Two Projectiles Connected by a Flexible Tether Dropped in the Atmosphere

This study investigates the atmospheric flight dynamics of a munition system that is released from an aircraft at altitude and drops toward a target on the ground. The munition system consists of two projectiles connected by a tether line. Initially, the two projectiles are rigidly attached. At a specified time, the projectiles separate and subsequently unreel the tether line. After the tether line is fully payed out, the system settles toward a steady state as it approaches the ground. It is shown that while projectile position results converge for a relatively low number of tether line elements, the maximum tether loads require a significantly larger number of elements. For a low follower-to-lead projectile mass ratio, the tether line unreeling process is predominantly due to the follower and lead projectile separation. Conversely, for a high follower-to-lead projectile mass ratio, the tether line tends to billow and subsequently unreel itself, independent of the lead and follower projectile motion.