European Stars And Stripes (Newspaper) - August 14, 1988, Darmstadt, Hesse                                Roller coasters Are delivering new thrills As designers find More ways to create a Rush of drops and climbs twists and turns. Upside Down at 70 Mph the new physics of by William j. Broad new York times the Century old terror machine known Ashe roller coaster is delivering new thrills inthe United states As designers drawing Ona series of recent innovations find evermore devious ways to hurl the human Frame toward the limits of its endurance. Gone Are the trial and error Days when creating amusement rides was an informal affair that often ended in Accident or injury. Designers now rely on physics computers accelerometers and a Host of High strength High technology parts and materials to create a Rush of drops and climbs twists and turns. Designers Are also using new skills to renovate and improve the safety of old coasters. Today we get into the physics of it the dynamics of it said William l. Cobb a longtime coaster designer based in Dallas. We know what s going to happen even before we put it on  in the argot of physics the coaster designer s goal is to produce As Many accelerations on the body As possible. The main breakthrough was the discovery in the 1970s, and the wide application in the 1980s, of several ways to safely turn a train Load of screaming people upside Down. In april the trend saw its greatest refinement in the opening of the Shock wave a new ride at the six flags great America amusement Park in Gurnee Iii. The Shock wave is billed As the world s tallest and fastest roller coaster. Riders Are lifted almost 17 stories carried at about 70 Miles an hour in a hefty drop sent into a giant Loop that turns them upside Down thrown into a Boomerang that rapidly reverses their direction in a pretzel like welter of turns and finally twisted in a series of Corkscrew spirals. All told riders Are upended seven times. It s pretty wild said Ronald v. Toomer a former rocket scientist who designed the ride. Technology is creating the ability to Send your body through More demented configurations than would have been dreamed possible 10 years ago said Randy Geisler president of american coaster enthusiasts a group based in Chicago. The new generation of coasters is so intriguing scientifically that High school teachers in the United states Are using it to elucidate Basic physics. High tech rides have so Many variations that you can illustrate More principles said John h. Mcgehee a physics teacher at rolling Hills High school in rolling Hills estates Calif. Each year he leads a Field trip to six flags magic Mountain near los Angeles. The source of much of the current excitement is the clot Hoid  at top of Teardrop Means faster cars More centrifugal Force to keep riders i place. Longer radius at Teardrop s base Means Gen Tler upswing. Not clot Hoid Loop a Teardrop shape that makes it easy to turn people upside Down. The Loop is hardly new. Its mathematical basis was explained by history s most prolific mathematics Genius Leonhard Euler of Switzerland in the 18th Century. But it was Only about a decade ago that coaster designers realized that Euler s shape was perfect for achieving the Long sought goal of the vertical somersault. Designers previously had Little Success with what would seem to be the logical Choice for a Loop a 360 degree Circle. When entering such a Circle a speeding coaster car moves rapidly upward generating a Strong centrifugal Force that presses riders into seats with too much Energy. The danger at the top is just the opposite. The cars decelerate sharply and if a car slows too much Gravity can pull riders from their seats while the cars Are upside Down. As Early As 1900, a circular Loop was attempted at Coney Island in new York. But it had Many limitations and was soon dismantled. By contract the clot Hoid shape smoother out the acceleration so riders Speed safely along the Interior of the Loop. The secret is the Loop s changing radius which controls the Speed of the cars varying it according to a scientific Law known As the conservation of angular momentum. This principle can easily be visualized. The Speed of a Small weight tied to a string and whirled in a Circle will be controlled by the radius of the Circle. The weight will move slower if the string is lengthened and faster if the string is shortened. Elongating the Circle into an Ellipse provides Radii of varying lengths. Thus a Comet in an Elliptic orbit about the Sun moves faster As it nears the Sun and slower when it is far away. So too a coaster entering a Teardrop Loop moves relatively slowly As it arcs upward across a Large radius at the Bottom of the Loop lessening the centrifugal Force on riders. At the top the radius is much smaller. The coaster thus moves faster than it would in a Circle creating a greater centrifugal Force to counteract Gravity and keep riders safely in their seats. This innovation allows vertical loops to be quite Large because coaster cars will not lose As much of their Energy at the top As they would in a Circle. The biggest of the three clot Hoid loops on the Shock wave ride sends riders head Over heels while they Are 13 stories above the ground. Designers say the coaster revolution is far from Over despite dozens of patents already filed and a decade of Competition that has covered the country with increasingly innovative rides. There s a lot of Progress yet to be made said t. Harold Hudson vice president for engineering at the six flags corp. In Arlington Texas one of the world s largest chains of amusement Parks. The limit is probably the economics of it not the  the origin of the roller coaster is credited to russian sled riders who some 400 years ago hurled Down artificial mountains of ice and Snow that were supported by Wood frames. In 1804, the French adapted the idea removing the ice and replacing a sled s runners with wheels. In 1884, an american inventor Lamarcus a. Thompson refined the French idea by setting wheeled cars on an undulating track. Thompson s Switchback Gravity pleasure railway at Coney Island reached a top Speed of six Miles an hour As it moved Down a Hill. At the Bottom riders got out while attendants pushed the cars up a second incline. Riders then climbed aboard for the return trip. By 1900, the modern ride was born. In terms of physics the characteristic feature of the roller coaster is that its potential Energy gained As a Chain drive lifts cars through the Earth s Gravity to the top of that first drop has been mostly converted to kinetic Energy by the time the ride ends. The cars coast to a Stop or close to it often aided by brakes. There Are no engines no motors just Gravity pushing riders along. Since speeding cars have no Energy of their own they can never climb higher than that first Hill. Secondary Hills get progressively smaller As the potential Energy is used up. Designers who renovate coasters have been perfecting classic rides generally for reasons of  the old Days if people got roughed up they did t file a lawsuit said Curtis d. Summers a coaster designer in Cincinnati. A key redesign tool is the accelerometer a device that can show the strength of centrifugal forces acting on coaster riders. Its readings Are usually Given in is with one g representing the acceleration of Gravity. A fighter Pilot going through a tight turn can take about 10 or 11 g s before blacking out. Coaster designers generally try to limit centrifugal forces to 3.5 or 4 g a except for a Short spurt where they May go higher. On old coasters accelerometers often reveal that cars rapidly going Over the Crest of a Small Hill develop negative g a meaning a coaster car is accelerating downward faster than the rider a potentially dangerous situation. Some of the old rides had a tendency to lift you out of your seat Summers said. His usual goal in redesigning the rides is to smooth out the Hills so riders going Over them always experience a slightly positive Force of about 0.3 a negative g s Are thrilling he said but you Don t want people to get the sensation that they re being thrown out of the  another goal in redesign efforts has been to Bank turns More steeply. On old coasters the centrifugal forces of Sharp turns often threw riders to the Side of the cars in some cases causing injuries. In renovated coasters tracks Are banked on turns so that centrifugal forces press riders deep into their seats rather than to the Side of cars. The perfect cd rate was a bad idea Circle of earlier design dangerous slowdown at top circular loops were tried and rejected decades ago because roller coaster cars moved too fast at the Bottom and too slowly at the top. The rapid upward climb created excessive centrifugal Force that pressed riders into seats uncomfortably. But the slowdown at the top could let upside Down riders fall out of their seats As centrifugal Force weakened and Gravity became the dominant Force. Today s designers realize that they control the Speed of a roller coaster by modifying the Radii of the Loop. Thus in a Teardrop shaped Loop the cars move More slowly across the Large lower radius than they would in a perfect Circle and More quickly at the top where the radius is Small. Not Why do people crave the experience by Daniel Goleman new York times by do people submit themselves to roller coasters and their mutations the scream machines that seem so ubiquitous on the summer landscape some clearheaded analyses of the allure of wild rides Are emerging As scientists study Why certain people seek the thrill of great velocities upside Down suspensions and other sensations that the human body can read Only As pure torment. The roller coaster question touches on some Complex physiological issues. New research suggests for instance that the craving of thrills May be hard wired into those who thrive on the level of primitive brain activity that physical danger stimulates. Another Appeal is that roller coasters in simulating danger provide the illusion of mastering a great peril. It is a deeply satisfying feeling in which mock danger provides the exhilaration of self affirmation. Fear is the key component As has been shown in research into More dangerous activities like skiing and Parachute jumping. If you ask Accident prone skiers if they Are scared when they Are on a High risk slope they la say they would t bother to ski the slope if they weren t scared said Seymour Epstein a psychologist at the University of Massachusetts they want a slope that terrifies them. Parachutes say the same thing. After you take the plunge there s an immense Relief and sense of Well being in acting a fear that does t  that kind of exhilaration is particularly appealing to a personality Type aptly known As thrill seekers people who have been studied by Frank Farley a psychologist at the University of Wisconsin. People who Are High in that trait Farley said seek variety Novelty intensity and  not everybody goes on scary rides like roller coasters or comes Back a second time if they try it Farley said. It s those with the thrill seeking personality who come Back again and again. They like adventure like High diving and hang  underlying the propensity for physical thrills Farley believes May be a neurological need for the biochemical state that comes from intense physical excitement. One theory holds that the brains of thrill seekers Are usually at a lower level of arousal compared with most other people. This theory holds that the sense of danger and the physical extremes of a roller coaster ride prime a neural network at the base of the brain called the reticular activating system which in turn heightens the level of activation throughout the rest of the brain. They feel fully alive when something raises their level of brain arousal Farley said of thrill seekers. Another theory put Forth by Marvin Zuckerman a psychologist at the University of Delaware proposes that those who need to seek out intense stimulation the roller coaster being a prime example have an imbalance in a brain chemical Mono Amine oxidase which has also been implicated in some forms of depression. Excitement seems to change the Levels of the chemical in some people lifting them from torpor to elation. Heightened concentration is at play too. Being totally absorbed is in itself pleasurable Epstein said. Complete concentration that Blanks out everything else temporarily relieves you from All conflicts. Even if it s scary its a Way to drive out disturbing  Epstein added it makes you feel very alive to be so scared. When you react to something that demands your full attention so forcefully All your senses engage. It s a very different feeling from being in your usual Semi awake  Page 14 the stars and stripes sunday August 14,1988 the stars and stripes Page 15