Hi Dave,
FWIW. We have a new InPractis system at the course I practice at and it
has a 60-fps cameras in it with shutters (electronic, I'm sure) that are
fast enough to stop the motion of the club. I made up some 200-g tip
weights that I could bond onto the end of shafts and built up two identical
clubs except one had an A-flex shaft and the other an S-flex shaft. The
effects of the differences in oscillation frequency are obvious in the
behavior of the clubs during the downswing. The A-flex shaft bent at the
beginning of the downswing, recovered to straight at about the 3-O'clock
position (remember I'm left handed and am looking face on with the camera)
and was bent forward at the impact position. The S-flex shaft was
recovered to straight at about the 2-O'clock position, bent forward at the
4-O'clock position, and back to straight at impact. I used tip weights for
this to take the clubhead offset c.g. effects out of the tests.
This being the case, I believe that there is some influence on dynamic loft
(that due to the bend of the shaft) from the stiffness of the shaft and the
'butt frequency', if you will, and undoubtedly some effect from the
stiffness profile on both this and the offset c.g. effects, but I guess I
believe Tom when he says that these effects are small compared to all the
other things that affect ball flight. I think it is likely that the
stiffness profile affects the 'feel' of the club much more that the ball
flight. The hands pretty much only excite a fundamental mode of
oscillation, ball impact is going to excite a bunch of them and I think it
likely that the stiffness profile of the shaft will influence what modes
are excited and how they reach the hands.
Regards,
Alan
At 11:23 PM 1/16/2006 -0500, you wrote:
At 10:23 PM 1/16/2006, BTM_Clubs wrote:
Dave: If you talk to any of the shaft manufactures they seem to agree
that profile is important. If you look at enough different shafts there
is a huge difference in profiles and I'm sure its not a random happening
but a detail design effort to get to a specific point.
I would like to believe this. I'm not sure I do. The shaft manufacturers
have a stake in our believing there is no such thing as a generic shaft.
That's what allows them to charge non-generic prices for them.
We briefly had a rep from a shaft manufacturer on one of the forums.
(Spinetalk? True Temper? Don't remember for sure.) He didn't last long.
Questions about profile difference were met with BS along the lines of,
"Trust us. We understand, but it's too complicated for you." That attitude
has me believing that shaft manufacturers will only tell us self-serving stuff.
That said...
I too believe that from customer feed back profile makes a difference
in club performance for a given golfer and swing.
And I have myself experienced the difference. So I'm a believer. But not
because of anything the manufacturers tell me.
Cheers!
DaveT
PS - Hey, I AM in curmudgeon mode today. I wonder why. Don't feel
particularly cranky. Had a good day, actually. I guess my training and
life experience has taught me to be skeptical first -- and I've had a lot
to be skeptical about today.
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