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Thread: 20 yard pull at 26,000 fps

  1. #1
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    20 yard pull at 26,000 fps

    Path was straight, clubface square. Why does ball pull left? Could it be that the toe of the club was moving 10 mph faster than the heel?





    How do we know the path is straight? The yellow line is perfectly horizontal (zero path):

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    Jeff

  2. #2
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    I see more of the white dot under the yellow line in the first pic, less in the second. Path was not "perfectly horizontal" or "straight."

    At a decent clubhead speed it doesn't take much to move a ball 20 yards with a driver...

    and why use range balls?

  3. #3
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    How are you calculating the toe v heal speeds and showing a 10 mph difference between the two? My math [S=D/T] doesn't seem to bring about the same conclusions.

  4. #4
    Quote Originally Posted by Cloran View Post
    How are you calculating the toe v heal speeds and showing a 10 mph difference between the two? My math [S=D/T] doesn't seem to bring about the same conclusions.
    This is on the Phantom software. Manual digging of two points will give me a speed.

  5. #5
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    Quote Originally Posted by Cloran View Post
    How are you calculating the toe v heal speeds and showing a 10 mph difference between the two? My math [S=D/T] doesn't seem to bring about the same conclusions.

    Interestingly enough, the University of Loughborough paper also reports about a 10 mph difference between the toe and the heel. That was an issue with Trackman that they mentioned: nobody knows what part of the clubhead is being measured to gather clubhead speed. They have a lot of questions about Trackman, especially the calculated values.



    Jeff

  6. #6
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    Quote Originally Posted by Cloran View Post
    I see more of the white dot under the yellow line in the first pic, less in the second. Path was not "perfectly horizontal" or "straight."
    The drawn yellow line is at zero degrees to the horizon, which is "perfectly horizontal". If you want to call that path "inside out", go ahead. How many degrees do you measure it to be inside-out?


    At a decent clubhead speed it doesn't take much to move a ball 20 yards with a driver...

    Give us some examples.


    and why use range balls?

    What's wrong with range balls?





    Jeff

  7. #7
    why no range balls ? a quality issue ?

    if they're the same quality, maybe one benefit nonetheless : it could be easier to figure the ball shape with a ball that spins more

  8. #8
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    Quote Originally Posted by Cloran View Post
    I see more of the white dot under the yellow line in the first pic, less in the second. Path was not "perfectly horizontal" or "straight."

    At a decent clubhead speed it doesn't take much to move a ball 20 yards with a driver...
    I used the drawing program on Objectus since the Screen Protractor software Kelvin uses isn't compatible with my Mac. Objectus can only measure in full degree increments, so it is a little crude, but good enough for this discussion. At most I get a path that is in-to-out by 1 degree and a face that might be a degree open to that path, but I could by off a degree or two. Maybe it is square. Impact is in the middle of clubface. Would anyone play this game if that club/path relationship by itself created 20 yard pulls?


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    Use whatever drawing program you want and check my work. Replication is the key to the scientific method!


    This clubface is about 12 degrees open to the path and created a 25 yard slice. That's the kind of club/path divergence I'd expect to create a massive miss.


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    Jeff

  9. #9
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    Quote Originally Posted by Jeff Martin View Post
    Path was straight, clubface square. Why does ball pull left? Could it be that the toe of the club was moving 10 mph faster than the heel?





    How do we know the path is straight? The yellow line is perfectly horizontal (zero path):

    Name:  Screen Shot 2012-10-27 at 6.57.10 PM.png
Views: 637
Size:  301.4 KBName:  Screen Shot 2012-10-27 at 6.57.40 PM.png
Views: 640
Size:  281.5 KB





    Jeff
    I would suggest the quality control, multiple use and unknown previous treatment of the 'multiple-use range ball' significantly affected the deformation asymmetrically during impact and is the major sources of the 20 yard unexpected flight.

    You may be able to get a visual clue by superimposing varying diameter circles connected at the leading edge of the golf ball as it is compressed to see the asymmetries as the ball is compressed.

    If this should happen again, recover the ball and 'float and spin it' to ALSO determine the true center of gravity at least in the 'uncompressed' condition.

    IMO, all of these ball deformation and quality control factors will affect ball flight within the values you are trying to study, and draw reliable conclusions, so please at least try drawing the circles starting with the uncompressed ball.

    Thanks,
    Art.

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