Ball testing part II

6/8/01

Last week I wrote about the old Iron Byron outdoor test for determining if golf balls conformed to the rules of golf. Outdoor testing has its limitations. There are so many factors that contribute to how far a ball goes, and with Iron Byron, it wasn’t possible to isolate these -- nor was it necessary.

Come January, Iron Byron will be replaced by a launcher that fires a ball into a 70-foot tunnel lined with sensors (the Indoor Test Range, or ITR). In development for the past five years, the new indoor test allows the USGA to measure all those properties that control the trajectory of the ball -- its aerodynamic lift and drag, which is influenced by its speed through the air and its specific spin rate at that speed. With the aerodynamic properties identified, the trajectory of each ball can be simulated in the computer. The weight and size are also taken into account. The ball is fired into the tunnel at a speed determined by the equivalent of a clubhead speed of 109 m.p.h.

The ITR thus helps identify the aerodynamic "fingerprint" of each ball, and using the computer simulation, it eliminates all outdoor variables such as wind, temperature, barometric pressure, humidity and turf conditions.

Under these set conditions, the testers can then find the very best launch angle and spin rate for each ball, to obtain its maximum possible distance. This is called optimization. Each ball will then be tested for conformance based on the distance it goes under its own specific optimum launch conditions.

Any balls that exceed the distance standard will be deemed nonconforming. (The number will be different from the 296.8 yards standard adopted in 1976 -- see last week’s column -- as the procedure will have been changed to launch the ball more efficiently at its optimum, rather than a standard set of launch condition.)

This new test method will result in an increase in distance for every ball. Some balls will go as much as 10 or more yards longer under the optimum conditions, compared to the old test method. (The optimum launch angle, by the way, is about 13 degrees, and the optimum spin rate is about is about 1,500 revolutions per minute. And guess what? These are not far off Tiger Woods' actual, real-life launch conditions.)

I might be a little biased because I directed the development of this new standard, but I believe that it is the most scientifically sophisticated standard in the world of sports. The Royal and Ancient Golf Club, which governs golf outside the U.S. and Mexico, has reviewed the new method and has agreed to adopt it. Such consensus is important. Unlike with nonconforming drivers with a "spring-like effect," where there seems to be no good news regarding conciliation, it appears there will be no divide on the proposed new golf ball testing procedure.

The new indoor test will not lead to any golf balls currently on the present conforming list being declared nonconforming -- the new standard will be set so as to include all current conforming balls (it will actually be set at the optimal distance of the longest existing legal ball, plus a small test tolerance). What's more, the USGA has shared its software with ball manufacturers, which means that the manufacturers can now use this sophisticated procedure in conjunction with their own R&D efforts to design new customized balls for all kinds of different golfers. In other words, expect a lot more choice of different types of balls and ball flight patterns in the future -- there will certainly be balls designed for golfers with slower swing speeds and abnormal trajectories.

And who knows, that could even translate into lower scores.

Ball Testing
Question: What are the standards for golf balls and how are they tested(click for the answer)?

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This column appeared on golfdigest.com where Frank contributes on a weekly basis. Check it out every Saturday.