THE CHEMISTRY OF SOLID PROPELLANT COMBUSTION: NITRATE ESTER OR DOUBLE BASE SYSTEMS**Crown Copyright Reserved. Published by permission of the Controller, Her Britannic Majesty's Stationery Office

During the last decade there has been a great increase in the scale of application of solid propellants in rocketry and a corresponding increase in our empirical knowledge of the internal ballistics of solid propellants. Superficially, it would appear that our understanding of the detailed mechanism of their combustion has failed to keep pace. In this lecture an attempt will be made to review the current state of knowledge in this field and to place it in perspective in relation to the general field of combustion chemistry. We shall discuss the broad trends in research on flame propagation during the last ten years and examine their relevance to problems of solid propellant burning. At the beginning of this period there was a tendency to regard the combustion of all solids and liquids as a gas-phase flame coupled to the surface of the condensed phase by heat and mass transfer processes. The successes and failures of this simple picture will be examined with reference to nitric ester propellants.