Mayf--
I haven't commented on the subject up to now because I've never researched
the aero mechanism of these two devices, and mainly because I'm not SURE I
remember the history and applications correctly. But I'm getting a little
stirred up now, so here is what I THINK I remember from my days working with
CART:
1. Two DIFFERENT devices, used for different purposes.
2. Wickerbill used in several different series (including CART) as a sort
of "trim-tab", to help fine-tune the front and rear wing downforce.
Typically adjusted by selecting a strip of rigid material of a particular
height, and sliding that into a slot near the trailing edge of a wing.
Aerodynamically inefficient, just as a trim-tab is; creates about as much
drag as downforce. You trade straightaway speed for better control in the
corners. The brave guys (and gals--???) pull these out for qualifying!
These wickerbills are typically not mandated by series rules, but an
expedient that the teams find useful for chassis tuning.
3. Gurney Flaps (if I remember correctly) originated as a device MANDATED
by CART to control speeds (some say to "bunch-up the field") on some ovals.
Michigan was one. I never saw one in use, but it seems like I remember that
they were basically a "board" turned sideways to the wind, and their sole
purpose was to slow the cars by creating drag-- not to aid in downforce, at
all. I also think I remember that some of the drivers liked them because
they created such a strong slipstream that you could use the "slingshot
effect" for passing. Some folks were saying that these should have been
mandated for the Ft. Worth CART race ("the race that didn't happen"). I
think that if they had been, M. Andretti might not have "seen the elephant"
and got them to cancel the race-- notice that he's retiring right before IRL
goes there!
And then again-- I may be remembering this about the wickerbills and Gurney
flaps all wrong!
Russ, #1226B
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