[chbkk]

Jeff

I now feel that winning you over from the dark side is my challenge. Unless Yoda kicks both of us out of his forum before long..

Please consider my response. Your statements are in quotations, each followed by my opinion or question.

"I agree with Yoda when he states that a golfer swings the clubhead."

What do you exactly mean by "swings the clubhead"?



"I will even partially accept the idea that he specifically swings the sweetspot of the clubhead."

My own statement would be to swing the clubhead and to keep the COM of the clubhead on a plane.


"However, where I differ from the majority viewpoint is that I believe that a golfer must swing the clubhead along the clubshaft plane, and not sweetspot plane 2, in order to get the sole of the club to be parallel to the ground, and along the surface of the ground, at impact."

1) So in your mental image, the clubshaft plane is the plane board and by swing the clubhead along the clubshaft plane, you mean to have the clubhead including the hosel touch the plane board at all time regardless of the clubhead orientation? Then the clubhead rotation must now be restricted to the rotation around the hosel with its COM moving in and out of the plane board which I find hard to accept.
2) “Swinging clubhead along the clubshaft plane” is not the necessary and sufficient condition to get the sole of the club to be parallel to the ground and along the surface of the ground at impact.

You can see from the example in my post #154 Experiment 2, that we can setup the swing machine to swing the COM of the clubhead along the pp#2 to COM axis and still get the sole of the club to be parallel to the ground and along the surface of the ground at impact.

"Yodas Luke's demonstration with a big club provides experimental proof that supports my belief."

Not at all! Quite the contrary in my opinion.

"In the backswing, he took his clubshaft up the clubshaft plane (not sweetspot plane 2)"

OK, there is a plane shift from backswing to the downswing probably exaggerated by the parallax effect. Yodasluke is not a robot. Or is he? His swing is the most precised I have observe of any human. The backswing stage is of low energy and it does not matter much that you need to keep the sweetspot on plane during a backswing. But he sure keeps the sweetspot on plane during the downswing.

"... and during the downswing he took his clubshaft down the clubshaft plane (and not the sweetspot 2 plane)."

Jeff. Either you need a new pair of glasses or we need to agree on some common terms and definitions. Can you illustrate your statement here in the images?


"From its address position on the sweetspot plane to its end-backswing position on the clubshaft plane, the sweetspot rotated away from sweetspot plane 2 to get to the clubshaft plane by the end of his backswing. From the delivery position to impact, the sweetspot rotated away from the clubshaft plane to get to the sweetspot plane 2 by impact."

I see the hosel dragging the clubhead and the sweetspot down along the sweetspot plane until the swivel moves the hosel away from the sweetspot plane and squares up the clubface for impact. Meanwhile, the sweetspot stays very precisely on plane.


"This exactly what I predicted when I wrote in post #165 that a golfer would always have to swing his clubshaft along the clubshaft plane, but he would have to make an accomodation for a greater hosel-sweetspot distance not by altering his on-plane swing (as he would perform it with a clubshaft that lacked a clubhead), but by simply standing the appropriate distance away from the ball"

Any golf club must have a clubhead.
The dowel that you swing should represent the line segment from pp#2 to the COM of the clubhead, not the clubshaft.
The flashlight that you use to trace the SPL should represent this line segment too, not the clubshaft.
A golfer must prepare his posture and his muscles differently for different hosel-sweetspot distance to centripetal-pull along this line segment with varying direction from different location of the COM of the clubhead. Can you please explain, as an expert in human anatomy, how one must have different posture for different direction of pull?

"In other words, I believe that the experimental evidence from Yodas Luke's demonstration swing with a big club supports my belief that the sweetspot rotates away from, and to, the clubshaft plane - and that the hosel doesn't rotate away from, and to, the sweetspot plane"

A big NO, Jeff. We still have major disagreement.