Early on in project DAWN, we decided that many tests would have to be conducted to ensure that we can prove that a hybrid motor is a viable concept for Stratos II. To do this, we needed a test bed with a fast turnaround time. While we already had a test motor, it had to be resealed with silicone and left to dry before each test.

This left a lot to be desired and so the last few weeks we have been redesigning the injector and nozzle and devised a way of sealing the combustion chamber without messy silicone. We have done this by crushing the two o rings in between the edge of the combustion chamber walls and the injector or nozzle. Once the bolts are done up, the o rings are crushed between the two parts, creating a tight seal as in the following picture.

During February we have been busy with the production of the new injector and nozzle and currently we are waiting for the ¼ gas fitting to be put onto the injector (second picture, bottom) after the midterm break. Once that is done, a dry pressure test using compressed air will be conducted to ensure the motor is sealed properly. Then the nozzle can be drilled out (second picture, top left), completing the motor. The new design should allow us to do at least one test per hour, and hence many tests in one day. Coming spring the architecture field we use for testing is going to be filled with Hybrid smoke!