Abstract

Imparting topspin on a golf ball from putter impact can be achieved either by oblique impact from negative-lofted putter faces or by vertical eccentric impact (commonly referred to as ‘vertical gear-effect’). Negative loft gives a small amount of topspin but should preferably be combined with positive putter-head trajectory to give the ball lift at impact. Vertical gear-effect can provide high spin rates for impacts above the sweet spot and desirably gives the ball a small upward lift at impact. This paper outlines the theory of spin generation in putter impact, discusses how high vertical gear-effect can be implemented and considers the effect that such designs have on putt length control, directional accuracy and impact vibration. Ballistic measurement techniques to validate putter designs are described and an unexpected experimental result dependent on shaft coupling is analysed. Verf.-Referat