Ball-flight laws are now studied in a three-dimensional concept called the D-Plane (descriptive plane), which originated with Theodore Jorgensen’s book “The Physics of Golf.”
With new information available because of technology such as Trackman launch monitors, we now know that clubface at impact influences starting line of flight by 85 percent.
The path of the clubhead will take care of the rest of starting line direction. However, the path of the clubhead at impact is the main reason for curve, right or left, of the ball in the air.
The ball will curve if the clubface is pointing in a different direction from the path. For example, if a right-handed player has a clubface that is aimed right of target at impact and the path is moving further right, he will hit a draw.
Paying attention to the initial starting line of ball flight is very important to swing analysis. It tells you where your clubface points at impact.
Checking how the ball curves in the air will dictate path of clubhead at impact, which in turn can help you predict shaft plane swing tendencies.
A steep swing plane (overly vertical shaft) will often cause a cutting of the clubhead across the ball at impact and a slice ball flight, which is a major problem for many players. So the golfer must change his feel in the swing to correct the issue and shallow the plane the club travels on.
To feel a more rounded or circular arm swing around your body, place a headcover under the lead arm. Hit half swing 9-irons feeling your lead arm swing across your chest on the backswing.
The lead arm will now swing on the same pitch as your shoulders so the club’s plane will flatten. With the flatter plane the club’s path at impact will improve and less side spin will be imparted on the ball.