Red Bull RB9: Ducted Nose Slots

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Following on from the under nose slot of two years ago and the letterbox slot of last year, this years Red bull continues to explore aero solutions around the nose box.  However with revised nose rules this year, it’s an idea from Sauber that found its way onto Newey’s drawing board.  Now letterbox opening faces backwards and is joined to the slot below the nose with a duct, to overcome aerodynamics issues presented by the nose box.

Last year I explained that Red Bulls letterbox opening was largely to overcome the issues of the stepped nose.  Sauber also had a ducted solution aimed at the same issues which also resolves some of the airflow problems under the nose.  This year’s Ferrari 2013 nose slot has also been explained here.

A short modesty fairing, removes the 2012 slot but keeps the lower slot (arrowed)

A short modesty fairing, removes the 2012 slot but keeps the lower slot (arrowed)

In an attempt to keep the nose box cross section as small as possible and according to Newey to save weight, Red Bull haven’t adopted a full modesty fairing, instead the stepped nose is smoothed with a small fairing.  This modesty fairing removes the letterbox opening use last year.  But the high pressure generated under the nose and increasing boundary layer remain an issue, as does keeping the airflow attached over the step.  So the car keeps last years under-nose slot, but rather than exiting into the monocoque to cool the electronics, the slot now feeds a duct that curves up in an “S” shape to exit rearwards in the scalloped top of the monocoque.

RBR_Noseslot_flow

The lower slot feeds the “S” duct, as witht he Ferrari F138 lower slot, this relieves the pressure and boundary layer building up below the nose.  The duct then exits rearwards over the chassis.  As with Saubers solution last year, this helps keep the flow attached behind the stepped nose.

The "S" duct sends flow from below to over the nose

The “S” duct sends flow from below to over the nose

Although I’ve drawn the ductwork separately, the “S” duct is actually bonded into the nose box and isn’t removable.  No doubt we will get some pictures of the reverse face of the nose box once the season begins, to see the ductworks full details.

The V-Shape to the chassis creates the rear facing slot (arrowed)

The V-Shape to the chassis creates the rear facing slot (arrowed)

Packaging the duct requires some repackaging around the front of the bulkhead.  The bulkhead features a rounded indentation at the bottom to help turn the air fed through the lower slot through 90-degrees and then the anti roll bar and brake fluid reservoirs are packaged into the top half of the bulkhead and flanked by carbon fibre mouldings that follow the shape of the duct.

Red Bull have always kept a slight V-shape to the cross section to the front of the monocoque, this keeps the blockage in between the wheels to a minimum and aids the lower wishbone geometry.  The resulting valley in the top of the chassis allows the flow out of the nose duct to exit.

What’s interesting about the new nose layout is that the 2012 RB8 lower slots purpose to cool the electronics and the upper slots purpose to cool the driver are no longer catered for.  This further underlines the slots purposes were for external airflow and not primarily for cooling or other internal purpose.  It’s likely that the nose will gain a conventional driver cooling hole in its tip for hot races.

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