Acura's
interpretation of the
'09 specification rear wing. The reduction in span from 2
meters
to 1.6 has significantly reduced rear downforce. Indeed, Acura
suffered somewhat given that very late-hour regulation change as the
car was designed around a slight front biased weight distribution.
But the reduction in rear downforce meant the new ARX-02a
suddenly had a mid-corner snap oversteer issue. In
fact, the
ARX-02a was described as a "dog" in the first back to back test with
the new rear wing. Ultimately this probelm was mollified by
shifting that slight front weight bias rearwards. But naturally
this meant that because of that late regulations change the ARX-02a was
forced to move away from the hard wired design solution and was less
optimized in the end.It has since been optimized and most certainly some of what was lost has been regained through not only optimization of the rear wing, but of the rear end in general.
It's
hard to overlook the rear wing mounts. The "swan necks" mount
to
the less sensitive, less important, high pressure side of the wing freeing up
low pressure side wing area and reducing airflow disruption. This all came about becuase the reduction in chord from 300 mm to 250 mm for '09 (in addition to the span reduction) led to the use of wing profiles with increased camber. These more aggressive profiles were inherently more sensitive to wing disruptions and tended to result in very large flow separations when run at higher and higher angles of attack (given the desire to try and recoupe lost downforce). The Acura's rear wing mounting solution was designed to reduce these surface disruptions as much as possible.
For the record, the rear wing mounts on the Acura are actually referred to as "Quillars", which is an amalgamation of "Question Mark Pillars."
Naturally
the ARX-02a's rear end is much more aggressive than the ARX-01a/b.
We also suspect additional development work was carried on
the
rear end since the car initially rolled out in order to reclaim back
some of the lost rear downforce. Note that the diffuser strakes come all the way out to the trailing edge of the diffuser.
The
combined rear spoiler/gurney. At the Wheels Down Winter Test the spoiler had a full length gurney.
At the 12 Hours of Sebring, the full width gurney was replaced with a center gurney.
Starting at Sebring the rear diffuser strakes were trimmed back from the trailing edge of the diffuser.