Reducing the drag of a two element wing through stall

[mx_tifoso]

I have merged the 'MP4-25 Air Intake' thread and a few others about stalling into this one, now we have one super thread!

[ringo]

Therefore, turn this situation upside down and a car going slow round corners would not create much down force because the airspeed over the wing is slower. Allowing extra air to pass through the middle of the wing or behind it in some other way would reduce 'stall' and make the wing more efficient, thus pushing the car down on the ground more.

So, Macca run a setup with less wing giving them a straight line speed advantage but due to this anti stall system create as much down force as a higher wing setting on a normal rear wing system.

This is how Sauber have used the blown wing in the past (to prevent airflow separation from the wing) - lets them run a steeper wing angle, thus more downforce.

But the theory (as I understand it) is that McLaren have found an additional effect; by overloading the blowing of the wing, causing the airflow to separate & reducing drag - thus more straight line speed.

could be the opposite maybe;

Speaking to Gazzetta dello Sport, Newey said: "McLaren's F-duct is intelligent and opens new ways. However I'm worried about the safety aspect. The system works by stalling the rear wing and getting rid of the load. To force a driver to make a sudden movement to change normal load conditions has to do with safety."

The only way a wing loses load is if a big hole is shot through it to disrupt the suction, or if pressure is taken off of it.

[Phillyred]

I imagine there is still a minor load on the wing.. So the wing is under a relative stall.

[ringo]

ferrari's seemingly passive system. It has the shrouded pipe on the bridge wing as well.

[raymondu999]

Hey all. Just asking here. How much advantage does it actually bring? Not in terms of laptime as that would probably vary per circuit. But in terms of drag reduction. Say the rear wing is set at an AoA x degrees. So what does the duct do? Does it cut down the rear wing drag by y%, or does it increase the top speed by y km/h, make it work like a wing set at (x-y) degrees, or what? I've seen claims that it just benefits the car linearly in terms of straight line speed like 10km/h, but I'm not sure I buy this as I'm thinking the stalling will have a different effect at, say Barcelona with its high wing, compared to when done at Monza with their low wings.

[Just_a_fan]

At Monza they should be able to carry slightly more wing than a non-F-duct car can. This means they will have slightly more downforce in the corners (and so be quicker through them) and still be as fast on the straights. This should equate to a reduced lap time.

How it will help in the actual race will be interesting. I wonder if the driver could use the rear wing stall to balance the loss of front wing performance when behind another car - this would give less overall downforce but it would be balanced across the car rather than mostly reduced at the front end as usually happens. Because the overall downforce levels are so much lower at Monza the reduction in downforce doing this might not be too dramatic for a skiled driver. Not sure I'd try it but I reckon J Villeneuve would have done!

[wesley123]

well, there is a simple problem with it, you cant go to incredibly low AoA's as then there is no way of ducting it, i dont know how they will do it in monza

[autogyro]

well, there is a simple problem with it, you cant go to incredibly low AoA's as then there is no way of ducting it, i dont know how they will do it in monza

I would go the other way and have a default low angled stalled wing and blow on corner entry to increase DF.

[raymondu999]

The blowing would *decrease* DF though. You would set a higher AoA and blow it for the straights, then stop blowing in teh corners for more DF. And I see what wesley means. The duct in itself wouldn't fit.

[forty-two]

Mercedes debuted a McLaren like F-duct system on Michael Schumacher's car on Friday morning in China.

Team reserve driver Nick Heidfeld said a decision has not been taken about whether the device, activated in the cockpit by the driver and designed to spoil the downforce to the rear wing on straights, will stay on the W01 for qualifying and the race.

"It is now being analysed to see whether we use it on both cars for the rest of the weekend," Heidfeld told the German broadcaster Sky.

The 32-year-old said he thinks the system works well, after the wind tunnel data looked "promising".

Meanwhile, unlike the side pod mounted inlet on the Sauber, and McLaren's on the upper monocoque, Ferrari's new aero vent system lets air in via the actual engine cover itself.

Following his engine failure on Friday morning, Spaniard Fernando Alonso returned to the Shanghai track for the afternoon session with the V8 he used to win in Bahrain last month.

Sorry if I'm late to the story, but does anyone have any pictures of Mercedes' F-Vent system at all?

[raymondu999]

It's in the Mercedes thread. It's a weird half-donut looking thing on the rear wing, can't miss it

Here's a preview for you (originally posted by timstr:

[nacho]

Ferrari topped the speed trap by 5 km/h, I guess they were running the system wide open and closed to see the effect.

[PlatinumZealot]

Massa topped the speed sheets and he wasn't running an F-duct.. I guess he was using a low angle wing?

[autogyro]

The blowing would *decrease* DF though. You would set a higher AoA and blow it for the straights, then stop blowing in teh corners for more DF. And I see what wesley means. The duct in itself wouldn't fit.

At Monza a low angled smaller wing is needed to decrease drag on the long straits.
If a low angle wing can be designed to be in a stalled condition by default it would produce less drag and blowing the boundary layer would create DF by attaching the flow for corners. Same way an aircraft blown flap works.

[raymondu999]

AFAIK blowing it would reduce the drag, and when you hit near the corners you want to stop blowing the wing, for more downforce.