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. 

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 

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.