We've been flat out this week trying to get things ready for the open day this Saturday. The main project has been a rebuild of the Acceleron booster. This is our biggest booster to date at ~33L capacity. Acceleron III was 24L and Acceleron IV was 18L because it used 1.25L bottles.
The new booster has three 2L bottle spliced pairs tornado coupled together per segment. There are three segments in total. At 130psi the pyro rocket equivalent is an H310. (~250Ns total impulse)
We have simplified the pod at the top of the booster. The deploy mechanism is the same as the previous versions of Acceleron based on a FC, pressure switch and servo, but the parachute is no longer located in the pod. This meant that the pod could be smaller and lighter. The parachute now resides between the bottle necks of one segment so there is no extra drag. The parachute will be deployed using the piano hinge technique we have been using recently. This should mean the parachute opens sooner. Too many times before the parachute deployed late.