The Prince ball machine soon worked well enough to capture half that market, but Head's game remained crummy. His problem was one that is familiar to hackers everywhere; whenever he hit the ball off center, which was frequently, the racket would twist and often almost spin out of his hand, sending the ball awry.
Head repaired to his basement workshop and began tinkering. He shaved the face of one racket and added weights to the rim. Then he hung it upside down from a suspended door spring, spun it slowly and timed the rotations. His hope was that the weighted racket would show a significant increase in its polar moment of inertia, which is technotalk for resistance to twisting. But, alas, says Head, "Not only didn't the weights succeed in reducing the spin, but when I tried to play with the racket it broke."
Head mulled over the problem for nearly two years. Then, as in a scene out of Young Tom Edison, he awoke late one night with a hot flash and snapped his fingers: "Make it bigger!" Bigger because the laws of physics dictate—and the fat man on the disco floor can verify—the wider something is the more resistant it is to twisting. Witness Dorothy Hamill spinning on her ice skates; when she extends her arms, she increases her polar moment of inertia and slows down. Moreover, the principle decrees that the polar moment of inertia increases as the square of the width. Thus, Head realized, by making the racket just two inches—or 20%—wider, he would increase its resistance to twist by about 40%, a bonus worth being stubborn about.
But would his Excalibur fit into a rule book that specifies everything from the width of the lines on the court to the length of the fuzz on the ball? With some trepidation, Head checked with the U.S. Tennis Association and was told that Rule 4 states only that the racket is "the implement used to strike the ball."
Theoretically, says Head, "You could hit the ball with a barn door or a card table with a handle attached." Or with a broom, which Bobby Riggs has been known to do when the money is right. Or even, as a British tournament player with a shaky backhand did in the 1950s, with two rackets, one in each hand.
The only no-no, which was added in 1978, is any stringing variation that "would result in a change in the character of the game." That restriction was designed to ban the infamous "spaghetti racket," a springy, double-strung device that allowed its wielders to put a bewildering array of spins on the ball.
But beyond the spaghetti clause, almost anything goes. Why—in the long history of the game—has there not been more experimentation with racket design? Mainly because of the limitations of wood. If wooden rackets were made larger, they would be too heavy or would snap like toothpicks. But what of the strong, light metals that were introduced into racket design in the 1960s? Why were such space-age materials made to conform to age-old formulas? Head knows the answer. The invitation to innovate went unanswered, he says, because the traditional geometry "is so fixed in people's minds that it just never occurred to anyone that bigger might be better."
Nevertheless, avowing that "there is more wisdom in the gut than in the head," Head has an almost mystical respect for designs that evolve through use, independent of technology and fashion. "My experience with the ski helped when it came to the tennis racket," he says. "I found that skiers weren't looking for a lighter ski. They were looking for something that made skiing feel even better. So I learned not to mess with that particular esthetic 'rightness' a body feels, the kinesthetic feedback from a piece of equipment that feels good to use."
Thus, from the start, "thinking peripherally" so he could eliminate problems before they arose, Head conformed to his own Rule 4: thou shalt not mess with the length, weight and balance of the traditional racket configuration. Actually, the design he fashioned out of a rugged high-alloy aluminum that was developed for bumper supports on cars is, on the average, half an ounce lighter than the standard racket, a reflection of a trend, he feels, in the "rightness" formula.
Though he was unaware of it at the time, Head's biggest breakthrough was not in making the face two twist-resistant inches wider but in extending it three inches into the throat of the racket. Head, one of whose skis has hung in the Museum of Modern Art in New York as "a sleek, gleaming statement of pure functional design," explains that an "internal, esthetic logic" demanded that the widening of the racket be complemented by a proportionate lengthening. Though art made him do it, he concedes that it was science that ultimately turned those three little inches into a "fortuitous gold mine."