The
GTP ZX-T bodywork introduced at Portland in 1986 was a departure from
the Lola 810 starting point, especially in regards to the rear wing
location and position. During wind tunnel development Yoshi
Suzuka noticed that the closer the rear wing was in relation to the
tunnel exits, the more effective the car’s tunnels were. Now this
isn’t to say that Yoshi Suzuka was the sole originator of this idea,
certainly this was going on at other outfits at around the same time
(think Tony Southgate and what he was up to at TWR). But Suzuka methodically documented his results and
scientifically came to the conclusion that the rear wing’s effect on
underbody downforce was indeed substantial.The test concluded that the wing itself was generating 1833 lbs of downforce from the car’s total of (for this test) 5408 lbs. More importantly, the wing was influencing the generation of an additional 1575 lbs of downforce, making the wing responsible for 3408 lbs, or more than half of the car’s overall downforce!
Now without any doubts about the interaction between the rear wing and the underbody Suzuka proceeded to define the exacting location of the wing, methodically testing various positions until the sweet spot was found.
Note the prominent aluminum beam running the width of the car and integrated into the engine cover. All the wing loads were transmitted into the engine cover through the integral rear wing endplates.
Suzuka
adopted a double element rear wing, designed by Bernard Pershing, and
introduced it during the ’87 season, replacing the Lola-derived single
element wing. The Pershing wing’s secondary flap's center section
had a longer chord than at the tips and outboard trailing edge was
chamfered as a result. According to Suzuka, the large radius
leading edge of the main element was designed to compensate for
turbulent air.
The
GTP ZX-T's rear wing loading is divided between the two outboard
endplates as well as a central pickup that locates off of the gearbox.
As the rear wing was direcltly mounted to the endplates, which
were in turn bonded to the engine cover, the central mount here was
only pinned so that the engine cover could be quickly removed as needed.