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.

Tuesday, February 20, 2007

Flight Day 25 - Polaron III, Underwater.

We had a successful launch day this weekend. We flew Polaron III, J4 II and Acceleron. All three rockets performed very well and we obtained some nice in-flight video. We also performed more underwater launches from a greater depth.

The full details of the flight day are now available very on our website.


Anonymous said...

Hello, Mr. Katz.

I am a fellow ( I hope ) water rocket enthusiast in the United States as the owner of the blog, I am absolutely inspired with your superb rockets and your spectacular footage from your onboard cameras.

I have a small question for you. How is it that you link bottles via the Robinson coupling? I am having an extremely hard time with this, and to make things worse, I have limited resources. Do you have any advice?

George Katz said...

Hello Mechstan

I assume you are having trouble getting everything to seal properly.

In order to get a good seal make sure that the holes you make in the bottle/lid is
as close to the center as possible. Make sure you remove all burs and there is no dirt or pieces of plastic around the hole - inside and out.

We found that holes bigger than about 14mm in the bottle made it difficult to seal because of the shape of the bottle. Try to keep it as small as your threaded tube.

Make sure that you have seals in all the right places. Each bottle/lid wall should have a seal on both sides.

The seals (washers) should be made from hard rubber as that prevents them from being deformed when you tighten everything.

Having a long tool to hold one nut in the bottle always makes life easier.

Try attaching a lid to a base first rather than base to base as it makes it easier to hold one side of the coupling. You can then screw the other bottle into the lid.

Make sure you tighten everything really well.

Good luck.

- George