D-Plane EXPLAINED!!!!!! by Brian Manzella

[jymetalwood]

I read about D-Plane, but where can I find some good explanation?
I found one piece by Brian, which didnt clear up much.

Thanks for the help

Joe

 

[savydan]

Search it from early 2009.

Or you can know that the ball starts out about 80% in the direction of the clubface and curves away from the club path.

When the path is downward (like an iron) the path is still moving out.

When the path is upward (like a driver off a tee) the path is still moving a little inward.

You can read about D-plane for hours, but this is basically what you need to know until you get a Trackman in front of you and play with it.

 

[savydan]

As the name implies, D-plane is a plane.

It is a plane defined by two vectors starting from impact and moving in the general direction of the target.

The bottom vector is the direction of the clubhead through impact.

The top vector is the direction of where the clubface is pointing at impact.

From those two vectors, you have a plane.

The initial direction of the ball is along this plane, about 80% towards the clubface vector.

The ball will curve along the plane, away from the path vector until wind, gravity, etc. take over.

You can do a search and study this for 100 hours if you like.

 

[Richie3Jack]

Basically it's talking about what causes initial ball flight direction and what causes ball curvature, aka the 'new ball flight laws.'

Clubface Angle at impact is about 85% responsible for the ball's initial direction. The other 15% is the clubpath. So you have a shot that starts right, the clubface is going to the right to some degree. Have a shot that starts left, clubface is going left to some degree. (In general terms).

Curvature of the ball is dependent on path in relation to the face at impact. Inside-to-out paths (in relation to the face) cause draw spins. Outside-to-in paths cause fade spins.

So, if you had a clubface that was 5* open and the path was 5* inside-to-out, that would cause a straight push. Old ball flight laws would call for a push fade, but with the use of accurate physics and backed up by Trackman technology, we now understand that the ball in this case would be a straight push.

I think the 'swinging left' vs. 'swinging right' stuff is important, but understanding the new ball flight laws should be the first thing to learn when it comes to D-Plane, IMO.





3JACK

 

[savydan]

So, if you had a clubface that was 5* open and the path was 5* inside-to-out, that would cause a straight push. Old ball flight laws would call for a push fade, but with the use of accurate physics and backed up by Trackman technology, we now understand that the ball in this case would be a straight push.
3JACK

Even the old ball flight laws would say the above was a straight push.

If the path was square to the face, what would cause the horizontal curvature?

I think the confusion lies (to this day) in that with the old ball flight laws, the face angle was typically given in relation to the path.

With the new ball flight laws/D-plane/Trackman, the face angle is typically given in relation to the target line.

Note: We are not taking into account the angle of attack.

 

[Brian Manzella]

THIS IS AN UPDATED EXPLANATION.....

I feel the need to educate the golf world on these three important concepts:

The "U" Plane

and...

The "D" Plane
​

The "D" Plane is the concept defined by Physicist Dr. Theodore Jorgensen in his book "The Physics of Golf."

Simply explained, the "D Plane" is the plane (A flat surface that can tilt any which way, and extends infinitely in every direction) that the golf ball flies on until gravity and wind act on it.

Here are the definitions...

The "U" Plane

The Clubhead and its SWEETSPOT (the clubhead's center of gravity or CoG) are traveling on a plane to and through IMPACT (when the clubhead first hits the ball). We call this the SWING PLANE.

This travel "describes" ("draws") a "U" shape on the face of this plane (see pic above).

This is the U PLANE.

When the clubhead contacts the ball, the CLUBFACE is "pointing" somewhere in space (up, down, left, right) at impact SEPARATION (when the ball leaves the clubhead). Like a lie angle tool (see pic below). I call the "direction of the point" the TRUE CLUBFACE.

During this IMPACT INTERVAL (the time while the ball is on the face)—and the sweetspot describing the U PLANE, which is a curved shape—the sweetspot is moving a basically straight line—also somewhere in space (up, down, left, right). It is basically a staright line because the "U" is a somewhat flattened ellipse, and the size of this flattened ellipse, is so large that the one-half to three-quarters of an inch of the impact interval is "basically straight." And again, that straight line is pointing somewhere in space.

These two "somewheres in space" of the sweetspot path at the impact interval, and the "true clubface" create VECTORS (the direction of a force), these vectors intersect at the ball.

This vectors create the "D" PLANE, which is a plane that is "Descriptive" of the ball flight off of the clubhead separation.

This flight happens on this D Plane until the wind or gravity or something else diverts it from this path.

Easy enough, huh?

Well....

Because there is a "plane line," a "target line," a "stance line," goofy completely incorrect Gary Wiren-era thing called the "PGA Ball Flight Laws." and this little yellow book called "The Golfing Machine."

Among other things.

Let's take these one at a time....

Plane Line - The base line of a plane as it intersects with the ground (remember, a plane extends through the ground, the planet, and the galaxy).

An example would be the gutter on a roof.

Target Line - The straight line from the ball to the desired target.

Stance Line - The line formed by the feet of the golfer, either using the toes or the heels to "draw" the line, as it relates "somewhat" to the target line.

Gary Wiren/ PGA Ball Flight "laws" - Written after the PGA decided against using "The Golfing Machine" as the official PGA Teaching Manual, these misguided non-laws, suggested that the ball would always start on the 2D (on the ground representation of the) clubhead path (which they had NO WAY to measure), and curve to the 2D (on the ground on the ground representation of the) clubface (which they had NO WAY to measure either), if these two points pointed on different places. Other wise the ball went where they were both "pointing." Sort of.

The Golfing Machine Ball Flight "Rules" - Suggested that the plane line would always act as the "path" and the TRUE CLUBFACE would be—well—the true clubface.

Homer Kelly thought that the ball would start nearly on the vector of the TRUE CLUBFACE and curve toward the "path." This turned out to be quite correct.

One little problem...

The "path" part.​

And the little "Hinge Action" theory (but that's another story for another day).

The "path" will always be different than the "plane line" unless the TRUE PATH and the "plane line" are the exact same, which can only happen if contact is made dead level to the ground. Which doesn't happen very often.

So, I explain the divergence of the Plane Line and the True Path with my little invention called The "U" Plane.

Whew!

Now, come on you "Brian can't explain the D-Plane and his forum visitors are all confused" knuckleheads out there.

Take your shot at doing better.

 

[alexlimco]

THIS IS AN UPDATED EXPLANATION.....

I feel the need to educate the golf world on these three important concepts:

The "U" Plane

and...

The "D" Plane
​

The "D" Plane is the concept defined by Physicist Dr. Theodore Jorgensen in his book "The Physics of Golf."

Simply explained, the "D Plane" is the plane (A flat surface that can tilt any which way, and extends infinitely in every direction) that the golf ball flies on until gravity and wind act on it.

Here are the definitions...

The "U" Plane

The Clubhead and its SWEETSPOT (the clubhead's center of gravity or CoG) are traveling on a plane to and through IMPACT (when the clubhead first hits the ball). We call this the SWING PLANE.

This travel "describes" ("draws") a "U" shape on the face of this plane (see pic above).

This is the U PLANE.

When the clubhead contacts the ball, the CLUBFACE is "pointing" somewhere in space (up, down, left, right) at impact SEPARATION (when the ball leaves the clubhead). Like a lie angle tool (see pic below). I call the "direction of the point" the TRUE CLUBFACE.

During this IMPACT INTERVAL (the time while the ball is on the face)—and the sweetspot describing the U PLANE, which is a curved shape—the sweetspot is moving a basically straight line—also somewhere in space (up, down, left, right). It is basically a staright line because the "U" is a somewhat flattened ellipse, and the size of this flattened ellipse, is so large that the one-half to three-quarters of an inch of the impact interval is "basically straight." And again, that straight line is pointing somewhere in space.

These two "somewheres in space" of the sweetspot path at the impact interval, and the "true clubface" create VECTORS (the direction of a force), these vectors intersect at the ball.

This vectors create the "D" PLANE, which is a plane that is "Descriptive" of the ball flight off of the clubhead separation.

This flight happens on this D Plane until the wind or gravity or something else diverts it from this path.

Easy enough, huh?

Well....

Because there is a "plane line," a "target line," a "stance line," goofy completely incorrect Gary Wiren-era thing called the "PGA Ball Flight Laws." and this little yellow book called "The Golfing Machine."

Among other things.

Let's take these one at a time....

Plane Line - The base line of a plane as it intersects with the ground (remember, a plane extends through the ground, the planet, and the galaxy).

An example would be the gutter on a roof.

Target Line - The straight line from the ball to the desired target.

Stance Line - The line formed by the feet of the golfer, either using the toes or the heels to "draw" the line, as it relates "somewhat" to the target line.

Gary Wiren/ PGA Ball Flight "laws" - Written after the PGA decided against using "The Golfing Machine" as the official PGA Teaching Manual, these misguided non-laws, suggested that the ball would always start on the 2D (on the ground representation of the) clubhead path (which they had NO WAY to measure), and curve to the 2D (on the ground on the ground representation of the) clubface (which they had NO WAY to measure either), if these two points pointed on different places. Other wise the ball went where they were both "pointing." Sort of.

The Golfing Machine Ball Flight "Rules" - Suggested that the plane line would always act as the "path" and the TRUE CLUBFACE would be—well—the true clubface.

Homer Kelly thought that the ball would start nearly on the vector of the TRUE CLUBFACE and curve toward the "path." This turned out to be quite correct.

One little problem...

The "path" part.​

And the little "Hinge Action" theory (but that's another story for another day).

The "path" will always be different than the "plane line" unless the TRUE PATH and the "plane line" are the exact same, which can only happen if contact is made dead level to the ground. Which doesn't happen very often.

So, I explain the divergence of the Plane Line and the True Path with my little invention called The "U" Plane.

Whew!

Now, come on you "Brian can't explain the D-Plane and his forum visitors are all confused" knuckleheads out there.

Take your shot at doing better.

Einstein couldn't have explained it better. But I am still confused. Maybe it's bcoz I am such a dork.

 

[niblick1]

Also, to repeat something said several times here before - the Trackman newsletters are "must reads" to get some application of the principles.

The July '09 article on the "straight shot" is particularly interesting.

 

[savydan]

"the U PLANE, which is a curved shape"

Planes do not have curves - they have a flat surface that extends to infinity in all directions.

Please explain what part of the U PLANE actually curves.

 

[Brian Manzella]

"the U PLANE, which is a curved shape"

Planes do not have curves - they have a flat surface that extends to infinity in all directions.

Please explain what part of the U PLANE actually curves.

The "U Plane" is the SWING PLANE.

The clubhead/sweetspot describes an ellipse-like "U" on the face of the SWING PLANE.

So, it could be called "The U on the Plane"....

 

[footwedge]

The "U Plane" is the SWING PLANE.

The clubhead/sweetspot describes an ellipse-like "U" on the face of the SWING PLANE.

So, it could be called "The U on the Plane"....

Could it also be called the "you" on the plane.

 

[savydan]

The "U Plane" is the SWING PLANE.

The clubhead/sweetspot describes an ellipse-like "U" on the face of the SWING PLANE.

So, it could be called "The U on the Plane"....

Got it, makes sense, thanks.

 

[MikeD2]

In "The Physics of Golf," Dr. Jorgensen wrote the following:

"Euclid, the famous geometer, says something to the effect that two intersecting lines determine a plane. The normal to the clubface (ed.what Brian calls the direction of point) and the line on which the clubhead is moving at impact (ed.the U Plane) intersect at the ball and therefore determine a plane. The line along which the ball leaves the clubhead also lies in this plane. We shall call this plane the D Plane because it is descriptive of the collision between the clubhead and the ball."

I think that Dr. Jorgensen's book was the first time the term "D Plane" was ever used in describing golf physics. My question is, based on the last sentence of the above quote, did he call it the "D Plane" because a compressed ball at clubface separation looks like a capital D?

Thanks to all for a very helpful forum.

 

[savydan]

"Two intersecting lines determine a plane."

I don't see how two parallel lines would not determine one (and only one) plane either. (Edit: This is just a sidebar comment on how Jorgensen paraphrased Euclid - not a direct comment regarding the D-plane definition).


As for the name, D, haven't heard, but seems reasonable.

 

[Burner]

"Intersecting" lines are an X in appearance and form the point at which two separate planes meet and cross over; i.e intersect.

"D" Plane is a derivative of the word Delta and its shape. See the yellow lines, brown line joining them and the shaded (delta) area within their parameters in the diagram BManz has put in post #6 above.

 

[savydan]

Are you saying that the intersection of two planes, in general, is a point?

Can you describe the two planes associated with the D Plane?

 

[spktho]

I would think that an intersection of two planes is a line that lies on both planes.

A point is where two lines intersect. I believe the point of origin of the D plane is at impact. One line(the top line) extends from where the clubface is pointing at impact and the the other line(the lower line) is in essence the end-on (DTL) view of the swing path at impact.

Feel free to correct me if I'm wrong.

 

[benhogan55]

All I know for sure is that until I learned to aim left with the short irons I never hit those shots where the ball never left the flag stick. I am still working on the curvature aspect but when I have a 7-sw in my hands my FIRST concern is
setup.

 

[savydan]

I would think that an intersection of two planes is a line that lies on both planes.

A point is where two lines intersect. I believe the point of origin of the D plane is at impact. One line(the top line) extends from where the clubface is pointing at impact and the the other line(the lower line) is in essence the end-on (DTL) view of the swing path at impact.

Feel free to correct me if I'm wrong.

I think you're correct. The reason for my questions was to get burner's viewpoint on the D-plane.

In the Sam Snead D-plane diagram, I see one plane in effect, not two.

To me, the purpose of the D-plane is to say the initial ball flight occurs on the one single plane as defined by the face and path lines.

It's difficult to show a curved path in 2 dimensions existing on a slanted plane.

That's one reason I implied in posts #2 and #3 that you might find it difficult to do early searches on D-plane and have it make sense if you don't "own" the information stated in those posts.

 

[spktho]

I think you're correct. The reason for my questions was to get burner's viewpoint on the D-plane.

In the Sam Snead D-plane diagram, I see one plane in effect, not two.

To me, the purpose of the D-plane is to say the initial ball flight occurs on the one single plane as defined by the face and path lines.

It's difficult to show a curved path in 2 dimensions existing on a slanted plane.

That's one reason I implied in posts #2 and #3 that you might find it difficult to do early searches on D-plane and have it make sense if you don't "own" the information stated in those posts.

I should read more closely. I see that I just restated what you did in post 3.

A curved path can occur on the slanted plane in 2 dimensions--basically up and down the path. I think a golf ball moving up and down a slanted plane will look as if it is drawing or fading--probably look as if it is doing both.