With irons or any shot with the ball on the ground:

According to D Plane information, in order for the ball to fly straight, the normal to the clubface(the 3d location of the where the clubface is pointing) and the club path must point at the target at the hit. It is also a requirement that the ball is hit absolutely solid(right in line with the CoG). This location is basically a point and any mistake left or right will alter the shape of the club during the hit.

I mentioned in a previous blog that I am having some research done on this topic but hopefully it confirms my thoughts and trackman’s claims.

Back to the topic. Because the ball is hit with a downward angle of attack on a crisply struck iron shot, the club is still traveling downward and outward after hitting the ball until it reaches low point. Because the club travels to the right after the hit the path of the club(relative to the ball) is inside out. The impact path is right of the low point swing path.

This Picture will help you picture this is it doesn’t make sense.

It is for this reason that you must either aim or swing a little left for the ball to actually fly straight. Even though the club is swinging left, relative to the ball the club path can now point exactly at the target.

Keeping the club constant, the more down angle you have in your strike the more to the right the clubs actual path becomes. Thus, you will have to aim more left. The amount of left you aim depends on your angle of attack and what club you are using.

There’s a relationship between the shape of the swing plane and the amount the club is moving out after the strike. As the swing plane get’s more vertical the amount of out becomes less all while the amount of down is increasing. Ferris wheel would have all down and no out.

As the swing plane get’s flatter, the amount of out is increasing while the amount of down is less. A merry-go-round would have all out and no down.

Depending on a persons impact angles, it will depend on whether or not they aim/swing more left with shorter clubs or longer clubs. If someone hit all clubs with the same angle of attack, they would have to aim/swing more left with a 3 iron vs a wedge.

If the player’s angle of attack get less by more than 1 degree from wedge to 3 iron than that player would aim/swing more left with the wedge.

Most player’s will fit into this second category where they aim/swing more left with shorter irons than longer ones.

Understanding the D Plane shows why the anatomy of a straight shot is the biggest eye opener for most. It helps explain why swinging way to the right can be more frustrating to good golfers than swinging to the left.

Understanding the D Plane helps us learn how to work the ball and curve it out of trouble.

The D Plane will help teach you how to aim based on your swing shape or tell you, that if you want to aim a certain way, what changes you need to make to your swing shape.

Here are two articles that are absolute must reads from Trackman. They are from their newsletter and very informative.

Secret of Straight Shot
Secret of Straight Shot II

These two articles are what you use the D Plane for. Once you understand what causes what then you can go see someone. They can teach you how to make the club do what you want.

If the teacher doesn’t know the two above articles, turn around and call someone else. There simply isn’t room for someone trying to be their best to be given information that isn’t real or doesn’t work.

I always have to know why. These kinds of articles and information explain the “why” to me and it helps me to help you. I will continue to dig into the depths of the science so I can simplify it for my students.

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.