Wings/Spoilers make a difference in drifting?

[malcolm]

Originally posted by Whisky
I'm quite familiar with the Subaru WRC rear wing and the purpose of the strakes, but that also comes at a loss of efficiency.

remember, we're not talking about a perfect wing... just something to give the rear a bit more grip.

...speeds are greater in WRC then they ever will be in drifting.

true, hence my suggestion for a multi-element wing, unlike the single element WRC wing.

Airflow separation is largely dependent on the car

true, to an extent. however, with cars like an MR2 that have no rear "fastback-style" window, even though the flow has seperated, it will continue a path much like one where it is attached to a fastback, but instead of being attached to the glass, it just flows over a big layer of turbulence

interesting case in point: For the longest time, I would drive my AW11 MR2 with the rear decklid open, just to let out a little more heat from the engine bay. It helped a little bit, and the lid always stayed down. That car had a few problems, so we got another one (we're not big spenders... cheaper to replace than repair!). The next one had a sunroof. Shortly after, I am driving down the highway, and I decide to pop the decklid to let the engine run a little cooler... all is good. Then I decide I should give myself the same treatment, and open the sun roof. all is good... then I notice that the decklid seems to be floating up about 45 degrees from horizontal.

I figure that the airflow with the sunroof down came down and attached to the back of the car just before the decklid, thus pushing it down. However, when I put the sunroof up, it was just enough to engulf the decklid with turbulence and lift it up. It seemed that the air just attached later, and a particular swirl of turbulence just picked it up.

Therefore I would deduce that even on that car, with no fastback, a wing mounted even 4" off the trunk would be effective. Perhaps it wouldn't be as effective as if it was roof height, but still, it would work reasonably well.

...focused on a Formula SAE project working to develop low-speed aero downforce. If I recall correctly they had some success, but the car was ugly as can be.

I've seen a few, and yes, most are ugly. I saw one car that used single element wings, which are useless for low-speed stuff like auto-x. Another (UTS, I think...) used multi-element wings, but I don't think they were big enough for the low-speed course, and there wasn't enough of an angle of attack. There was a third one, and I think they got it right. When I go home this weekend, I'll check rummage through all our magazines and try to find out more.

We should keep this going MalcoLm, see if we can come to any interesting conclusions...

for sure

[Whisky]

I think you misunderstood. Perhaps I phrased it poorly, but I did not mean to suggest that adding a rear wing would make any significant change in frontal area. I was simply trying to say that management of frontal area is of prime importance in aerodynamics, and that when a car is sideways its frontal area is obscene.

Regarding separation points, I agree that the air is unseparated along the roofline, but nearly every street car will suffer from some separation at the back of the roof where the rear gless slopes downward. Hence the effectivenesss of your sunroof as a spolier.

I don't dispute that there is still airflow down along the glass and off the rear deck of any car (even dropping the tailgate in my F250 made a difference in highway fuel efficiency), but I do still maintain that it has largely separated and is capable of providing very little downforce close to the decklid. My earlier comment that it is now "useless" was a generalization meant to keep the point simple.

The most interesting aero aspect of drift cars, to me, is cooling. To that end, I saw a car at the D1 driver's search (McKinney car maybe? Erns would know) with a vertical fin pointed straight forward off the nose. Essentially it directs airflow into and thru the intercooler and radiator in similar fashion to the strakes on the Subaru car. When I saw it I immediately - and still do - wondered why nobody else does this. Its not pretty, exactly, but were it made out of expensive materials people might think it was cool I would be more impressed by body kits if they were also functional in directing air to cooling ducts for the radiator, intercooler, oil cooler, etc.

Controlling airflow under the car might also prove more useful for a drift car than any rear wing.

[malcolm]

ahh, I see where you're coming from. But one thing to remember is that there are almost open engine rules... so if you increase the drag of the car, you can always add more power to offset that (well, budget permitting).

Controlling airflow under the car might also prove more useful for a drift car than any rear wing.

hmmm... interesting. The problem would be, where would you place the "nozzle" for the ground effects? The front of the car? surely the flow would become detached by the diffuser if it had to go that far... Through the side?

Here is a little mock-up of what might work. the yellow box has a view of the diffuse with strakes at from the back (it would be the left hand side of the diffuser... the right side would have the strakes curved the other way to allow the air to flow under them easier... or should it be the other way around so that it catches the air, pushing it up, perhaps acting like a little splitter/air-dam arrangment? hmm). The car is in the red box with the ground-effect tunnels laid out.

[malcolm]

Its not pretty, exactly, but were it made out of expensive materials people might think it was cool I would be more impressed by body kits if they were also functional in directing air to cooling ducts for the radiator, intercooler, oil cooler, etc.

Actually, imagine that, integrated with a splitter, and more strakes to direct air over the nose as well. It might not look pretty, but it would look aggressive for sure.

If i was more into drifting, and had a dedicated car for it, I would go nuts on aero and do some testing...