On February 25, 2018, the club conducted a successful test fire of the Hybrid Motor 7 – Heavy propulsion system. The important shift in this test fire is that we have identified and resolved past issues with combustion stability and thrust. Our propulsion team discovered that the regulator between the pressurant tank and the oxidizer tank was not sufficient, and there was not enough flow for our larger heavy variant of Hybrid Motor 7. We placed two of our smaller regulators in parallel for this most recent test fire, and we produced sufficient thrust to clear the launch rail with a safe speed. The thrust curve for the engine is below:
This test served as a proof of concept that increasing flow between our tanks will increase our thrust. With a new single regulator with a higher flow coefficient, performance may even increase beyond what we have achieved in this test. The next steps are to do a full duration test fire to verify the engine continues to operate for a full 17 seconds, and a test launch to verify the system as a whole is ready for IREC. The video of our most recent test fire can be found here. Look out for more updates!