P1: Nitrous at Balls in '09
Fifth Hot Fire Test
Last Update, 1/1/09 by Stephen Daniel
Summary of Results
Both burns were successful. Two nearly identical burns. Good data from one. C* efficiency estimates are still being worked on, but look to be in the ~70% range. Video from test 11 is up on YouTube. Pressure data and simulation results are here.
Goals for this test:
Based on analysis of our last test, we've made these decisions.
Test day is December 29 at Rik's.
Evan and I plan to arrive by 11:00 AM.
Spectators are welcome at 11:00, and should definitely arrive before noon.
First hot-fire test: push the button some time between 12:00 and 12:30.
Lunch between tests.
Second hot-fire test: push the button no later than 3:00. Goal is 1:30.
Depart: goal is 4:00.
Mark-4 pyro-valves. Ready.
Hydrotesting did not go well. We managed to get a fair amount of air into the system which in turn meant we spent a lot of time and effort for little result. Valve #2 was measured to hold at 600 psi before the system leaked down to 400 psi. The leak was at the injector end, and our belief is that the leak was fluid passing the main injector bulkhead rings. Our assumption is that the rings are loose and that our silicon hydraulic fluid managed to get past the grease.
We pulled the injector, cleaned and inspected the rings, cleaned the motor, and reassembled. We did not repeat the hydrotest. (Note: injector bulkhead rings are viton.)
We will use 12" ABS grains that were prepared for the last test.
I exchanged our 50 lb nitrous cylinder (mostly empty) for a 75 lb nitrous cylinder. We'll be using Mike's 15 lb cylinder for testing. We need to refill Mike's cylinder before testing.
Weights and Measures
First test will be grain #2, valve #2.
DAQ firmware needs some slight tweaks, but is basically ready to run. We will continue to use our temporary mounting for this test.
Final weight of the nitrous supply tank was 24.6 lbm, indicating we consumed 8.4 lbm of nitrous during these two tests.