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The stuff of screams

Known for marrying aerial acrobatics with the steel roller coaster, a design team tests gravity's bounds again at Busch Gardens.

Published April 20, 2005

[Times photo: Ken Helle]
Walter Bolliger stands in front of Busch Gardens' new SheiKra ride, which is set to debut on May 21. It is the first of Bolliger & Mabillard's so-called dive coasters in North America.
[Busch Gardens]
SkeiKra's second drop plunges riders 138 feet into a tunnel. The coaster's cars have three rows of eight seats and are wider than the track.

Holding on for dear life on Montu at Busch Gardens or the Incredible Hulk Coaster at Universal Orlando's Islands of Adventure, riders might not understand the common inspiration for these white knuckle rides.


"We take people through experiences of flying, and by that I mean all the sensations of freedom from gravity," said Walter Bolliger, half of one of the world's most prolific coaster design teams.

That's no surprise to the squeamish, whose experiences range from a little tickle in the tummy to a chat with an air sickness bag. But coaster fanatics likely don't fully appreciate how linked their thrills are to aviation. And nobody has married aerial acrobatics with the steel roller coaster like the Swiss design team of Bolliger and his engineering partner Claude Mabillard.

Beginning with the Iron Wolf at Six Flags Great America in Illinois, they invented many of the first coasters that mimic flying: inverted coasters that hang from a track, and coasters where the floor drops away so passengers' feet dangle. B&M's Superman in Atlanta even tilts riders to a prone, flying head-first position while they zip along at 60 miles per hour suspended from a coaster track.

Bolliger was at Busch Gardens Tampa Bay on Tuesday to test ride SheiKra, the pair's 59th steel coaster, which makes its public debut on May 21. The first of Bolliger & Mabillard's so-called dive coasters in North America, the ride has been tested about 300 times, loaded down with 170-pound water dummies. But Bolliger said his first spin in the ride's unconventional eight-seat wide train was "fantastic."

You were trained as a structural engineer. How did you get in the coaster business?

As a child I would help set up the rides when the fair came to town. I hoped they would give me a free ticket. But my dream was to design bridges. Our firm designed several (steel aqueducts) that carry water from the mountains down to electric plants. We did a revolving restaurant that's on top of a mountain. But Intamin AG (a ride manufacturer in Lichtenstein) hired us to design swinging boats and other rides for amusement parks. Claude and I went off on our own in 1988 and were hired by Six Flags Great America to modify a bobsled (style coaster). We did the first standup coaster for them and an inverted one. But it was Kumba, our first sit-down coaster and fourth overall, that really propelled our reputation.

Most of the maneuvers you build into your designs are actually stunt pilot acrobatics such as cobra roll and the Immelmann. Why?

We like airplane acrobatics because they play with gravity in a very natural way. They provide a smoother and enjoyable ride. If you force the train through unnatural motions like many coasters today, it's a much rougher ride.

Computer-assisted design enables today's coaster designers to make far more precise calculations of the physics and structural dynamics. Do your designs start at the computer terminal?

No. We start with a blank sheet of paper and think creatively. We think of the elements we can use, how to sequence them and how to balance the ride with transitions. Then we go to the computer. The risk analysis, anticipating what happens when something goes wrong, is all brain work. SheiKra took about two years to design, but the physics are not that difficult. There are more than 20 surprise elements designed into SheiKra. They start at the lift hill, then there's the complete stop to stare straight down the first 200-foot drop and they go right on through the final banked turn.

The first two dive coasters opened in the United Kingdom and Taiwan eight years ago but no park bought another. Was that because critics considered it a one-trick ride?

I think so. They helped increase attendance. A face-down drop into a fog-filled hole in the ground is interesting. But Busch Gardens wanted one that was much different . . . and had many more diverse elements. We see this as the beginning of the second generation of our dive coaster.

Why the weird looking train that's eight seats wide and only three rows deep?

We needed the very short train because the drop is straight down. So we had to widen the coaches. That amplifies every motion the train makes and gives different experiences on each seat. Four of the eight seats are not over the track so you're out there in mid air. In an airplane you sit in a cabin. We thought "wouldn't it be wonderful to sit out on the edge of the wing?' When the train goes through a curve, one wing tip rises and the other dips.

Your rides are known as the Mercedes of the coaster industry because of the smooth ride. Are there other big keys to doing that?

We always follow the heart line as the centerline of the track. That's a line drawn through the path of a spot plotted just above one rider's heart through the entire ride. That way there are no lateral Gs pulling from side to side. So all of our G-forces are vertical ones that press the rider into the seat or negative Gs that eject them from the seat. Going down the first drop on SheiKra, people in the back coach will be lifted out of their seats, but held in by the harness.

You have sensors throughout and many braking spots in the track. How does that part of the safety system work?

We have redundant computers, each using using different software. They read what the sensors say. The controller is always asking them whether to let the train proceed to the next set of sensors. If they do not agree, the train is stopped.

Some coasters built in the past decade had problems with trains unexpectedly stalling or stopping in midair loops. Has that ever happened with a B&M coaster?

No. We have had trains stop when the safety system said stop. But we have never had a train stuck or stop on its own. Our coasters have always been about not pushing the limits. To us this is not about being the fastest or having the tallest lift hill. It's about creating sensations of flight that are enjoyable. I cannot speak for all our competition.

Some coaster designers are using lineal induction motors and accelerators to make them shoot off to a start or pick up speed. You have stayed away from that except for the Hulk at Universal Orlando, which is frequently rated as the best steel coaster in the world. What happened?

We prefer to stick to what we know best, which is gravity. Universal wanted the launch accelerator, so after a lot of discussion, another firm installed the accelerator.

In addition to an escape stairway, SheiKra has an elevator for passengers in case they get stranded on the first lift hill. Why?

It was Busch Gardens' idea because the (45-degree angle) stairway (up the 200-foot tall hill) is so steep.

[Last modified April 20, 2005, 07:43:41]

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