rlaifatt

I'd say almost any corner in which you are not full throttle without it, you can go faster with it (except for maybe the tightest hairpin). Anywhere that you can do full throttle without it, then it slows you down with drag. So the net benefit depends on the track. High speed, lots of straight it may slow your times.

mikegarrison

Richard's right, but there's a little bit more to it. If you crank the wing up, for instance, then you will get more downforce and more drag at a given speed. That means that if you want the downforce at lower speeds, crank it up, but you might have too much drag at higher speeds.

Basically, the most important corners on the track are the high speed corners that lead onto straights. It's not so important to worry about what happens in the low speed corners, as long as you don't screw them up too much.

rlaifatt

I think that's what I said when I said it could slow your times on certain tracks.

JackOlsen

In general, they're not going to do much under 75 mph, and they're going to be doing more than you need above 100 mph. It's a very rare track where you need much dowforce at very high speeds. Even at Willow Springs, a wing will help your lap times much more for what it does in turns 1, 2, 5 and 9 than for what it does in 8. And of course, it will slow you down on long straights.

Here's a graph showing front and rear ride height changes on my car (sorry, not an S2K) between 80 mph and 130 mph. You can see the rear come down as the speed increases, but you'll also see a cantilever effect where the front comes up as the rear drops, which only aggravates itself as the rising front allows more air to get under the car.



Being a guy with more fabrication time than good sense, I tried a couple of different tricks to try and keep the front down at speed. So far, my ideas for the front end have been as ineffective as they are ugly.

Nobody

Nice try, Jack! That front wing didn't help, eh?

How about a giant fan mounted in your front trunk that sucks air from under the car and blows it out the top like those banned race cars from the 70s? When the speed of a fluid increases....

JackOlsen

[QUOTE=Nobody,Oct 8 2006, 06:53 PM]How about a giant fan mounted in your front trunk that sucks air from under the car and blows it out the top like those banned race cars from the 70s?

iam7head

What about a tipical Ricer/APC dual decker wing?

on a short course like willow on a stock S, would you recommend using a wing to control the rear end or go uses bigger front sway bar instead?

THANKS in advance

krazik

Jacks car already "sucks"



btw with enuf elements and attack angles a wing can make a diff at 20mph. But then its going to REALLY slow you down at say above 70mph

mikegarrison

Not to get too aero-engineerish on you, but there is a huge difference between a multi-element wing and a biplane wing. You have to specify which you mean.

But if you mean a biplane wing, they are less effective than a single wing, with a lot more drag. There's a reason you don't see any biplanes flying around these days.

But there is a reason you used to see them, and there is a reason why some of the most modern aerobatics planes are biplanes. While a biplane has less lift and more drag than a monowing, it does have less "wing loading" (lift divided by planform surface area). That was important in the old days when airplanes were made out of wood and fabric. It is also important in extreme aerobatics. But it is a stupid design for a race car, unless you have to work around some rules or structural constraints that end up compromising your aero design.

Multi-element wings (wings that are behind each other rather than directly on top of each other) are a whole different story.

malcolm

Sorry to revive a long-dead thread; however, since the thread is linked in the FAQ thread, I feel obliged to expand a little on Mike's post.

Multi-element:
Think of one as a single wing, but with slots cut into it to allow air to flow from the top of the wing to the bottom of the wing. This "energizes the boundary layer", which means it shoots high-speed air under the wing which speeds up the air that has already gone under the previous element. The effect? Same as a Gurney flap: you can run the wing at a higher angle of attack without separation.

Biplane wing/Bi-wing/dual-decker:
These are only used when there are either packaging constraints, like Mike said, or when ground effect is being used.

Some cars will have a certain packaging space available, but no limit to the amount of elements they can run. They run variations on the bi-wing theme by simply trying to fit as many wing elements as they can into the allotted volume.

When ground effects are used (either a flatbottom-diffuser arrangement or full ground-effects tunnels), sometimes teams will run a bi-wing. The upper element (or elements) will act as a wing by themselves independent of the lower wing or the tunnels. The lower element(s) are used to help extract air from the tunnels or diffuser. This acts in the same way a multi-element wing works by "energizing the boundary layer" (speeding up the flow, thus reducing pressure under the wing, thus encouraging air under the flatbottom and tunnels to be accelerated as well, thus decreasing the pressure under the flatbottom even further).



As said before, all sorts of wings will start working at different speeds. For most single element, moderately cambered wings at 0-10 degrees of attack, 60 inches wide with a chord of about 8", 50 mph is where the most sensitive drivers would feel it. The majority of drivers would feel it around 65 or so. If you have too much angle and you are inducing flow separation, you might not feel it until 85+ mph when the top of the wing starts acting like an oldschool nascar spoiler.

As for ride-height changes due to wings, you need to tune the suspension to suit the aerodynamic load. More importantly, if the front is rising, it sounds like your car isn't aerodynamically balanced. Also, fast corners are where downforce matters most. With the huge Prodrive wing on my Corvette, with accompanying splitter, I can pull 7-8 car-lengths on those with simple spoilers into Corner 8 at Mosport (fast 4th gear corner, 5th gear in Erik's S2000 if I recall correctly). The only reason why you would trim out the wing on a high-speed track is if there are long straights. If there are short straights and fast corners, then more downforce will greatly benefit your laptimes.