The US PGA’s “Ball Flight Laws” state that the ball will start in the direction of the club path and curve if the club face is pointed in a different direction than the club path.
The D Plane shows that the ball actually starts just about where the face is pointed(approx 85% of it’s direction) and curves if the path is in a different direction than the face. The only assumption made here is solid contact. If the ball is hit off the sweetspot, the club will turn before the ball separates from the face and gear effect will affect the spin axis of the ball.
So how is the 3d path determined?
For most good players, they take a divot with an iron after the ball. This means that the ball is hit before the low point. So, relative to the ball, the 3d path is to the right of the plane line(TGM term for the base of the inclined plane) for an iron shot(see picture below). 3 dimensionally, the club head continues to travel downward, forward and outward until it reaches the lowest point. Immediately after this, the club head begins traveling inward and upward. Because of the fact of when we hit the ball relative to low point, in order to hit it straight at a target, the club must be traveling to the left of the target(for downward angles of attack) while the face is pointing at the target at the hit/seperation. We are trying to get the 3d path to point at the target not the base of the plane.
This contradicts aiming parallel left with iron shots unless a person swings left. If you aim parallel left, make a perfectly on plane swing, hit the ball with the face pointing at the target, hit it solid and take a divot after the ball the ball will start just right of the target and draw left of the target.
Obviously, the opposite is true for players that hit upward on their drives. Just reverse the above information and you’ll see you have to aim/swing right(for upward angle of attack), with a face pointing at the target, to hit it straight. Assuming again solid contact.
Looking at the picture attached you will see the target line, 3d club path(club head velocity direction for a perfectly low point strike), club face normal(3 dimensional direction face is pointed) and initial ball directon(horizontal ball velocity direction). You can see that the 3d path(club head velocity direction) is to the right of the club face and the initial ball direction is just right of the club face normal. This is the D plane of a push draw. Path is right of target, face is right of target but left of path so ball will draw.
Follow this link for a good way to visualize the D Plane.
Here’s a link to another blog where I talk about how to use the D Plane.
Check out the D Plane Page for videos explaining visually what the D Plane looks like.
Please leave me some comments if you are having trouble understanding this. Picture was provided by Mandrin from the brian manzella forum.
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John,
great stuff on the d plane. I just had a training session with the staff on this subject a few days ago. I had the Jorgensen book but understand it even more after your explanation. This is what I always called “club face override and the ball flight lies”. I was looking for your video on the d plane and could only find the gravity torque one. Keep up the good work
guru
I’m really confused by all this new flight rules. From what I read regarding trackman studies, The initial flight is of the ball is more influenced by clubface alignment than the swing path.
Thinking back to my old days of slicing, I tried to correct it by opening my torso and aim left (made me slice more!)
Cosing my torso felt strange to me. I didnt feel like I could hit the ball properly.
The only way I could “correct” a slice was to shut the clubface then adjust the stance and body accordingly.
Dave,
I can understand your confusion but it sound like you have it right now. Most people that slice don’t understand that the initial reason why they started slicing is because the clubface is open to the path. They try and swing more left because it sorta makes sense. Like you, they start slicing more and feel lost. Learning how to get the clubface more square needs to come first. Only after they start hitting shots left, will the “proper’ set up seem more appropriate.
Hi John, If the swing path is on line (same direction) as the target line and the clubface is open to the right x amount at separation then the ball will fade to the right and vice versa if the clubface is closed at separation the ball will draw to the left. Am I correct in assuming this. Thank you John
John,
It depends. Let me add a couple qualifiers. If the swing path is in the same direction as the target, at impact, and the face is to the right (x) amount at separation with a centered hit, for a right hander, the ball will start right and fade more right. Vice versa for a closed clubface at separation.
You always have to imagine the path at impact (not the low point plane line) and assume a centered hit. Gear effect can cause a straight flying ball with the above conditions. In your example of the fade, a ball struck on the toe could create a straight flying shot.
JG
Hi John, I fully understand where the D Plane is for a Push Shot to the right of the target line (both swing Path and Clubface are on top of each other in the same plane. Now if the swing plane is on the Target Line and the clubface is aiming 10 degreees to the right of both the Target Line and Swing parth the spion on the ball is on the angle of the D Plane (at right angle to it anmd continuing on the angle of the D Plane. I realize the ball will take off approx 85 % in the direction of the clubface. The Question. Why then does this shot Slice to the right?
Hi John, A friend of mine who plays off Plus 3 always hits his 9 iron to the left. This can also be with opther irons also and can hit his driver left and right but not often straight. We played golf yesterday and he asked me to stand behind him when he played this 9 iron into the green to see what I felt. His alignment was excellent, Backswing very good but I told him to me it looked as though he came over the shot but not quite from the top but more from Release through. The only thing was that his divot went way right and the ball went left (straight Pull) of the target. He has been doing this for sometime now. As far as the D Plane is concerned what does this tell us?
Great question.
Ok. So here’s what we know the D plane would tell us. Assuming a centered strike, a straight pull can only happen with face and 3d path directly over each other( if we are thinking 3 dimensionally) pointed left of target. Based on your description, let’s assume that the path actually was to the right based on the shape of the divot. In order for the ball to start left of target, the club face would have to be pointing left at impact/separation. Assuming a centered strike, this would clearly be a pull hook (face left of target, path right of target).
So, the big question is why didn’t it curve? Assuming the path right of target and face left of target, the only variable left that can influence the spin axis on the ball is the contact location. For this case, it would have to have been a strike on the heel. This would cause a gear effect that imparts a spin axis tilted right to some degree. Combine that with a spin axis that should be tilting left because of the path and face relationship and we can get a left shot with no curve.
The next time you practice with him, use some impact spray and see where he is actually striking the face. I would also check his lie angles if his divots aren’t level with even amounts a toe and heel turf removal.
I hope this makes sense. Let me know if you have any questions.
John,
In discussing alignment, is there an inference of ball position? That would certainly go a long way in determining the angles of all paths and planes.
George
George,
There is no inference of ball position. Certainly, the more back ball position encourages a path more to the right and forward ball position a path more to the left. Aside from that, the ball doesn’t know where it is. It only know what happens when it gets whacked.
John