Results 1 to 7 of 7

Thread: Research-a-thon Case Study: Clubhead speed and smash factor

  1. #1
    Join Date
    Jan 2012
    Posts
    4,096

    Research-a-thon Case Study: Clubhead speed and smash factor

    Most of the long-drive participants at the Research-a-thon were familiar with radar-based launch monitors like Trackman and Flightscope, and were aware that a player's clubhead speed is typically reported lower by a Trackman than other devices. However, nobody knew for sure exactly why. Now we do, or at least are on a pretty good track to finding the truth.

    For each swing videoed with the Phantom, the crown of the clubhead was marked with tracking dots placed at the toe and the heel, and one close to geometric center. "Post-production", these dots were tracked by ProAnalyst and the path and speed of each recorded.

    In addition, before each shot, we sprayed the clubface with foot powder, then photographed the face post-impact. Also using ProAnalyst, we were able to precisely measure the impact location and determine, in inches, how much impact was either towards the toe or the heel, or above or below center.

    With this impact location information, we were able to program ProAnalyst to also track the impact location and determine the clubhead speed at that point on the crown. Here is a screen cap of a completed ProAnalyst tracking (the image contrast has been heightened in ProAnalyst to improve the tracking quality of the white dots). The red line is the path of the toe dot, the green reflects the middle dot, and the blue traces the path of the heel. The magenta line tracks the impact location, as determined through the foot powder exercise. In pink, ProAnalyst has calculated the face angle at maximum compression at the point of impact, taking into account the influence of bulge, which was also determined through the impact location data:


    Name:  ProAnalyst.PNG
Views: 2212
Size:  105.0 KB


    Here is the corresponding post-impact photograph:


    Name:  Impact location.PNG
Views: 2511
Size:  957.1 KB



    After ProAnalyst tracking, we gathered and compared the Phantom captured data to the simultaneous Trackman data. So far, we have analyzed 97 swings with an overhead view, where we had both valid Phantom and Trackman data. Below is a summary of measured clubhead speed and smash factor (we did not calculate ball speed using ProAnalyst, so we use below Trackman's reported ballspeed for our smash factor calculation):


    Name:  Summary.PNG
Views: 2044
Size:  21.6 KB


    What we found is that Trackman usually has a very hard time determining the center of the club and typically reports a clubhead speed that is more representative of a location nearer to the heel than the center of the clubface. Since the clubhead is traveling on an arc, points closer to the center or toe will travel faster than those closer to the heel. As a result, Trackman consistently under-reported clubhead speed relative the middle of the clubhead, as well as relative to the impact location. When we re-calculated smash factor using the Phantom determined clubhead speed at the point of impact, the average smash factor dropped by 0.05x.

    Interestingly enough, there were two driver heads that Trackman "saw" better than the others: the Nickent 4DX and the Callaway FT-i (which looks like the Alien mother-ship in Independence Day). For these two driver heads, the Trackman reported clubhead speed matched up well with the Phantom-determined speed of center of the clubhead. However, for every other model of clubhead, the Trackman clubhead speed was well below that measured by the Phantom for the clubhead center or point of impact.

    As you might imagine, this Trackman flaw can lead to some misleading data. You may recall that a week or so ago I posted an analysis, relying solely on Trackman generated numbers, of two players at the Research-a-thon:

    http://jeffygolf.com/showthread.php?...ith-the-driver

    In that thread, I noted how Player B's smash factor almost every time topped the theoretical maximum of 1.49 and was consistently well above Player A's smash factor. But, was Trackman reporting the correct smash factor? Below I have displayed the clubhead speed and smash factor data for Player A and Player B. I'll add that Player A used the Nickent 4DX and Player B swung a TaylorMade R11S. What we learn is that, contrary to what AAA speculated in the earlier thread, Player B's driver is not at all "wildly out of spec". But Trackman is.


    Name:  Player A - clubhead speed and smash factor.PNG
Views: 4237
Size:  43.8 KB
    Name:  Player B - clubhead speed and smash factor.PNG
Views: 1995
Size:  38.9 KB


    For Player A, the Trackman data is closest to the clubhead speed at the middle of the clubface (where Trackman purports to measure), whereas for Player B, the Trackman clubhead speed is closest to the heel speed. When the smash factors are re-calculated using the Phantom impact location speed, the players have identical smash factors.

    Since Trackman was under-reporting Player B's clubhead speed, while coming pretty close to Player A's, Player B appeared to be getting "a lot more" out of his driver swingspeed. But, instead, it was mostly a case of apples and oranges.

    So, Trackman users, the good news is that, unless you are swinging a Nickent 4DX, a Callaway FT-i, or a similar monstrosity, you most likely have a clubhead speed around 4mph higher than what is reported on Trackman. The bad news is you have a lower smash factor (assuming the ballspeed is correct, which we did not measure)!




    Jeff

  2. #2
    Lloyd Higley Guest
    Nice work Jeffy

  3. #3
    Join Date
    Nov 2012
    Location
    Bath, UK
    Posts
    120
    Great work Jeffy and Kelvin. The research-a-thon paper is going to be a must read for anyone involved in the game.

  4. #4
    Join Date
    Apr 2012
    Location
    France
    Posts
    108
    Amazing!!!!

    Thank you very much

    Quote Originally Posted by Jeff Martin View Post
    (assuming the ballspeed is correct, which we did not measure)!
    As the ball's diameter is 40mm (which gives a scale), and assuming you can follow the ball on a sufficient distance, maybe would it be possible to measure the speed with Proanalyst?

  5. #5
    Join Date
    Jan 2012
    Posts
    4,096
    Quote Originally Posted by MattF View Post
    Amazing!!!!

    Thank you very much



    As the ball's diameter is 40mm (which gives a scale), and assuming you can follow the ball on a sufficient distance, maybe would it be possible to measure the speed with Proanalyst?


    Definitely possible, and Quintic is doing a lot of research into ball speed, spin rates and spin axis tilt using their Phantoms v. Trackman. Unfortunately, for nearly all of our videos, we didn't capture enough frames of the ball to get reliable ball tracking results.



    Jeff

  6. #6
    Join Date
    Jan 2012
    Posts
    4,096
    Quote Originally Posted by MattF View Post
    Amazing!!!!

    Thank you very much



    As the ball's diameter is 40mm (which gives a scale), and assuming you can follow the ball on a sufficient distance, maybe would it be possible to measure the speed with Proanalyst?

    After talking to Rick Malm, we are going to try tracking some balls and see what we find. We'll keep you posted.

    Rick also pointed out that we can make a "2D to 3D" adjustment for clubhead speed by using the Trackman angle of attack information. For everything but a perfectly level AoA, that will increase our clubhead speeds.


    Jeff

  7. #7
    Join Date
    Aug 2012
    Location
    Pacific Palisades, California
    Posts
    73
    Quote Originally Posted by Jeff Martin View Post
    Most of the long-drive participants at the Research-a-thon were familiar with radar-based launch monitors like Trackman and Flightscope, and were aware that a player's clubhead speed is typically reported lower by a Trackman than other devices. However, nobody knew for sure exactly why. Now we do, or at least are on a pretty good track to finding the truth.

    For each swing videoed with the Phantom, the crown of the clubhead was marked with tracking dots placed at the toe and the heel, and one close to geometric center. "Post-production", these dots were tracked by ProAnalyst and the path and speed of each recorded.

    In addition, before each shot, we sprayed the clubface with foot powder, then photographed the face post-impact. Also using ProAnalyst, we were able to precisely measure the impact location and determine, in inches, how much impact was either towards the toe or the heel, or above or below center.

    With this impact location information, we were able to program ProAnalyst to also track the impact location and determine the clubhead speed at that point on the crown. Here is a screen cap of a completed ProAnalyst tracking (the image contrast has been heightened in ProAnalyst to improve the tracking quality of the white dots). The red line is the path of the toe dot, the green reflects the middle dot, and the blue traces the path of the heel. The magenta line tracks the impact location, as determined through the foot powder exercise. In pink, ProAnalyst has calculated the face angle at maximum compression at the point of impact, taking into account the influence of bulge, which was also determined through the impact location data:


    Name:  ProAnalyst.PNG
Views: 2212
Size:  105.0 KB


    Here is the corresponding post-impact photograph:


    Name:  Impact location.PNG
Views: 2511
Size:  957.1 KB



    After ProAnalyst tracking, we gathered and compared the Phantom captured data to the simultaneous Trackman data. So far, we have analyzed 97 swings with an overhead view, where we had both valid Phantom and Trackman data. Below is a summary of measured clubhead speed and smash factor (we did not calculate ball speed using ProAnalyst, so we use below Trackman's reported ballspeed for our smash factor calculation):


    Name:  Summary.PNG
Views: 2044
Size:  21.6 KB


    What we found is that Trackman usually has a very hard time determining the center of the club and typically reports a clubhead speed that is more representative of a location nearer to the heel than the center of the clubface. Since the clubhead is traveling on an arc, points closer to the center or toe will travel faster than those closer to the heel. As a result, Trackman consistently under-reported clubhead speed relative the middle of the clubhead, as well as relative to the impact location. When we re-calculated smash factor using the Phantom determined clubhead speed at the point of impact, the average smash factor dropped by 0.05x.

    Interestingly enough, there were two driver heads that Trackman "saw" better than the others: the Nickent 4DX and the Callaway FT-i (which looks like the Alien mother-ship in Independence Day). For these two driver heads, the Trackman reported clubhead speed matched up well with the Phantom-determined speed of center of the clubhead. However, for every other model of clubhead, the Trackman clubhead speed was well below that measured by the Phantom for the clubhead center or point of impact.

    As you might imagine, this Trackman flaw can lead to some misleading data. You may recall that a week or so ago I posted an analysis, relying solely on Trackman generated numbers, of two players at the Research-a-thon:

    http://jeffygolf.com/showthread.php?...ith-the-driver

    In that thread, I noted how Player B's smash factor almost every time topped the theoretical maximum of 1.49 and was consistently well above Player A's smash factor. But, was Trackman reporting the correct smash factor? Below I have displayed the clubhead speed and smash factor data for Player A and Player B. I'll add that Player A used the Nickent 4DX and Player B swung a TaylorMade R11S. What we learn is that, contrary to what AAA speculated in the earlier thread, Player B's driver is not at all "wildly out of spec". But Trackman is.


    Name:  Player A - clubhead speed and smash factor.PNG
Views: 4237
Size:  43.8 KB
    Name:  Player B - clubhead speed and smash factor.PNG
Views: 1995
Size:  38.9 KB


    For Player A, the Trackman data is closest to the clubhead speed at the middle of the clubface (where Trackman purports to measure), whereas for Player B, the Trackman clubhead speed is closest to the heel speed. When the smash factors are re-calculated using the Phantom impact location speed, the players have identical smash factors.

    Since Trackman was under-reporting Player B's clubhead speed, while coming pretty close to Player A's, Player B appeared to be getting "a lot more" out of his driver swingspeed. But, instead, it was mostly a case of apples and oranges.

    So, Trackman users, the good news is that, unless you are swinging a Nickent 4DX, a Callaway FT-i, or a similar monstrosity, you most likely have a clubhead speed around 4mph higher than what is reported on Trackman. The bad news is you have a lower smash factor (assuming the ballspeed is correct, which we did not measure)!




    Jeff
    Dear Jeff,

    Has the research/data reduction been finished, and if so can it be posted here for continuity, please ??

    I have been using the already posted data to discuss the importance of having a better understanding of the 'impact dynamics, to augment what I believe are other important/critical swing characteristics that control the quality of a swing, ie., 'dynamic balance and stability margins' of the pelvis, torso, shoulders and arms.

    IMO, the impact dynamics when better understood will determine/control the launch conditions of the ball as it separates from the club face , and therefore from any movement, change the delivery parameters of the club head, ( ie speed, angle of attach, club path and club face inertial position, etc. ) at the moment of initial impact.

    From the data you have already provided, it appears the ball conditions at separation could be as much as a few degrees different from the initial contact conditions especially for off center driver hits, so I hope the plans are still to share the results of your testing.

    Sincerely,
    Art

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •