krnmike

The image above shows the wing on top (fully exposed to the oncoming air) & a wing that is positioned just right behind the body).

I'm guessing that the wing positioned above would have more drag than the wing positioned behind the body. Correct me if I'm wrong..

But what about the downforce? Which one has more downforce? (they are identical wings).

I came to wonder about this because the BTCC civic hatchbacks use a wing that is positioned behind the chassis, whereas J's racing / Memory Fab have wings that are positioned right above the chassis. How do they differ?

any speculations?

PDS

I'll give it a shot. The wing that is in the cleanest air flow will provide the greatest amount of downforce. Now, I would assume (oops) that the first illustration meets that criteria.

I will also speculate that the BTCC rulebook dictates the position of the wing on the second example.

JackOlsen

I'm not an aerodynamicist by any stretch of the imagination, but...

The second wing -- downstream of the car -- would be in a lot turbulence. I don't think you'd get any meaningful downforce out of it all.

Above the trunk. you still don't have the cleanest possible airflow. The cabin disrupts it, and the characteristics of a soft top makes it even worse. But it's the better of the two you are considering.

A common misconception is that if your wing is higher than the roofline of the cabin, then the airflow is clean and parallel to the ground. That's not true. 20-odd inches above the decklid of my car (not an S2000), the air is still moving at a 12 degree angle. You've got to get VERY high up before the air is no longer conforming to the shape of the car as it moves.

VERY high.

JackOlsen

And actually, with the hatchback design, you really aren't talking about wings in those two examples. The second would be useful as a spoiler, although not as useful as a functional wing, which you've got with the first example.

Drag isn't a huge issue, even with what are considered low-hp or momentum cars. At least, not at most tracks.

mikegarrison

It's more accurate to say that maximizing downforce is more important for laptimes than minimizing drag. But that's not quite the same as saying drag is of little importance.

krnmike

totally forgot about that..

krnmike

I was thinking that trying to achieve as much downforce as possible without gaining drag (or even having less drag) is to use an underbody panel (Fully enclosed, unless parts for cooling), & louvered hood (well.. in general). The reasoning behind the louvered hood would be so that the air that enters through the front radiator (or just front in general) would want to exit through any cracks inside the engine compartment. Therefore, having a louvered hood would efficiently pull the air out instead of exiting underneath the engine compartment (which is wide open on all s2000) am i on the right path here?

speaking of a hatchback, isn't there a vacuum behind the hatch which basically "slows" down the car? I guess I can say it pulls the car back? It seems like the air passes through the car itself and all of a sudden has to fill this giant space right past the hatch.

Voodoo_S2K

It was my understanding that hatchback designs like the CRX, Insight, and Prius with abrupt ends are better for aero.

mikegarrison

Look up boattail. There are subtleties involved here, as with most aerodynamics.

The goal is to try and have the flow going past the end of the body moving straight, with little or no abrupt turning into the stagnant zone behind the body.

INTJ

Yes, and controlled eddies from that turbulent flow, since a 9 foot long tail is not practical.