Roller coaster inversion

A roller coaster inversion is a roller coaster element in which the track turns riders upside-down and then returns them to an upright position. Early forms of inversions, dating as far back as 1848 on the Centrifugal Railway in Paris, were vertical loops that were circular in nature. They produced massive g-force that was often dangerous to riders, and as a result, the element eventually became non-existent with the last rides to feature the looping inversions being dismantled during the Great Depression. In 1975, designers from Arrow Development created the corkscrew, reviving interest in the inversion during the modern age of steel roller coasters. Since then, the element have evolved from simple corkscrews and vertical loops to more complex inversions such Immelmann loops and cobra rolls. Featuring fourteen inversions, The Smiler at Alton Towers holds the world record for the number of inversions on a roller coaster.

The first inversion in roller coaster history was part of the Centrifugal Railway of Paris, France, built in 1848. It consisted of a 43-foot (13-meter) sloping track leading into a nearly circular vertical loop 13 feet (3.9 m) in diameter. During the early 1900s, many rides including vertical loops appeared around the world. These early loops had a major design flaw: the circular structure produced intense g-forces (hereafter "Gs"). The Flip Flap Railway, designed by Lina Beecher and built in 1895 on Coney Island of Brooklyn, United States, had a 25-foot circular loop at the end which though initially popular caused some discomfort in passenger's necks, and the ride soon closed.Loop the Loop, another looping coaster, was built later in Coney Island as well. This time the loops were slightly oval-shaped rather than circular, though not clothoid in shape like modern loops. Although the ride was safe, it had a low capacity, loading four people every five minutes (48 people per hour, compared to 1800 riders per hour on Corkscrew, an early modern coaster that opened in 1976), and was poorly received after the discomfort of the Flip Flap Railway. As their novelty wore off and their dangerous reputation spread, compounded with the developing Great Depression, the early looping coasters faded and disappeared.

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