Flight day 4 - Nozzle issues
Date: 14.11.2009 (11:00 - 12:45)
Weather conditions: overcast, 10°C, light winds
When analyzing the data of flight day 3 we discovered that the third launch which was completely unstable had been done with a nozzle of type "B". This particular nozzle is somewhat heavier than the nozzles of type "A". With the next couple of flights we wanted to learn wheater the nozzle was the root cause of the instability.
Furthermore we wanted to try a new launch site near "Heuberger Tor".
Launch #1 with a nozzle of type "A" didn't show the unstable behavior we had seen before. Antares Ia went to the west in a slight arc. The parachute deployed just at apogee. After 21 seconds Antares Ia touched the ground approx. 40 meters west of the launch pad. The recorded height was 74.8 meters with a launch pressure of 8 bar and 900 ml of water.
Launch #2 was done with the same nozzle and again didn't show any unstable behavior. In order to gain more heigth we aligned Antares Ia slightly to the east. But immediately after launch it went to the west again. However, apogee was higher this time. After 28 seconds Antares Ia touched the ground only a few meters west of the launch pad. The recorded height was 93.4 meters with a launch pressure of 9 bar and 950 ml of water.
We refrained from doing a launch with a nozzle of type "B" because we were worried about the integrity of Antares Ia. So we don't have the evidence that nozzles of type "B" cause the instability. But we have shown that nozzles of type "A" can be used without an issue.