Force India: New Front End Aero

Sahara Force India ran a new front end in testing, with some of the distinctive features from the launch car dropped. The new set up is aimed redirecting the flow along the edges of the nose towards the floors lower leading edge. The new package consists of; a revised nose tip, front wing pylons and different turning vanes.
The team also ran a revised sidepod package with McLaren style exhaust outlets. I will cover this development in a separate post.

From the cars launch and through the first four races, the nose tip sported a hammer-head style twin camera set up. Now the cameras have relocated to further back along the nose and the nose tip now forms a more aesthetically pleasing rounded shape. Although neutral in aero section, the camera pods are placed in a position where their shape will interact with the airflow to create some aero benefit downstream on the car.
Below this the pylons mounting the front wing have been extended and form a linger vane like shape. This was something FIF1 have worked with a lot over the past few seasons. Using this shape as part of the cars aero set up for different speeddownforce circuits. Typically longer pylons for higher downforce tracks and smaller pylons for places like Monza. Although the vanes may well create some low pressure behind the neutral front wing centre section to create load at the front axle, I expect they are more for directing the airflow along the y250 axis. This is a longitudinal line along the edge of the chassis, 250mm from the cars centre line. This is effectively as far outboard aero devices are allowed and hence where teams tend to focus on vane development. Creating different flow structures along this axis, helps creates the airflow distribution at the floors lower leading edge which is critical to diffuser efficiency.


Along similar line are the new turning vanes, on the launch car these were the popular “L” shaped hanging vanes (pictured above), mounted beneath the nose cone. Now they are a pair of curved vanes under the front suspension, a similar solution to SauberRenault and adopted by Red Bull last year. Again similar to these teams there is a small split in the vane to induce a stronger vortex effect along the y250 axis.

InDetail: Force India Front Corner

Not everything in F1 is aggressive, extreme, radical or innovative. In fact in many areas the car’s are very close in general design terms. Some time it’s enough just to soak up the detail engineering and explain what all the little bits and pieces do on the car. In this series of short articles, we’ll do just that, thanks to these amazing photographs from MichaelD.
This is the front left corner of the VJM05, seen without the wheel to expose the brakes, suspension mounts, hub and electronics. Details vary from team to team, but what we see here is typical of most F1 cars, indeed some of the components are standard (electronics) or lightly modified by the supplier (brakes).

Brake Caliper

Dominating the picture is the brake caliper. This is supplied by AP Racing and will be designed around Force India requirements, albeit based on their current iteration of an F1 Caliper.
F1 Bake calipers must have no more than six pistons, two pads and two mounting points. The material is restricted by an 80Gpa stiffness requirement; aluminum lithium is most commonly used.
AP have a unique design of caliper for many Formulii, with their RadiCal (Radical Caliper) design. This being the way the inner and outer sections join via the complex bridge structure, to make it as stiff as possible. We can see the caliper is bridged in two places and a radial brace is also used. Keeping his area open is important for cooling the brake disc.
Cooling is also behind the structure around the pistons, the cylinders the six pistons within are nearly completely exposed, with just some links to the calipers structure and internal passageway to route the brake fluid. This allows the most airflow around the cylinderpiston to keep them cool. The pistons themselves are made in titanium and have a series of radial holes machined into them to also keep heat from getting into the brake fluid.
We can see the brake line entering the caliper at the bottom, having been routed through the lower wishbone. At the top of the caliper are the two bleed nipples, these allow bubbles trapped within the system to float up and be removed for better brake feel.
The carbon panel on the outer section of the caliper is either an aero piece or some protection for the caliper when the wheels are slammed back on during pitstops.

Discs and Pads

F1 moved to Carbon discs and pads in the eighties, having moved straight from Cast iron discs. Strangely ceramic discs have not been a development seen at races. Rules limit the diameter and thickness of discs, but no other regulatory restrictions are placed on these parts.
Disc and pad material varies according to their manufacturer (Carbon Industrie & Hitco). It is also tuned for each race and even for each driver. Additionally cooling patterns will vary from track to track, For Force India in Melbourne we can see the high density drillings, with three small drillings across the disc. With Melbourne being heavy on braking the pads are also drilled in attempt to keep the brake system cool. Brakes and pads wear at an equal rate, so the few millimeters gap in between disc surface and drillings is all the wear these parts will see, before catastrophic failure. As wear increases with temperature there are sensors measuring the disc surface temperature and also wear sensors for both the inner and outer pads.

Electronics
To monitor all the functions on the front corner, there will be an array of sensors fitted to the parts. These are all linked back to the main SECU, rather than cabling for each sensor passing through the wishbones to the cars main wiring loom, there is a hub fitted to the upright that collects all he signals and passes them back via a single cable. This Hub Interface Unit (HIU) is a common part supplied by MES to all the teams. It has inputs from the aforementioned Pad wear and disc temperatures sensors, as well as two wheel speed sensor (two in case one fails), also a load cell for measuring pushrod (or pullrod) loads.

Wishbone mounting


Although the aluminum upright can barely be seen beneath the brake ducts, the key function of the upright is joins the hub to the suspension. F1 does not use adjustable suspension in the same way as many racecars. That is with threaded adjusters, but instead solid suspension links are mounted the hard points with shims. These shims are used to alter the camber, ride height, pushrod offset and castor.
Teams are no longer aligning the track rod for steering with the FTWB. So often the track rod needs a separate lower mounting point on the upright. When adjusting camber, a different FTWB shim will alter the steering toe angle, so an additional shim needs to be fitted to the track rod clevis t maintain toe angle.
In this picture, we can see the upper clevis that mounts the front top wishbone (FTWB) and track rod. Force India have done this with the VJM05, but have still been able to join the FTWB and track rod to the same clevis assembly. This way camber can be adjusted with a single shim, rather than separate but matched shims for separate clevises.
We can also see the extremely high front lower wishbone position (FLWB); it’s nearly at the front axle height. Having wishbones spaced further apart is better for reducing the loads fed through them, but aerodynamics demand a higher position. We can’t see the outboard joint with the upright; neither can we see the outer pushrod joint. It’s probably that FIF1 mount these mount to the upright in a set up called ‘pushrod on upright’ (POU), this helps eight transfer with steering angle in slow corners.

 

Analysis: Force India VJM05

 

Car: Force India – Mercedes VJM05
Concept
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.

Layout
By using the entire McLaren Mercedes powertrain, the car is largely fixed in layout.

Nose

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,

 

Front wing

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.

 

Roll hoop

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.

 

SidepodsCooling

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.

Exhaust

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.

Rear suspension
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 andor the amount of rake the car now runs warrants a different wishbone position to allow the higher rear ride height.

Diffuserrear 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 plategurney 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.

Gearbox
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.

Features

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.

KERS
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.

Engine

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.