抄録
Wind tunnel experiments were conducted to study the aerodynamic characteristics of the spinning soccer balls with variously oriented spinning axes, of which balls are observed in a real game. Ball suspension apparatus with the piano wire strings and a shaft-bearing system through a soccer ball are studied with the cautions to obtain good linearity of spring support, non-interference to the other independent directions and the higher natural frequency of the system. The smooth rotation of a ball was accomplished with well spinning technique of dynamic balance. The 3-components aerodynamic forces of spinning ball in the fundamental arrangement of the axis are reported with the flight path calculations compared with ball flight observation.
