Dustbin_Fairing.jpg

In 1957 dustbin fairings were banned from road racing, now some people think it's a good idea to bring them back- They are seriously mistaken.

Editor's note: Michael Czysz is the man behind MotoCzysz, one of the chief innovators in electric motorcycle racing. The dustbin fairings have been made a part of the TTXGP racing rules which were stolen by the FIM for e-Power and, as such, will be used in TT Zero. They include the limited use of dustbin fairings, the first time the devices have been on racing rulebooks since 1957.

Update: Michael's written more about streamlining, check it out here.
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There are many debates about why the dustbin (AKA "garbage can") fairing
was ruled illegal in '57. The reasons range from aesthetics to politics
but one of the undisputed reasons is that several crashes were
attributed to the dustbins and their negative effect on handling- and
that was on a 1957 motorcycle! What made the dustbin fairing dangerous
for 50's era racing motorcycles makes it suicidal for 2010 era racing
motorcycles.


Old

From my office desk I can see my Grandfathers (Circa early 1960's)
125cc Grand Prix motorcycle, this race machine was state of the art for
the era. Though 125's have the slowest top speed they often achieve the
highest apex speed. 125's are designed with very aggressive geometry to
be the quickest steering and best handling bikes on the grid. Want to
understand the ultimate handling abilities of motorcycles from a by-gone
era? Look to 125's.

My Grandfather's 125 looks old, old tires, old steering angle, old Cg,
old suspension everything looks old- because it is. The steering rake is
26.5 degrees the trail is more than 100mm, the tires have virtually no
profile and the Cg looks lower than any modern motorcycle I have ever
seen and this was one of the best handling motorcycles of the era. This
"razor sharp" 1960's Grand Prix motorcycle would be considered a slow
steering street bike by today standards- it is all relevant to speed.


New

As motorcycles become faster, so must steering. The faster you ride a
motorcycle the less time you have to do... well... everything. Speed
compresses time. For a given bike to go thru a series of corners faster
it must brake harder, steer quicker, transition faster and do so ideally
with the same amount of rider input as before. Since the beginning of
motorcycling every part of the motorcycle has evolved to allow the
motorcycle to turn faster with less effort. Since the 1957 ban, rake has
steepened, trail decreased, Cg raised, wheelbase shortened and tires
profiles optimized. Modern motorcycles turn significantly quicker with
less input than they did "back in the day".


Racing

Racers push the limit, that's what racers do and the "race line"
is no exception. Racers enter a typical corner inches from the outside
edge of the track, ride an arch to the apex then again to the outside
edge of the track on exit. They do not just steer this arch changing
trajectory at will like you do in your family car, this is the
consequence of carrying the maximum speed possible thru a corner. This
optimum line is duplicated by nearly every racer, ever corner, every
race, it is the limit and there are only millimeters of cushion between
being on line and running off the track.

1994_Fireblade.jpg

When the best racers in the world arrive at a track with winds in the
15-25+mph range a modified fairing can be fitted to their bike. This
fairing has less surface area, often achieved by drilling a series of
holes in it. The holes reduce the overall area and help balance the
Delta P (pressure drop) across the fairing caused by a side wind. This
pressure differential creates a very noticeable force on the motorcycle
sucking the fairing into the low pressure area opposite the direction of
wind.


Remember motorcycles turn by leaning and modern motorcycles turn/lean
very easily. Take a modern motorcycle and add a large side area or
fairing to it and it will be subjected to forces beyond the rider's
control. Stretch that fairing fore and aft the wheels and you have now
increased the leverage of that force and effect. Add additional height
and now the fairing is subject to even higher wind speeds that have an
even greater lever to lean and pull the motorcycle. More freighting, the
rider can only overcome the unwanted change in direction by turning the
motorcycle towards its new trajectory as to counter the lean initiated
by the wind. This is a very counter intuitive maneuver that takes
additional time and real estate most racers do not have.

Cigars and Toothpicks

Even straight line instability can be the
experienced (no need for side winds) if the motorcycles center of
pressure is too far forward ahead of the Cg which is typical to dustbin
style fairings (with no tail). There is a great simple explanation of
this in the "Worlds Fastest Indian" (highly recommended). The
instability caused by this miscalculation is even an issue at Bonneville
where riders only go straight, have miles of course and can't even find
anything to hit. If Bonneville was 24' wide and lined with stone walls
streamlining would be banned- and so it should be at the IOM.

Electric racing is still racing

There is a place for streamlining. Our
joint venture with Bajaj has identified aerodynamics as a project
priority and one of the best methods to achieving greater efficiency and
range in our project. The original C1 spent time in CFD and actual wind
tunnel testing, by no means am I opposed to improved aerodynamics. As
efficiency is such a component to electric racing it is easy to see why
someone may think this is a good idea but I am certain this same person
has no modern day racing experience.


Personally I have ridden at pace at, Willow Springs, Las Vegas and
Miller Motorsports; tracks that get periodic winds. I have been blown of
track several times, sometimes from a tailwind at the end of the
straight, other times at corner exit. I can personally attest that in
every case the bike would have been more out of control if it had a
larger fairing- suicidal with a dustbin.

I hope the other manufactures and team owners will stand with me and
personally elect not to race the IOM with the antiquated dustbin
fairings. As our rider Mark Miller recently said: It's war out there,
this is not some college HPV project."

-- MC

MotoCzysz

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