This past summer I was able to spend a few hours on TrackMan thanks to Joe Bosco at The Glen in Glenview, IL. I took a particular screenshot with my phone because it sparked some questions in my mind that relate to what influences the golf ball’s starting direction and curvature. See picture featured above.
Although the image shows me at address (south paw lefty), the lines of different colors on the ground relate to what was happening at impact and the Purple Line is the resulting line of flight. Or so we shall see anyway.
For this particular shot I was trying to produce a noticeable amount of curvature on the golf ball’s flight and decided to feel like my clubface was a decent amount open at impact.
Let’s take a look at the different colors presented on the snapshot. The Blue Line is the direction the Club Path was travelling while the Red Arrow indicates Face Angle at impact. The numbers were as follows: Club Path 1.0 degrees, Face Angle 5.1 degrees, Face to Path 4.1 degrees, Launch Direction 4.5 degrees.
From a quick glimpse of the Purple Line indicating ball flight, you would think the ball started very closely to the Blue (or Club Path) line. This very much confused me as TrackMan’s Launch Direction was telling me the ball started 4.5 degrees to the left but I saw it starting much closer to the Club Path number of 1.0 degrees when looking at the Purple Line. The visual implied the ball took off much closer to the Club Path while the numbers implied the ball took off much closer to the Face Angle.
With the help of John Graham (@johngrahamgolf) and James Ridyard (@jamesridyard) I was able to understand the difference between the visual and what numbers were indicating. The difference occurred because of how a 3D event is displayed and represented on a 2D image. James told me to look at the SHADOW of the ball flight, or the Black Line on the screenshot. You can see this Black Shadow Line starts much closer to the Red Arrow (Face Angle) and then the Black Shadow Line curves to the left towards the very end of the ball’s flight as the shadow moves down the driving range. From my perspective, the Purple Line looks more like a straight push to the left, while the Black Line shadow indicates the true ball flight I saw when watching the shot live, where the ball started left and then curved more left.
Therefore, in harmony with what TrackMan’s numbers implied, the Black Shadow Line of the ball flight indicated the ball started (4.5 degrees) much closer to the Face Angle (5.1 degrees) than to the Club Path (1.0 degrees). Even though the Club Path was left of the target, because the Club Path was moving to the right of where the Face Angle was positioned at impact, the ball still curved to the left as it neared the end of its flight. The shot was a push fade.
So, What? … The Conclusions:
If looking at the Purple Line, one may assume the ball took off close to where the Club Path was pointing and curved later in its flight because the Face Angle was to the left at impact.
If looking at the Black Shadow Line one would assume the opposite: the ball took off close to where the Face Angle was pointing and curved later in its flight because the Club Path was to the right at impact. These are very different explanations. Fortunately, TrackMan’s numbers themselves prove the Black Shadow Line to be the accurate ball flight.
There are other factors involved such as speed, loft, centeredness of contact, and angle of attack that affect the golf ball’s starting direction and curvature. However, an overall rule of thumb would be that the ball takes off closer to the Face Angle and then curves accordingly if there is a difference between Face Angle and Club Path at impact.
Thanks to John and James for their help. Hopefully this can also help you read your ball flight to indicate what your Face Angle and Club Path is doing at impact. Reading ball flight is a good habit as it tells you why your OK shots did what they did and also why your excellent shots do what they do too.