On April 5th, we had our 5th static test fire. Leading up to the test we had no major issues to combat such as we did last semester with the night-before-changes to the instrumentation. Going into the test, we were all feeling pretty confident in the structural redesign that was implemented due to the failure of STF 4. Be sure to check out the last structure subsystem update to get an idea of the redesign.
We also had some visitors from South Dakota School of Mines and Technology to watch our fire.
The setup during the day went fairly well and Michael Webb from Frontier was a huge help in troubleshooting a couple of the issues with mounting the rocket to the load cells. By dinner time, however, we were about 1 hour behind schedule. We decided to go ahead and do the test that night, even though it wound up being about an 18 hour day for us.
Fill and pressurization went well and then we were ready for ignition and fire. The ignition sequence worked great and the main valve was opened about 6 seconds into ignition to allow oxidizer to start flowing. We obtained data for a solid 8 seconds before our nozzle blew off once again. This time, however, it was for a different reason (which we are still investigating). See the video below for the full, live-view fire as well as a peak into the control room during the ignition sequence.
For the rest of the semester, we will be investigating the nozzle failure, documenting everything we’ve learned, and focusing on getting things ready for next semester’s team.