In the past few months the hybrid propulsion group has been working along with other fellow students in a minor at the TU Delft. A minor is a semester during which students can choose to specialize in a field or discover new areas non-related to their field of study. The minor not only allowed more students to discover rocketry but to get closer to a flight ready design.

One significant improvement was the design of a vertical test bench with reduced friction and restrains movement in the vertical direction thus allowing for more accurate data gathering and analysis. Further integration resemble to a ready design was made by designing an in house developed tank to hold the oxidizer. To ensure the safety one tank was tested up till its burst pressure at 147.9 bars and the second tank was tested to be leak tight to at least a pressure of 95 bars. These test were performed at the company Advanced Lightweight Engineering

A heating system was added to be able to heat the tank to an operating pressure of 60 bars and obtain comparable data. To perform this a coil of heating wire was wrapped around the tank and epoxy was applied to the outside of the tank and the tank was insulated. The coils were equally spaced to prevent spot heating. Once all design and production was completed hot fire test were performed as shown in the picture below.

Hot test fire on veritcal test bench

Three successful hot fire tests were performed with HDPE and sorbitol both fuels using nitrous oxide as oxidizer. Problems were encountered with the ignition of the engine, as it did not behave in the same way as in horizontal test setup. In the following weeks this problem should be resolved. The hybrid propulsion group will now work further to integrate this propulsion system into a rocket.