10/19/08

18-liter pop bottle rocket

The largest capacity rocket I've made to date.   Uses 9 2-liter pop bottles configured in 3 independently pressurized stacks of 3 bottles each connected with hollow, threaded lamp rod couplers.   

The bottles coupled together before assembly into the rocket. 
Click on any of the images to enlarge.

The rocket assembled.   This version had a nose cone made from an easter basket, but that was replaced later with one made from another 2-liter pop bottle, with a deployment system that worked much better.   This new version is shown in launch pictures below.  Unfortunately I didn't take a closeup picture of the new nose cone and deployment system.    It was similar to the type used on my 6-liter rocket, uses a tomy-timer.

The launcher - just zoom in to see the detail (click on it).

In action..   It had 2 successful flights with perfect chute deployment.   I launched with CO2 at 80 PSI.  This rocket is a real crowd pleaser.  While it doesn't go as high as the FTC rockets, it sounds really cool, and is powerful.  I estimate it flew about 300 feet high.

On the 3rd launch I wrapped the chute retention rubberband too loosely and it didn't have enough strength to pull the pin from timer shaft and deployment failed.