Technical analysis: Force India VJM02
|By Craig Scarborough||Monday, March 2nd 2009, 10:37 GMT|
Force India were the last team confirmed for 2009 to launch their car. The gestation of the VJM02 was interrupted by a late switch to a McLaren Mercedes power train in November last year.
Equally the departure of the chief technical officer, Mike Gascoyne was announced around the same time must have also had an impact on the car's development. Despite these apparent setbacks, the car rolled out today shows some innovative thinking and is a far more complex design than might be expected from the team.
By adopting the McLaren carbon gearbox with its associated hydraulics, plus the Mercedes engine and KERS. Technical Director, James Key and designer Mark Smith had a major redesign very late in the car's design phase, with very little time to pen the alterations. From the fuel cell area backwards, the car is largely brought in by McLaren Mercedes, thus the team had to alter the rear of the monocoque and the cooling design.
This inevitably forced delays in the car's launch, but has allowed more time for the aerodynamicists to focus on the new aero package. This is perhaps where the team show their creativity and the car exploits several features not yet seen on many better-resourced teams' cars.
Indeed, this level of attention to detail in exploiting every surface for aero benefit, harks back to Mike Gascoyne's philosophy, clearly his influence on the car lives on despite his departure.
Starting with a relatively high nose tip, long pylons drop down to a straightforward three-element front wing. The wing separates the movable outer flaps from the static parts by quite large fence: this probably acts both as a turning vane and to maintain the pressure difference between the two parts. The nose also exploits a blind spot in the bodywork rules to fit a small turning vane below it: this area has also been exploited by Toyota.
Behind the new nose cone is what appears to be a completely new monocoque, and not just the old having to be altered to accept the McLaren engine and KERS. This new tub departs from the VJM01, in having a mid-placed steering arm, the link now sits between the upper and lower wishbones to aid aerodynamic performance. While the chassis is much higher at the dashboard bulkhead, creating more space under the nose. Lastly the roll structure gains two vertical supports. Coincidentally many of the design features are also seen on the new McLaren Mercedes.
Hanging from under the raised chassis is a pod containing a laser slip angle sensor. The sensor detects the speed and direction of the track passing under it - this is matched to the angle the wheels are steered at and the difference tells the team if the car is under steering. This solution is used by many teams: the high nose and short range of the laser demands the device is mounted in a remote pod, rather than inside the nose cone as has been the case for may teams in recent years.
Underneath the raised section of the monocoque, the car eschews bargeboards and instead a simple vane runs under the chassis, which leads to complex sidepod inlets, preceded by mirror mounts that form a flow-conditioning profile with an upswept join to the chassis that bends up to mount the mirrors on their outboard face.
Mirrors and their mountings are excluded from many bodywork rules and hence are often used to create shapes that would not allowed with other bodywork. To the outside of the sidepods, clever pod wings shape the flow around the flanks of the car, aided by two vanes connecting them to the car.
In profile, the sidepods drop suddenly in height, in line with the rear of the monocoque, then appear to follow a Renault-like coke bottle shape with internal duct formed by bulging the pod: this exit was closed off for the launch and no doubt these bulges may be reduced as testing proves how much cooling the car needs.
Perhaps uniquely, this year Force India have chosen to exit their exhausts through tall fairings in the sidepods. Also aiding airflow to the rear end are curved fences mounted to the floor around the rear wheels.
As the car adopts the McLaren gearbox, the team were constrained by the rear suspension mounts that McLaren also use, resulting in a very high mounted top rear wishbone. Trailing behind the gearbox is the rear crash structure - this rises well above the current diffuser, allowing scope for development in the future.
Currently the diffuser is a simple 175mm tall single tunnel, albeit separate internally by six internal fences. Mounted atop two support struts, the rear wing takes a cue from last year's Toyota and features a narrow slot in the main plane. This allows the rear wing to be more aggressive without stalling.
By using the entire McLaren Mercedes power train, the team are also using their KERS solution. For McLaren this is believed to be an electrical battery solution, with a motor\generator mounted to the front of the engine feeding the batteries mounted in the sidepods.
As McLaren are unsure if their KERS solution will be race ready for Melbourne, Force India will also have to wait until the system is signed off as race ready before they can adopt it.