OK, I hear you.
So was this marking with the sharpie not necessary? Were the software updates in any way related to GE? Just askin.
TrackMan customer David Howell had his system updated with TrackMan Performance Studio during the BMW
Championship at Wentworth. While TrackMan inventor Fredrik Tuxen introduced David to the ground breaking TPS
software, he also opened David’s eyes to the importence of center impact… in particular with the driver.
Figure 1. One of the swings from TrackMan Performance Studio
that initiated the discussion is shown. The club path is slightly
in-to-out (0.5 deg.) with a 1.8 deg. closed face angle relative to
the path. Normally this would produce a small draw, but instead
a slight fade resulted. The explanation lies in the fact that the
ball, as can barely be seen on video is impacted a little towards
the heel, resulting in a gear effect tilting the spin axis towards a
fade shot – in this case actually more than compensating for the
closed Face-to-Path. After the impact position on the club face
was brought up during the testing, David marked every single
ball with a sharpie to verify the impact position.
Figure 2. Shows a mirrored situation of figure 1. This shot reveals
a 1.4 deg. open Face-to-Path, but because of the slight toe
impact (pay attention to the head position at impact relative to
the aiming stick which remained fixed relative to the ball position
throughout the testing), the horizontal gear effect overrides the
open face angle creating a slight draw.
The impact position on the club face is not only important because
of its influence on the spin axis through the gear effect,
but is also important when studying the Face-to-Path data. Due
to the bulge of the driver, if the ball is impacted ½ inch (12.7
mm) towards the heel, the face angle will at this point on the
club face be 2 deg. closed relative to the center of the club face.
Likewise, if the ball is impacted ½ inch towards the toe, the face
angle at this point will be 2 deg. open relative to the center of the
club face. This rule-of-thumb actually works for all drivers on the
market.
The above raises an important question when analyzing the TrackMan club data.
Is a 2 deg. closed Face-to-Path due to a center hit with a truly closed face, or is it a square club delivery, but heel impact?
When David continued hitting about 30 drives each being checked for impact position and club delivery data, the answer in his case
was slowly revealed. David’s club path was very consistent within +/-1 deg., whereas the Face-to-Path had twice as much variation.
The very interesting thing was that the variation of the Face-to-Path closely followed the impact position on the club face – meaning
that whenever a closed Face-to-Path number occurred, the impact on the club was slightly towards the heel and vice versa for open
Face-to-Path numbers. Or as David summarized his learnings “the Face-to-Path variation I am getting for my driver has much more
to do with impact position on the club face rather than the way I swing the club”.
