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Old 06-13-2013, 09:55 AM   #281
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Any idea how they control it? How does it know when to reduce/increase the AOA? I guess you could reduce AOA after cornering G's fall below a threshold value, and then increase it again as brakes are applied... but then what about corners you don't brake for? You wouldn't want to wait for cornering G's or steering input, because by then its too late. Maybe a button on the steering wheel?

Or you could map out the course and pre-program it using GPS.
I would think you would want a button/switch on it just like F1.

Ferrari has now moved their DRS to a switch next to the brake pedal. DRS is only activated when the driver's foot is on the switch.

Apparently they deactivate the DRS flap before getting on the brakes so the air has time to "reattach" to the wing.........I'm sure I did a poor job of explaining it.
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Old 06-13-2013, 10:35 AM   #282
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Hm I was under the impression that the DRS stayed open until you hit the brakes and thats how it was regulated to be. Tap the button to open the flap, hit the brakes to close it.
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Old 06-13-2013, 11:48 AM   #283
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Hm I was under the impression that the DRS stayed open until you hit the brakes and thats how it was regulated to be. Tap the button to open the flap, hit the brakes to close it.
Each team implements it slightly differently compared to the others.

http://www.auto123.com/en/racing-new...m?artid=155397

http://scarbsf1.com/blog1/2013/05/22...rs-activation/
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Old 06-13-2013, 01:10 PM   #284
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Originally Posted by Handy Man View Post
Any idea how they control it? How does it know when to reduce/increase the AOA? I guess you could reduce AOA after cornering G's fall below a threshold value, and then increase it again as brakes are applied... but then what about corners you don't brake for? You wouldn't want to wait for cornering G's or steering input, because by then its too late. Maybe a button on the steering wheel?

Or you could map out the course and pre-program it using GPS.
I could imagine a number of ways to activate/deactivate it...depending on the use of the adjustable foil. If used for braking- could be button activated and deactivated by the brakes; could be speed dependent and read off of vehicle speed; could be a push-button on/off on the steering wheel. Given the picture has it activated and no brakes lights on might show it's driver operated or speed operated

While not one of having aero/fluid education, I could imagine that using it for high-speed corners where brakes are not used could upset the balance of the car in an unpredictable way- sudden increase in drag/downforce on the rear reducing front grip when it is needed or even changing the pitch of the car/flow of air over the whole car when not under braking.

I find all of this stuff VERY interesting and do like to try to understand it as best as I can.
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Old 06-13-2013, 01:13 PM   #285
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I'd imagine one of the best ways would be a direct ratio between Brake position and wing angle. The more you press the brake the higher the angle.
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Old 06-13-2013, 01:32 PM   #286
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I'd imagine one of the best ways would be a direct ratio between Brake position and wing angle. The more you press the brake the higher the angle.
Having the aero balance change while you are in the braking phase doesn't sound like a good idea at all.
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Old 06-13-2013, 01:37 PM   #287
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How come? Because i dont see any negatives to it.
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Old 06-13-2013, 02:34 PM   #288
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I was thinking about this a few months ago, came to my own conclusion that the best application for someone without a wind tunnel or the desire to be the guinnea pig to test how much turning the wing into an air brake at 130 mph upsets the car, would be to simply have a button on the steering wheel that returns the wing to 0* aoa. Press it once you straighten out your corner exit onto a straight, gain a few mph, let go of the button a moment before you enter your braking zone and the wing returns to your pre-set aoa for however you have your aero balance set up.

In the second pic I posted, I am not so sure that the wing is being used as an air brake there - I think they were using the active wing similarly to how I suggested above, and given that they then could go for maximum downforce regardless of drag because it would zero out for the straights, they cranked the aoa on the wing up a lot. That pic looks like he's coming out of a turn and on the throttle, so there's no reason he'd have it running as an air brake at that point..

-Ryan
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Old 06-13-2013, 02:42 PM   #289
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Originally Posted by triple88a View Post
I'd imagine one of the best ways would be a direct ratio between Brake position and wing angle. The more you press the brake the higher the angle.
The need for breaking power is not directly correlated to the need for down force. Two examples come immediately to mind: 1. As mentioned earlier, maximum down force is desirable in flat-out cornering where the throttle is either pinned or just briefly let up. 2. In the middle and second half of a corner where, at most, brakes are lightly being used for trail braking, or not at all, such as when beginning to feed in throttle to exit.
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Old 06-13-2013, 02:44 PM   #290
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There are two different kinds of active aero, and its important that we differentiate between them

1. Air brake. This is simple. When you are on the brakes, an aerodynamic element creates drag to assist braking. You can simply activate it with a brake switch.

2. Drag reduction. This is more complicated. In racing it is usually implemented by reducing the effectiveness of the wing and thereby also reducing its drag and down force. You have to have to either activate it manually, or have some sort of control scheme that knows when you don't need downforce.

A button on the dead pedal is fine for flapy paddle cars, but if you have to work a clutch your wing would be flapping up and down while you shifted gears :P
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Old 06-13-2013, 02:52 PM   #291
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Thank you. I was just thinking in my head how I should write that out.

The way I see it, both can be useful, but the implementation of an air brake should be left up to the people with high powered CFD and wind tunnels as it has the potential to greatly upset the car. I think a DRS is more straight forward and is easier for the amateur to implement.
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Old 06-13-2013, 02:53 PM   #292
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Well no, the angle is important, there is downforce and there is a point where it stalls and u lose all downforce and get a parachute. Of course theres also low downforce for high speeds.

Perhaps something along the lines of an integration between (numbers are just random numbers)

high speed + max throttle 10 degrees angle

any speed + 0-99% throttle 20 degrees

any speed + brakes % 20-70 degrees with the % of brakes varying the angle of the wing.
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Old 06-13-2013, 02:54 PM   #293
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Originally Posted by Handy Man View Post

A button on the dead pedal is fine for flapy paddle cars, but if you have to work a clutch your wing would be flapping up and down while you shifted gears :P
You could use a button on the steering wheel the same way Ferrari uses the foot switch. You probably have a bit more real estate to work with:

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Old 06-13-2013, 02:57 PM   #294
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I think that transitioning a wing from a high downforce AOA to a low downforce AOA (DRS) is more predictable and stable than transitioning from a high downforce AOA past the stall angle and into a weird, vortex generating state that the wing was never designed to operate in (Air Brake).
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Old 06-13-2013, 03:33 PM   #295
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Quote:
Originally Posted by Handy Man View Post
Any idea how they control it? How does it know when to reduce/increase the AOA? I guess you could reduce AOA after cornering G's fall below a threshold value, and then increase it again as brakes are applied... but then what about corners you don't brake for? You wouldn't want to wait for cornering G's or steering input, because by then its too late. Maybe a button on the steering wheel?

Or you could map out the course and pre-program it using GPS.
I've got a data acquisition system that can control it now based on G forces and other inputs.

Left G, right wing up
Right G, left wing up
Brakes, both wings up
acceleration, wing angle decreases as speed increases

You could also tune the angle for speed, and even tune it per track.
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Old 06-13-2013, 04:25 PM   #296
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Left G, right wing up
Right G, left wing up
Brakes, both wings up
acceleration, wing angle decreases as speed increases

You could also tune the angle for speed, and even tune it per track.
I would program it just like that except I would program the wings to keep making downforce until WOT. Like I said earlier, you want downforce in the last part of a corner when you are on the throttle, but not all the way.
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Old 06-13-2013, 04:33 PM   #297
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On another note, I haven't actually gotten to mess around with aero much on track. I really enjoy the aero aspect of going faster and I want to play with just aero for a while. I was thinking of going back to completely stock (or maybe getting another, stock Miata) and using aero only to start dropping lap times. My question is, will stock tires and suspension components interfere with aero testing or make tweaks more apparent?
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Old 06-13-2013, 05:02 PM   #298
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Originally Posted by mx5autoxer View Post
On another note, I haven't actually gotten to mess around with aero much on track. I really enjoy the aero aspect of going faster and I want to play with just aero for a while. I was thinking of going back to completely stock (or maybe getting another, stock Miata) and using aero only to start dropping lap times. My question is, will stock tires and suspension components interfere with aero testing or make tweaks more apparent?
You'll probably get more benefit with more than stock power, since you'll need more power to get past the added drag from a wing, and the aero stuff make more of a difference the faster you're going.
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Old 06-13-2013, 05:14 PM   #299
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IMO, the only way to properly do it is via a GPS signal unless you want to manually control it. If you wait until braking then you will be changing the balance in mid turn in a lot of cases. If you you base it off of G force then, again, you will be changing the balance of the car while turning. There are also plenty of turns that I go into WOT with aero that I couldn't without it, so having it work until WOT wouldn't really work either.

Having the active aero independent of strictly either G forces, throttle position, or brake actuation alone would allow you to properly set it up. Until then, I think you will be sacrificing speed one way or another.

You could probably set up something like what you guys are describing and be faster than without it. One possible way it to have it tied to the brake light, but on a 3-5 second timed relay. That way you lightly tap the brakes before a turn to activate it and go through the turn with it regardless of throttle position, brakes on, or g force. That is about the most efficient way I can think of to manually control it.
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Old 06-13-2013, 05:16 PM   #300
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Rather than G control, its not very hard to add a steering position sensor.

I'd rather have my DRS on a button for the straight.
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