Attitude Dynamics of a Torque-Free Variable Mass Cylindrical Body

Abstract

This paper investigates the attitude behavior of a variable mass system of the rocket type in free flight. The initial shape of the system is taken to be that of a right circular cylinder, and continuous and substantial mass loss is permitted from one of the ends of the cylinder. The model used allows internal fluid flow within the system, and permits mass center shift as well as variations in system inertia. The focus is on the qualitative and quantitative characteristics of the system’s rotational motion as propellant is depleted. Results obtained indicate that mass loss has, in general, minimal effect on spin rate. The magnitude of the transverse angular velocity will generally decrease with time as a result of mass loss. However, it is possible for the transverse angular velocity magnitude to grow exponentially with time for certain system geometries and fuel depletion patterns. The analyses presented capture a great deal more of the vital characteristic of the attitude motion of the system than previous work in this area.