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The rear of the car is very simple as well. Chevrolet does not seem to be using the wheel guards for any kind of flow conditioning. The new aero seems to focus on drag reduction. Honda seems to have a slight top end power advantage, so this may be an attempt to catch Honda on the straights. However that low drag can be problematic in traffic as turbulent air produced from other cars reduces the effectiveness of the car’s aero package.
The Honda camp has focused on downforce. Their front wing mainplane is noticeably smaller than Chevy’s. What else is very obvious is the much smaller radiator inlets on the Honda. The design of the rear of the sidepod is much more conventional as well. Also note how their rear wing has swan neck mounts, similar to the prototypes at Le Mans. This is done to clean up flow on the bottom side of the wing, improving its efficiency and helping to reduce turbulence off the diffuser.
Much like their road course kit, Honda uses the wheel guards to extend the width of their rear wing, adding winglets on the outside of the end fences. These are braced to the rear guards. The guards themselves seem to be used for flow conditioning as well. Contrast this to the Chevy above, which just blows air through. Honda’s engine cover has a large stabilizing fin, similar to their old F1 cars.
Now that we have a broad overview of the cars, let’s look at the details, starting with the Honda of defending 500 champ Ryan Hunter-Reay. From this angle we can get a better idea of how Honda is directing the air over the nose of the car. The nosecone itself is still a Dallara piece, as per IndyCar’s rules. Honda’s front wing is very reminiscent of the original Dallara wing. In fact, the two are nearly identical. There seems to be a bit of shaping on the Honda end plates to help divert air around the front tires. The end fences are also longer and the main plane has more of a contour to direct air below the car and toward the diffuser. But other than these slight differences, the Honda and Dallara wings are very similar.
Here, we can get a better view of the end fence. This is area of the wing Honda modified the most from the Dallara piece. We were unable to see the backside of the wing, but it is very likely the rising slope of the end fence works with the bottom of the wing and the end fence to direct air around the tires, towards the radiator inlets, or under the floor. One noticeable omission on the front wing is individual adjusters for angle of attack. The Dallara wing only had one adjuster to adjust the angle of the entire wing. It seems Honda has stuck with that as well. This seems a bit odd as adding or removing downforce on only one side of the car would be a useful tuning tool. There are small Gurney flaps on the outer edges of the front wing next to the end fence, but replacing these during a race is time consuming. IndyCar pit stops are second only to F1 in their speed, so spending minutes replacing Gurney flaps isn’t going to work in the heat of battle.
