Car: Force India – Mercedes VJM05
In common with other teams Force India have followed an evolutionary path for their car since the aero rules changed in 2009. Despite having a strong year in 2011, the team had already decided to follow a new car concept for 2012. Thus the car we see has little in common with the outgoing VJM04, starting from the concept of a new front wing and a new nose above it. Then the sidepod philosophy has been switched to the Toro Rosso style of deeply undercut (or double floor) sidepods.
By using the entire McLaren Mercedes powertrain, the car is largely fixed in layout.
Even without the 2012 nose rules, it looks like FIF1 were going to follow a new direction in their nose design. Recent cars sported a narrow high nose, with a bump beneath it to create some downforce from the neutral centre section of wing. The team also tested a McLaren style under-nose snowplough in 2011, but weren’t able to get it to work for them. So they have opted for quite a wide and rounded nose section, the tip being formed into hammerhead shape by the two FOM cameras.
The nose joins the chassis with quite a smooth transition; the front section of chassis has a slight “V” shape to aid the step between the nose and chassis. When looking at the front bulkhead, it’s possible to see how the concave shape created on top of the chassis has to be matched with similar convex section at the bottom of the chassis in order to meet the regulations on minimum chassis cross section.
Currently the wing mounting pylons are extended rearwards, but this is an area FIF1 tend to alter between circuits, so we may see some different iterations of this vaned pylon,
As the starting point for the new aero concept, the front wing follows the modern F1 pattern, the three element wing is formed from a split main plane and a flap trailing it. The outer section of flap fixed and along with the tips of the main plane curls down to meet the endplate. As is common for this style of wing the flap gains an extra slot in the upper corner to aid flow. The endplate is formed by a vane help direct the airflow outboard of the front wheel. Also in keeping with the theme are the cascades which are mounted to the endplate-vane, there being one larger and one smaller winglet above the main wing.
The 2011 car switched to a blade style roll hoop on the grounds of less weight and better airflow to the rear wing. This year the design has switched back to a deeply undercut shape, with the metal inner structure exposed beneath appearing as the four supporting struts for the engine inlet snorkel. Technical Director Andy Green explained that they were able to make this structure even lighter than the blade design. Adding that with raised nose and sidepods, losing weight high up kept the cars Centre of Gravity nice and low.
Along with the nose assembly, the sidepods are next biggest departure for the team. By keeping the radiators and sidepod volume high and narrow, the resulting undercut in the sidepods flank creates the double floor effect and allows more airflow to pass directly over the top of the diffuser. Unlike Toro Rosso’s rounded interpretation of the undercut sidepod, FIF1’s has much flatter sides, particularly in the coke bottle region near the exhausts; the sidepod shape is particularly slim.
The entire sidepod is formed form a single moulding, when removed the entire cooling set up and side impact spars are exposed. This should make altering the sidepods profile during much easier.
Cooling for the radiators is via the Red Bull style tail funnel, or ‘Tulip’ exits as Green describes it.
Force India’s exhaust system is tucked in close to the cars centreline towards the rear of the legality box. I suggested to Green that this was neutral position and probably did not produce the downforce of other systems. Green suggested the “looks may be deceiving”, but did concede that it was less sensitive placement in order to get the best performance around a lap rather than the maximum possible downforce. As with most teams other systems will be tried, but this set up will probably make it to the opening races. The exhaust plume plays over the tail of the engine cover and over the gearbox box. With the rear wing gaining a 15cm central winglet, the idea is probably to blow this central area for a little bit of extra downforce. The engine cover has a unpainted heat shielded that rises quite high, so the exhaust plume may be diffused over the cover to spread itself event between the beam wing and winglet.
By using the McLaren gearbox Force India are forced to use similar in board wishbone mounts and the same pullrod mechanism. The top rear wishbone appears to be mounted lower than last year, no longer is the rear leg aligned with the wishbone, suggesting one of two things, the gearbox itself is a lower design and\or the amount of rake the car now runs warrants a different wishbone position to allow the higher rear ride height.
Diffuser\rear impact structure
Again somewhat tied to the same mounting points of the McLaren gearbox, the rear impact structures sits low and exposed the beam wing above and the diffuser below. The diffuser uses the maximum width to expand laterally, such that the sides of the diffuser cannot sport a gurney. There is a gurney mounts along the top edge of the diffuser, with a slotted section between the rear wing endplates. As is common, a tall plate\gurney is mounted between the diffuser and the crash structure above.
Looking from the front of the diffuser the undercut sidepods and crash structure allow a clear flow of air into the boat tail section of diffuser; this leaves the exposed and probably gains a slight blow effect from the better airflow. This aids through the awkward centre section of diffuser. As yet the rear wing endplate does not extend downwards behind the diffuser, but is attached to the diffuser with two vane-like mounts.
As already mentioned the gearbox is supplied by McLaren, this is a carbon fibre cased unit and features pullrod operation of the springs and dampers. Last year the springs were mounted vertically and the dampers mounted inside the casing. The only external element was the anti roll bar which sat atop the casing, with drop links down to the low mounted rockers.
As with Last year, FIF1 have BBS wheels with integrated fairings. These are all that’s allowed in terms of non structural spoke son the wheel, since the ban on the wheel fairings seen in 2009. They aid the airflow around the wheel and in doing so may aid brake cooling and/or general aerodynamics.
Again Force India uses the Mercedes AMG KERS, similar in design to last year, the combined battery Pack and power electronics unit sits below the fuel tank.
As with all teams the engine specifications are frozen, only the mappings to accommodate the new regulations on on-throttle blown engine maps are allowed. The engine manufacturers suggest this will affect the engines drivability, as these maps pre-existed blow diffusers, and were used to smooth the power delivery and harvesting of KERS energy during braking.