HTP/PLA Hybrid Reliability Test

This month I showed that the class I engine performance was consistent, reliable, and ignition occurs in ~ 1.1 sec. The parameters were the same for each of the three test: propellant tank pressure, 130 psig; HTPE blend O/F ratio, 27.5, initial HTPE flow rate, 14.8 ml/sec; mass flow rate for HTP and ethanol, 19.7 gm/sec and 0.4 gm/sec, respectively; cross sectional area for the fuel cores, ~1.1 cm2 ; and the ignition "oxidizer" flux, ~ 17.6 gm/cm2 /sec. All three test used the same batch of distilled HTP with 2.0 ml of ethanol. The thrust was ~ 16.5N.

The results were about the same across all three test. The average: ignition, 1.1 sec; mass flow rate, 12.4 gm/sec; chamber pressure, 105 psia; characteristic velocity, 1280 m/sec; efficiency, 86%, thrust, 16.5 N; regression rate, 0.23 mm/sec; O/F ratio, 3.0.