11/09/92 - Life's Ups And Downs Can Send You Loopy

Date: 11/09/1992
Publication: Sydney Morning Herald
Page: 1

As they loop the loop upside down 12 storeys from the ground this weekend, most riders on the new Demon rollercoaster at Australia's Wonderland won't be thinking about the laws of physics.

It's not likely that Isaac Newton will be on their minds as they scream through 270 metres of track at speeds of up to 75 kilometres per hour. The law of conservation of angular momentum probably won't occur to them as they are pressed into their seats by a g-force 3.8 times normal gravity. This is equivalent to accelerating from rest to 134 km/h in a second.

Yet track designers rely heavily on these laws as they calculate ever more devious ways to toss carloads of people through the air in unnatural configurations. On the Demon ride, designed in the Netherlands and built here at a cost of $5 million, the train is drawn backwards on a chain and lifted 38 metres (about 12 storeys) into the air. Once released it surges down the track, where it does a triple somersault via two half screws and a full loop. It runs up to a second lift point from where the cycle is repeated -backwards.

Says Mr Todd Coates, park attractions manager at Australia's Wonderland: "It's very, very, very, very disorienting. I don't like it much, but then again I'm just the manager."

Designers have settled on upside down teardrops and corkscrews as the best shapes to deliver the maximum thrills safely. Although a circle would seem an obvious choice for a loop, teardrop shapes are used instead because they make it easier to turn people upside down without having them fall from their seats.

This is because a change in velocity when moving through an arc is related to the size of the radius, explains Ms Sue Hogg, senior lecturer in physics at the University of Technology, Sydney.

So what does all this physics do to you physiologically? Professor Robert Holland of the University of NSW's Department of Physiology and Pharmacology says the g-force is "not enough to make you black out but it will put a lot of your blood towards your legs and backside and might well cause a transient lack of blood up to your brain".

Professor Holland says people might also get a funny feeling in their stomachs at the bottom of the loop as their livers are forced downwards.