Jim bailey - 928 International

The Mercedes/ Mclaren SLR..." Certainly, with the SLR capable of 200-plus mph, it's nice to know that the movable rear spoiler can rotate up to a 65-degree angle to work as an airbrake when jumping on those ceramic binders. This same spoiler tilts 10 to 30 degrees at 60 mph and above to aid high-speed stability."

Fastest928

The only way to analyze wings accurately is via the NACA number andt he cord length.

O f all the wings I have seen in the Porsche 928 aftermarket, no one yet has provided a NACA profile of their wing....

The goal is max downforce with minimal drag. Stan and others WHAT ist he NACA profile of your wing ... is it a Liebach or what #???

Stan, take a picture of your bearings and let me see the wear pattern, I might be able to provide some info...

Marc

Stan.Shaw@Excell.Net

Hi Marc,

I don't know the wing profile, perhaps one of the Dave's knows. (Roberts, Lloyd or Chamberland).

The bearings from the first motor failure are in a pile, and I am not sure I could tell them apart from other motor bearings, but I will check. Thanks for the offer!

worf928

Yup.

Yup.

But, with a good visual of the profile you can punch in the profile to a number of programs which will allow you to gauge the rough performance of the wing. No. It isn't as accurate as if you actually had a NACA number. But, you can determine approximately the angle of attack of zero lift, maximum lift, the approximate onset of stall and the approximate attack angle where aero efficiency drops off. You can also get a relative gauge of comparative performance between two profiles.

And in any case, without some good data on flow around and over the rear end of the 928 there's no use in trying to tune the attack angle to exact degrees. Given the lack of data, lack of wind tunnel test time, and lack of NACA number it is better to pick a robust profile that has good performance over a wide range of attack angles than a wildly cambered profile that as great performance in a very narrow range of angles but is worse than the conservative profile outside of the narrow range.

worf928

I wasn't able to find a NACA profile that matched DL's profile. That doesn't mean that it doesn't match a known profile. It might mean that the match is not included in the various programs available to me.

Fastest928

Well, we used to offer a NACA 4115 wing, but the guy making them went out of business! We can get Lieback wing profiles in both Aluminum and CF ... but the cost starts at 1500 and goes up!

They are REAL wings ...

Marc