| 摘要 |
<p>PROBLEM TO BE SOLVED: To set a sweet area by adjusting to the actual hitting point distribution of average golfers. SOLUTION: The frequency transmitting function of this head is set to be 800 to 2,000 Hz. When the head 1 is mounted on a horizontal plane HP at a specified lie angleβand a loft angle, coordinates comprise a Z axis which passes the center of gravity of the head becoming an origin 0, and is vertical to the horizontal plane HP, an X axis which is horizontal and is in parallel with a tangent M coming into contact with the figure center Ag of a face surface 2, and a Y axis which is rectangular to the Z axis and the X axis. In such coordinates, a first straight line E, wherein a principal axis of inertiaξof which the angle to the X axis is smallest from among principal axes of inertiaξ,ηandζof the head 1 is projected on the XZ plane, inclines to the X axis at an angleθ1 of 5 to 30 deg. with the toe side tilting upward. On the projected face plane wherein the face surface is projected on the XZ plane, an angleθ2 of the principal axis of which the angle to the X axis is smallest from among the principal axes with the figure center as the origin, and the angleθ1 satisfy|θ2-θ1|<=8.</p> |
