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

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 

   Bahrain

                                                                             

 

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  .