In preparation for launching Polaron IV we wanted to make sure that the whole launcher will work with the boosters and the main stage all together. We weren't sure if it would come off the launcher cleanly, or if the boosters would fall off, or how the new guide rail would go.
We built a dummy main stage out of old bottles and an old nose cone that used the nosecone-off-at-apogee technique for deploying a parachute. The main stage only had the bottom 2 L bottle pressurised. And had 1.5L of water in it so virtually no air. We added a little ballast into the nose in the form of a zip-lock bag with water in it.
We had two successful vertical take-offs with the boosters all falling off almost simultaneously on both occasions. The boosters were filled with 1L of water and everything was launched at 100psi.
The dummy main stage weighing in at close to 800 grams was still able to reach ~80-90 meters
The parachute opened on the first flight right at apogee, and failed to open on the second flight.
The dummy main stage was destroyed, but luckily all the bits we needed for the Polaron IV rocket survived. The boosters also survived their tumble recoveries.
We proved to ourselves that this particular launcher and booster concept works, and so we are hoping to get at least one flight out of the Polaron IV rocket on Saturday. There are always things that can go wrong on the day, but we will worry about those when they happen.
We have also finished repairing the Hyperon and J4 rockets, so we will have those as backups on Saturday as well.
Full details of the days events with videos of this booster test will be again published on our main site after the launch day.