Insufficient rear downforce production was noticeable on Sauber and thus team soon pushed to develop new rear wing designs towards downforce increase .
The initial wing version seen in Jerez had two distinctive V cuts on the trailing edge of the movable upper element where the two flap fasteners exist, while the main flap had a slopping downwards profile close to the endplates to benefit as possible from the clean airstream coming unblocked by the main airbox body. Such main flap design philosophy springs its origin from old Renault team (now renamed Lotus) back in 2006 .
A new version put under test in Bahrain two weeks after which had a wider main flap and three fasteners this time. The upper element was also new because it featured only one V cut in its middle section now. Additionally a mini plane made its appearance above the rear structure.
For Melbourne the Bahraini spec modified further, regaining back the two flap fasteners structure design but loosing the V cut. The mini plane also removed .
PS= The V cut bleeds pressure from the wing decreasing drag with small negative impact on downforce production
Amazingly ToroRosso tested from launch to the very first 2014 race in Australia three in total rear wing specs, very similar in basic structure but different in details. The spec for Melbourne race was similar to the one seen in launch, having two flap fasteners and a curvy upper flap. The team tested during Winter testing one more version with three flap fasteners and reshaped upper flap, an evolution of which having a single pillar briefly equipped on Jean-Eric Vergne car for the Aussie GP free practice sessions.
Force India proceeded on minor rear wing revisions for the Aussie race weekend. The changes involved the number of wing’s flap fatheners, the number of which now reduced to two from three.
The new rear wing design, launched at last pre session test, has a taller and rocket shaped carapace of the DRS activator and reshaped planes with double flap fasteners instead of three .