Wedges: Friction and Trajectory

The other day during a Three Day Golf School I hit four demonstration pitch shots for my students. My intent was to repeat the same shot in each attempt, with the only difference being how I manipulated the amount of friction between the club face and the ball.

The amount of loft I was able to deliver for each of the four shots was between 44.3º and 45.3º - the best I've been able to do! The interesting part is that the launch angles ranged from 30.4º tall the way up to 40.0º. How does that happen?

The Four Shots

The reasons why the launch angles are different is something that too few golfers (and coaches) understand and while I've written on this before it's a mission of mine to get the good word out. My intent was to carry each shot 50 yards and they are all played in the same fashion, with the same club except for shot 4.

Shot 1 - clean, dry club face and a clean, dry range ball. Spin rate - 6246 rpm. Launch is a respectable 32.1º

Shot 2 - clean, wet club face and a clean, wet range ball. Spin rate - 2782 rpm. Launch is a whopping 40º

Shot 3 - clean, dry club face and a clean, dry premium ball. Spin rate 6923 rpm. Launch is the lowest at 30.4º

Shot 4 - clean, dry grooveless club face and a clean, dry range ball. Spin rate is 5837 rpm. Launch is decent at 33.6º

I must mention that in order to 'manage' the friction between the club face and the ball each of these shots is played off a tee so as to eliminate grass and outside matter from interfering.

While the loft is maintained the launch, spin rate and peak height can be greatly influenced by the amount of friction generated between the club face and the ball. The moral of the story here is that the best pitchers in the world hit low launching, high spinning shots when the conditions allow. There is more at play than simply the loft at impact determining the launch angle. As you can tell friction plays a massive role too. It is my hope that in understanding this you will be less likely to try and 'fix' something that isn't broken. Hope this helps and thanks for reading!

Luke Donald

Optimal Strike Point for Longer Drives

We've all heard the saying 'high launch and low spin'.  With the help of TrackMan I have been able to learn which part of the clubface to strike the ball with in order the get the ball to launch higher, spin less and ultimately travel further. Watch the following video...

optimal strike point

Here are the factors that make a slightly high and toe sided hit optimal:

Launch Angle

• Due to the roll/curvature of the face there is more loft above the center line than below.  The static loft of the club is measured in the center of the face, so if a club has 9.5 degrees of loft that is only in the one central location.  Half an inch above the center line the loft increases by around 2 degrees and vice versa for below the center line.
• A strike above the center line will always lead to a higher launch angle and can often be achieved quite easily by teeing the ball higher.

Spin Rate

• Due to vertical gear effect a strike that occurs below the center line will have a substantially higher spin rate than one higher on the face.
• I have seen increases of almost 1400 rpm with low strike points - in addition to distance sapping lower launch angles.

Gear Effect

• Most of the golfers that I teach need to hit draws.  A golf ball that is struck on the toe side of the clubface will tend to have a greater inclination to draw than one struck towards the heel of the club.

Clubhead Speed

• If a shot is hit out of the center of the face with a swing speed of 100mph a spot on the face 3/4" out side of that will be travelling at almost 103mph and a spot the same distance inside that will only be travelling at 97mph.
• The ball will travel faster and most often further with higher club speed.

If you'd like to get a feel for where you are striking the ball on the face try dry erase marker or Dr. Scholl's Odor X - they both work like a charm and give instant feedback.