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While I expect most CR4ers to be well versed in this type of
drafting…
 ...via Wikimedia
…many of my sports readers might be expecting this type of drafting. But...
 ...via Oilers Nation
I'm actually talking about this kind of drafting.
 ...via Canari
(Note to self: Destroy all bike shorts in my closet)
Do
you catch my drift? Sorry, I know my jokes are a real drag.
(Note to self: Abandon comedy career)
You can witness aerodynamic drafting in just about any sport
that involves the competitors racing simultaneously. While the implementation
for each sport is different, the natural principles affecting athletes in
speedskating, cycling, and motorsports remains the same. Drafting is a rather
simple technique, but requires a lot of practice and skill to perform
correctly.
Drafting
is the process of streamlining the air-resistance faced by racers at high
speeds. Normally, drafting isn't needed for slower-speed racing (like marathons
or off-road races, like the Mint
400) because the separated boundary layers have time to re-adhere. Effects of drafting become noticeable at
speeds exceeding 65 kph/40 mph.
Remember that air is considered a fluid, and an object
literally must force its way through the displacement of the air. This drag
force means a higher level of energy output is required. To draft, a racer
positions themselves exactly behind the leading racer (or even just the racer
in front of them), sometimes to within increments of inches. They depend on the
leader to split the boundary layer so they can position themselves within the
air wake and face much less drag. This allows the trailing racer to maintain a
similar speed as the racer in front of him or her, with up to a 40% decrease in
effort.
 ...via eFluids
In
some instances it is not only the trailing racer that gains an advantage. At
race car speeds, the trailing vehicle relieves the leading car of drag on its
spoiler by assuming the drag on its own rear end. This alleviates some of the
downward force on the front car's rear-end, and the following car's front end.
It can be dangerous to draft with three cars, because the middle car loses a
very large amount of downward force on both axles. This animation may help clear
up my awful explanation.
Perhaps the most impressive form of drafting comes from the
so-called 'sling-shot' draft, made more famous recently by the buddy-comedy
Talladega Nights. As Ricky Bobby and Cal
Naughton Jr. would say, "SHAKE
N' BAKE!" (Say, isn't that trademarked?)
(Note
to self: Make grocery list)
The stock-car sling-shot takes an experienced driver to ride
higher in the turn. The racer will position himself so that upon exiting the
turn he has a downhill advantage. While racing down the banked curve, he times
it so he laterally passes behind the leading car. He gains an additional
advantage from the drafting, and hopefully has gained enough velocity to pass
the car along the inside part of the track.
(Note
to self: Selflessly apologize to Danica Patrick for using the masculine pronoun
so heavily in the above paragraph. She is very feminine, indeed.)
 ...via Self.com
The
leading racer in the drafting pattern is always subject to more energy expenditure
than those who follow. For events like the Tour de France, where the energy is
provided by humans, it becomes imperative to preserve energy. As such, it's
common to see cyclists--even those in direct competition--cooperate to relieve
some burden from riders. A 'Belgian tourniquet' is one such method of
cooperation, which involves the group of riders rotating in an ellipse
 ...via Wikimedia (Somebody tell me how to correctly embed .gif files already, okay? Or else you get stupid links like this one.)
Speedskaters employ a method known as "nose-to-butt," where
they….(Admin's note: No. No they do not!)
 ...via Zimbio
It has been proven that drafting works on freeways as well.
Cars positioned behind tractor trailers enjoy fuel savings, so says Mythbusters.
However, this is extremely dangerous, so it should not be tried by anyone,
anywhere. Also note that tailgating in many provinces and states is illegal.
So folks, there it is. Next time you're walking behind
someone who is super slow, see if you can draft them. I'm sure they won't mind.
Resources
Exploratorium - Drafting
eFluids - Bicycle Aerodynamics
Wikipedia - Drafting
How Stuff Works - Stock Car Drafting
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