Posts Tagged ‘d plane golf’

D Plane for Off Center Hits

April 5th, 2010

I started a thread over at Brian Manzella’s site talking about the future of the D Plane.  As a model, I think it needs a little refining to handle the off center hits.  I’m not exactly sure what that refining will turn into but I have a theory.

I was talking with David Colclough about this topic and he really got me thinking.  I’ve asked some very smart people about my theory and will discuss the results after I hear back.

Ok, so here’s my theory.  The D Plane suggests that the spin axis on the ball will be perpendicular to the plane formed by the 3d club path and clubface normal.  It also suggests that the lift forces will be perpendicular to the spin axis.  This model works wonderfully for center hits.  However, for off center hits, the spin axis and lift forces are not in the D plane because of the gear effect caused by the off center hit.

My theory, which allows for center hits and off center hits to be accurately described is to use the 3d direction of the spin axis as the top vector and not the clubface normal.  This would allow for a properly shaped D Plane for any outcome.  I don’t know if I’m right and I’m pretty sure someone much smarter than me will come up with the right model.

I can say this.  The email I received from Fredrick Tuxen  shows agreement that the D Plane model is not sufficient to explain off center hits

Let the tweaking begin.

D Plane for Uphill Lies

February 19th, 2010

I’ve talked a bunch about how to hit straight iron shots using the D Plane as a guide.  I have assumed in my previous cases that I was dealing with a level lie.  Let’s look at the situation of an uphill lie.  This post will not talk about a ball above your feet as in a sidehill lie.

D Plane for Uphill Lies:  In order to hit these shots well, there are some things we have to do with our setup and swing to account for the slope.  Typically, we are told to aim a little to the right, get the shoulders at the same angle as the slope, move the ball a little forward and try and swing with the slope.  What does this do to the swing?  Because we are swinging with the slope, we end up with positive angle of attack relative to the target line.  The club reaches it’s lowest point before it strikes the ball.  How can the club reach it’s lowest point before the ball if I take a divot after the ball?  It’s possible because of the slope of the ground.  So, if my swing is directly at the target at low point, when the club gets to the ball the club has started to come inward and upward.  The more positive the angle of attack also gives us more time to close the face.  For these two reasons, these shots will tend to go left.  This is the why of aiming a little to the right for a right handed golfer for an uphill lie.

D Plane in the Bunker

January 11th, 2010

There was an extensive discussion this week on twitter about how do we use the d plane when in a greenside bunker.  I initiated a discussion about what influences starting direction when the club doesn’t actually contact the ball.  Did the face still have the majority impact on the balls starting direction?  There was input from golf pros from all over the world.

Here’s a video provided by James Ridyard to support his claim that the face still played the major role in starting direction.  Follow this link to see the video:  http://twitvid.com/F7002.

James stated, correctly, that the path of the club is more to right(for right handed golfers) when the club hits the sand because it’s well before lowpoint.  It doesn’t actually reach lowpoint because of the bounce and sand deflection.   D plane helps to explain why it is necessary to aim more left(even if we don’t open the face) because of how right the path is as it is entering the sand.

The general consensus was that we still believe the face has the greater impact on starting direction out of the sand than the path even though the face never hits the ball.  No reason to believe that the little grains of sand would act any differently when contacting the face.  Out twitter group will try and collect some trackman club data from a bunker and I will post that when and if it becomes available.

I still have a bunch of concerns about this topic because I believe if done correctly, the face doesn’t contact the sand until after the initial collision with the bounce.  It seems to me, that the direction of this bounce will start to move the sand first and thus play a greater role in the balls starting direction.  Then there’s the fact of turning the clubface in for a plugged ball with the ball coming out right instead of left.

Please leave your comments and opinions and let’s see if we can’t come up with the correct answer before trackman does the heavy work for us.

Straight Iron Shots-D Plane Style Part II

December 19th, 2009

In the first blog, http://johngrahamgolf.com/blog/dplane/hit-an-iron-straight-d-plane/, I talked about general conditions that need to happen to actually hit a shot straight.

In this blog, I will provide the hard cold facts and numbers to help you do this.  Here is a link to a download that will help you.  http://johngrahamgolf.com/downloads.htm

Please, leave your name and email address to gain access to the download.  Here’s a little explanation of what the chart does and what it does not.  This chart is based on information that can only be collected by using a Trackman club delivery and ball flight device.  The chart determines the adjustment to the horizontal swing plane due to the angle of attack and the vertical swing plane.

For example, if a player hits down on the ball, the direction of the club head at impact is different than the direction of the club head at it’s lowpoint.  This chart determines how much that difference is depending on the angle of attack and vertical swing plane.

This chart does not tell you how to determine what your angle of attack is or what your vertical swing plane.  It will only tell you where you would need to aim left or right (left for down angles of attack and right for up angles of attack) if you made a perfectly on plane swing to hit it perfectly straight.

Please leave questions and comments and I will add this download to the D-Plane page.

D-Plane?

November 29th, 2009

Let’s go back in time and talk to some golfers that are playing golf in the 1930′s and 40′s.  Let’s ask them what makes the ball curve.  What kind of answers to you think we would hear?  No internet, no d-plane talk and no high speed video or trackman.  What would they say?

Let’s think of some advances that might give us a clue.  In the late 1800′s, there was a change starting to take place from long nosed wooden heads to smaller and thicker wooden heads.  A new kind of driver was created that has a curved shape face.  Why in the world would they put a curve in the driver face that points away from the target vs. one that was curved to point the edges toward the middle.  This curve, or bulge, would lead to clubs name as a bulger.

They had noticed that shots struck on the ends of the club put a spin on the ball.  Toe shots added hook spin and heel shots added fade spin.  This spin was enough that it would curve a ball significantly away from the target even if the face was square.  By putting a slight curve in the face, so the toe pointed right of target and the heel pointed left of target, they found that the ball would end up closer to the target.
Effect of bulge
They did this because they saw the ball would start farther right before the hook spin from a toe hit brought it back.  The ball started farther right because of the shape of the face.  Over 100 hundred years ago they figured out that the shape of the face controlled it’s initial direction.

I think most golfers of the 30′s and 40′s era would say face first.  90% of the people I asked that know nothing about golf think that the face shape would control it.  I remember arguing at my PGA Checkpoint. I noticed when trying to curve the ball around the tree that I couldn’t aim the face behind the tree. I kept hitting the tree.

Is the d-plane earth shattering? No way.  It only helps with understanding what causes what.