pitot tubes on race cars

[Louis-Alain_Richard at computerhorizons.com]

>From the position of the tube, I guess its for measuring the actual 
undisturbed air speed. The reason must be linked to the "flying Mercedes" 
of  LeMans 1998.
These cars took off because, after getting closer from behind to another 
slower car, their front downforce was impaired to the point of being nil.
I guess the driver wants to know when the air speed is way slower than 
road speed.


Louis-Alain




Out of curiosity, anyone know why a number of the prototype ALMS cars 
sported pitot tubes?  I've seen the same thing on pictures of F1 cars.

Sorta visible here if you click on the image for the larger version:
http://frank.mercea.net/zoph/photo.php?album_id=20&_off=8

(right in front of the headrest hump)

Oh, and much better visibility here:
http://frank.mercea.net/photos/cars/CRW_4399.jpg


Generally in aircraft they provide:
-speed indication
-vacuum (or pressure) for driving the gyros in an emergency

Neither seems terribly useful in a racecar with four perfectly good 
wheels to measure speed from(and an accelerometer to tell when 
there's wheelslip, for example).  If you need an artificial horizon 
gyro in a racecar, you're doing something wrong :-)

Only other thing I can think of is for measuring aerodynamics, but 
would one fixed point be all that useful?  Maybe a reference pressure 
for other ports along the car?(if so, they're well hidden!)

So I give up.  What's it for?  Google turned up nothing useful.

Brett