Sauber pushes ahead with unique F duct solution


By kineticKid
March 25 2010

If it's true that Alonso is worth 6 tenths in car development, then surely de La Rosa is worth at least 3 tenths in the same regard, as that is what the F duct is speculated to have given McLaren in terms of lap time.

All joking aside, while de La Rosa's experience as a McLaren gave him a solid understanding of how the Woking based squad's system worked, the solution developed in Hinwil is a function of the team's innovation and long-standing willingness to employ new and untested technologies.

Sauber rolled into the Melbourne paddock with a snorkel fitted to the left sidepod of the car above the radiator inlet.  Like McLaren, the rear wing slot that makes useful stalling possible was also featured on last year's car. The ducting required for stalling the rear wing on demand is new, however.  This can be seen on the spine of the engine cover.

The system differs from McLaren's in that air leaving the duct is blown onto the main profile, as opposed to the upper element.  Briefly, the system operates through the opening and closing of a valve which is actuated by a diaphragm adjacent to the driver's braking leg.  On the straights, the position of the driver's left leg allows for airflow to be channeled through the car and to the rear wing slot.  This airflow disrupts the vortices that trail the wing which induce drag inherent with downforce.  When the driver brakes, this air is channeled back into the cockpit for cooling, and the rear wing creates the downforce required for cornering.

Tomorrow's practice sessions should make for interesting viewing as the system is tested for the first time and the team evaluates whether it will be raceable for Sunday's grand prix.  Pedro will find out for the first time how the driver actually operates the valve.  Surely many teams will be in a rush to develop their own system now that the ingenious idea has been given FIA approval, so the sooner it is race ready on the C29 the better for the Hinwil concern.

Sauber pushes ahead with unique F duct solution
Posted by: BMW Sauber F1 (IP Logged)
Date: 25/03/2010 06:56

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Re: Sauber pushes ahead with unique F duct solution
Posted by: Raid Phoenix (IP Logged)
Date: 25/03/2010 09:25

Here is an interview with pedro about this topic LINK Interview, and pic of one of the ducts
http://cdn.gallery.autosport.com/picture_free.php/dir/2010oz1/image/su_10aus341-2
And here the engine cover:
http://i39.tinypic.com/mqypc.jpg

Racing against the machine!



Edited 1 time(s). Last edit at 2010:03:25:09:28:23 by Raid Phoenix.

Re: Sauber pushes ahead with unique F duct solution
Posted by: Gemm (IP Logged)
Date: 25/03/2010 10:12

Can someone explain to me in idiot proof words how the 'stalling of the wing' actually works. What happens exactly when driver blocks thar air duct.

BTW, howair driver is going to block that air stream in Sauber case? The inlet is on sidepod?



Edited 1 time(s). Last edit at 2010:03:25:10:13:19 by Gemm.

Re: Sauber pushes ahead with unique F duct solution
Posted by: RA106 (IP Logged)
Date: 25/03/2010 10:52

Maybe its a different system maybe its not knee operated? Also funny how De La Rosa gets involved with a spygate at McLaren and suddenly Sauber is the first team to try out the device before anyone else tongue sticking out smiley kidding hats off to Sauber!

Re: Sauber pushes ahead with unique F duct solution
Posted by: old_robin (IP Logged)
Date: 25/03/2010 13:21

The rear wing works by air flowing over it like and upside-down aircraft wing producing down-force. If you present the wing at too large an angle to the air, the airflow breaks away from the surface and the wing stalls. At this point the lift disappears and the drag decreases.
An alternative to increasing the angle is to feed air onto the wing to induce stall which otherwise would not have happened. This air come in the open duct by the driver's knees and then is fed and released onto the wing at the back of the car, so that it "stalls" at high speed along the straight which reduces the drag and increases the car's top speed.
OK?

Re: Sauber pushes ahead with unique F duct solution
Posted by: KineticKid (IP Logged)
Date: 25/03/2010 13:37

Of oldrobins two explanations, the second is closer to the actual functions of the system. The stall created by too large an angle of attack is you would have on the flap of an aircraft is a different type of stall and is not used here.

I have made a slight correction to the article, as I was going by AUTOSPORT's original claim earlier today that showed a picture of the existing inlets on the deck of the car, with their assumption that they would be used for the F duct. The snorkel is actually on the left sidepod.

Re: Sauber pushes ahead with unique F duct solution
Posted by: scarbsf1 (IP Logged)
Date: 25/03/2010 21:22

More info on here
[scarbsf1.wordpress.com]

Re: Sauber pushes ahead with unique F duct solution
Posted by: Raid Phoenix (IP Logged)
Date: 26/03/2010 09:18

Quote:
scarbsf1
More info on here
[scarbsf1.wordpress.com]

I Scarbs, I was about to post that link! smiling smiley

By the way, you say "Or the duct merely adds mass flow to the exisiting blown slot (raced in Bahrain) to allow the wing to be run even steeper and create yet more downforce."

I don't think it's the case, as it seems the angle is very steep, almost perpendicular to the profile, so it pretty much looks like is indeed trying to detach the airflow with that injection, don't you think?

Racing against the machine!

Re: Sauber pushes ahead with unique F duct solution
Posted by: Gemm (IP Logged)
Date: 26/03/2010 09:25

Hi, Scarbs!

Great to see you joining our community.

I am big fan of your writing, for many, many years.

gemm



Edited 1 time(s). Last edit at 2010:03:26:09:27:00 by Gemm.

Re: Sauber pushes ahead with unique F duct solution
Posted by: barteks (IP Logged)
Date: 26/03/2010 14:17

Quote:
scarbsf1
More info on here
[scarbsf1.wordpress.com]

Nice to see you here! (Sm152)

2008 Prediction Champion

Re: Sauber pushes ahead with unique F duct solution
Posted by: Gemm (IP Logged)
Date: 26/03/2010 18:01

btw, why this invention is called "F" duct? :-)

Re: Sauber pushes ahead with unique F duct solution
Posted by: KineticKid (IP Logged)
Date: 26/03/2010 18:59

Great to have you Craig!

Not sure, but the name probably has to do with the shape of the ducting on the Mclaren.

Pedro hinted at an answer to one of the questions I had about the system. If the duct only opens when the driver's knee is lifted, as when he is not braking, how does rear wing created the necessary downforce for corners that are full throttle but create high lateral Gs?

Pedro says the system can be operated by the driver's hand as well, so I suppose he could push a switch (it would have to be a latching switch as opposed to a momentary one since the driver wouldn't have a free hand while cornering). I suppose he could then release the switch after a corner or sequence of corners.



Edited 1 time(s). Last edit at 2010:03:26:19:00:42 by KineticKid.

Re: Sauber pushes ahead with unique F duct solution
Posted by: KineticKid (IP Logged)
Date: 26/03/2010 19:14

Also, as Craig suspected earlier, the Sauber system can be used without driver input, but it is less efficient. The system would use increasing pressure to the pitot port to cause the ducts in the system to vent airflow to the rear wing and induce stalling.

Sauber didn't expect the FIA would approve a system that could be operated by the driver. When the Macca system was given the green light, they modified their own version because you receive the full effect whenever desired, even on shorter straights.



Edited 1 time(s). Last edit at 2010:03:26:19:15:49 by KineticKid.

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