Re: What is your swing speed and carry?
Originally Posted by powerfade
Reprinted from Tom Wishon's E-newsletter:
A New Visit to High Launch/Low Spin Driver Fitting
Ever since the introduction of the award winning Search Series of books, we at TWGT receive a lot of contacts from golfers who have read our books and contact us with questions about their equipment. While the topics vary, one of the most frequent involves their interest to know how they can achieve a “High Launch + Low Spin” result with their driver. Because there is a lot of confusion in the golf equipment market place about this subject, TWGT feels it appropriate to re-visit this subject to offer the very latest in technical information about this topic in clubfitting.
Speaking from a purely theoretical fitting point of view, it is true that the ultimate driver fitting should result in the combined launch parameters of “high ball speed + high launch angle + low spin.” The problem is the fact that humans swing golf clubs with a variety of different techniques, some which are not conducive to being able to achieve this theoretically perfect combination of launch parameters. In addition, this combination of “high ball speed + high launch angle + low spin” is intended to deliver the maximum carry distance – a factor which may or may not result in the greatest overall driver distance, depending on whether the fairways are more or less conducive to the roll of the ball after landing.
High Ball Speed
Of the three primary launch parameters, achieving the highest ball speed for each individual golfer is the most important and the easiest to accomplish – all you have to do is fit your golfers into one of TWGT’s driver designs and then fit the golfer with their best combination of length + shaft weight + swingweight (MOI) to ensure the golfer hits the ball on center the highest percentage of the time!
All kidding aside, TWGT is very proud of our ability to design high performance driver designs which deliver a consistently high “Smash Factor” (ball speed divided by clubhead speed) over a large area of the face. The highest possible Smash Factor capable from a USGA conforming driver for any golfer, as calculated by the most accurate launch monitor in the game, is 1.50.
(Actually, it is 1.495, but because the TrackMan launch monitor reports Smash Factor to the nearest 0.01 number, TrackMan will round an actual Smash Factor of 1.495 up to 1.50)
Because of TWGT’s variable face thickness design ability, impacts ½” to ¾” above, below and to the side of the center of the face of our driver heads will still result in Smash Factors of 1.48 to 1.49, as recorded by TrackMan™. So even when the golfer has a slightly less than perfect point of impact, achieving the highest possible ball speed for their clubhead speed is the easiest of the three primary launch parameters to deliver to the golfer.
Students of the technology of fitting are aware that the optimum launch angle for every golfer has to be related to their swing speed. It is a myth to think all golfers need to achieve the same launch angle to maximize distance. The lower the clubhead speed, the higher the launch angle must be to achieve maximum distance, and vice versa. In addition, the more downward the golfer’s angle of attack, the lower their optimum launch angle will be, and the more upward to angle of attack, the higher the optimum launch angle will be.
What specific loft angle each golfer must use to achieve their optimum launch angle for maximum total distance depends on the golfer’s swing speed + the golfer’s angle of attack + the condition of the fairways with respect to the roll of the ball on the golf courses they play. Without question, the angle of attack is extremely important to know to be able to help any golfer find which loft generates the optimum launch angle for their swing speed.
The angle of attack is the direction the clubhead travels to impact in relation to the ground. The A of A is measured in degrees Upward or Downward, or Level to the ground. The ideal condition for maximizing driver distance is an upward A of A. Golfers with a downward A of A are at an immediate disadvantage when trying to maximize distance off the tee.
The more the golfer swings with an upward A of A to the ball, the lower the driver head loft can be to generate a high and optimum launch angle. The lower the loft of the driver head, the lower the spin rate on the ball. Hence, an upward A of A is the best way to achieve the ideal combination of high launch + low spin. To contrast, the golfer with a downward A of A has to use a higher loft to achieve their optimal launch angle, and with that higher loft comes more backspin.
After the ball velocity, the launch angle is the second most important launch parameter to optimize to deliver maximum distance to each golfer. Spin is definitely in last place.
The role of backspin in optimizing distance is a launch parameter that is least understood and most confusing. The reason that lower spin is considered to be beneficial for maximizing driver distance is because the higher the spin rate and speed of the ball, the more friction is generated between the ball and the air through which it flies. The greater the friction between the air and the ball in flight, the sooner the speed and lift of the ball can decay and contribute to a decrease in distance.
Loft has the greatest effect on changing the launch angle of the shot. However, loft is also the number one clubhead specification which controls spin; the higher the loft, the higher the backspin. Elements such as the shaft or clubhead center of gravity do not generate as much change in launch angle as many golfers are led to believe. Changes in launch angle from the shaft can only happen for golfers who possess a relatively late unhinging of the wrist-cock angle before impact, further limiting the shaft’s effect on launch angle.
The slower the golfer’s ball speed, an increase in spin may be required to keep the ball in the air to fly its maximum distance. Even for golfers with a high ball speed, there is a point at which the spin can be too low to generate enough lift to combine with the ball speed to keep the ball in the air to fly its maximum distance.
It is extremely important for golfers to achieve their optimum launch angle in order to optimize their potential for distance. To sacrifice the launch angle to achieve a perceived low spin on the ball is a mistake that will result in significantly less distance than the golfer is capable of achieving.
Once the correct loft is known that will combine with the golfer’s angle of attack to result in the golfer’s best launch angle for distance, there is very little that can be done from an equipment standpoint to change the spin while keeping the launch angle stable. Changes in the ball design do not typically offer more than a few hundred rpms of spin difference. What’s more, the slower the golfer’s ball speed, the less the rpm difference between a high and low spin ball design.
Changes in the center of gravity position between clubheads will elicit their effect on spin by changing the dynamic loft of the head at impact through the effect of the CG on the forward bending of the shaft. As a result, such CG changes alter the launch angle, which in turn will require another change in the loft to correct. When the golfer finds the driver head loft which generates the best launch angle for their ball speed + angle of attack, but the spin is still too high in relation to the “theoretical spin guidelines,” reducing the spin on the shot is something that can only be remedied by a change in the golfer’s swing technique.
Putting it All Together
Thanks to our technical association with the good people at TrackMan™/ISG AS, we are happy to share a couple of charts of information compiled from research being done with a wide variety of golfers by the TrackMan™ launch system. The following charts show the optimum launch parameters for maximum driver distance.
Chart 1 shows optimum launch parameters for different clubhead speeds + different ranges of angle of attack to achieve maximum CARRY DISTANCE. Chart 2 shows the optimum launch parameters to achieve maximum TOTAL DISTANCE of carry + roll, based on lowering the angle of descent of the ball to the ground to take advantage of more roll from firm to dry fairway conditions.
One of the most important bits of information to derive from this information is how much a downward angle of attack limits the golfer’s potential for distance. Take a look at the difference in carry distance for the +5° and -5° Angles of Attack for each clubhead speed. For example, at 90mph, which is very close to the average man’s driver clubhead speed, the optimum launch parameters show the 90mph golfer with a 5° upward angle of attack can carry the ball 27 yards farther than a golfer with the same clubhead speed but with a 5° downward angle of attack. Yes, the lower launch angle of the 90mph / -5° A of A will generate a little more roll but not enough to make up the distance difference. For all clubhead speeds, the golfer with a downward angle of attack is losing significant driver distance compared to what they could achieve were they to have a level or upward angle of attack.