PR-V6 PDM3 - 23/12/2013

Full load test with four grains processed through H2O mixing and subsequent evaporation. This procedure reduces casting time and increase fuel-oxidant mixing.

We had some trouble with the ignition system. Three more igniters have been made. Moreover, ignition batteries have been discharged during ground test procedures. Eventually the motor started after four hours of work. Pressure and thrust levels as predicted by corrected theoretical model.


Acquisition frequency [Hz]: 2000
Channel: 2
Load cell offset [N]: +4.79
0 voltage Red PS [V]: 2.074
0 voltage Green PS [V]: /
Propellant: P-1
Propellant mass [g]: 315.3
Mean density [g/cm^3]: 1.907
Ideal density ratio: 99.0 %
Grain number: 4
Spacing (between grains) [mm]: 5
Total grain length (without spacing) [mm]: 243.1
Port grain diameter [mm]: 16.32
External grain diameter [mm]: 33.65
Throat diameter [mm]: 10.5
Expansion Ratio Ae/At [/]: 10.5
Inhibition: External
Action time (ta) [s]: 1.375
Maximum thrust [N]: 333.4
Mean thrust (tb)[N]: 251
Mean pressure (tb)[bar]: 24.4
Total impulse [Ns]: 345.1
Specific impulse [s]: 110.0
Combustion efficiency [%]: 93.7
Nozzle efficiency [%]: 82.7

Propellant: P-1
Grain mass [g]: 4.8
Grain length [mm]: 29
Port Diameter [mm]: 3
External Diameter [mm]: 11.6

Motor total mass before burn [g]: 1091
Motor total mass after burn [g]: 785
Non-burned mass [%]: 4.4

Environmental data:
Atmospheric pressure [mbar]: 1027
Air temperature [°C]: 9