golf shaft momentum transfer

Question
On your website (http://probablegolfinstruction.com), you state that the shaft mass does not significantly affect ball speed. I have been doing some research into this and I think that it might have more influence than some people think. A perfectly rigid shaft will contribute 25% of its mass as if it was on the clubhead itself. Of course, shafts are far from rigid with EI stiffness values of about 50 NM^2. However, with this stiffness, enough of the mass of the shaft is involved in the collision to be a factor in calculating ball speed. Also, the heavier the shaft, usually the stiffer it is which also increases apparent coefficient of restitution of the club and increases ball speed. Do you also agree that IF we could keep swing speed the same (e.g. with a robot), that a heavier shaft should result in a longer drive?

Answer
HI John Paul,

Very interesting question. Haven't thought about his issue for a while. When you've been doing some research, what have you used for resources?

Have you read, "Search for the Perfect Swing?" A classic. You'll find a reference to it here:
http://probablegolfinstruction.com/golf-books.htm

The authors were involved in an incredible amount of research on the game in the mid to late 60s. One of the experiments they did was to construct a driver with a hinged head so that it moved freely on its own, as if barely connected to the shaft. Kind of like the Medicus Hinge Clubs you see advertised on the internet and Golf Channel:
http://www.medicus.com/land10.php?sid=54566&g=1&affid=Sha

If you were to hold the club horizontally, the club head would swivel and the toe would point towards the ground, at 90 degrees relative to the shaft. Thus, if you were to hit a ball, you would expect the club head to be effected and not stay in line with the shaft.

They experimented hitting a number of balls. What they found was there was no effect on the clubhead at all. It remained in line with the shaft just as if it was a normal club. It's as if the clubhead was free and independent of the shaft.

From this research, I was convinced that the shaft mass has no part in ball speed. But, I'm always open to examination.

Let me know what you think at [email protected]

BEst regards,
Ken TAnnar