Angle of Attack: Its Role in Fitting
BY Tom Wishon
Over the past several years, the golf industry has said in countless magazine articles that the ideal conditions for maximising driver distance is to fit the golfer into a driver that generates a high launch angle with a low amount of backspin.
Let’s take a look at that using TrackMan launch monitor data from two of the members of the PGA Tour, Bubba Watson and Charles Howell III.
We need to first state that both players are generating the optimum launch monitor results for their respective swings.
Bearing that in mind and looking at the difference in the two players’ launch angle measurements, what is missing from this analysis that could possibly account for such a big difference in these two players’ launch angle, given the fact that both players are fully optimised for their driver performance?
|Player||Ball Speed||Launch Angle||Spin Rate|
|Charles Howell III||172mph||7.0°||2800rpm|
Angle Of Attack
The answer lies in a parameter of the golf swing called the Angle of Attack. The Angle of Attack defines whether the clubhead is traveling on an upward, level or downward angle with respect to the ground when it moves through the impact area with the ball. In short, some golfers hit up on the ball, some hit down on the ball, and a few swing so that the head is traveling level with the ground when it hits the ball.
The Angle of Attack is hugely important in the determination of the optimum driver loft for all golfers because it has a big influence on the dynamic loft of the head at impact. An upward angle of attack increases the dynamic loft and increases the launch angle of the shot for any given static driver loft. A downward angle of attack decreases the dynamic loft and lowers the launch angle of the shot for any given static driver loft.
Now let’s add one more parameter to the information from the data collected from the TrackMan driver analysis of Bubba Watson and Charles Howell III as follows.
|Player||Ball Speed||Launch Angle||Spin Rate||Angle of Attack|
|Charles Howell III||172mph||7.0°||2800rpm||-5°|
As you can see from the additional information, Bubba Watson swings the driver with a 5° Upward Angle of Attack, while Charles Howell III swings the driver with a -5° Downward Angle of Attack.
Each golfer’s Angle of Attack is purely a product of their swing characteristics. Quite simply, some golfers simply develop different Angles of Attack into the ball as a result of various individual swing habits and characteristics. Now let’s add one more column to the chart.
|Player||Ball Speed||Launch Angle||Spin Rate||Angle of Attack||Driver Loft|
|Charles Howell III||172mph||7.0°||2800rpm||-5°||11.5°|
Keep in mind that both players are fully optimised for their driver performance as a result of having gone through extensive testing with the golf companies with whom each has an equipment endorsement contract. Because of the difference in their Angles of Attack, Bubba Watson is fully optimised for his driver performance with a loft of 7.5° while Charles Howell III has to use a driver with a loft of 11.5° to be able to reach his optimum driver performance.
In other words, the more any golfer delivers the driver head to impact on a downward angle of attack, the more loft they have to use on the driver to be able to be fully optimised for distance performance. Conversely, the more the golfer brings the head to impact on an upward angle of attack, the lower loft they can use on the driver head to reach their point of distance optimisation.
What is interesting to note is the fact that the higher the loft, the more backspin is generated. Golfers with a downward angle of attack are always going to have to use a higher loft to reach their point of being optimised for distance. Higher loft always generates more backspin, so golfers with a downward angle of attack are always going to generate more backspin than golfers with an upward angle of attack.
For players with a very high ball speed such as professional tour players, more spin equates to a slight loss of distance. At ball speeds in excess of 155mph, the greater the spin, the greater the friction between the ball and the air through which the ball is flying. The more friction generated between the ball and the air, the sooner the ball’s velocity decays and the sooner the ball falls back to the ground.
Downward Angle Of Attack
A golfer with a downward angle of attack is always going to be at a disadvantage in overall driver performance to the golfer with an upward angle of attack. The more the golfer swings with a downward angle of attack, the more loft they will need to play on their driver to offset the effect of the downward angle of attack on the dynamic loft and resulting launch angle. The higher the driver loft to achieve the optimum launch angle, the more backspin is generated.
To give you an idea how much of a problem the downward angle of attack can be, let’s go back to our PGA Tour player with a downward angle of attack.
|Player||Ball Speed||Launch Angle||Spin Rate||Angle of Attack||Driver Loft||Carry Distance|
|Charles Howell III||172mph||7.0°||2800rpm||-5°||11.5°||278yds|
|Charles Howell III||174mph||12.8°||2100rpm||+5°||8.0°||306yds|
From the information, you can see that if Charles Howell III were able to somehow change his swing to be able to deliver the driver to impact with a 5° Upward Angle of Attack, he would gain a incredible amount of carry distance. However, the question certainly would be, if CH III were to embark on such a major swing change, would he still be able to retain the swing consistency necessary to take advantage of the potential for more distance.
From this we can learn a few points to keep in mind with respect to Driver performance and fitting:
- Optimum launch conditions for maximum distance are primarily dependent on clubhead speed and the angle of attack
- If the clubhead speed and angle of attack of the golfer is not known, it is not possible to tell from ball launch conditions if the golfer is maximising his/her potential for distance or not.
With the assistance of TrackMan, we can offer the following chart which reveals the most optimum launch parameters for maximum CARRY DISTANCE for a number of different clubhead speeds (swing speed) and different angles of attack
Keep in mind that when fairways are firm and very dry, it is always best to reduce the loft/dynamic loft/launch angle and reduce the carry distance to lower the shot trajectory and take advantage of more roll on the fairways for the greatest total distance.
Optimal Driver Launch Parameters for Maximum Carry Distance
|Clubhead Speed (mph)||Angle of Attack (degrees)||Ball Speed (mph)||Launch Angle (degrees)||Spin at Launch (rpm)||Carry Distance (yards)||Dynamic Loft at Impact (degrees)||Probable Driver Loft|