Metal Alloy Making Quite a Racket
By Morris Dye
In 1992, a pair of researchers at the California Institute of Technology in Pasadena developed a revolutionary metal alloy intended for use in rocket engines and jet aircraft — a substance stronger than steel or titanium with a remarkable ability to store and release kinetic energy. Today this futuristic material, dubbed Liquidmetal by its creators, also helps the likes of Andre Agassi and Marat Safin launch high-velocity tennis balls.
"If you look at a standard molecular structure of metal, there are gaps in it," explains Roger Petersman, the senior business manager for Head/Penn Racquet Sports, which introduced a line of Liquidmetal tennis racquets last summer. "When you get impact, those gaps collapse, and that takes energy out of the racquet. In Liquidmetal, there are no gaps, so all of the energy that you put into your shot, you're getting back out of it."
Liquidmetal is one of several technical innovations Head has brought to the game since the late 1960s, when the company branched out from its origins as a manufacturer of ski equipment and began producing professional-quality metal tennis racquets.
Delve into the design and construction of Head's latest models and you'll find that these intricately engineered devices bear only the most superficial resemblance to earlier wood and wood-laminate racquets, which have all but disappeared from the sport.
Like most competition-level racquets made since the 1980s, Head's Liquidmetal frames are made from various distinct materials bound together in a lightweight carbon fiber composite. Petersman says that after gaining exclusive rights to develop tennis racquets using Liquidmetal alloys, Head engineers tested the material in a range of positions within the composite construction before settling on a design that includes four bands of Liquidmetal at the 2, 4, 8 and 10 o'clock positions around the head of the racquet.
"By putting it in those four positions, we could maximize the effect of Liquidmetal," he says. "It's basically where the ball is impacting the racquet. If you add stiffness where the ball is going to have the most impact, you're helping return more energy to the ball."
Petersman adds that the enhanced stiffness also serves to expand the area on the strings where players get the best combination of power, control and comfort from their shots.
"We have about 31 players in the top 100 on the ATP tour that are playing with Head racquets," Petersman says. "I'd say a good 80 percent of those have switched to Liquidmetal, and I would bet that in the next four months, the other 20 percent are going to switch as well."
Another trademark component of Head's high-end racquets is a substance the company calls Intellifiber. Petersman says this "piezoelectric material," which has been incorporated in the handle and part of the head of most models, converts the mechanical energy of a ball striking the racquet into an electrical impulse.
One model, the Intelligence i.x.16, even has microchip circuitry embedded in the handle designed to concentrate the electrical impulse and instantly transmit it back through the Intellifibers in the frame. Head claims that this ChipSystem technology reduces vibrations by 50 percent, making it a good choice for players who suffer from tennis elbow.
Intellifibers are also said to resist pressure and help the frame spring back to its original form as the ball bounces off the strings. "It actually helps slingshot the ball off the racquet, and creates more power," Petersman says.
These and other proprietary design features have earned Head exclusive endorsements by both major teaching organizations in the United States, the Professional Tennis Registry and the United States Professional Tennis Association.
USPTA CEO Tim Heckler says his organization favors Head racquets in part because they are used by more pros on the ATP tour than any other single brand, and also because Head assures quality control by manufacturing racquets at the company's own plant in Austria instead of subcontracting to lower-cost factories in Asia.
"The other reason we feel Head is such a strong brand is that the people who manage the company are tennis enthusiasts who live and breathe the game every day," Heckler adds.
Head's top-of-the-line Liquidmetal racquets are available in a spectrum of sizes and weights appropriate for different kinds of players, with prices ranging from about $150 to $225. Andre Agassi's racquet of choice, the Liquidmetal Radical OS, retails for about $180, while a racquet of similar quality in Head's Prestige line, which has no Liquidmetal, costs around $50 less.
Of course, even the most sophisticated racquet is no substitute for ability and training, but Petersman insists that state-of-the-art engineering can make a difference.
"Technology is going to allow you to be able to do more within your own game. It's going to make the racquet basically do a little bit more for you," he says.
For more information, write to Head/Penn Racquet Sports, 306 S. 45th Ave., Phoenix, Ariz. 85043, call (800) 289-7366 or visit www.head.com/tennis.
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