Presented by Nine Lives Racing
clutchmaster
clutchmaster New Reader
8/2/23 3:32 p.m.

Thanks in advance. I've searched, looked at other folks cars. There must be some reasoning or deciding factors for which shape wing to use.

Anyone have some guidelines for choosing? This is more of a HPDE car, with some standing mile (Arkansas) thrown in. Share your knowledge, guesses, logic.

 

thanks,

Lewy-D   

Xratti
Xratti Reader
8/10/23 11:23 a.m.

In reply to clutchmaster :

Standing mile, you'll want to take the wing off, unless you have some high instability in the car, just drag otherwise.
For an HPDE car, and many racecars, a straight wing will do the job just fine (If, by wing shape, you're talking about geometric twist, or raised center, etc). With regards to airfoil shape, there are many available, some are better than others. If it was my car and I had budget, I'd be looking at Zebulon or Verus Engineering to start, but PCI and Nine Lives have much cheaper options, with trade offs in performance.

clutchmaster
clutchmaster New Reader
8/11/23 8:28 a.m.

Thanks Xratti! we picked a Nine Lives wing to start (10" chord?). I agree about not needing the wing at the mile. Z's aren't super stable past 140 with out some help. I looking for another hatch to bolt on a little spoiler or maybe a whale tail for the mile events. 

sleepyhead the buffalo
sleepyhead the buffalo GRM+ Memberand PowerDork
8/21/23 11:04 p.m.

the NineLives foil comes out closer to 9.25" in chord from the extrusion process.  Unless you've bought one of their carbon foils.  iirc

the spoiler might be good to have with the foil (assuming your "rules" allow them in combination), because the added height of the spoiler can change the inflow angle (i.e. Angle of Attack) into the foil to better match the inflow angle 'seen' by the portions of the foil that are outside the body (assuming the foil is wider than the car body).

Here's a series of tuft tests from an FFR Daytona Coupe running a 3D APR wing, showing how adding a spoiler to the original kammback spoiler evens things out:
 

 

VolvoHeretic
VolvoHeretic GRM+ Memberand Dork
8/24/23 10:56 p.m.

In reply to sleepyhead the buffalo :

Is it just me or is the air coming off of the back window and under the wing in the next video stalled out?

sleepyhead the buffalo
sleepyhead the buffalo GRM+ Memberand PowerDork
8/25/23 9:45 a.m.

so the first three videos are a single setup captured in different runs, since JC only had the single GoPro; and that setup doesn't have the spoiler under the wing (I foreget if JC details what angle the first 3 tests are at; he does a better job in the intro for the later tests).  Basically what JC ended up finding out was that there wasn't a way to get the APR 3D wing in a position where the two different sections were working correctly (this is a bit of an issue with a "generic 3D wing"... there's a high likelihood that the sections will be out of place to work for the backend shape of many cars).

iirc, the end result was a custom variable height spoiler and a constant chord, untwisted APR wing.  although, they're now primarily doing some LeMons & Chump racing, and afaik aren't running the FFR Daytona Coupe as much.  (these tests were all almost 10 years ago)

Colin Wood
Colin Wood Associate Editor
8/25/23 10:18 a.m.

Just passing through to drop this article that might have some useful advice (It's still a GRM+ exclusive for 45 days, but the article also can be found in the June 2022 issue)

[How to test your car's aerodynamics for less than $100]

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