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LIAM McHUGH: Whether or not you're a fan of the Winter
Olympics, it is likely you know his name.
ANNOUNCER: Shaun White, incredible execution!
McHUGH: Claiming his first gold medal in 2006, a feat he
repeated in 2010, Shaun White has long been the biggest name
in the snowboard half pipe event.
ANNOUNCER: It's athletes like Shaun White that make you think
the impossible is possible.
SHAUN WHITE: The only trick you really remember
is the last one because it's the do or die trick,
you better make that one to get that score.
McHUGH: With tricks that dazzle fans and fellow
snowboarders alike, at times Shaun White seems to defy
the laws of nature.
ANNOUNCER: All eyes to this hit. Oh!
WHITE: I had worked so hard at that point to learn this trick,
the Double-McTwist 1260, I had crashed time and time again.
ANNOUNCER: There it is, right there. Oh my gosh! That is a
move that encompasses three and a half rotations, two flips,
the Double McTwist!
McHUGH: What allows Shaun White to do these tricks is more than
just his incredible athletic skill and years of hard
training. It's also the engineering and design of the
half pipe that allows him to gain enough speed to
generate big air.
BRIANNO COLLER: Height is all speed. If you can get that
speed, you can get the height.
McHUGH: Brianno Coller is an engineering professor at
Northern Illinois University and funded by the National Science
Foundation. He says an important factor in the design of the half
pipe is the height of the walls and the radius, or curvature.
COLLER: The reason why you make your wall higher is so you can
fit a bigger radius inside that curve.
McHUGH: At the 2014 games in Sochi, engineers have built a
half pipe that is 22 feet high, 65 feet wide, and 557 feet long.
The radius is crucial because it allows the snowboarder to change
direction at high speeds, from barreling down the hill, to
soaring into the air.
COLLER: While he's going around this turn, he's experiencing
some rather dramatic forces. You have to take this momentum
that's going this way, convert it to momentum going that way.
McHUGH: As Shaun White rides the curve of the half pipe, he has a
velocity, a speed with a direction. As he begins
to change direction, he experiences what scientists
call centripetal acceleration.
COLLER: You might be headed this way, and then be headed this
way, and because you're changing direction, you actually get an
acceleration that way.
McHUGH: Acceleration is defined as the rate of change in
velocity. Acceleration that changes direction is called
centripetal acceleration. As Shaun White changes direction by
riding up the curvature, he is experiencing centripetal
acceleration. For snowboarders like White, the force from
centripetal acceleration can be over two G's.
COLLER: The extra force that Shaun White feels just by going
around that curve is about two and a half, 2.7 times his own
weight. Shaun White has to carry his own weight plus the two
and a half times his own weight just to pull himself
through that turn.
McHUGH: If Shaun White wanted to get twice as much air, he would
have to increase his speed by almost half. Entering the curve
at this higher speed would require an increased
acceleration to change his direction, placing a much
greater force on his body.
COLLER: So instead of carrying 2.5, 2.7 times his weight
through that turn, he'd be carrying about five times his
weight through the turn. It's like putting five of his
buddies on his back and trying to maneuver
through that transition.
McHUGH: To lessen the force of centripetal acceleration,
engineers are continually optimizing the dimensions of the
half pipe, allowing for a larger radius. And a larger radius also
means higher walls. When the snowboard half pipe made its
Olympic debut in 1998, the walls were much lower than they are
today. But with each Winter Olympics, advances in
engineering and design have led to larger and larger half pipes.
COLLER: They went from twelve feet to fifteen feet to eighteen
feet to twenty-two feet. So over the past two decades they've
essentially doubled in size.
McHUGH: Allowing snowboarders to go faster, get more air time,
but not increase the forces on their body.
COLLER: The more gentle this turn is, the lower those forces
are. So if you make that radius twice as big, you make the wall
twice as big, that force gets cut in half.
WHITE: Whether you win or lose, you're an Olympian so it doesn't really
matter. You're there for the thrill of the fight.
McHUGH: This close relationship of half pipe design to maximize
speed and air time allows snowboarders like Shaun
White to push the limits of their skill, bringing the sport
to new heights.
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