Clubhead vs. Path: Need clarification.

[TryingtoPlay]

I always hear the adage that the clubhead dictates the direction of launch while the path dictates movement in the air. Studying the ball flight laws I must admit that I am seeing the opposite in the characteristics of ball flight, namely that path dictates direction of launch and clubhead position relative to path dictates movement in the air. I need some clarification on the ball laws and how each interaction induces each ball flight.

Thank you

[Kalnoky]

Hello @TryingtoPlay have you ever looked into the "D-Plane"? There are several videos explaining the physics of D-Plane on YouTube. It's a real model devised by a professor at the University of Nebraska. Some golfers have built clever visual aids that make it easy to understand the relationships of path, clubhead relative to path, and loft. It's hard to argue with the science. Anyway, maybe you already know all of this... 

A couple of weeks ago I stumbled upon D-Plane as I was desperately trying to understand why I struggle so much with my driver.  

[chspeed]

https://thesandtrap.com/b/playing_tips/ball_flight_laws

 

[TryingtoPlay]

4 minutes ago, Kalnoky said:

Hello @TryingtoPlay have you ever looked into the "D-Plane"? There are several videos explaining the physics of D-Plane on YouTube. It's a real model devised by a professor at the University of Nebraska. Some golfers have built clever visual aids that make it easy to understand the relationships of path, clubhead relative to path, and loft. It's hard to argue with the science. Anyway, maybe you already know all of this... 

A couple of weeks ago I stumbled upon D-Plane as I was desperately trying to understand why I struggle so much with my driver.  

I have looked at D-Plane before but when I did I honestly did not really understand it.

 

I am going to go through the shots and see if I am understanding this correctly.

If I am understanding correctly then the traditional (old) ball flight laws would incorrectly tell us that:

1. An out to in swing with the club face open relative to the path would induce a pull-fade/pull-slice.

2. An out to in swing with the clubface square relative to the path would induce a pull.

3. An out to in swing with the club face closed relative to the path would induce a pull-draw/pull-hook.

4. A straight path would an open clubface relative to the path would induce a straight fade/straight slice.

5. A straight path and straight clubface would induce a straight shot.

6. A straight path and a closed clubface relative to the path would induce a straight draw/straight hook.

7. An in to out path with an open clubface relative to the path would induce a push fade/push slice.

8 An in to out path with a square clubface relative to the path would induce a push.

9. An in to out path with a closed clubface relative to the path would induce a push draw/push hook.

[Ernest Jones]

 

@TryingtoPlay

In simple terms, the ball starts where the face is pointing and curves away from the path.

[TryingtoPlay]

11 minutes ago, Ernest Jones said:

 

@TryingtoPlay

In simple terms, the ball starts where the face is pointing and curves away from the path.

 

11 minutes ago, Ernest Jones said:

 

@TryingtoPlay

In simple terms, the ball starts where the face is pointing and curves away from the path.

That is actually not how I understand the new ball flight laws. If you swing in to out and the face is square to the path then you will still push the ball.

[Slowcelica]

20 minutes ago, Ernest Jones said:

 

@TryingtoPlay

In simple terms, the ball starts where the face is pointing and curves away from the path.

This should be appended to this. 

In simple terms, the ball starts where the face is pointing and curves away from the path, IF the club face is open or closed to the path.

[Kalnoky]

19 minutes ago, Ernest Jones said:

 

@TryingtoPlay

In simple terms, the ball starts where the face is pointing and curves away from the path.

That's my understanding as well. This is why the wedges hook and the driver slices - one is set up before the bottom of the swing arc and one after. 

[mvmac]

5 hours ago, TryingtoPlay said:

If I am understanding correctly then the traditional (old) ball flight laws would incorrectly tell us that:

To say it simply the "old" ball flight laws would tell us that path determines start line and the ball curves to where the face is pointed. Correct ball flight laws are what @Ernest Jones said and when the face matches the path it results in a straight shot in the direction of the face.

Incorrect/Old Ball Flight Laws:
Face square to target, path 3° right would start the ball right of the target and draw back.

Correct Ball Flight Laws using same numbers: Ball starts at target and curves left.

https://thesandtrap.com/b/playing_tips/ball_flight_laws

[Ernest Jones]

3 hours ago, TryingtoPlay said:

 

That is actually not how I understand the new ball flight laws. If you swing in to out and the face is square to the path then you will still push the ball.

 

If your face is pointed in the same direction as your path, there will be no curve. The curve is caused by the  differential  between face and path.

3 hours ago, Slowcelica said:

This should be appended to this. 

In simple terms, the ball starts where the face is pointing and curves away from the path, IF the club face is open or closed to the path.

 

Correct. The curve is caused by the differential. If there is no differential, there is no curve.

3 hours ago, Kalnoky said:

That's my understanding as well. This is why the wedges hook and the driver slices - one is set up before the bottom of the swing arc and one after. 

 

I'm not sure I understand. The ball will curve away from the path, never towards it. A wedge and a driver will have the same type of curve if hit with the same face and path conditions. The curve will be more severe with the driver because there is less loft. Keep in mind, loft is where the face is pointing in the vertical axis, the more loft you have the more it will over-ride the horizontal axis...if you know what I mean...I probably did a crap-ass job of explaining that...sorry.

[Hardspoon]

5 hours ago, Kalnoky said:

That's my understanding as well. This is why the wedges hook and the driver slices - one is set up before the bottom of the swing arc and one after. 

 

1 hour ago, Ernest Jones said:

I'm not sure I understand. The ball will curve away from the path, never towards it. A wedge and a driver will have the same type of curve if hit with the same face and path condition

Yes, all he is saying is that since the clubhead path is angular, if you hit a ball earlier in the arc, the path will (tend to) be outward, while later in the arc it will (tend to) be inward.

That's why punch shots played with the ball far back in the stance tend to be struck with a more outward path.

[natureboy]

On 10/14/2016 at 10:37 AM, TryingtoPlay said:

I always hear the adage that the clubhead dictates the direction of launch while the path dictates movement in the air. Studying the ball flight laws I must admit that I am seeing the opposite in the characteristics of ball flight, namely that path dictates direction of launch and clubhead position relative to path dictates movement in the air. I need some clarification on the ball laws and how each interaction induces each ball flight.

Thank you

I'll give the simplification a crack in a way that hopefully will help you visualize what's going on.

The club is basically an inclined plane ramming into the back of the ball. During impact the ball deforms slightly and slides/rolls up the face which creates spin.

If the club and path are perfectly aligned vertically and horizontally the ball will spin backwards relative to the target and the axis of that spin will be horizontal to the ground. The spin of the ball gives it lift in a direction that is perpendicular to the axis of the ball's spin (somewhat like a wing). This is due to the Magnus Force. The speed over the top of the ball is faster than the speed on the bottom of the ball where the spin opposes the direction of the air flow. So like an airfoil you get lift.

(pic above is a side on view and the spin axis would be through the center of the ball coming perpendicularly out of your computer screen).

If the clubhead was square to the target, but it approached the ball slightly from in to out (relative to the target line), this sideways friction from the oblique (from the side) path tilts the axis of rotation away from a perfectly aligned strike. Essentially it pushes the bottom of the ball out from under the top - a bit as the ball slides/rolls up the clubface.

The lift due to the spin of the ball is still perpendicular to the spin axis, but this is now tilted so the lift force is tilted off vertical. In the example of the path coming from in to out the axis is tilted so the left side is lower and the right side higher. The lift force arrow is now pointed left of vertical (as you face the target). This will cause the ball to experience lift toward the left and carve a bit of a turn. - sort of like a plane banking. In golf speak this is a draw. The opposite applies to a fade.

To make the ball curve there must be a difference between the face and the path (otherwise you are 'aligned' and get a horizontal spin axis and only vertical lift). The relative difference between the direction of where the face is pointing and the path affects the amount of curve you get.

On average for irons and woods the ball starts ~ 75%-80% in the direction the face is pointing at impact. So the ball basically starts where the face is pointing and then curves in one direction or the other according to the relative difference in the face/path alignment and the tilt that gives the spin axis.

---

One addendum to the post above. For a 'functional curve' (say from the tee to a straight-ahead fairway) you generally want the ball to start to one side of your target line and curve back onto it. The typical terms for these two basic ball flights (for a right-handed player) are a push draw and a pull slice.

Push Draw requires a face that is open to the target line, but closed to the in-to-out path at impact

Pull Slice requires a face that is closed to the target line, but open to the out-to-in path at impact.

In other words the face will generally be facing in-between the path and the target line (unless you want to hit a real peeler).

Edited October 14, 2016 by natureboy

[nevets88]

Keep in mind all this assumes perfect contact, all this is pretty much out the window with toe, heel, thin and fat shots.

[TryingtoPlay]

Simply put, the face angle is the predominant determinant of the initial direction of launch and the differential between the face and the path dictate movement in the air.

Remember that a path that is square to the target and an open clubface will result in a push slice/fade. That is a slice, not just a push.

Edited October 18, 2016 by TryingtoPlay

[rehmwa]

On 10/14/2016 at 10:30 AM, TryingtoPlay said:

I am going to go through the shots and see if I am understanding this correctly.

If I am understanding correctly then the traditional (old) ball flight laws would incorrectly tell us that:

1. An out to in swing with the club face open relative to the path would induce a pull-fade/pull-slice.

2. An out to in swing with the clubface square relative to the path would induce a pull.

3. An out to in swing with the club face closed relative to the path would induce a pull-draw/pull-hook.

4. A straight path would an open clubface relative to the path would induce a straight fade/straight slice.

5. A straight path and straight clubface would induce a straight shot.

6. A straight path and a closed clubface relative to the path would induce a straight draw/straight hook.

7. An in to out path with an open clubface relative to the path would induce a push fade/push slice.

8 An in to out path with a square clubface relative to the path would induce a push.

9. An in to out path with a closed clubface relative to the path would induce a push draw/push hook.

1. no - it'll fade, but the starting line will be 'about' whatever the actual (not relative) face points could be a pull or a push or straight
2. yes
3. yes - but the start line is more pull than you are thinking as it's square to face, not path
4. no - push fade
5. yes
6. no - pull draw
7. yes - but the start line is more push than you are thinking as it's square to face, not path
8. yes
9. no - it'll draw, but the starting line will be 'about' whatever the actual (not relative) face points, could be a draw or push or straight

You are thinking about it backwards (you are assuming line is path, then the curve is based on the spin (tilt) created by face relative to path) -

Turn it around:

A.  Path starts square to face at impact

B.  THEN, look at the spin (they prefer to say 'spin tilt') based on the face vs path differences to see the flight shape

[TryingtoPlay]

3 hours ago, rehmwa said:

1. no - it'll fade, but the starting line will be 'about' whatever the actual (not relative) face points could be a pull or a push or straight
2. yes
3. yes - but the start line is more pull than you are thinking as it's square to face, not path
4. no - push fade
5. yes
6. no - pull draw
7. yes - but the start line is more push than you are thinking as it's square to face, not path
8. yes
9. no - it'll draw, but the starting line will be 'about' whatever the actual (not relative) face points, could be a draw or push or straight

You are thinking about it backwards (you are assuming line is path, then the curve is based on the spin (tilt) created by face relative to path) -

Turn it around:

A.  Path starts square to face at impact

B.  THEN, look at the spin (they prefer to say 'spin tilt') based on the face vs path differences to see the flight shape

Yes, I was listing what the old ball flight laws told us. 

[iacas]

3 hours ago, TryingtoPlay said:

Yes, I was listing what the old ball flight laws told us. 

Old: ball starts along the path, curves to where the face was pointing.

New: ball starts close to the face, curves away from the path (unless face/path match).

It's that simple, really.

[TryingtoPlay]

1 hour ago, iacas said:

Old: ball starts along the path, curves to where the face was pointing.

New: ball starts close to the face, curves away from the path (unless face/path match).

It's that simple, really.

Again, with a path that is 0 degrees to the target and a face that is 6 degrees open, that ball is going to start on the line of the face and it is going to slice. That is a fact. So, it depends on exactly what you mean.

Edited October 19, 2016 by TryingtoPlay