Archive for the ‘Design and Development’ Category

Built final 2 pressure chambers

Sunday, May 18th, 2008

Today I had a bit of spare time so I did some more experiments with the robinson couplings. I think I have finally found the solution.

Using the rockets my Scouts started work on a few months ago, I tried placing some metal washers either side of the joint, to allow me to compress the inner tube without tearing it when tightened. I have managed to tighten the nuts quite a bit now, enough that now the limitation is my grip on the bottle….so very tight!!!

Here’s a picture of the two completed pressure chambers.

I have decided to name these two rockets Dewey and Huey, for the upcoming competition I will rename Weston Wocket to Louie, these are the names of the 3 robots from the film “silent running”.

I pressure tested both to 100psi. They both passed so it looks like I have finally have a working design for Robinson Couplings.

Finished Construction of Parachute Modules

Friday, May 16th, 2008

Tonight after Scouts, I held an extended session to finish construction of the 2 parachute modules for the last 2 rockets. They are exactly the same design as the one that flew on Weston Wocket.

We also constructed the two parachutes to go with them.

Once I have found a good way of stopping the leaks in the pressure chambers, we can assemble the last two remaining rockets and give them some test launches.

Robinson Coupling Development

Saturday, March 1st, 2008

Today I have been working on trying to get a better seal with the Robinson coupling. My original idea of putting a o-ring between the bottle and the nut is a utter failure. The o-rings are too soft and either get squashed out of the way or pushed through the hole. The rocket isn’t even water tight let alone air tight.

However I have been working on a new method today which seems to be working quite well. I am using bicycle inner tube to act as a rubber washer between the nut and the bottle. It seems to hold air up to about 30 psi, so its an improvement at least. I tried tightning the nuts some more, but they just seem to chew through the rubber. More research needs to go into this area but progress is being made.