then i suppose our project in the windtunnel in the belgian aerodynamics institute was useless...
Our conclusion was that on normal streetcars (also the most streetlegal sportcars) a normal sized trunkspoiler doesn't work because the air that goes over the trunk is no way near linear and turbulent as hell. We did lots of measurements on a E36 M3 and we had to go as high as the roof to find some air flowing relatively stable over the car to be able to make a spoiler work as a wing of a plane generating downforce.
That's why real trackcars have BIG wings, sometimes stupidly looking big...
Measurements showed us that spoiler on a height of halfway between trunk and top of the roof was just pulled backwards and made a kind of rotative movement on the trunk... (pushing one side and pulling the other side) Important : not always in the same direction, depending on the airspeed the spoiler was pushed forward or backward, which shows the turbulent flows depending on the speed. In some cases the air flew backwards over the spoiler, in other more or less in the right direction...

Aircrafts fly through turbulent air because of the much higher speed they have, however they can have "airsunks" on the way, which is the lift being instable during the flight because of turbulence around the airplanewings for a short moment.

I'm nog saying I'm an aerodynamics specialist here, just sharing our conclusions...

 

Good post Rob.. Interested to read what others post. If a splitter was curled up at the front similar to a upside down slat on a wing could you see any advantage from this or would it just create more drag?

 

Graphtuner, If Formula 1 wings weren't acting as wings they wouldn't throw up the massive rooster tails when running on a wet track. You also need to let the NASCAR guys their trunk spoilers aren't working.

 

I'm not saying the F1 spoilers don't work as a wing, i stated above that they do work as a wing.
F1 is one of the few sports with enough budget to do real investigation in windtunnels, so they can shape the cars to make the spoilers actually work. That's also the reason why they need a certain minimum speed to have the downforce needed to take some corners (remember the F1 experience of Hammond in Top Gear where he didn't have the balls to go fast enough to profit the downforce)

As far as nascar : I'm quite sure those cars would just get too much lift at these speeds because of the very smoothly shaped bodywork. Too much lift is not enough grip... those spoilers will bend the airflow behind the car to reduce lift... you can never talk about wing effect with those shape of spoilers (no air going under and over the spoiler at the same time) but they do work in terms of reducing lift indeed

 

Graphtuner, so you're saying that "99% of S2000 wings" aren't acting as wings because there's not enough airflow below the wing to generate a low pressure area which generates downforce? That the wing is simply acting like a NASCAR style trunk lip spoiler? If that's the case then let's seal up the area under our wings and see how slow the car would be. I know the air coming over the top of the car isn't laminar airflow but it's clean enough to act on both sides of the wing.

Also most S2000 wings extend outward beyond the hard top and get relatively clean air--the outside 2/3 of the wing is definitely acting as a true wing.

 

I considered that but was concerned it might interfere with airflow underneath the wing, reducing the effectivness of the wing. My GTC-200 isn't very high off the trunk deck. The 2in APR riser might help a lot with that.

 

With all the race car aerodynamic study done worldwide I assume if a better splitter shape was possible it would have been discovered by now.

 

That could be an issue even with the risers. I'll have to do some more research before I start bending metal and drilling holes in my trunk

 

Dries (Graphtuner), I think we might be having a little bit of a language issue and I apologize because your English is much better than my French (or any other language). After carefully re-reading all your posts I think I understand what you're saying but I find it hard to believe the underside of most S2000 wings aren't generating some downforce--especially the outside sections of the wing.

 

That's why Dan Gurney found his flap to be so effective. It not only gave him more downforce, but less drag.