lordpantsington

I know there are 12 positions on the wing upright, and each position is separated by 1°.

In my case I'm treating a 21mm difference in front to rear ride height as standard. I know that the ride height is measured to specific places. It does not appear to me that even though there is a 21mm difference in the measured ride height, that the flat bottom of the car is pitched at all. Although the measured ride height isn't exactly on the axle centerlines, 21mm difference is about 0.5° rake. Half a degree is probably too close to the margin of error of a measurement, but I'll ask anyway: Is the flat bottom of the underbody completely horizontal?

Is the flattest wing position completely horizontal? Obviously the rake of the car influences the angle of the wing. If anyone has a measurement of wing angle, indexed to position, with respect to rake it would help me out tremendously.

Edit: Almost forgot, haven't seen anything in my travels aside from the MK1 to MKII relative numbers,(reduced front lift 25%, reduced rear lift 40%) but has anyone information on how the Aero balance was changed from 6Cup MKII to 7 Cup MKI?

Thanks,
Andrew

Phokaioglaukos

Also I note that the factory manual suggests position 7 for the wing when using Michelin tires. Which holes are used for that position? Does one count holes from the top down?

Matt Romanowski

Is flat considered in relation to the ground or is relative to a surface on the car? If the airflow is impacted by the lines of the car, then wouldn't rake be immaterial?

lordpantsington

For my application, consider flat to be relative to the ground (parallel).

Chris, this is a cropped photo off the facebook car:

1 is the most flat, 12 steepest angle of attack.
and this is what helped me understand the most:

7 is marked in red.

Phokaioglaukos

Thank you! I have more rake than I probably need.

lordpantsington

Woo!
http://www.porsche.com/uk/motorsport...-britain/cars/
996 Cup, 40% less DF than 997

jrgordonsenior

Just to be sure you measuring at the correct places.....

lordpantsington

Thanks,
What I don't know is how far those measurements are located from the axle centerline.

This is the only juicy data I could find with respect to Porsche Cup Aero:
http://www.reverie.ltd.uk/Downloads/...orscheData.pdf

And while I can use the Cd/Fa of a 996 and the 40% number to get Overall Df, and Drag, I'd still be missing the split between front and rear. I'm not sure I should even base numbers off that test because of the ride heights. The amount of lift on the front end is astounding.

cstreit

Did I scan through this correctly that raising the ride height just a bit actually is reducing drag?

lordpantsington

I think you might be looking at the stock GT3 vs the modified Oakley Design Aero package.

There are videos of the test here:

I wonder if they raised the ride height of the Cup car to get a better baseline for comparison?

HiWind

Just an aside - anyone using/used on of those sequential simulators they make?

lordpantsington

Also looking for the wing profiles/splitter data of Cup and WC aero packages.

lordpantsington

Found some specs, 55" (1410mm) x11.75" (298.45mm). Looking for Camber to % Chord, and Thickness to % Chord. Yes, I just found http://www.grc.nasa.gov/WWW/K-12/airplane/foil3u.html

Skypalace

I always ran a fair bit of wing in my 996 Cup, even on fast tracks, as the car is so limited in rear downforce. Much easier to keep rear tires under you in the last half of the race. Ignore the top holes, you'll never use them unless you're doing the Texas Mile or such...

The 997 (esp .2) has a much more efficient rear wing (wider and higher, much more into the airflow) so a much wider range of the wing can be effectively used.

lordpantsington

So I found the rule book for ALMS GTC, 997.2 spec wing = 1710 (including uprights), x 295.25? (is a bit blurry).
Press release: http://www.conceptcarz.com/vehicle/z...1-GT3-Cup.aspx states 997 @ 1460 x ???

Gives credibility to my 1410mm number.

So has the wing profile changed at all? 295.25 or even 285.25 is really close to 298.45.