International Journal of Energetic Materials and Chemical Propulsion
RECENT DEVELOPMENTS IN GUN PROPELLANTS AND GUN PROPULSION RESEARCH AT S.N.P.E.
SNPE / Advanced Technologies and Propulsion Division Centre de Recherches du Bouchet - BP N° 2, 91710 VERT-LE-PETIT, FRANCE
This paper describes recent developments in gun propellants and gun propulsion research from the energetic material point of view, performed under French MOD sponsorship and directed toward providing technical solutions to new weapon system requirements.
The three main types of solid propellants on which research is conducted at SNPE are: conventional nitrocellulose-based and multibased propellants, composite gun propellants based on inert binder and composite gun propellants based on energetic binder. Recent results obtained for each kind are shown and discussed.
Common granulation propellants cannot offer required performance improvement. Modular charges, or charges in two pieces for large caliber guns, need higher loading density to get good ignition, to minimize pressure waves, and to reach required performance levels. Therefore, SNPE performed some studies on new partially-cut multi-perforated propellant sticks ("kerfed" sticks). Some results are presented showing their advantages in better ignition of a modular charge and vulnerability reduction.
For future 45 mm medium caliber guns, consolidated charges obtained by agglomeration of propellant grains with an energetic binder, provide up to a 40 % increase in volumetric loading. This configuration of grains allows caseless ammunition manufacturing and also charge arrangement for telescoped projectiles.
The paper also describes recent improvements in theoretical dimensioning tools developed by SNPE, which help in diagnosis, research orientation, and firing behavior prediction. The thermodynamics code BAGHEERA has been adopted by NATO, the chemical kinetic code BALOO takes into account new propellant types and gun barrel wear; the interior ballistic code family MOBIDIC has been selected at the French national level for future research. The last includes a version with internal boundaries and is able to take into account discontinuities.