## Friday, November 6, 2009

### Answers to Your D-Plane Questions: Part III

Let's take a look at some Trackman numbers and the results that the shots produced:

1. Clubhead speed = 87.3
2. Ball speed = 127.1
3. Attack angle = -3.4
4. Club Path = 5.7
5. Vert swing plane = 63.1
6. Horiz swing plane = 3.9
7. Dyn Loft = 11.3
8. Face angle = -3.6
9. Smash factor = 1.46
10. Vert. angle = 7.2
11. Horiz angle = -0.9
12. Spin rate = 6194
13. Spin axis = -17.9
14. Max Height = 15.5
15. Carry = 165.4
Okay, let's break this down into the numbers that have the biggest influence on ball flight. This shot was taken with an iron.

Attack Angle = -3.4*

So, if the golfer wants to zero out their path to hit it dead straight (provided the clubface is 0.0* to the target), they would need a horizontal swing plane of -1.7*

Let's take a look at that horizontal swing plane.

Horiz swing plane = 3.9

Whoa. Not good. The golfer needed to swing to the left by -1.7* and instead swung out to the right. This is characteristic of a golfer that gets 'underplane.' This should make the 'true path' way out to the right an for the golfer to hit a semi-accurate shot they will need a pretty open clubface angle. Let's take a look at the True Path and Clubface Angle.

Club Path = 5.7
Face angle = -3.6

So the path is going quite a bit to the right while the face is going quite a bit to the left. This screams pull hook or duck hook.

Here's the results.

Side = 29.3L
Length = 178.5
Side yards = 34.1 L

Yes, that's yards to the left of the target. Big hook.

But like I mentioned in a previous post, you can't hit that pull hook with an open face. So even if the golfer's true path was going way out to the right (or 'inside-to-out'), they could have salvaged a pretty good shot if they could have gotten the clubface open to the target at impact.

Let's take one more, this time with a driver:

swing speed = 106.6
attack angle = 4.3*
club path = -.07*
vertical swing plane = 50.8*
horizontal swing plane = 2.8*
dynamic loft = 14.8*
face angle = -1.8*
Okay, let's look at the angle of attack.

attack angle = 4.3*

Now remember, the spin axis is different with the driver than an iron. So in order to zero out the true path with the driver, the horizontal plane has to 'match' the angle of attack.

Here, the angle of attack is +4.3, so the horizontal swing plane would need to be 4.3* to the right in order to 'zero out' the path.

horizontal swing plane = 2.8*

Pretty close. It's out to the right, but not exactly matching the AoA. But close nonetheless.

club path = -.07*
face angle = -1.8*

So, the club path is very, very close to being 'zeroed out.' But the clubface is closed by almost 2 degrees. This should cause the ball to start initially slightly to the left of the target, then draw a smidge. Most people would take this shot.

Here's the results.

carry = 260.2 yds
side = -9.0 yds

9 yards to the left of the target, like predicted. That's good enough to find the lion's share of fairways.

3JACK