From the Print Edition:
Don Johnson, Mar/Apr 02
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Now Ogg has come up with another idea: dump the dimples. Instead, he developed a pattern of tubular ridges that interlock as hexagons and pentagons around the entire surface of the ball. In testing, Callaway says that its HX ball flies farther than any ball it has tested while providing high-performance feel characteristics. Ogg claims that the HX has better distance control that the Pro V1 or any other ball, and is more consistent in any orientation whether it is teed up or lying in the fairway.
Callaway's move from dimples to tubular lattices -- hexagons and pentagons -- may be the next major step in golf ball design. Dimples were a part of golf ball construction for the better part of the twentieth century, and an intentionally roughened surface of the golf ball has been around since the introduction of the gutta percha ball in the mid-1800s.
The first golf balls may very well have been the roundest stones that shepherds could find to bat about the fields to relieve the boredom of tending the flock. The Dutch played the earliest known form of golf (called colf) from the late 1200s to the early 1700s using wooden balls made of beech or elm. In the middle 1700s came the age of the featheries, leather balls stuffed with cow's hair or boiled bird feathers. Featheries may have been easier to get airborne than wooden balls, but they were full of faults. They weren't perfectly round, got soggy in the rain, and were easily cut along their sewn seams.
In the 1840s the gutta percha ball debuted. Gutta percha is a sap from Asian trees that could be molded and hardened. It could be made more perfectly round and produced much more quickly than the featheries. As golf grew in popularity, it became necessary to produce more balls than the feathery makers could turn out, and the solution was gutta percha. The surface of the original guttie was basically smooth. If these balls, like the featheries, were not hit flush and on plane, they duck-hooked and snap-sliced with abandon.
But some players noted along the way that if the smooth surface of the balls was roughed up, they would fly somewhat straighter and would definitely fly longer. Thus, the art of making a golf ball like the feathery would be displaced by the science of constructing one. This is where the Bernoulli Principle came into play, even if ball makers didn't know what it was. This is also where fluid dynamics became important, even if ball makers may have thought that it referred to golf balls floating on water.
The Bernoulli Principle describes the lifting properties of an object flying through the air. In its general form, it applies to a golf ball and a 747 jumbo jet. It says that an object propelled through the air attains lift from the air if the air speed at the bottom of the object is slower than it is at the top. This creates a lower-pressure area above the ball, or airplane wing, and causes it to rise.
Airplane flight and golf ball flight differ widely in the desired amount of stability. With a golf ball, turbulence is good. With a wing, turbulence is bad, as many a flier will attest when their newly poured cup of coffee comes in contact with their newly-pressed wool pants. Golf balls need turbulent flight to fly farther, and that's why manufacturers put dimples on them. The first gutties designed to produce turbulence had raised bramble and reversed hatch mark designs on the surface. The depressed dimple ball, known as the Haskell ball, was introduced in the early 1900s as an improvement in a new line of rubber-cored balls wound with rubber bands. Ball research was now in full flight.
The reason that balls need turbulent flight is to narrow the region of dead air immediately behind the ball, by closing down the airflows. "In aerodynamic terms, in turbulent flight the air stays attached, the molecules flow closer to the surface, " says Ogg.
"You end up with a smaller wake. Think of the difference between a rowboat and a kayak. With a rowboat you have those big swirling eddies behind the hull. In a kayak the flow stays attached along the surface of the boat instead of creating those swirling eddies with a dead space in between. What you want to do with a ball is try to eliminate as much of that dead air region behind it as possible, which means you are eliminating drag. A ball without dimples flies maybe 40 percent as far as a ball with dimples."
With manufacturers then competing with rubber-cored and dimple-covered balls for greater and greater distances, the USGA took steps, starting in 1930, to regulate them. The process culminated in a set of weight, diameter and initial velocity specifications adopted in 1942 that are still used today. In 1976 the overall distance standard of 296.8 yards was introduced. That year, the USGA also debuted for testing purposes the swing machine know as Iron Byron, which was modeled after the swing of legendary player Byron Nelson. There have been subsequent versions of Iron Byron, but the USGA is still swinging the same model club -- a steel-shafted, wooden-head driver -- at a speed of about 109 miles per hour and belting balls into a large expanse of mown fairway behind its headquarters in Far Hills, New Jersey.
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