Abstract
A device to rotate an actual golf ball stably at a maximum of 10, 000 rev/min was developed. By this, drag, dynamic lift, and aerodynamic torque applied on the ball under various flight conditions were measured in a wind tunnel air current. Also equations of golf ball flight trajectory had been restricted to 2-dimension so far, but 3-dimensional flight trajectory was formulated in our study. The trajectory equation of a ball in flight was obtained under a concept that the mechanism of slices or hooks of a ball is caused by an inclining of the balls rotating axis, and the direction in relate to the rotating axis of the ball is constant. Using the aerodynamic force coefficients, mathematical calculation of the flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Ejection experiments were made using a robot. Ball initial conditions, flight distance, and side deviation distance were obtained in the experiments. The validity of the formulation was verified by comparing the calculation results with the experiment results.
