Rossi Aero - Fuzzy 46

Ok, I'm sure everyone has noticed the change in Rossi's leathers this
year. Not just the change in livery, but the "fuzzy" 46 on the back. I
have noticed street and show bikes in the US that are completely
"fuzzy" instead of a regular paint job. So I didn't think much of it.
Maybe just something different.

But after seeing the following image (linked) on Motogp.com I started
thinking. What's the deal there? The 46 is gone, but there still
appears to be some sort of "fuzzy" material on the hump of his back. I
immediately thought about aerodynamics. I've read a few articles and
columns about bike aero packages. (specifically the changes made from
the RC211V to the RC212V) The area of stale air behind the rider seems
to play a significant role in how "slippery" the aero package is, most
notably at top speeds. With Rossi struggling for top speeds to catch
the Ducati I wonder it this is some sort of turbulance generator that
Yamaha is experimenting with.

I have read about the "vortex generators" that Mitsubishi installed on
some of their Lancer Evolution models in recent years and it seems
that they actually make quite a significant difference in the overall
aero package of the car. (helping to increase fuel milage as well as
actually helping the rear wing create more down force?)

I have had the thought of olympic swimmers and those hi-tech suits
that many of them wear. Something like the dimples on the surface of a
golf ball helping create a turbulant pocket of air around the ball. I
had wondered why there hasn't been any sort of aero development work
done with the riders' leathers. It seems like a textured surface on a
rider's leathers could help in this same way. (especially Hayden!!)

I know many of the frequent posters in this group are quite
technically inclined and may have some knowledge about this topic that
I'm not familiar with, or at least some good comments on this subject!

I'm not sure when that photo was taken, but I'm interested to see what
Rossi's leathers look like when they start FP1 at Donnington Park!
There may be something to the "fuzzy" 46. Or maybe I'm just thinking
WAY to hard about this! haha

http://images.motogp.com/multimedia2/567/567111_36108.jpg

- Kyle

 

i think you're onto something, but i think it's more accurately a
"turbulator".

somewhere in that region the airflow no longer follows the curvature
of the rider/helmet. the airflow separates and becomes very
turbulent, creating bubbles of air which dramatically increase drag.

turbulators and vortex generators create very small swirls of highly
energized airflow which encourage the airflow to follow the surface
longer, delaying the onset of this turbulent air and minimizing the
drag increase. the same theory applies to golf balls, the rapidly
rotating dimples energize the airflow - a perfectly smooth golf ball
doesnt fly nearly as far as a dimpled one.

many aircraft have vortex generators these along the top-surface of
the wing for the same reason, to forestall the onset of airflow
separation (i.e., stalling or increasing the effectiveness of control
surfaces).

 

So the lucky rabbit's fur stuff was just a cover story ?

Cheers,

 

lucky rabbit's fur story? i had never heard any mention at all about
that. is that what Rossi said? i think he's trying to hide some super
alien technology from everyone under the mask of superstition! ;-)

- Kyle

 

That cam on the back of Dani-no-smiles looks like a friggin dildo. ;

Z

 

heh

--
Andrew
00 Daytona
00 Speed Triple
71 Kawi H1
05 Infant

 

Mark N whines:

This has got to be a joke on your part Mark N. But just in case it's
not,
Spidi and Dainese are two entirely different companies. If you think
Yamaha controls Rossi's leathers, beyond some badging, you're
mistaken.

Beyond that, I'd be mightily impressed if a patch there, of that size,
has any effect on aerodynamics. It's *really* small in relation to
total
area and behind the helmet where flow has already probably separated.

Probably.


Go fast. Take chances.
Mike S.
and that hump

 

I used to do a bit of club racing on a supersport bike. I didn't have
teh hump in my leathers. I used to know when someone was slipstreaming
me close because the back of my leathers started to flap. Obviously
turbulence was an issue.

 

T3 asks:

My guess is he's just furred out, ala the Starboyz
http://www.starboyz.com/pages/gallery/gallery.pl

Something Vale might find funny.


Go fast. Take chances.
Mike S.

 

OK, no change in Rossi's lucky rabbit's furr for the dry FP3 or QUAL
sessions... I still can't figure out what the deal was with that
square grey patch on his back during the Catalunya test. If we see it
again in the next testing session then I'll really start to wonder
about some aerodynamic experimentation. I know that something like
that would not make much of a difference at all, but in F1 and MGP
it's the small advances that add up to create monsterous machines! If
they weren't concentrating on the small stuff I don't think a 2400cc
V8 could make 700+HP, or a 800cc V4 / I4 could make 220+HP.

- Kyle

 

speculates:

Another pure specalution is that it's a patch of velcro. Slap - you
put on the furry "rossi". Slap - you put on an el dottore 3/8
high bas-relief model. Slap - you put on an entire Fiat punto.


Go fast. Take chances.
Mike S.