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Technologie: Aerodynamik: Page 6

Common Myths (continued)


Myth: Large, shallow dimples make a ball fly higher.

This notion is only half wrong. It probably traces back to the early 1970s, when the so-called ''Big Dimple'' Titleist was introduced. This ball had a noticeably higher trajectory than many of its contemporaries, and its novel dimple pattern had noticeably large and shallow looking dimples, and thus was made the connection. But the truth is somewhat different: All else being the same, its true that shallower dimples will generally make a golf ball fly higher. But larger dimples will actually make it fly lower. Why, then, was the ''Big Dimple'' Titleist a high flier? Because even though the dimples were large, they were also very shallow for their size, shallow enough that the net result was a higher trajectory.


Myth: More dimples make a longer ball.

In 1983, Titleist introduced the 384 Tour, a new generation ball which had 60 more dimples and, for many golfers, significantly more distance than its predecessor. This ignited a ''dimple war'' in the industry, when many companies' marketers went for the easy sell with ''more dimples = more distance'' campaigns. If this sounds entirely too easy (Want more distance? Just put more dimples on the ball . . . ), well, it is. Just a little thought will reveal that it doesn't even make sense. If it were true, then thousands of tiny dimples would make a very long ball. And millions of microscopic dimples would let anyone reach par fives in one. But aren't these balls becoming more like smooth balls? We already know that smooth balls only go about half the distance of dimpled ones.

The truth is that the number of dimples is not a very important parameter. Any number from around 300 to around 500 works quite well. It's far more important to carefully optimize the dimensions of the dimples to provide the desired lift and drag characteristics.


Myth: Golf balls lose distance in humid air.

This is another one that is easy to believe because it agrees with our common sense. Humid air feels heavy, and therefore the ball should have a tougher time punching through it. But in truth, humid air is actually lighter than dry air, and the ball will actually fly farther. Strike three. But don't bother seeking out muggy days to do a John Daly impression, because the advantage is truly minuscule. The best one could hope for would be a gain of about 18 inches.


Myth: Put overspin on the ball for more distance.

There are television golf commentators who time and again will attribute a particularly long carrying and/or rolling shot to the player ''putting a lot of overspin on the ball.'' This is utter nonsense for two reasons: first, it is impossible to put any overspin on any shot other than a cold-topped one, and second, even if it could be done, the shot would be much shorter than one with backspin. With overspin, the lift force, which normally helps hold the ball in the air against gravity, reverses and helps gravity pull the ball down. Such a shot would only fly a small fraction (perhaps 1/4) of the normal distance, and even with a lot of extra roll will still wind up short by about half.


Myth: A golf ball should generate maximum lift and minimum drag.

Guess what? Another appealing notion, and another wrong one. A well engineered golf ball creates the correct amount of lift and drag to achieve the desired trajectory shape while maximizing distance. A blind pursuit of maximum lift and minimum drag will usually produce a very high flying ball with an annoying affinity for the dreaded upshoot. Given the right conditions, such balls can achieve a carry distance improvement, but it comes at the cost of wind-performance you wouldn't wish on your favorite sandbagger And the loss of roll distance brought on by the high trajectory usually means that the total distance is no better, and often worse.


Epilogue

To beginners and pros alike, the flight of a smartly struck golf ball is a thing of beauty, marvelous to behold and boosting to the ego. No matter how badly we might play on any given day, no matter how many three-putts in a round, it's that one purely struck shot that keeps us coming back for more. If this is the addiction of golf, then dimples must bear the shame. Without them, we wouldn't bother.