some good weather.
I didn't use any welds.
I did put a second top-of-a-bottle over the rocket just like when you reinforce a bottle. I made flaps on the fins and slide them trough slips in the outer bottle.
On top of the bottle I did put a 2nd top-of-a-bottle that goes all the way down and over the bottle at the other end. If tested the attachment and can push 4 kg on the 3 fins together without a problem. I hope it will suffice.
I used some molten PET to put in the top bottle for some extra weight.

George Katz said...

Hi Jan,

That sounds great with the way you attached the fins. Do you have any pictures or video of your rocket? I'd like to add a link to it from the 10 challenges page. Please let us know how you go with the flights. Good luck with the challenge!