Monday, February 2, 2009

Manzella Explains D-Plane

'D-Plane' is something I've struggled with learning...but I had it right without even really knowing it. D-Plane was created by Theodore Jorgenson, a University of Nebraska physics professor who wrote the book 'The Physics of Golf.' The big part that confused me was I just didn't understand where the name D-plane came from. Here's a great thread on the subject (

The old PGA standard of ball flight says that the direction a ball starts at is almost exclusively due to the path of the club. And the curvature of the ball is due to the angle of the clubface. Here's a pic Manzella uses for that:

The new D-plane rules (the correct rules) tell us something different. It says that Snead's shot would not start out to the right and draw to the middle of the green because the ball starts out mostly to where the face is angled. I've heard clubface angle has anywhere from 70-90% influence on the direction the ball flies to, but the common percentage I hear is that the influence is 87%.

So to make it easy, the ball starts out where the clubface is angle (for the most part) and then curves due to the club path. Let's say that Snead's clubface is 1 degree open and the club path is 10 degrees in-to-out. The D-plane laws say that the ball will actually travel like this:

Once you understand the D-plane rules, you can immensely improve your game. Not only can you figure out how to work the ball, but when you hit poor shots, you have a decent idea of what happened at impact.

Just another reason why is one of the best golf forums on the 'net.



granitebaynotary said...

Dave Tutleman wrote a great article on the laws of ball flight.

Check it out at

Rich H. said...

Very good, thanks for the info!