Selection of High Performing Propellants for Torpedoes

T NUMBER of candidate propellants for use in propulsion of underwater missiles or torpedoes by means of a heat engine is possibly as great as is the number considered for use in rocketry. Also, in general, similar considerations apply in choosing the optimum system for a given application in either space or underwater applications. These include the important factor of performance capability, based on the intrinsic thermodynamics of the propellant, and practical considerations of suitability under use conditions. This paper is concerned primarily with providing an understanding only of the intrinsic performance capabilities of the propellants. In contrasting the processes involved in this country in the actual selection of propellants for underwater and rocket usage, it is notable that in underwater applications greater emphasis has been placed on practical considerations and that the attainment of a truly high performance capability generally has been relegated to a secondary role. In this regard, there has been a far greater tendency to apply blue sky techniques to achieve spectacular success in rocketry than has been true of underwater studies. In fact, quite often underwater propellant development waits on successful accomplishments in rocketry and, where possible, adapts these successes to torpedo use. Set forth are the factors involved in selecting chemical propellants for use in heat engines of underwater missiles based only on the maximum performance available, performance figures on several candidate fuels, and means of carrying out the propellant reactions.