[Mike O]

[quote=jmessner]Mike O - Ok, yes I think we're talking about the same thing - and you're right, clubmakers call it droop. I know nobody here gets Golf Digest, but the latest has a good picture of Camilo Villegas on the cover at impact from up the line that shows this. Put a straightedge on the handle and see how much the tip of the shaft has bent downward.

Also, your point on camera angle is well taken. However, I would say that if you could get an image with the head say 6 inches or so before impact the droop would be pretty much invisible (because it's directly perpendicular to the camera angle) to a camera viewing face-on and you'd be seeing the forward or backward bending predominantly.
We're in agreement here- exactly my point- thanks for seeing it.

That's why the deflection curves generated by strain gauges that indicate the kind of shaft behavior I described are somewhat more convincing to me. Still, the images I have seen with that just by chance have clubhead very near the impact point have not shown a lagging clubhead - but you never know.
See my last comment in this section- I think it applies to your comment here.

Anyways, I think I've kind of beat this subject to death, but while I'm somewhat clear on the difference your referring to with swinging and hitting (longitudinal vs radial), I don't think I understand why the centrifugal (centripetal) force of the clubhead on the shaft would be much different between the two. I'm probably missing the point here but from my college physics days, the centrifugal force would be equal to the clubhead mass times the clubhead speed squared all divided by the radius of the circular motion of the clubhead (at high clubhead speeds it turns out to be quite a large force). None of these factors would seem to be dependent on swinging or hitting given the same clubhead speed(maybe radius slightly?). Maybe TGM is using the term centrifugal force differently than the literal scientific meaning. I'll have to go look at the book again. Good points- would love for you to post the formula with an example- only if you have the time and interest- Hey, there's other things in life to do! As far as your understanding of the clubshaft differences between hitting and swinging- I'm thinking that you aren't quite seeing the difference in regards to TGM- Let's cover it a little later in this thread when I have time.

BTW, I'm not sure I've been very clear on this, but I wasn't suggesting that there was never clubhead lag in the swing - there certainly is and it is lagging for most of the downswing until the point the clubhead reaches a speed where the centrifugal force overwhelmes any pushing or pulling acceleration on the shaft and drives toward the center of gravity alignment we discussed. Maybe you're saying the same thing in your last paragraph before the PS? Good discussion.

I was justing that it might be possible that if the sweet spot was far enough back from the shaft- that you might have a condition where the shaft would curve forward- but the sweetspot would be at or behind that line of pull or longitudinal center of gravity- thereby having lag looked at in relation to the sweetspot but appearing to have throwaway if looking at the clubshaft. That's making a big assumption that the center of gravity that was back of the shaft- would move in line with the shaft by moving forward - and not just close the clubface to get in line with the shaft- as Homer notes on page 82.[/QUOTE]

Notice my comments above, but I'm with you we've beat this horse enough that I've A) lost some interest and B) reached my limit of any significant understanding of the subject matter.