Archive for the ‘MP4/25 rear wing & F-duct’ Category

Mc Laren MP4/25 – Back to Spanish rear wing spec at Hungary


            At slow and high downforce  Hungaroring the team brought back the rear wing spec firstly presented at Spain which produces greater amount of downforce .


Mc Laren MP4/25 – No rear wing change for low downforce Canadian circuit

          At Canada it was surprising to see Mc Laren keeping its Turkish rear wing version  as teams traditionally reduce the rear planes chord in favor of achieving top speed at long straights. For sure Mc Laren’s  revised F-duct system launched there  helped the team to sustain a good top speed .

Mc Laren MP4/25 – Updated Chinese rear wing spec for Turkey


           The rear wing introduced at Turkey regained the pre-Spain main flap profile with the  leading edge  at the central section to be raised up so as to divert more air under the planes (drag and downforce reduction by this configuration ). Furthermore the second flap had its chord being lengthened  at its central section to gain some of the lost downforce  . Apart from the former mentioned,  the endplates slot-gills were also increased in number just like before the Spanish race  .




        Furthermore  the wide inlet in the middle of the main plane and the two more additional smaller ones on either sides were rejected and as a result of  it  the second plane  lost its additional slot at its rear surface  in favor of a single shorthened one . Finally there was a new blowing slot of reduced length of the F-duct system, placed lower.


  Spain & Monaco




           The new rear wing design is not “new”  for Mc laren as it was  extensively used during the past years time and it replaced the maximum downforce rear wing used at Monte Carlo . The new wing may produces less downforce but significantly less drag .

Mc Laren MP4/25 – New rear wing at Spain alongside with an updated F-duct system


            At Spain a new rear wing was introduced with  revised planes and a new connection of the F-duct system’s tube to the wing . There is now a wide inlet in the middle of the main plane and two  additional smaller ones on either sides (yellow arrows ) . These combo of inlets provide with air a slot extending up to all  the plane’s width ( in white No 1 )  and help to  prevent wing’s stalling in high speed and high attack angle . As a result   the F-duct system’s tube connection point  to the wing is now moved further up and shoots air to a modified also slot ( in black No 2 ) , placed above the previous mentioned one . 




            Lastly the endplate itself featured less slots to let less air bleed out of the wing  favouring downforce production .


Mc Laren MP4/25 – Bahraini rear wing details


       Mc Laren’s rear wing features the following major characteristics :

1.The main profile is bending upwards in its middle to divert airflow under the wing and not over, in an attempt to reduce turbulence around the connection point between the shark fin and the plane .

2.Single pillar to ensure wing stiffness

3.At the top of the endplate, there are multiple shark gills

4. Endplates have a deep cut at their rear upper part . That cut helps to reduce drag

5. Gurney tab , differs from the rest red plane as it is in black color

Mc Laren’s innovative rear wing system ( F-duct)

December 14, 2010 3 comments

Mc Laren constructed  its 2010 condenter , the MP4/25 , equipped with a new innovative system , called the F-duct which helped the car to achieve higher top speed at straights without loosing downforce at corners .

Official name of the system :

         While press and media called the system “The F-duct” , Mc Laren officially coded the system as  “RW80” meaning Rear Wing version 80

What is the benefit from such a  system :

          The driver at will can blow a high velocity airstream to the rear wing at straights , causing the it to stall , gaining a significant greater top speed for the MP4/25 up to 7-12 km/h  according to the tuning of the system and the track characteristics . The system was found to be within the rules by the FIA .

Why the system was considered to be legal :

        Several teams protested against the legality of the system when it gained publicity but FIA had already gave the green light to Mc Laren to develop such a system because the non movable-flexing wing plane principle is not violated as the system alters only the airflow around the wing and not the wing’s flexibility  .  Rival teams rushed to copy the system with the first one to be Sauber , while Ferrari , Red Bull , Williams , Force India and much later Renault and Toro Rosso also launched their own versions of the system .

    For 2011 the rear wing stalling system was ruled out of the regulations in favor of the new  rear wing attack angle adjustment mechanism .

How the system is activated :

       The air entering the nose snorkel can be blocked by the drivers left leg at will and as a result  the airflow  inside the engine cover is forced by changed pressure to circulate via a certain tube to reach  the rear wing causing it to stall .

Parts of the system :


The system  functions with the combination of  three different air inlets which are :

(A)  a nose duct  ( spotted where the F letter of the Vodafone logo exists and so called F-duct ) –  (Number 4 )

(B)  an inlet located behind the driver’s helmet  under the primary airbox inlet to receive airflow –  (Number 3 )

(C)  airbox second upper  inlet –  (Number 1 )

[The number 2 inlet feeds the engine with air and has nothing to do with the system]

         The received airflow from the nose duct  is directed via a tube inside and around the cockpit ending inside the engine cover . There it meets a second  richer airflow coming from the (B) inlet. The summoned airflows then enter a  system of tubes housed inside the engine cover .  The airflow coming from the  (C) airbox upper inlet also enters this system of tubes

How the system functions :

     Activated  system                                                                    


         When the system is active ( at driver will ) the airflow entering the (C) airbox inlet  circulates via a certain tube , gaining gradually velocity  with the help of a venturi effect , to reach  a hole located on the centre zone of the rear wing profile ( yellow arrow ) . The airflow  hits the wing and exits  behind the  wing’s profile  via a small additional pair of wavy shaped slits  , disrupting airflow and causing the wing to stall . As a result  the  wing’s drag production is significantly decreased in favor of top speed   .

      blown aiflow wing inlet

wing blown aiflow exits behind the  wing’s profile  via a small additional pair of wavy shaped slits 

When system is inactive  the air inside the engine cover flows into a second tube  exiting  above the  beam wing  leaving the rear wing unaffected .

   deactivated system

Pre-2010 season variations of the system  :

        The system is much complicated and the team tested various versions before launching it at Bahrain . The visual variations regarding the nose snorkel  are the following  .

    Winter testing      


   Winter testing  – a rectangular piece of carbon seals the  upper inlet surface 




Developments during 2010 season of the system

       During season Mc Laren developed further the system . The season developments regarding the  system’s activation way ,which was revised from driver’s knee to driver’s hand  and the different system’s tuning and air exiting  ways , are going to be described in future posts  .

Mc Laren MP4/25 F-Duct Explained by Martin Brundle

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