ABSTRACT

Small-scale solid rocket motors are routinely fired by propulsion industries to measure propellant burning rates for research and development of new propellants, quality control during manufacturing, and service life (aging). A Working Group of the NATO Advanced Vehicle Technology Panel has recently completed a 3-year study in this area. The purpose was to analyze the many procedures employed to deduce burning rates from test motor pressure traces and thus lead to an improved control of manufacturing and aging processes. For a matter of time, the Working Group activities have concentrated on ideal (computer generated) pressure traces and less on real world pressure traces (obscured by imperfect measurements including variations in motor manufacture, variations in motor operation, instrumentation noise, etc.). In this paper, both computer-simulated and experimental pressure traces from industrial small-scale test motors are examined. Several data reduction methods based on the thickness-over-time definition, used by leading European companies, have been applied. In treating simulated pressure traces, the Hessler and Glick two-point procedure provided the best results among all thickness-over-time methods; but had to be modified for real motor applications.