Sagitta Launch #3 - 06/03/2016





The goal of this test was to verify the structural and thermal loads on the motor case. A pressure sensor was fitted near the bulkhead protected from hot gases by water. The calculated and corrected thrust is visible in the graph below. A 3-grains geometry was adopted to underload the motor for safety reason.
The pressure measured is much lower than theoretical one. The next test will verify pressure at full load.

Photo

Acquisition frequency [Hz]: 80
Load cell offset [N]: /
0 voltage Red PS [V]: 2.0862
0 voltage Green PS [V]: /
Propellant: P-1
Propellant mass [g]: 237.7
Mean density [g/cm^3]: 1.904
Ideal density ratio: 98.9 %
Grain number: 3
Spacing (between grains) [mm]: 5.5
Total grain length (without spacing) [mm]: 186.2
Port grain diameter [mm]: 15.8
External grain diameter [mm]: 33.20
Throat diameter [mm]: 10.5
Expansion Ratio Ae/At [/]: 10.5
Inhibition: External.
Action time (ta) [s]: 1.787
Burn time (tb)[s]: =ta
Maximum thrust [N]: 210.8
Mean thrust (tb)[N]: 137.4
Mean pressure (tb)[bar]: 14.4
Total impulse [Ns]: 257.6
Specific impulse [s]: 110.5

Pyrogen:
Propellant: P-1
Grain mass [g]: 5.25
Grain length [mm]: 33.3
Port Diameter [mm]: 3
External Diameter [mm]: 11.6

Environmental data:
Atmospheric pressure [mbar]: na
Air temperature [°C]: na