Aero Aids, Do They Work? In Particular Gt Wings? Now You Know!

[siksII]

Something to consider....From an article i read in CAR magazine:

Whilst speaking to one of the R34 GTR engineers from Nissan the guy said that they could have set up the GTR to have more downforce but they didnt want lots mainly due to the fact that once traction is broken through a corner, if they car was relying on grip produced by downforce, the more downforce the more sudden and violent the loss of traction.

If you somehow got your GT wing producing big downforce and consequently grip i think this would be something to think about.

[STATUS]

mate there is no way those 4kg over the rear wheels will make a noticable difference. Just put 4l more fuel in next time.

To increase rear traction, look at:

* the line you take through the corner (turn in later)

* increased throttle control

* better or wider rear tyres

* decreased camber at the rear

in that order

haha you still have no idea do you... 4kgs .....meh.... but i do agree that it probaly isnt his issue money would be better spent on tyres or weight transferral aids.

[STATUS]

Something to consider....From an article i read in CAR magazine:

Whilst speaking to one of the R34 GTR engineers from Nissan that the guy said that they could have set up the GTR to have more downforce but they didnt want lots mainly due to the fact that once traction is broken through a corner, if they car was relying on grip produced by downforce, the more downforce the more sudden and violent the loss of traction.

yeah this is common for road car engineers it makes for a safer numbnuts car.... these cars are built for average joe and he/she doesnt read the limits of their car all that well.... the easier the limits are to find safely the lesser the chance of a big off..... brown pants are better than dead customers

[siksII]

yeah this is common for road car engineers it makes for a safer numbnuts car.... these cars are built for average joe and he/she doesnt read the limits of their car all that well.... the easier the limits are to find safely the lesser the chance of a big off..... brown pants are better than dead customers

Yeah of course, hence nearly any stock car tending toward understeer more than anything else.

I find that what makes the pants really brown is when you get out of shape in a car that has safely and easily found limits since when your in a dangerous deathtrap you sort of clench continuously getting ready to be thrown off the road lol

With all this talk of downforce, how about some discussion about lift?

I dont know much about aero, but i hear that keeping air from getting under the car helps stability.. Maybe modifications to this end would be more realistic for most of us rather than trying to create high downforce with ricey gt wings :laughing-smiley-014:

[STATUS]

I dont know much about aero, but i hear that keeping air from getting under the car helps stability.. Maybe modifications to this end would be more realistic for most of us rather than trying to create high downforce with ricey gt wings :laughing-smiley-014:

the rear wing will have ultimately more aero effect on anything compared to any other aero device due to its size and placement..... i am trying to figure out a way to measure canards atm

[driftmeister]

Hope this link would help everyone understand further...Cheers!

http://www.sportcompactcarweb.com/tech/061...rt_2/index.html

[GTRgeoff]

Interesting toy but mostly useless from an engineers perspective that has a specialisation in aerodynamics. As Duncan says 4 kg is a worthless increase, especially given the height and the distance behind the rear wheels. Keep increasing the height above the axle line and you will impact the front contact loads.

For Matt: at 45 deg you are well into stall for a wing so you will get only drag. 16-20deg is optimal depending on foil design. Your typical trendy GT wing is mostly useless. When you see them on real race cars then maybe they will be worth buying.

An interesting concept is that of putting a wing on a slide mobile. Most of them probably don't analyze the effective change of chord length as a result of the change in the angle of incidence of the air on the wing when sliding, effectively lengthening the chord and logarithmically reducing the downforce. So essentially pointless.

If you want to measure aero performance then invest in a decent Motec setup with suspension displacement loggers and use a wind tunnel or if budget is a problem a very smooth road and plenty of data smoothing. Then to compare the drag effect top speed runs are your best bet for the road runs. I've used a couple of tunnels in Melbourne and RMIT is about the best.

[siksII]

the rear wing will have ultimately more aero effect on anything compared to any other aero device due to its size and placement..... i am trying to figure out a way to measure canards atm

Canards look awesome!

In terms of the wing having the most effect.... im not so sure. I should at least read that article before commenting, but a lot of modern supercars do not use rear wings, or use very small read wings. I guess with some cars the whole body of the car is designed to produce downforce, but i also assume that a lot of the aero of handled by the front/rear diffusers and undertray of the car.

Examples of supercars that were clearly designed with aero and downforce, but with no rear wing:

Lambo Murcielago

Lambo Gallardo

Ferrari F430

Ferrari Enzo

Koenigsegg CCX

etc etc.

If the rear wing had more effect than anything else why dont these cars use one? I know they all produce some/lots of downforce without rear wings.

I guess when looking at cars not designed with much aero in mind like ours, a wing could make the biggest difference, but i have doubts.

[Snowman]

I think you'll find you are wrong in your thoughts there. A couple of those cars have rear wings that raise at certain speeds.

And the best example of all can be shown with the CCX. The Top Gear Tests showed considerable increase in lap times with the addition of a rear wing to the car. (Not to mention high speed stability)

Koenigsegg CCX

[Ant97GTR]

Another thing that a lot of those supercars have instead of huge rear wings are under body diffusers. I fitted one to my old gtst with some impressive 'seat of the pants feel' improvment. Despite only fitting a rear diffuser I found that the car was far more stable in braking zones and allowed me to brake much later without the car feeling like it was going to turn around on me.

[siksII]

I think you'll find you are wrong in your thoughts there. A couple of those cars have rear wings that raise at certain speeds.

And the best example of all can be shown with the CCX. The Top Gear Tests showed considerable increase in lap times with the addition of a rear wing to the car. (Not to mention high speed stability)

Koenigsegg CCX

I dont think any of the cars i listed have wings, although i im aware that some supercars do have wings that come up at speed such as Porsche 911, Carrera GT (My fav) and Bugatti Veyron. Are you sure any i listed have wings that rise up... I didnt think they did.

I knew someone would bring the CCX up

Im reckon they could have designed the car to create the downforce it gains with the wing.....without the wing if they wanted to but didnt to keep the top speed higher.

[Snowman]

The Gallardo definitely has a wing. (abiet tiny)

And the F430 and Enzo have a raised boot lip that is designed to act as a wing.

[Ant97GTR]

Correct there Snowie but the whole reason they can be that small is the fact the the under car diffusers are doing all of the work....without that they would have wings that the lambos and Ferraris had during the 80's

[STATUS]

Correct there Snowie but the whole reason they can be that small is the fact the the under car diffusers are doing all of the work....without that they would have wings that the lambos and Ferraris had during the 80's

the flanks on these cars also provide enourmous downforce.... function as well as form.

[siksII]

Correct there Snowie but the whole reason they can be that small is the fact the the under car diffusers are doing all of the work....without that they would have wings that the lambos and Ferraris had during the 80's

Thats sort of my point. I personally dont see those little lips as 'wings' ie on the M3/M5 etc, i know they provide significant downforce but its the design of the body that allows them to be so effective. Ie. if you attached those lips to your r34, im sure they would do next to nothing, so its not really the wing on its own that does it.

the flanks on these cars also provide enourmous downforce.... function as well as form.

I love how the air intake on one side of the Murcielago is bigger than on the other side. Looks awesome!

[GTRgeoff]

Not a wing on the murcielago but another diffuser. it gives a sharp termination to the rear of the car to reduce high speed harmonic motion caused by von Karman vortices. To be a wing it has to have a proper aerofoil shape.

Ants diffuser pulled the rear of the car down visibly at about 4th gear change at Calder.

Under car effects are far more usable than wings on top. A 20mm increase in the length of a front splitter can increase front downforce by 60%.

[djr81]

I thought I might add a couple points to this discussion about rear wings & things.

1. The rear wing will feel as is it is producing more rear grip because in part it is, but also because it is degrading the front grip. The down force & the drag that the wing produces, respectively behind & above the rear axle line will induce an uplift on the front axle.

2. Front splitters & rear difusers only work well when they are located close to the ground. The difusers becoming fashionable on the new cars are mainly for show & also to lessen drag by cleaning up the undercar air flow.

3. Very few production cars can actually produce any downforce, let alone meaningful downforce. Check the V8 supercar figures if you don't believe me. For all the size of their wings the downforce produced is suprisingly small.

[9krpm]

The Gallardo definitely has a wing. (abiet tiny)

And the F430 and Enzo have a raised boot lip that is designed to act as a wing.

the Gallardo wing is also raised at high speed by about a few cm

4 kg where you need it most is still better than an oversteer

[scathing]

Whilst speaking to one of the R34 GTR engineers from Nissan the guy said that they could have set up the GTR to have more downforce but they didnt want lots mainly due to the fact that once traction is broken through a corner, if they car was relying on grip produced by downforce, the more downforce the more sudden and violent the loss of traction.

Pretty much, yeah. It depends on if you're building the car as a pure race car driven by an experienced driver, or a road car to be driven by all sorts.

Keeping the car's behavior progressive is a must for any engineer setting a car up for OEM. That's why they make the suspension choices they do - you may not be able to corner as fast as with harder suspension, but when you approach and exceed the limits they're well telegraphed and very predictable.

[siksII]

the Gallardo wing is also raised at high speed by about a few cm

4 kg where you need it most is still better than an oversteer

On some corners i wish i had something that would suddenly remove kgs from the rear

Pretty much, yeah. It depends on if you're building the car as a pure race car driven by an experienced driver, or a road car to be driven by all sorts.

Keeping the car's behavior progressive is a must for any engineer setting a car up for OEM. That's why they make the suspension choices they do

Yeah im aware, but personally i would like to have the limits high, telegraphed (a little at least!) and predictable! Im sure even race drivers dont like their cars to be a threatening drive..

So who apart from Ant97GTR has succeeded in making some real improvements to the aero of their car?