118 Aerodynamic principle of flying disc

Abstract

A flying disc can fly through the air because of the combination of the lift and drag forces by the oncoming air flow. Actual fight conditions were confirmed to perform the wind tunnel experiment beforehand. In order to clarify the mechanism of flight of flying discs, the flow field structure and the fluid force were investigated on non-spinning and spinning conditions. In the fluid force measurement, lift and drag forces were taken by varying wind speeds, spin speeds, and angle of attack. Drag and lift forces were found to increase as spin increased. The angle of attack on the maximum range of lift-drag ratio or glide ratio was found to be wide from 6 to 13 degrees which was suitable for a long distance throwing. Using a smoke wind tunnel, flow visualization around the disc was performed in order to understand the effect of disc spin. It was found that spin enhances lift force by attracting the Coanda effect on the trailing edge.