Sauber: F-Duct detail

The duct on the sidepod runs through the slot in the rear wing and possibly the cockpit too

Having declared they had rushed through their own version of the F-duct, we can speculate how it might work.  We know that the McLaren duct is vented into the cockpit around the drivers legs.  Then it is their leg that closes the duct to feed the rear wing.  This alters; the flow through the slot in the rear wing flap, stalling the wing, reducing drag and increasing top speed.

Sauber have already run with a vented rear wing, theirs uses the inlet on the front of the wing, to blow through a slot underneath the wing.  This allows the rear wing to be steeper without stalling, for more downforce.  Their new shark fin bulging with the duct moulded inside it, feeds into this same slot.  they could be aiming to blow even more airflow through the slot or like McLaren alter the flow to stall the wing. 

But the flow through McLarens slot is driver controlled, so Sauber need to find a way to ‘switch’ the flow on and off.  This could be done purely by the airflow being overcome by the drag creating inside the tortuous duct and hence cutting off the flow above a certain airspeed.  Or they have found a way to vent the duct into the cockpit. 

the hollow side impact spar coud lead into the cockpit to allow the vent to closed

In Saubers case the duct does not pass through the footwell of the cockpit as in McLarens case, so how might they enable the driver to seal the duct?  The placement of the duct may be gives us a clue.  It is possible that an opening exists within the side ofthe moncoque.  Sited near both the ducts inlet and running accross the frotn of the sidepod to the side of the tub is the impact spar, this could lead to an opening into the cockpit and allow the drivers elbow to seal the duct and redirect the airflow.  Its not normal for teams to want to create any opening in the side of the chassis to improve stiffness and crash protection.  But it is possible.

Therefore the driver presses his elbow against the opening at high speed to achieve the same stall as McLarens drivers get with their leg.

21 thoughts on “Sauber: F-Duct detail

  1. Scarbs, does this system really gives the car an advantage over the other teams in Australia. It doesn’t have a long straight and its quite high on downforce. Besides that it’s a big distraction for the driver focussing on their legs or elbows rather than driver their cars.

    • I would agree the advantage is diminished due to the nature of the melbourne track. But a gain in top speed for no loss in the corners, will always be worth something and does offer the potential to overtake in the race.
      I wouldn’t have thought it was a distraction for the driver. on the straight he is effectively only just sat there with his right foot down on the gas pedal, his other leg is doing nothing, why not use it?

      • Well it’s a distraction if you’re fighting on the straights with an other car.

        I’ve just read that Renault doesn’t believe in the F-duct and won’t participate or develop it.

  2. “The driver has to activate the system !” de la Rosa told reporters about the system. “You can do it with the knee, you can do it with your hand. You just have to make sure you activate the system. The whole purpose is to gain top speed

  3. What if they go through T8 @ Istanbul, not the smoothest corner, but veeery high G. The ride for the driver isn’t comfy at all there and he’s got super high G, so thanks to a bump he moves his elbow, knee or whatever to block the opening. Next thing he knows, the rear wing stalls & the car is sent spinning towards the wall with over 250 kph!
    This sounds pretty hairy scary!
    I think it must be banned… I don’t understand how this can be legal, yet Renault’s damper system is not!?!?!? It’s much more reliable and safe.

    • The airflow out of the duct into the cockpit would be with some considerable force. I’d I have thought that it would need a degree of effort for a seconds to activate the stall effect.
      I dont think this would happen accidentally.

  4. I think Sauber had a hole in the chassis waiting for this mod.

    This is F1, if the driver can’t multi task, they will find one who can.

    Brian

  5. Scarbs

    Off topic- Appreciate if can enlighten us on today’s Martin Whitmarsh comments on Red Bull’s and probably Ferrari’s ride height controlling system. I remember thinking about it during Bahrain’s race when watching both RedBull and Ferrari skimming the track in both quali and early part of actual race (before pitstops).
    Just wondered whether that was the real reason for Ferrari changing their engines in Bahrain ?

    I am happy to defer to your undoubted technical nous.

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  7. I don’t think Sauber will ever get the system truly effective. Their current budget doesn’t allow much “non-traditional” devepment, and I think plain old aero efficiency updates would be more cost effective.

    • I’m not sure if I agree. I think its a fallacy that small can’t develop to a high level. I think its fairer to say they are restricted in the number of avenues they can explore and any development needs to pay for its lap time to offset the cost in manufacturing this. with Sauber already running a shark fin and slotted rear wing element, they have little left to develop than the duct itself. It sounds like a cheap bit of performance.

      • That’s a good point about having most of the system already for other reasons, I guess it wouldn’t cost much just to come up with a tube in the sharkfin, but I was referring to actually tuning the rear aero to be able to use it properly without hurting their effiency otherwise. From what I’ve read the entire rear of the Macca had to be designed differently so the extra air could stall it. The official F1 site’s tech section makes it sound like many different parts of the rear work together to stall it.

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