抄録
Wind tunnel experiments were conducted to study the aerodynamic characteristics of the spinning baseball ball 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 ball are studied with the cautions to obtain good linearity 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 tuning technique of dynamic balance. The 3-components aerodynamic forces in the 4-seam arrangements of the axis are reported with the variations of pitching and yawing angles. Ball trajectory calculations were also reported using these aerodynamic characteristics.
