For the acceleration data I believe Pat may be on to something.
If you can imagine the acceleration curve as an upside down v and pick a clubhead speed such as 100 mph and imagine it at the peak of the V, and if you can further imagine that at just before the peak and just after the peak you have a clubhead speed of 99 mph I would expect that you would achieve a higher ball speed at 99 prior to the peak than you would after it.
David,
I'm pretty sure I understand the model you propose, but let me check. You're saying that the ball speed will be higher if the clubhead speed is 99 and accelerating rather than 99 and decelerating. (BTW, you meant the velocity curve, not the acceleration curve, to be a "V".)
If that's the assertion, I know of nothing in physics to support it. We're talking about momentum transfer and kinetic energy transfer. Both of those depend on the velocity and mass of the objects, but not their accelerations.
But you do suggest something that may be relevant. Are you sure that the clubhead speed readings were clubhead speed AT IMPACT, rather than the maximum clubhead speed? Most speed meters would measure the maximum clubhead speed.
Now, suppose that: * The numbers in the tables were MAXIMUM clubhead speed, and * Impact occurred AFTER the clubhead speed maximum.
Then the clubhead speed that affects ball speed (the clubhead speed at impact) would actually be lower than the number in the table. If it were enough lower, that fact alone could explain the discrepancy. However, it would have to be about 10% below maximum in order to explain the difference, which is frankly a lot worse than I would expect from a skilled long-drive competitor. But it happens all the time with less-skilled players.
Cheers! DaveT
