There is nothing radical on Force India VJM06 diffuser .The most striking points on the design are the perforated ( slotted) tab and the three in a row vertical fences separating the inner section from the our tunnels.
Like several other teams in 2013, Force India does also share a carapace of carbon to enclose both the lower rear wishbone and the driveshaft.
Caterham tried a modified diffuser at first Barcelona test, featuring a new perforated tab fence demarcated between the rear wing’s endplates . The new design improves diffuser’s suction ability, thus improving downforce production . The perforated diffuser concept is not new in Formula 1 but present since few years ago.
Caterham shows a respective development rate for a small team . The fruits of hard labor delivered so far a new front wing , multiple cooling configurations and even a new diffuser .
The new diffuser came alongside with the new double openings at sidepods tail . Firstly the side tabs are much wider , meeting the width of the horizontal tab to isolate better the outer diffuser chambers from turbulent air created by rear wheel spinning.
The double openings at sidepods tail release hot air following an up-wash direction pattern with the help of the horizontal tab . That helps the central zone of the diffuser to extract more air from underneath the car. Additionally small portions of air bleed through the engine starter hole to reach the central diffuser chamber and energize the flow .
The new diffuser philosophy dictated the removal of the two central vertical fences as there was no reason to keep apart the airflow coming from skid sides and the one coming from the centre because now the two types of airflow are closer in energy level .
The big changes at rear end, both referring to diffuser and cooling openings, curved the path for the team to develop new Mc Larenish style exhausts that were tested during the Mugello test on May at Italy.
- Caterham CT01 – cooling ( up to Bahrain) (formula1techandart.wordpress.com)
Ferrari tried a modified diffuser before Melbourne but the new diffuser is not yet raced so far ( up to Bahrain) . It features an arched roof above the two large vertical fences ( enclosed by a yellow circle in the illustration below), a design concept origins from Red Bull RB6 ( 2010 car) .
The team exploits the vortexes spilled by the V shaped areas of the roof to prevent any mixing between the flow coming out from the centre zone with the flow coming out from the side tunnels of the diffuser .Of course absolute prevention of mixing is not possible to happen but the lesser degree it takes place the more efficient the diffuser becomes .
- Red Bull RB7 – arched diffuser roof at Germany (formula1techandart.wordpress.com)
To strengthen the stiffness of the diffuser and rear floor , Sauber connected the later to the rear crash structure via a pair of cable supporters . Their task is to eliminate possible vibrations that would potentially harm the aero behavior of the rear end . To even increase rear end stability an extra mini plane was added on the beam wing ( in yellow) .
- Sauber C31 – Rear beam wing (formula1techandart.wordpress.com)
C31 diffuser may lack any eye-catching innovations but is nevertheless full of interesting details . The roof tab is slotted to allow portions of air bleed through hence reducing drag, a trend carried over last season and pioneered by Toro Rosso STR6 . There are three vertical fences , two of the same height and an outer shorter , at both diffuser sides symmetrically placed to allow not any interaction between the air flows travelling through the channels formed by the fences . The centre part ( magnified ,in the inset above ) looks very interesting and totally different than that of C30 -2011 car . It clearly exploits aerodynamically the motor access hole to gain extra downforce . The flow travelling around sidepods bottoms reaches the slim rear end and penetrates through the starter hole to rich the diffuser zone to increase diffuser ability to pull air from under the floor. The contribution is enhanced by the warm air escaping from holes in the area of the gearbox and aided by a little flap . That flap apart from its aerodynamic role reduces the overall size of the engine starter entrance to comply with the article 3.12.7 of the FIA technical regulations . Not far in the past that hole raised significant protests against Mc Laren which forced FIA to further clarifications about the size of the hole .
The Belgium diffuser version was obviously a platform for further modifications which were seen at next race at Monza . The main tab fence gained the same arched patern of the diffuser roof but with less deep cut . The side curved tabs were replaced with enlarged and slotted ones .Finally the rear brake winglets were shaped back to Silverstone configuration .
The too many diffuser versions is not a surprise because red Bull raced also many different front wings which from their part effect and direct rear end modifications .