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New Coasters Push Thrills, and the Body, to the Limit

Yancey Hall
for National Geographic News
May 24, 2006
 
It's supposed to be fun—throttling down a track like a rocket, climbing towers taller than the Statue of Liberty, and slingshotting through corkscrews and loops.

Now, thanks to cutting edge research and engineering, roller coasters, always tortuous, are edging ever closer to torturous. The key question: How much can the body handle?

For decades roller coasters were mostly wooden. The use of tubular steel track, beginning in the 1970s, ushered in a sort of arms race, with amusement parks vying aggressively for the titles of fastest, tallest, and scariest.

(Watch a preview of the National Geographic Channel's SuperCoasters TV special, which premieres Sunday at 8 p.m. ET/9 p.m. PT in the United States. National Geographic News is part of the National Geographic Society, which is part owner of the National Geographic Channel.)

Coaster Wars

One of the first parks to lay claim to the speed title was Cedar Point amusement park in Sandusky, Ohio.

In 1989 the park inaugurated one of the world's first supercoasters, the Magnum XL-200.

At a height of 205 feet (62 meters) and racing at speeds of up to 72 miles an hour (116 kilometers an hour), the ride was the first so-called hypercoaster and set the standard for roller coaster design.

But by the late 1990s these height and speed records were shattered by 300-foot (91-meter) "gigacoasters" that launched passengers at speeds of over 100 miles an hour (185 kilometers an hour).

Monty Jasper, vice president of maintenance and new construction at Cedar Point, has overseen much of the development for the park's extreme roller coasters.

"Roller coasters are big potential energy machines," Jasper said.

"Traditionally they involve releasing [the train] from a chain at a great height. That is a classic roller coaster. Now roller coasters are getting extra things."

One of these things is cable, which has come to replace the chain as a coaster's chief method of propulsion.

Traditional coasters use chains to slowly drag a train to the top of an incline, then release the cars, whose downhill acceleration is greatly due to gravity.

The advantage of cables is that they can essentially catapult passengers, sending them speeding uphill. Of course, once the coaster starts downhill, the speeds increase on an already impressive launch velocity.

Cedar Point's Top Thrill Dragster is one such "launch coaster."

Opened in the spring of 2003, Top Thrill Dragster takes passengers from 0 to 120 miles an hour (193 kilometers an hour) in about four seconds and launches them over a 420-foot (128-meter) tower.

Launch coasters aren't without their share of headaches.

"When you try to do things that people have never done before mechanically, you are faced with problems that you have to surmount," Jasper said. "Reliability hasn't been the best with Top Thrill Dragster."

Sometimes, it seems, supercoasters are too high-tech for their own good.

Hundreds of computer sensors are needed to determine the exact speed necessary for the cars to clear the initial tower. Any slight change in wind speed or air pressure can result in a failure to launch.

But perhaps the biggest challenge in coaster design is the human body.

Pushing the Limits

On a coaster g-forces constantly push and pull at our bodies. If we go fast enough, the force of gravity can stop the flow of blood to our brains and eyes, causing blackouts or temporary blindness.

To counteract the force, roller coaster designers use computer-aided design (CAD) systems. CAD software enables a track's geometry to be rendered precisely so as to minimize the effect of g-forces.

Of course the only way to avoid coaster side effects is to stay off the rides—and many people do just that.

Why are some parkgoers paralyzed with fear, while others can't get enough death-defying thrills?

It's a question that Graham Holt tries to answer in his capacity as an engineer at Electrical Geodesics, Inc. The Eugene, Oregon, company specializes in EEG, or electroencephalograms—which document electrical activity in the brain, as measured by electrodes attached to the scalp.

Holt monitors two sets of riders—thrill-seeking and thrill-averse—before, during, and after a ride.

His conclusion? "The thrill seekers had level EEG patterns and heart rate throughout the ride," Holt said.

"The thrill-averse had raised activity before, during, and after the ride. They were more excited and anxious."

(Related: "Fear Factor: Success and Risk in Extreme Sports.")

Holt believes psychology—simply anticipating the fear of the roller coaster—has more to do with roller coaster angst than the physical stress caused by the ride.

Given the multimillion-dollar price tags of extreme roller coasters, designers must find ways to push the limits without making their rides so scary that people refuse to ride.

The Future Is Now

Unlike the human body, roller coaster technology today seems to have hardly any limits.

Electromagnets have recently overtaken cables as the must-have launch mechanisms. The magnet-launched rides use powerful linear-induction motors to generate a magnetic wave that propels the cars down the track.

As president of the coaster-design company Premier Rides, Jim Seay is at the forefront of electromagnetic coaster technology. The company used the technology in attractions like the two Revenge of the Mummy coasters, one at the Universal Studios Florida theme park in Orlando and one at Universal Studios Hollywood in California.

At the heart of these magnetic systems are linear-induction motors.

"The vehicles have very lightweight, high-conductivity [aluminum] fins on them. When those fins pass through the linear-induction motors, that's when we create the traveling magnetic wave, which propels the fins," Seay said.

"It's almost like the vehicle is surfing a traveling magnetic wave," Seay said.

According to Seay, the next generation of rides will enable the cars to magnetically levitate on the track—using the same maglev technology touted as the future of rail travel.

The result would be a completely frictionless ride, without any of the bumps and noise of traditional roller coasters.

Advances in propulsion are only the beginning.

Computer-aided design and precision manufacturing of steel mean rides can now go to heights of 500 feet (152 meters) or more and still remain within safety parameters, experts say.

It's a long way down from coaster design's current dizzying heights—and that's just the way we like it.

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