Golf club head with flexure frequency matched with distortion-relaxation frequency of ball

A golf club head formed of a moldable plastic material comprising:

• a body member formed of polypropylene having a sole, toe, heel and a planar striking face extending upwardly from said sole between said toe and heel and having a predetermined acute loft angle measured with respect to a plane passing through the axis of a shaft fastenable to said body member,
• said body member being formed into a portion of an arcuate configuration with a plane surface thereof forming said striking face, and
• an elongated solid steel insert with a modulus of elasticity of approximately 30 million cycles per second embedded in said body member and arranged so as to be completely surrounded by said plastic material with one end thereof spaced one-eighth of an inch from the center of and substantially perpendicular to said striking face,
• said insert forming at least a part of the path for the shock wave produced when a ball having a resonant frequency of approximately 19 million cycles per second is struck by the head at approximately the center of said striking face, which shock wave moves through said one-eighth of an inch of the polypropylene material forming said body member, then longitudinally through said steel insert and the remainder of the polypropylene body member to the arcuate configuration of said body member and back the same path to the point of impact of the ball with the striking surface,
• the density of the plastic material of said body member and said insert being such that the recovery rate of the flexure frequency of the head substantially equals the distortion-frequency of the golf ball when propelled from the face of the golf club head.