Pat:
I respectfully disagree with that. If what you are saying is true than the oscillation pattern would be the same no matter what plane the shaft is twanged in. I know that is not true. I have also plotted the path an unloaded shaft takes in the first full cycle and the return path is different depending on the location of the NBP or Spine.
Don,
I think what Pat and Allan are saying is a little different from what you are inferring. Let me try to paraphrase:
In the absence of spine, if you roll a vibrating shaft along a table edge, the plane of vibration will not roll. It will stay in whatever plane you started it.
Now, let's add spine. No matter how you start it off, the shaft will assume all positions over a 90* quadrant, in going from initial load to impact. That's because the hands roll, so the club rotates 90* around the shaft axis during the downswing. But most of the bending (until centrifugal force -- tip droop -- takes over near impact) will remain in the target plane.
The consequence is that you have to decide where you think the spine alignment is most important:
- During the initial loading.
- At maximum load, which varies from golfer to golfer, but is usually on a diagonal.
- Near impact, where the load is small but the velocity is large.
These are facts. My OPINIONS (based on considerable analysis but fairly little data -- because there is fairly little reliable data):
* The first is the most important, then the second, and the third is of little consequence. That is not the reasoning taken by most spiners, who try for alignment of either N or S at impact.
* There have been no convincing controlled experiments to support the ideal alignment, if there is one. There is ample anecdotal evidence to convince me that alignment can make a difference, but nowhere near enough to quantify things.
* Not enough interest has been applied to the most interesting (IMHO) question: at what size does spine begin to matter. For instance, I suspect that the SK Fiber shafts would show no alignment effects in a controlled experiment. If that is where Harrison is going, I applaud them.
Cheers! DaveT
