Will someone explain this to me?  It can't be weight savings.  Aerodynamics?  I've seen it on older race bikes as well as the 250's/125's, but I can't figure out the advantage.

http://www.superbikeplanet.com/image/2009/motogp/assen/hugo/5.htm

I think it's to improve stability when there are bad cross-winds, E.

like dimples on a golfball.

Quote from: derby on June 26, 2009, 01:57:18 PM
like dimples on a golfball.

Not only is he good looking but he is brlliant as well! 

Quote from: derby on June 26, 2009, 01:57:18 PM
like dimples on a golfball.

Not the same as dimples in a golf ball. Golf ball dimples create a turbulent boundary layer that keeps the flow around the golf ball from separating prematurely. The effect is the reduction of form drag. the holes in the upper fairing help reduce the effects of cross wind and some drag but in a completely different way.

okay, thanks!

IMO, it's mostly for when they're laid over like this:



Leaned over like that, a gusty side wind is going to load up the front tire.
May not be too fun at ~300 kph when you're sliding both tires.
When it was windy at El Mirage or Bonneville, it always got my attention. 

Quote from: pennyrobber on June 26, 2009, 04:05:44 PM
Not the same as dimples in a golf ball. Golf ball dimples create a turbulent boundary layer that keeps the flow around the golf ball from separating prematurely. The effect is the reduction of form drag. the holes in the upper fairing help reduce the effects of cross wind and some drag but in a completely different way.

The DMF:  Home of the most brilliant, twisted minds since 2007.

I love this place.

i kinda disagree. i think it smooths out the airflow in high speed straights. the low speed turbulence behind the fairing would tend to build up the faster you go, the airholes allows the highspeed flow to break up that lowspeed area and flow it smoother past the rider.
will be interesting to see if they reduce the height of the fairing in the future to do the same thing.

Quote from: Raux on June 27, 2009, 05:46:44 AM
i kinda disagree. i think it smooths out the airflow in high speed straights.

so why do you think we don't always see them in that case?

Quote from: gm2 on June 27, 2009, 12:36:52 PM
so why do you think we don't always see them in that case?

It seems like only on certain tracks they show up.  Or could it be certain forecast? 

The might be be placebo's too like matched tires?

mitt

I think one of the mechanics got drunk on Dutch beer and went ape shit with the drill and due to new Dorna cost cutting rules they only had the one upper fairing.

i was suggesting that it's not to simply 'smooth out the airflow in high speed straights' -- or else we'd see it all the time, on all the bikes.  and cars.

Guess it is for cutting down the affect of the wind issues they were having in Spain
http://www.motogpblog.com/archives/916

pg 11 Stoner suffers bad wind
http://issuu.com/motorcyclenews/docs/mcn060509?mode=embed&layout=grey

Quote from: gm2 on June 27, 2009, 01:17:04 PM
i was suggesting that it's not to simply 'smooth out the airflow in high speed straights' -- or else we'd see it all the time, on all the bikes.  and cars.

actually you might have seen it and not known it. Jim Hall used it on one of his CanAm cars. well canam was right. and jim hall did some great designs... but i miffed the make of the car wiith the holes. it was a Lola