Wing questions

[miatagr]

After autocrossing the new car yesterday, it appears a wing will help. Especially for the higher speeds of track days.

Options...

I can get a wing off ebay for $50, The Exo stays $200, (wish I had ordered my frame with the bolt holes). Then modify the wing to fit the wider spacing.

A search showed that COT wings are still available for $400-$500. They say they are the show wings  but I think I saw on here that those still work. Get the Exo stays and it should be a bolt in.

Buy the new wing and stays from Exo for $1000 but there is a question in my mind. Most of the builds I see on here appear to be drivers and show cars.... The new Exo wing is beautiful and makes me wonder if it was designed for looks or or to work as well as the other two options? This makes me reluctant to buy it without more info...

Looking for responses from other track day/autocrossers....

[Stiggy]

Perhaps we should consider the down force required, front/rear? How much drag are we prepared to accept? Is it a time to ensure tyres/suspension (corner weights) settings are perfect for the track in question? Wings do look great but we should consider all other criteria that could effect handling too.

[Kevin Patrick]

Hi All - Here are the details of our new APR Performance GTC-200 wing for the Exocet. We worked with the team at APR to create a custom version of the GTC-200 with the optimal pedestal locations for the Exocet. A brand new mount set was redesigned out of Domex 700MC that is laser cut and CNC bent to properly integrate with the 10mm "aircraft grade" 6061 billet aluminum pedestals that support the airfoil. The mounting system has a lot of adjustability to allow drivers to fine tune the angle of attack.

The airfoil was designed for midsize and compact cars with the optimum efficiency range being 50-160mph. It spans 59.5" and has a height of 10". Each GTC Series airfoil is composed of lightweight and durable carbon fiber reinforced polymer (CFRP) composite materials. These airfoils contain pre-pregnated woven carbon fiber sheets for superior strength and low weight. All CFRP airfoils are made using pre-pregnated composite manufacturing processes (i.e. high-temperature autoclave and vacuum bagging) in high-quality aluminum billet molds. A Gurney flap can be added to the wing at additional cost.

Computational Fluid Dynamics (CFD) analysis was performed on this wing to support validation of its aerodynamic design and I have referenced their results below:

Data (without Gurney flap)


Speed Tables


Wing Forces




Data & Renderings (with Gurney flap)

[tomaff]

Delivery to the UK?

[miatagr]

Wow... Thanks Kevin for answering many questions for the engineers. I was about to ask about mounting heights before I drill holes in my support bars. Looking at where others have mounted their wings, it seems to me that the top of the seats and roll bar are in the air flow in front of the roll bar, reducing it's efficiency... As a self taught dirtball mechanic with no engineering background, is this true?.. Would mounting the wing higher than the roll bar be better?

[Warren van Nus]

The wing would indeed work a little better if it was above the rollbar, but it would need to be at least 5 inches clear before you're in "clean" air. Unfortunately that looks ridiculous and raises the CG significantly, and we have to cater to those customers that buy a wing for aesthetics as well as performance. Based on the quick CFD I did and general aerodynamic theory, you're better off placing turbulent air on the high pressure side of a wing rather than the bottom. The flow underneath is more important and harder to control. The horizontal cross sections of the seats and diagonals are much smaller than the tube, so the current position is a lesser-of-two-evils thing.

All this goes out the window with experimental data, though. If you'd like, you could rig up your own mounts out of sturdy rollbar clamps and slide them up and down. Here's a good experimental setup: tape some string to the bottom of the wing, and aim a GoPro at the strings and a phone with a GPS app showing speed. Whatever position has the strings staying laminar at the highest speed is likely the best performing one.

[miatagr]

Thank you Warren

[miatagr]

Thank you Warren