Archive for the ‘C31 cooling’ Category

Sauber C31 – cooling assymetry in Sepang


Another interesting point on C31 at Sepang was the asymmetric  cooling gills at cockpit sides . The right sidepod tunnels  accommodate the oil tank and thus need extra cooling care .




Sauber C31 – ducted rear floor

ducted floor , additional gills are pointed with yellow arrow . It was tested also at Barcelona on March

       Sauber  rushed to optimize further the rear end of the C31 and raced at Melbourne a ducted floor in front of the tyre profile . Ducted rear floor is not a new idea in Formula 1 and was a common feature a couple years ago . The duct is within FIA technical regulations because it is situated outside of the area of the  900 mm wide floor continuous surface , something that  article 3.7.6  imposes . It is believed that the duct feeds the diffuser with air coming above the floor level , air that is strengthened further  by exhaust gases that bent downwards due to the special shape of the bodywork behind the exhaust pipes (down-wash effect) .

 A logical step forward to enhance the effect of the design would be the following

–          two channeled sculpted bodywork ,behind the pipe , with the outer channel to expand further outwards .The expansion of the channel without dividing it into two would ruin somehow the direction control of the dpwnwash effect

–          new vertical floor fence with a benting inwards leading edge

likely development scenario

       Finally Sauber paid extra attention to the car’s cooling efficiency at very hot and moist Sepang circuit and added two slits close to the exhaust area , pointed with a yellow arrow in first illustration .

Different set up for Sauber drivers in Australia


In Australia Sauber drivers preferred to race with  different car set up and different wing specs . Kobayashi raced with the higher downforce launch front wing spec and the additional beam mini plane that guarantee a more stable car especially when braking late , something suitable to Kobayashi’s  driving style and his appeal of overtaking . On the contrary Perez raced with the lower downforce front wing , that was first seen at Jerez on February,  having also the beam mini plane removed , a configuration  more appropriate to his “velvet” driving style which is to prioritize conservation of tires in good condition . The later is reflected on Perez different pit stop strategy to Kobayashi .


Pit stop strategy

Sergio Perez  Medium -Lap24 , Soft –Lap 34
Kamui Kobayashi Soft –Lap 13 , Soft –Lap 23  ,  Medium –Lap 22



Lastly Australian rainy weather was not enough and Sauber  run both cars  having the large engine cover funnel  .


Kobayashi beam mini plane in yellow , large engine cover funnel in red

Perez large engine cover funnel in red

Many updates on Sauber C31 before Melbourne

The blue labels in the photos above are temperature indication stickers , used by teams to track down temperature along the route of the hot gases .

       In addition to changes concerning C31 cooling, many other revisions took place on the car before Melbourne . The rear silhouette of the sidepod  tunnels was heavily modified after launch at Jerez test . The new longer tunnels expand smoothly to reach floor level  in a such way to guide more drastically the exhaust gases towards the  inside area of  the rear wheel profile and reach the diffuser . To enhance the effect further,  a channel is sculpted behind the periscope exhausts and later at Barcelona test on February   a vertical fence was added on the floor along the route of the hot gases.

         Speaking for the rear floor morphology , it was reshaped twice with the first revision to take place at Jerez alongside with the sidepod expansion to the rear and the second revision at Barcelona on March with the trapezoid channel in front of the rear wheel to be replaced by a small duct .

trapezoid channel in front of the rear wheel

Barcelona on February,
Floor vertical fence in orange

Barcelona on March, ducted floor   



      A promising update for the team which took place also at Barcelona on March , was the connection of the sidepod panel  to the chassis via  a wavy winglet to force air flowing  above the  sidepod profile to follow the shape outline of the sidepod  stronger  and increase the downwash effect of exhaust gases to the diffuser .


Sidepod panel winglets

    Some interesting but important details on C31 are also the following

-a small duct , already present since launch , permits a small portion of air flowing under the floor to find exit above the floor level instead of bleeding to the sides .In some occasions the duct was partially covered with tape

– a  cooling duct for KERS components is spotted at left side only of the sidepod bottoms

-briefly Sauber tested a set of gills around the launch spec periscope exhausts

floor duct

KERS cooling duct

gills around periscope exhaust area

Sauber C31 – cooling options tested during Winter testing

     Winter testing gives the opportunity to teams not only to understand the new car but also to check reliability and to improve performance as much as they can . Part of the program is also to evaluate the cooling efficiency of the car, having in mind  a wide range of possible weather conditions , for instance from cold  to very hot conditions( Bahrain , Malaysia , summer races etc ) . A significant handicap is that 2012 winter tests  took place in Spain under the cold winter time , which forces teams only to figured out which are the  most appropriate cooling options at very hot races .

    C31 at its launch version had large outlets at the back end of the sidepod tunnels , through which hot air from radiators escaped .Additionally a series of gills at both cockpit sides contributed to cool down the car internal components .

Launch , sidepod end outlets (in red) and gills at cockpit sides

Launch , sidepod end outlets (in red) and gills at cockpit sides

At the very first test at Jerez Sauber featured an extra outlet for the hot air located at the end of engine cover .

Jerez test and Barcelona test on February , additional outlet at engine cover’s end , gills at cockpit sides were retained

Jerez test and Barcelona test on February , additional outlet at engine cover’s end , gills at cockpit sides were retained

The later concept seemed to be insufficient for even hotter conditions and thus Sauber moved a step forward and tested a Red Bull style engine cover funnel in Barcelona test on March . Of course the large funnel harms overall aerodynamic efficiency of the car and it is expected as an option only for few races ( such as Bahrain , Monaco , Malaysia , Hungary , Singapore , Abu Dhabi ) where high temperatures and low average speed will be a threat to reliability .

Barcelona test on March , a very large engine cover funnel replaced the former smaller outlet

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