YOU鈥橰E HELPLESS, upside down, hurtling backwards at 120 kilometres per hour
with your arms and legs flailing wildly. Your seat seems to be hanging in
mid-air. Suddenly you start to spin head over heels. You scream till your throat
is sore. And you enjoy it so much that you just have to go back for more. At
least that鈥檚 the plan of Arrow Dynamics, the manufacturers of X: the Fourth
Dimension.
When this amusement ride opens in the Magic Mountain park in Valencia,
California, this summer, its designers hope people will flock to try it. The
experience will be like flying, they say. And if flying backwards, upside down
and in an open cockpit is your kind of thing, you鈥檒l be hooked.
However, fun is becoming a tricky issue for ride designers. In order to
increase the thrill, they have been ramping up the accelerations to create the
most head-spinning forces possible. Getting it right is far from easy. Err on
the side of caution and people won鈥檛 bother coming back. Go too far, however,
and they may not be able to. 鈥淲e know the limits for the human body,鈥� says
Walter Stengel, who has designed more of the world鈥檚 rides than most. 鈥淲e are at
the limit鈥擨鈥檓 absolutely sure of this.鈥�
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If our thrill-seeking bodies can really take no more, what鈥檚 going to keep
dragging us back to the funfairs? Creating something new and exciting, yet safe,
is going to take some careful thought. Can designers tempt us with gentler
thrills, or is it time to let unruly chaos鈥攐r even the passengers
themselves鈥攖ake control?
Certainly a radical rethink is necessary. Some engineers, including Willem
Bles, a consultant for Vekoma, a Dutch company that designs fairground rides,
say they鈥檙e frightened by what鈥檚 allowed. For Bles, the problem with rides is
apparent every time he visits a park. 鈥淟ook at people鈥檚 faces,鈥� he says,
鈥渢hey鈥檙e not having fun.鈥� He believes that true innovation has been lacking for
a while鈥攖hat the new rides simply increase the horrors that people have to
endure. 鈥淭he rides are more about survival,鈥� he says.
But the industry has come a long way since the early days of roller coasters
(see 鈥淔atal attraction鈥�). Today鈥檚 rides may be gut-wrenching,but they are
certainly safer and better researched. Much of this research comes from people
like Bles and Stengel鈥攅ngineers and designers who treat their job more
like rocket science.
Stengel runs an engineering company in Munich that is almost exclusively
dedicated to funfair design. In the early 1970s, the Disney company asked him to
design a giant loop for their Magic Mountain park in Valencia. So he headed
straight to NASA to find out what kind of g-forces the body can take.
鈥淚 looked through NASA papers to see what pilots could stand,鈥� he says.
Find out what a pilot or astronaut can survive and you have a pretty good
idea where the safety limits for public rides should lie. Pilots have survived
more than 9g in sustained acceleration, he discovered. Go much beyond
that and they pass out. Go further still and their eyeballs can haemorrhage or
their internal organs split.
This kind of experience would rather take the fun out of funfairs. So Stengel
decided that the maximum vertical acceleration for the public should be
6g, and then only for a second or so. He also put a strict limit on the rate
at which acceleration can increase鈥攜ou鈥檒l never go down a 45 degree ramp
into a tight circular loop, for instance.
But stricter safety limits only intensify the need for designers like Stengel
to search for novel ways to thrill their customers. Roller coasters now include
ever more loops, corkscrews and inversions. You can ride sitting down, standing
up or upside down, you can copy aerobatic pilots鈥� manoeuvres鈥攂ut there鈥檚
still only so many ways you can turn a car when it鈥檚 on a track.
Take the car off the track, however, and you can create a whole new set of
sensations. This is exactly what Arrow鈥檚 designers set out to achieve with the X
ride. They call their prototype the Fourth Dimension because as well as playing
with the three directions of linear motion鈥攗p and down, left to right, and
front to back鈥攖hey can now send you spinning head over heels. Rotating
people has the added benefit of a 鈥渄on鈥檛 know what to expect next鈥�
sensation鈥攑assengers can鈥檛 always see what鈥檚 coming, one of the key
ingredients of thrill.
It鈥檚 hard to imagine you will ever need more adrenalin than when you鈥檙e
plummeting head first towards the ground at 100 kilometres per hour, while
spinning head over heels. Eventually, of course, you will. Humans are hard
creatures to please. Some hardened adventurers will even get used to X because
the spinning cars on Arrow鈥檚 ride are driven by gears, and their rotation is
carefully controlled by computer software. After a few goes you鈥檒l have some
idea of what to expect. The next step in designing rides, however, could throw
predictability out the window.
It鈥檚 based on the first law of having fun: lose control. And when spinning is
involved, losing control is easy. This step has already been taken in the newest
waltzers鈥攖ea cup rides鈥攁nd it could easily be applied to the next
generation of roller coasters.
Ride a waltzer and you鈥檒l sit in a car that spins on its own axis. The car is
on a huge platform that also rotates. In the past you could take comfort in the
fact that your spin rate was tightly controlled. As on the new Arrow ride, gears
turned your car at a rate determined by the rotation speed of the whole ride.
But that鈥檚 predictable鈥攕o last century. The latest waltzer cars now spin
freely, driven only by the passengers鈥� weight and the centrifugal forces created
by the car鈥檚 spin. It鈥檚 all governed by chaos theory: perhaps not the most
comforting thought when climbing aboard a ride. But they are very popular
attractions. 鈥淧eople seem to like these chaotic rides,鈥� Stengel says.
Chaos means that the position and weight of everyone on the ride can
influence just how good鈥攐r bad鈥攜our experience is. So you鈥檒l never
have exactly the same ride twice. In fact, it is so sensitive that even the
state of its bearings can influence the ride.
Despite being a passport to endless thrills, there is one rather obvious
drawback to chaos. It鈥檚 unpredictable. Usually, ride designers try to calculate
every single acceleration that you will experience, no matter where you sit. On
chaotic rides, however, their computations are much more complex since they must
attempt to find the maximum and minimum forces that will act. But they can never
be completely sure that something odd won鈥檛 happen. Especially since freely
turning systems can occasionally hit a resonance frequency.
When pushed at a particular frequency, a child on a swing can fly over the
top of the swing鈥檚 frame. Similarly, if you drive a spinning waltzer car at its
resonance frequency it could speed up uncontrollably. 鈥淲e have to be very
careful about resonance,鈥� Stengel says. 鈥淭his can be dangerous: maybe the stress
was never calculated for this acceleration,鈥� he says. If the waltzer or another
ride is subjected to unforeseen stresses, no one can guarantee that it will be
able to cope.
In Stengel鈥檚 experience, resonances are rare, and don鈥檛 last for long enough
to do any damage. Anyway, he says, in addition to computer simulations, doctors
always monitor new rides. Before they can open, volunteers decked out with
helmets, accelerometers and monitors to measure heart rate and blood pressure,
must go round the ride a few times. This gives a measure of the stresses and
forces that the public are likely to encounter on the ride.
But no one really knows what the safe limits of high rotational accelerations
are, let alone their effect on the human body. Stengel does know one thing
though: rotation can be very unpleasant, especially if you spin on two or more
different axes simultaneously. He has worked with the German air force, rotating
volunteers head over heels while also making them cartwheel or pirouette like a
ballet dancer. 鈥淚f you move them on all three axes they are so dizzy they鈥檙e
getting close to blackout鈥攚hen they get off they can鈥檛 walk,鈥� he says.
Stengel was expecting he might see something like this, but he was not prepared
for the delayed effects he observed. 鈥淪ometimes they complained of headaches and
other problems two days later. This is very strange,鈥� he says.
Since these effects aren鈥檛 understood, he tries to limit how people on his
rides are rotated: blackouts and nausea are a no-no. 鈥淲e want to spread joy and
fun, not pain.鈥�
With that goal in mind, Stengel feels that flinging people around in ever
more chaotic machines is no longer the way forward. Bles agrees
enthusiastically鈥攁nd has a radical solution in mind. In amusement parks of
the future, he鈥檒l be thrilling you gently.
Bles thinks that the way to make rides more fun is to put people through a
carefully designed series of relatively small accelerations. 鈥淚n many cases it
would be possible to come up with a profile, even for existing attractions, that
would lead to a higher amusement value,鈥� he says.
He has come to this conclusion after strapping Dutch air force pilots into
machines that throw them around to test their tolerances to a range of
accelerations. Bles has found that tumbling around in these machines doesn鈥檛
have to be unpleasant. When the force is kept low, he says, the pilots actually
enjoy the experience.
Bles and a team at the TNO Human Factors Research Institute in the
Netherlands use these machines to test the limits of the human vestibular
system. This is the set of fluid-filled vessels we have in our heads to give us
a sense of balance and orientation. It also responds to different kinds of
accelerations. This is key for the air force because new high-performance jets
can perform manoeuvres well beyond the pilot鈥檚 tolerance.
The pilots鈥� enjoyment of the spinning machines seems to come from surprises.
鈥淚t鈥檚 often connected to the unexpected,鈥� Bles says. Tilt the head while
spinning with the eyes closed, for example, and suddenly, an intense tumbling
sensation called the Coriolis illusion comes into play. 鈥淧eople find it
fascinating,鈥� says Bles, 鈥渁 very nice and unexpected sensation of movement.鈥�
So Bles and his researchers have set out to design the components for a
perfect ride. 鈥淚t gave us a lot of fun and a lot of surprises,鈥� he says. He is
currently waiting for a new spinning chair to test their theories: a chair that
accelerates the body in any combination of the three linear and three rotational
directions. If their theories work, fun will one day be measured in smiles
instead of screams.
鈥淚 think this is absolutely right,鈥� Stengel says. He believes the sequence of
accelerations, not their size, is what makes a good ride. 鈥淐hanging a small
acceleration is more interesting than always being on the limit that a passenger
can take,鈥� he says. A roll that includes a change of acceleration from small
negative g鈥攁 feeling of weightlessness鈥攖o a small positive
g鈥攁 slight crushing sensation鈥攈as an extraordinary effect
on people, for instance. 鈥淭hey have no idea where they are or what direction
they鈥檙e moving in,鈥� he says.
While the designers spend time exploring this new 鈥渓ess is more鈥� philosophy,
Stengel does have another, more dastardly trick up his sleeve. On the ride of
the future, you will be handed control, able to adjust the speed of your car鈥檚
rotation or even vote on the roller coaster鈥檚 path at an intersection.
Manufacturers are already coming to Stengel with passenger control in mind.
鈥淪ome people have asked for this, and I think it will come,鈥� he says. He is
cagey about specifics, but thinks that within a couple of years we could be
steering our own roller coasters.
It may sound enticing, but think it through. There鈥檒l be 30 or 40 other
people on the ride, all frantically pushing a button to vote. Do you choose left
towards the Death Loop or right to end the ride? During that sickening charge
down towards the junction, there鈥檒l be the wonderful possibility of a
last-minute reprieve if everyone else鈥攍ike you鈥攈as had enough. But
let鈥檚 be frank: they won鈥檛 have had enough, will they?
Be warned. Riding the coaster of the future, you will be at the mercy of your
fellow passengers. And nothing could be more terrifying than that.
A century ago, people were pushing the frontiers of thrill without quite
thinking things through. In 1902, Coney Island, then the world鈥檚 amusement park
Mecca, boasted the Cannon Coaster. Originally designed with a section of the
track missing, the cars were to use their momentum to make a death-defying leap
onto the tracks on the other side. However, on a breezy day, they often
missed.
And when the island鈥檚 first loop-the-loop made its debut in 1895, the first
intrepid passengers disembarked rather unamused: they had suffered whiplash
injuries and broken collar bones on the way round. A later innovation improved
the ride with an elliptical loop that reduced the forces on people鈥檚 necks.