may the force be with you

In the time it takes to finish reading this sentence, you and 17 others could have rocketed from 0 to 120 miles per hour, turned at a 90-degree angle and headed straight to the top of a 42-story building, plummeted in a free fall, whipped through a 270-degree corkscrew and traveled almost one-half of a mile.

If you were riding on the Top Thrill Dragster, that is.

The Dragster, which overlooks Lake Erie at the Cedar Point Amusement Park in Sandusky, Ohio, is worlds apart from the brain-dead roller coasters of old that relied on a greasy chain to clunk the car up a wooden hill. The Dragster's operators employ an array of modern technology to create an experience for riders that is the rough equivalent of being launched from an aircraft carrier deck, where jets accelerate from 0 to 165 mph in about 3 seconds.

Inner-workings

For starters, the Dragster is wired with 560,000 feet of copper cable to carry back performance data from 300 redundant pairs of sensors located throughout the track and engine room. The majority of the sensors are proximity switches that can measure the movement of the metal coaster car over the track. There are also thermal temperature and pneumatic sensors. If any one of the sensor pairs fails to match the readout of the other, the Dragster is shut down for a safety check.

But the data aren't just collected for safety. They also help produce the perfect ride on every launch. The parameters within which the Dragster has to operate are so finely tuned that variable load weights from people, wind speed and out-side temperature affect its performance.

So data ranging from the velocity of the roller coaster car at the top of the tower to wind speed and direction (taken from an anemometer atop the tower) are collected on every ride and analyzed using proprietary software developed for Cedar Point. After every third launch, the data are averaged and compared with historic launch data in an effort to create that perfect ride - the roller coaster must go fast enough to clear the top of the tower, but slow to between 7 and 15 mph in order to give riders the maximum lift effect at the top.

Based on the comparison of current and historical data, the Dragster corrects itself by adjusting the pressure of the engine and other parameters to produce as near perfect a ride as possible every time.

To create the Dragster, Monty Jasper, an engineer, roller coaster lover and, oh yeah, a vice president of Cedar Fair, L.P. (Cedar Point's parent) teamed up about five years ago with Intamin AG, a Swiss company that is one of the top roller coaster designers in the world.

The quest was to build a roller coaster that would top 400 feet for the first time, a feat some thought impossible. Jasper had just eclipsed the latest world's record by building a "giga-coaster," called the Millenium Force, which broke the 300-foot barrier. But was it really possible to pull off a 400-foot-high roller coaster in an area small enough and with technology affordable enough for an amusement park? Luckily for all roller coaster fans, the answer was yes. Price tag: $25 million.

Jasper and Intamin decided to use a hydraulic engine, which can achieve higher speeds than linear induction motors (superconducting magnets), the propulsion system that many steel roller coasters started using in the late '90s, according to Jasper. That means the roller coaster would require less track, and thus, less space and expense. But this wouldn't be just any engine; the Dragster would require a 10,000-horsepower unit (a real drag racer has a 6,500-horsepower engine).

Even with all that muscle, the cars on the Dragster sometimes fall below the minimum speed needed, and drop backwards down the same 42-story building and safely back into the station, where they are stopped by a long row of heavy-duty magnetic brakes. If this happens, the operators give chickens, uh, "tired" riders, the chance to get off.

Ready for takeoff

OK, so the technology is interesting, but what's it like to ride the Dragster? That's what I was wondering the first time I stepped into the front car and sat there with sweaty palms, waiting for what seemed like an eternity, for the launch. Because the process of pressurizing the engine and checking the safety sensors takes about 40 to 50 seconds, the Dragster makes you wait for the thrill. Riders were loaded simultaneously into two trains while the operators made sure the train just launched cleared the top of the tower. That means you sit with adrenaline pumping and heart racing for around a minute before the launch - about three times as long as the 22-second ride.

I had ridden great roller coasters before. Superman: The Escape at Six Flags Magic Mountain in Valencia, Calif., accelerates from 0 to 100 mph in 7 seconds, before turning 90 degrees up a tower, producing about 6 seconds of micro-gravity before dropping the car backwards to earth. So what if the Dragster accelerates twice as fast?

I was turning all this over in my mind when the car finally rolled into the launch position to await a series of lights on the gigantic tower in front of me to count down red, yellow green. . . . I didn't realize the first time I rode it (yes yes, I went back) that the telltale moment is a slight rollback of the train. That's when the catchcar (a locking device - a strong one I was hoping), attaches a 1-inch diameter launch cable that tows the one-ton car 262 feet down the track, where the car will hit 120 mph before the cable releases and the car is launched forward to "coast" up the tower.

Sound effects

At rollback, the operators turned on the sound effects - the blaring sound of a racing engine shortly followed by the screeching of tires as a jolt rocks you back hard against the seat and a blast of air hits you in the face.

Most of the fools who had been holding their hands above their heads firmly clutched the lap-restraint bar. I had just enough time to think to myself, "Gee that really wasn't so bad," when 2 seconds later, the catchcar stopped, and the car was detached and catapulted forward off the cable, producing a second, harder kick. We were about to make the 90-degree turn to race up the side of the 425-foot tower in front of me.

At the top, the car was suspended just long enough for riders to experience a Wile E. Coyote moment just before the . . . 90-degree drop.

At this point the front of the car was tucked under our chins. Just a few feet down, we entered the 270-degree corkscrew, which was a bit like going through the vortex of a tornado, and the train was positioned upright again to enter the station.

The only disappointment was that the ride is so fast your brain struggles to process the experience in real time. So there was only one thing to do: I took the ride again and again. It got better every time, and unlike some roller coasters, I can't imagine that a ride on the Dragster will seem boring.

After all, I got to find out what it feels like to be a human cannonball, or a Navy pilot, without the cannon, gunpowder, helmet or parachute.

source:http://www.networkworld.com/news/2005/071105widernetcoaster.html