THE EFFECT OF INERTIA IN THE WINCH LAUNCH

Abstract

Inertia of mechanical components is present in all transmission systems. When a winch used for launching sailplanes the inertia effect of the cable drum inertia is significant. The inertia of the engine, gearboxes all play a part and should be taken into account in the design of the detail of the winch system. Rotating masses, whatever their Inertia value, take up energy as they accelerate, and give out energy as they decelerate. Energy in the winch launch is the product of cable tension and cable speed. The presence of large inertia's in the rotating masses can increase cable tensions significantly in the course of the launch thus making management of the system difficult. The purpose of this paper is to show how inertia of the rotating parts influence the launch. A example is used that employs numbers for mass, speed and power that are typical of winch launch operations. The energy flows are defined throughout the launch. A better understanding of the winch launch system can be achieved.