Eliminating Propellant Bag Deterioration for the 105-mm M67 Propelling Charge

摘要

The rayon propellant bags of the 105-mm M67 propelling charge were observed to deteriorate in short periods of time to the extent that the bags can no longer safely hold the propellant. An engineering study was conducted to resolve this problem by replacing the rayon propellant bags with lightweight acrylic propellant bags. These acrylic bags have satisfactorily passed material compatibility tests, simulated rough handling and transportation tests as well as ballistic performance evaluations in a 105-mm howitzer at -50 degrees F, 70 degrees F, and +145 degrees F, leaving no residue in the gun tube. These acrylic bags have also shown remarkable resistance to deterioration (superior to rayon) when in contact with the propellant at elevated temperatures of 149 degrees F, 167 degrees F, 185 degrees F, and 203 degrees F (65 degrees C, 75 degrees 0, 85 degrees C, and 95 degrees C) at 75% relative humidity over a 28-week time period. When these high temperature data are extrapolated to ambient service temperature using an empirical (Arrhenius) degradation model, the acrylic bags are expected to exceed the service life requirements of 20 yrs in controlled storage and 2 yrs in uncontrolled storage.