Mercedes DRS Duct: How it links to the front wing

It’s now clear the Mercedes DRS-Duct system does in fact feed the front wing to stall the wing for better aero performance. Pictures have emerged showing how the system links the front wing to the rear wing.
Mercedes launched their 2012 car late, by missing out on the first test. It’s not clear if this delay was due to the need to repackage the car around the DRS duct, but clearly the Mercedes car needed some special adaptation to accommodate the car ducts along the car.

The plate attached to the flap uncovers the DRS duct - Copyright MichaelD

As I’ve already reported (https://scarbsf1.wordpress.com/2012/03/14/mercedes-f-duct-front-wing-operated-by-the-rear-wing-drs/) the Mercedes W03 has a unique system linked to the DRS. This uses the opening of the DRS flap on the rear wing to open a duct that sends high pressure air to other parts of the car. It was logical for many people to observe this was similar to the 2010 F-Ducts and stalled the rear wing for greater speed. As I pointed out in my first article on the system, I believe it is the front wing that was receiving this airflow in order to stall the front wing.
We saw from pictures of the Schumacher car in Melbourne, that there are slots under the front wing, this proves the front wing stalls, but not by which method; either the passive nose hole apparently tested last year or the DRS duct.

We can now see from images of the carbon fibre ‘cage’ fitted to the front bulkhead of the Mercedes that two tubes emerge and curve down to feed the flow into the front wing via the nose cone.

However this does not discount the rear wing is also being blown and stalled by the DRS duct, but I have yet to see any evidence of slots in the underside of the rear wing profiles or endplates. AUTOSPORT reported these were seen in testing, so perhaps there remains the chance the system could be used for both wing front and rear.

A complete explanation of why Mercedes use this system is in my first article on the subject.

How does it work?
When the driver has the DRS flap closed on the rear wing, the front and rear wings operate as usual, with no blown effects being used. Both wings create downforce in the usual way.

The DRS-Duct feeds through the hollow endplate towards the beam wing - Copyright MichaelD

When the driver opens DRS, the flap uncovers a pair of openings on the rear wing endplates. A passageway moulded inside the unusually thick endplates, creates a duct that feeds the DRS-duct system. These openings are fed with high pressure air, which has formed on top the rear wing.

Copyright MichaelD

As DRS rear wings use a very short chord flap, the main plane of the wing still has some angle of attack towards its trailing edge. This high pressure region feeds the ducts and each side appears to have its own dedicated duct from rear wing to front wing. There being one left and one right side duct, although it’s possible these ducts are linked to balance the system, left-to-right, as in yaw one duct might not have the same pressure feed as the other.
The endplate ducts flow in a “question mark” shape around the top and front of the endplate towards the beam wing. The airflow then passes inside the beam wing profile to a bulged fairing that directs the ducts forwards under the engine cover.

The beam wing duct leads (where the loose tape is) into two further ducts passing either side of the car Copyright Octanephoto.co.uk

These ducts are clearly visible from rear view shots; indeed in testing we saw one picture of the ducts unconnected to the beam wing. These ducts pass either side of the engine to the rear bulkhead.  A clear view of the ducts can been passing from the rear wing to the chassis in this screen shot.

Hidden by a white cloth the beam wing duct leads forwards into two ducts passing around the engine (both ducts removed in this picture) Copyright Mercedes AMG

I assume they pass outside the fuel tank area and into the cockpit area, where they then pass along the roof of the footwell to emerge at the front bulkhead. This tortuous routing within the tight confines of the car probably explains why two ducts are used and not one larger duct.

Copyright MichaelD

With the nose cone removed the front bulkhead is visible, like other teams Mercedes fit a carbon fibre moulding to aid refitting the nose accurately and without damaging any parts during rushed pitstops. In Mercedes case the ‘cage’ like moulding mimics the shape of the cosmetic panel fitted atop of the structural element of the nose cone. This cosmetic panel was the dispensation teams were given to fair-in the 75mm nose step. In Mercedes case the part of the nose cone that does the impact absorption is the very rounded and pointed lower section, the upper section probably provides some degree of bracing for the structure, but is not the same thick sandwich construction of the lower nose section.


Hidden behind this carbon fibre cage on the front of the chassis are two ducts, of similar size to those passing through the engine bay (as seen arrowed  in this picture ). The ducts turn 90-degrees to face downwards. When the nosecone is fitted, these ducts connect with corresponding holes in the nose cone to pressurize the nose and this in turn feeds the airflow down the front wing pylons to the front wing. Underneath the front wing there is a pair of slots. When DRS is open the flow through the ducts blows through these slots and stall the front wing.

For rival teams to replicate this system, they will need to find space to package the ducts inside the footwell area. As we saw in 2010, teams can be very imaginative in creating way to package this sort of solution. But this will take time and may explain some team’s opposition to the legality of the system.

51 thoughts on “Mercedes DRS Duct: How it links to the front wing

  1. Pingback: Mercedes: Are they blowing the Front or Rear wing? | Scarbsf1's Blog

  2. With today photos and the photo in Aus with the underside of Mercedes front wing i think the picture is clear.
    With DRS closed – the system feeds the underside of front wing (maybee of the beam-wing too) maximizing the downforce by skin-effect (Coanda one more time).
    Making holes in a convex side of a wing and blow pressurized air gives better laminar flux and gives you the chance to virtualy change the wing rope. In aeronautic is a idea with several decades. https://twitter.com/#!/gtmanpt/status/183249272538546176/photo/1.
    With DRS open – The movemente of the upper flap discloses the sideplate hole depressurizing the system. The front wing (and the beam wing maybee) loses downforce and drag, the upper section of the rear wing is (more) stalled too by the increasing of air speed by the duct. https://twitter.com/#!/gtmanpt/status/183250602934009857/photo/1.
    The draws is fast hand-made and the quality is not the better ….sorry…

  3. so people have an issue because there is a hole that is normally covered and it is uncovered when the drs activates. i can understand that.
    what if there was a hole that is exposed all the time, and under normal circumstances the area by the hole is subjected to low pressure air, so air does not enter (it may exit)? and what if, when the drs is activated, air is redirected, and the hole sees high pressure air? where would people stand on its legality then?
    what if the wo3 system does not physically touch the endplate, so there is a thin gap of air between the upper wing element and the end plate?
    i think this is why the fia are forced to accept this as legal.

    • I was thinking the same. There is a problem with this explanation. And I think that the system have also something to do with additional air intake behind airbox intake.

  4. Looks like we are heading in a new era of internal aerodynamics. This will be where teams will develop manipulating air movement inside the car further than the outside.

  5. Pingback: Der Mercedes F-duct : Formel 1

  6. Mr.Scarbs, if you check some vidoe from FP3 last night, you will see eary on in the practice session when they are getting nico’s car ready to go out they have the body work off the back of the car, and the camera clearly picked up the tubes that ran on each side of the motor!

      • Interesting. This confirms what I was talking about last time they are going in general direction of the exhaust. But still I don’t see all the crumbs connected. Front hole. Since you see additional driver cooling intake it is not for cooling the driver…

  7. Hi Craig, have you thought about whether the system might deliberately encourage unequal pressure on each side whilst in yaw? If only one side of the front wing could be induced to stall while cornering with DRS activated, it could help keep the front wing level with the road, which might be more beneficial than just reducing the drag.

  8. I don’t think that this is the full story. There are still thinks that do not add up. You are missing the nose duct. Since Mercedes added cooling duct on the top it is not for cooling. And I still think that additional intake is behind the air box intake and that what you wrote is not the whole story. I’m sure there is more to it.

  9. Now that there is credible photographic evidence that the front and rear are interconnected, there is still the question of exactly how the system works. You would think that Merc would try to reduce lag time in the change of front wing downforce. From that perspective it doesn’t seem practical to feed high pressure flow the whole way from the rear to the front.

    I think it probable that air to blow the front wing either comes from the nose hole (questionable legality but shortest response latency) or from existing intakes at the middle of the car (likely legal but at the cost of greater latency.) This could either be one of the three intakes above the driver’s head in the airbox area of maybe a scoop along the tub behind the sidepod inlet that is hidden by the radiators. Also, response latency would be considerably reduced by using a front wing that actually works best when blown and sheds downforce when the flow is interrupted.

    Again, since Ross Brawn has said this ” “We have an interesting system on the car and it’s not complicated at all…” it would imply that they have made efforts to ensure simplicity. From that, the simplest way of running the activation would be to configure the ducts to direct flow based on least resistance. When the DRS is not active, high pressure flow fills the ducts running from the intake source to the rear wing to the point that no more air can enter that section, at which time the flow runs forward to blow the front wing and increase its downforce generation. When the DRS flap raises, high pressure air bleeds out the aperatures along the rear wing endplates and further reduces drag (and possibly increases downforce) via improvement in boundary layer flow along the endplates or energizing flow under the rear wing flap. Since the path of least resistance is now to the rear, flow stops going forward to the front wing resulting in reduced downforce.

    • No. You would not blow the underside of a wing at that location to improve downforce.

      No. Blowing air out of the “aperatures” on the rear wing endplate would not reduce drag by any reasonably usable amount. In fact, it would probably increase drag.

      Why is it that everyone thinks there is some conspiracy or reason why using the rear wing to blow the front is so outlandish? I have never seen so many people arguing what is clearly evident.

      • I agree with Gil. ForHecksakepeople, how do stabilize, trick and cajole air moving at better than 300 kph to turn 180 degrees and flow back to the front? If there is pressure in / around the entrance to that port it is a negative pressure, not a positive one. I think if your physics were correct, it would be possible for a body to generate thrust based on shape alone. I’m not saying you’re incorrect, its just implausible to me. From what I have seen, the rear uprights are rudimentary airfoils withe the curved sides facing each other. So from rudimentary airfoils, what we now have is a rudimentary venturi. He’s pulling air from somewhere, exactly what he’s doing I don’t yet know but Gil’s argument is far more plausible to me.

      • Then there’s the argument of wake control. If from wind tunnel testing he can direct air into existing vortices via these apertures, then he could theoretically reduce drag, probably increase the cars ride height at speed…get more straightline speed. Just sayin’.

      • Clearly you all are more savy to the intricacies of fluid dynamics, something that is a hobby for me instead of a profession. BoogWar, I agree with your assessment, however, I reviewed many available pictures of the rear wing and from what I can tell the endplates have the same shape on both sides. I would think that they have net zero thrust. So I would disagree that the endplates alone form a venturri effect.

        If we take formula1.com’s drawing of the front wing to be accurate, then the front wing slots look very similar to those on the rear wings a few years ago, which were designed to shed flow, instead of attach. So if Formula1.com has it correct, then the front f-duct is for stalling the wing, which is something you wouldn’t do in a turn. Maybe the rear endplate ports are just a trigger, but those are some huge triggers. Either way, those front wing slots do not follow the contour of the wing, which would mean they would not help attach flow and increase the wing efficiency., i.e. not helping steeper wing angles and more downforce. So they must be used only when the DRS is activated.

        Actually, formula1.com’s drawing could help explain why the Mercedes has problems with rear grip. If they are running higher attack angles to get more downforce in the corners, and the car is aero balanced towards the front, then during qualifying they have the option of activating the DRS in the turns, thus balancing the car, but during the race the car would still be front heavy. I would think that would play havoc on tire temperatures. Nico did say that the car would run fine for the first few laps, just after the tire warmers were removed, but quickly fell off and continued to fall off the longer he ran. Maybe the rear tires are just loosing temperature, while the front are overloaded. You would have understeer and oversteer. Just a thought.

      • The thing that caused me to believe the front wing flow is normally blown (but not with DRS on) is because, after seeing the video and photos of Schumacher’s beached W03 at Melbourne, I have yet to see anything convincing regarding slots on the main plane’s underside (in the low pressure area.) Maybe it’s something with my eyes or PC monitors but the only slot I see is the one built in to the main plane that forms the gap below the lower “flap.” In the photo, I can even see sunlight showing through the slot gap for the right side of the main plane.

        For clarity, I hope my description above isn’t lacking but if the intent is to blow the front wing to increase down-force with no DRS, they may be directing the high pressure flow through apertures in the existing slot gaps such that it goes over the top side of the wing, improving flow over the flaps. How well this works when following in the wake of another car would seem to be a question, though. So I can see why they may instead blow the front wing with DRS active for the opposite effect.

      • Over the weekend I got the opportunity to look at the Melbourne photo of the underside of Schumacher’s W03 front wing on a better display. I can now clearly see the area where flow is being vented (at the base of the lower flap right above the slot gap) but quite frankly it doesn’t make it any clearer how the system works. In that position, the “slots” (though it looks more like rows of holes) could allow for improving OR shedding flow from the flaps depending on how the air is vented (either parallel to or tangentially to the under-wing flow.)

  10. Great work Scarbs! as always.

    Just a question, do you think this system – although ingenious – is that useful? Based on my limited understanding, I think this system is the key to their amazing qualifying pace, right?

    But is this system causing their high tyre degradation troubles? Or the tyre degradation is unconnected to this system?

    • You would think that since the system is only activated with DRS activation, and DRS is inactive in turns during the race, this would not cause increased wear in the turn at race-pace. The front wing should be performing as designed by the time they are into the turn. I think the current configuration was mentioned to be a result of a refinement of last year’s version, which didn’t have an on-off switch like the DRS and did have an affect on race-pace aero-balance.

      Still, if they designed the system to optimize qualifying performance then it could be effecting race-pace just because the car is in parc ferme after qualifying and they wouldn’t have time to make any aero adjustments until the first stop. There’s always some tradeoff.

    • I’m wondering the same thing – how come this system is not more useful? and also, how much aerodynamics affect tyre degradation vs. mechanical grip from other parts?

      And one more little detail is bothering me.. if ducted air flow direction was from rear wing all the way to front wing, doesn’t fast forward moving car’s huge G-force have some kind of counter-effect thus slowing air flow to the front, not blowing front wing good enough?

      Im with limited understanding as well so sorry if noob question.

      Really disappointed with Mercedes’ innovation, was expecting them to be A La Brown GP in 2009 to show all potential from the beginning but no go.. only 1 point after two races :O

      Hopefully they get this optimized until Chinese GP.

  11. Pingback: #F1 How Mercedes W03 DRS links to the front wing (Video) | StartingGrid | @utomotive lifestyle blog |

  12. I don’t believe that forward flow direction is a problem. Take Renault’s exhaust from last year and the sidecar boys (& girls) have used this system for years. As I understand it, as long as the gas (air in this case) is being scavenged, ie. into negative pressure, the system will work.

  13. Pingback: Controversial technical enhancements used by the Mercedes team « johnnyjohnsen. com

  14. Maybe the system works on differences in air pressure. If you have a window open upstairs in one room of a house, opening the front door downstairs might cause a door to slam shut upstairs. Imagine the front wing as the open window and the exposed holes on the rear wing as the open door that triggers a change in air pressure.

  15. Yeah maybe.. Anyone here from Merc factory? what’s up?🙂 I don’t understand fully hoew pressurized systems work but one thing they should do i think, if continued to develop it, they should integrate the tunnels as part of body work, not to have pipes.. could get rid off of small gaps between components.. like to make rear area and side pods more neat= better external aero. Also maybe if tunnels would be grooved in certain way would that make some differences maybe helping air flow? just thinkin..

  16. Pingback: FIA rejeita reclamação da Lotus sobre duto da Mercedes

  17. So, they are able to use the DRS system at all times during qualifying enabling them to increase the top speed of the car and get as close to the front row as possible, though only able to use DRS in the designated zones at race time. Neat tech, should cause a rule change during qualifying or be outlawed all together.

  18. This system has just passed a protest from Lotus regarding its legality.
    http://www.formula1.com/news/headlines/2012/4/13208.html
    The system contains no moving parts and is not activated by driver movement (directly) according to the article.

    Does this open up the possibility of other systems like this? For example moving the brake caliper while braking opens a hole that feeds air to the wings that boosts downforce and increase drag. Or the pitch of the car during braking opens (or closes) ducts located for example at the suspensions for the same reason. That could be applied to the car pitch during heavy acceleration aswell. Or why not the car roll during cornering altering airflow in ducts to increase downforce.

    These would be pretty complicated systems to get right, but I think it’s a possibility worth to look into. The knowledge that just a tiny flow of air can make such big difference is powerful.

    • No, other systems such as brakes and suspension would not be permitted to have a deliberate secondary effect of altering aerodynamics. In the ‘Lotus decision’ the stewards determined that the primary purpose of DRS is to reduce drag and increase top speed. Mercedes DDRS system simply enhances that ability by using a tube, in the same way that other teams use various other elements of the body work to enhance the DRS performance. The primary purpose of brakes, suspension etc is obviously not reducing drag, so altering aerodynamics as a secondary purpose would not be permitted in those examples.

      • My final comment on this thread; Merc really is placing a lot of weight on qualifying. Yes, it is very important to have a good grid spot, but they can’t even use the DRS for the first few laps, and how many times have we seen a race strategy thrown out the window after a poor start? Quite a few. Maybe a few years ago, when you absolutely could not pass, your grid spot was more critical, but with today’s “driver aids” the grid is less important in my opinion (despite what i said earlier to the contrary).

        This is why my money is on McLaren. They have good, consistent race pace.

  19. Pingback: Stewards declare Mercedes legal « johnnyjohnsen. com

  20. During the race the DDRS systems can only be engaged at specific points on a track when the user is within one second of the car being overtaken, ie: for the purposes of overtaking. I dont take issue with the DRS system at all, nor do I take issue with the DDRS system.

    During Qualifying and practice sessions the DDRS systems have a SIGNIFICANT advantage as the systems allow for a higher top speed and can be used at the drivers discretion, ie: all the time, except in cornering. This allows DDRS teams to be placed at the front of the grid on race day leading to a significant advantage.

  21. Pingback: 2012 Mercedes F1 DRS System | FluxAuto

  22. From what i remembered about the F duct, this worked by controlling a fluidic valve, so a drivers hand would effect a small airflow that controled a larger airflow which then stalled the rear wing. Surley the DDRS rear wing is doing the same as the driver controled f duct, ie controlling a greater air flow which is related to the front of the car.
    Just found this site btw, brilliant ! Thanks scarbs, just need to follow on twitter now too.

  23. What about … When DRS is employed the rear inlet opens and (not knowing exactly the geometry) they can at max get total pressure (Cp = +1.0, suppose inlet facing the oncoming flow). Then at front wings, or actually on the first flaps the exits are already in the recovery slope zone but still in low pressure area (maybe around Cp < -0.5) – this pressure difference drives the channel from rear to front. v = 80 m/s equals around q = 4000 Pa and the with the dCp = 1.5 the driving pressure is 6000 Pa or 0.06 bar). The channeling pressure losses will probably steal 2/3 of the 6000 Pa. But suppose the front wing is set close to stall then this extra blow across the flow lines would/could stall the front wing flap.

    Ok, it sounds a lot of work for a little gain since front wing downforce is cheap (L/D is great in front wing due to ground proximity). Ok, but what if added to this, when DRS is NOT employed the openings in the rear wing are in low pressure (leaking to behind the flap) and the system is reverted to act as a boundary layer suction at the front wing. Now that would give a little gain in the corner, but, as I interprete the regs it would be illegal.

    Now, I am a professional aerodynamicist but really I don't know for sure how it works. I can only guess like everyone else. In any case it looks like they've put some amount of work into it.

    • In this months RaceTech magazine (RaceTechMag.com) Pat Symonds quotes the Cp’s as +0.5 at the rear wing and -2.5 under the front wing. so there pressure difference is there.

      I love the idea of the DRS plate leading to a low pressure region when closed. I’ll have to have a look at that…

      • Ok, The front wing probably operates at around -2 > CL > -3 and Cl is basically the average dCp over the referred area … ok, makes sense. But I think the outlets are at the flap area after the slot peak – what we call recovery zone… but now that I think of the Cp could still be around -1…-2 because we are so under ground effect.

        With these Cp values to reverse the system into a bl suction system we’d obviously need a very strong peak Cp value some elsewhere … maybe down to Cp= -4 before we can create a so called passive bl suction. … rear wing peak or a core of longitudinal free vortex perhaps… or some trick with exhaust gases in which case think lifting off in the middle of the corner. A Senna exit in Copse years ago (around 1986–-1989) reflects to my mind. His foot slipped of from the pedal and the diffusor choked – out he went.

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