Lloyd, you've got to be kidding. Do you really believe that at any time in
the swing the hands are restraining the club the same as being clamped in a
vise? I don't know what your 'Professor' said, or what question he was
responding to, but I assure you the two boundary conditions on the
vibration of a golf club are vastly different.
Keep in mind that TT was trying to SELL us time on their Shaft Lab. I have
Shaft Lab data too and all it is is data from strain gauges on the shaft -
there is no velocity information there. If I were trying to sell shafts
and my engineers could find SOME instances where the shaft contributed to
the head velocity I might say the same thing. In general, I believe the
affect of the shaft on head speed is minimal, if at all.
Alan Brooks
At 09:01 AM 1/17/2006 -0500, you wrote:
Alan said:
"Lloyd, if the butt of the shaft were rigidly clamped than what you say
would be true - maximum velocity would occur when the shaft was
straight. But the shaft of a swung golf club is not rigidly clamped, it is
being held in the hands which are both moveable and soft. That being the
case the behavior of the shaft, hands, and clubhead are no longer simply
defined. The shaft is no longer in a simple mode of vibration and it would
be very difficult to make any general statements about the clubhead
velocity at a particular point in the swing. Tom Wishon, who has looked at
lots of swing videos, says that shaft bending does not significantly
contribute to clubhead velocity, and I believe him."
Alan
This subject has come up before and a college Professor said this same
thing last year in a presentation at the PCS Expo. I confronted him on the
subject following his talk by saying that during the first 1/4 cycle the
shaft in your hands are against rigid stops but after that it is like you
say restrained by soft stops, he agreed. But you also must understand that
it is only the first 1/4 cycle that affects the clubs return to straight,
beyond that we do not care any more how the natural frequency is affected.
To comment on your Tom Wishon statement I will go back to the 1995 PCS Expo
when True Temper was discussing their development of what was to be "Shaft
Lab". They said from their development work they had concluded that shaft
flex could account for as much as10 to 12% of the club head speed when
properly selected
llhack.
