LynnBlakeGolf Forums - View Single Post - Prestressed Shaft and Impact Deceleration

jmessner · #76 05-14-2006, 07:12 PM

Originally Posted by Mike O

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!

......

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.

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.

Mike 0 - Just to tie off our discussion because I agree it has run its course - here's the formula and example:

Centripetal Force example
F=m(v^2)/r
m=mass of clubhead (200g for a typical driver)
v=velocity of clubhead (let's assume 100 mph @ impact)
r=radius of curvature of clubhead motion (shaft length is a good approximation, but it could be slightly longer, let's try 45")
Anyway, then F=79 pounds force for this impact condition. The force is considerably less at other points in the swing.

There's a table with similar calcs here plus more discussion on shaft bending.

The second paragraph I quoted I think you have it right. Yes the shaft could bend forward and the sweetspot still not be even with the shaft. In fact, according to some, having the CofG inline with the shaft is the maximum condition that can occur but is not always fully achieved. There is some twisting going on too but I have to assume that it's not the biggest effect - otherwise we'd all be hooking our large headed drivers off the planet and most people tend to have more trouble getting the larger heads around.