We’ve now bonded in the coupling rings for the stage 3 parachute section. The parachute section is coupled to the motor section by an aluminium bulkhead. The parachute section contains two parachutes: (1) a small sprung parachute, that is deployed at high altitude to bring the rocket down quickly but safely, (2) a large main parachute that is deployed 1200m above the ground, to give a soft landing.
Using 12 high grade, countersunk M3 bolts, the bulkhead attaches to coupling rings that are bonded into the motor and parachute sections.
At the end of the parachute section is an aluminium ring that couples to the back of the nosecone (or back of the next stage, in the case of stage 1+2). The parachute section has 2 wiring tunnels for the explosive protractors that control parachute deployment. The protractors are golden coloured in the image below, and shown in the as-fired state with the pistons extended. The third tunnel guides the kevlar riser from the small primary parachute to a release mechanism on the bulkhead. When the riser is released at 1200m altitude, the primary parachute pulls the main parachute into the airflow.
