We test flew the Acceleron II booster (18.75 L capacity) three times this weekend with very good results. The encouraging results in the booster's almost always vertical launches means that we are ready to progress to the next stage of development - staging mechanism and the sustainer.
Full details can be found here:
We also took some measurements of the speed of the booster just after the start of the air pulse and had a close look at the sound the rocket generates in order to extract accurate timing of events during launch.
The twin parachutes also worked well to bring the booster to a safe landing each time.