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.
After Jerez test a heat sensor appeared on the inner surface of sidepod panel’s body to monitor front tyre performance . Sauber and Ferrari are other examples that used analogous sensors in that zone.
STR9 had a face lifting before Melbourne in an attempt to increase the amount of air passing under the nose . The new front end has elongated finger extension and highly arched and wider wing pillars which both increase the volume of space under the nose cone and furthermore curve a distinctive air channel above the nose. Channel shaped noses spring their origin back in 1998 on Mc Laren MP4/13, but in Mc Laren case the channel was shaped close the cocpit, rather than the nose end.
After Jerez test, Sauber tried a new front wing with a more boxy upper flap, revised main lower flap with wider slot also colored differently (more white color on its surface) , relocated cascade pillar and a less ducted endplate with new terminal body. The new wing retained for Melbourne .
Part of the upgrade package launched in second Bahraini test, was a front wing of new breed, much more sophisticated than the previous design. All crucial wing element-parts, like the upper flaps ( increased in number and reshaped both close to nose and endplates ),under flap vanes, cascade elements , main flap close to the endplates and even the endplate itself ( less ducted with enlarged horizontal plate on top) are reshaped in an attempt to divert air more effectively outwards the tyre profile and generate even greater amount of downforce.
However Alonso faced serious stability issues ( car bumping in vertical axis) in Melbourne, probably caused by knowledge shortage in terms of adjusting/setting up properly the new wing on car.