Aerodynamic forces and torque acting on the ball were measured under various flight con-ditions in a wind tunnel flow. Using the aerodynamic force coefficients, mathematical calculation of flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Furthermore the logarithmic law was applied to trajectory formation of a golf ball in order to include influence of atmospheric boundary layer. The trajectory formation considering atmos-pheric boundary layer was verified by two experiments. One of the experiments was con-ducted to measure wind velocity distribution. By this experiment, logarithmic law could be verified. Other experiment was conducted in order to verify 3-dimensional flight trajectory applied logarithmic law. Many golf balls were hit under various initial conditions of golf ball (initial velocity, launch angle, spin rate) by a professional golfer using various golf clubs. Initial conditions just after golf balls launched were measured by launch monitor and wind velocity distribution in the direction that golf ball flved was measured. In addition, golf ball trajectory under atmospheric boundary layer was calculated by using measured initial launch conditions and wind velocity distribution. As a result, the calculated result of drop positions by trajectory analysis agreed with the actual measured data. So far, we know the influence of wind upon trajectory only qualitatively Flight trajectory considering natu-ral wind was calculated by using 3-dimensional flight trajectory formation applied logarithmic law under various initial conditions in detail. As a result, we could get knowledge about 3-dimensional flight trajectory influenced by natural wind. Such as we found out that there are conditions that distance reduces by tailwind and showed the conditions. In addition, we could get quantitative data: the influence of spin rate and launch angle including wind upon distance. Moreover we analyzed the quantitative influence of spin rate and launch angle including wind upon curving e.g. hooks and slices.
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