Brazil tech: 2015 data gathering ramps up

As the penultimate race of the season and with the previous race just a week ago, the Brazilian Grand Prix did not seem like a race for big development strides. Yet Mercedes was still improving its 2014 car.

Elsewhere in the pitlane, a wide array of sensors were being employed by teams as they gather crucial data on planned designs for 2015.

MERCEDES

The evolution of the Mercedes F1 W05 Hybrid has been constant and iterative throughout the season.

Several major parts have had upwards of three versions during 2014. This weekend, it was the under-nose turning vanes that had changed.

What were previously three-element vanes hanging under the front suspension have been split into four separate elements.

Splitting an aerodynamic surface can be done for several reasons. With wings it tends to be to prevent separation of airflow from their under-surfaces.

With turning vanes which are primarily flow conditioners, it's to alter the vortices they produce.

So rather than a single vane producing one large vortex, which is hard to control, teams break up the working surface to produce several more controllable vortices.

How much more complex these areas can be become in 2015 after a further winter of development?

FERRARI

Ferrari again split its two cars with different rear suspension iterations, with Fernando Alonso running the usual rear suspension geometry and Kimi Raikkonen the newer one.

Most likely the revised geometry is tied to a specific gearbox so it will be difficult to remove from one car or introduce to another during the six-race gearbox cycle.

Closer examination shows there to be subtle geometric variations, although any performance differences are hard to ascertain.

It appears that it is the upper wishbone that has changed the most.

The new set-up has a steeper anhedral angle, the inner mountings are lower and the outer mountings are closer inboard.

That means the gearbox mounts and the top of the upright are altered on Raikkonen's car.

Intuitively, this gives more camber change on the new design, which would be expected to accelerate tyre warm-up and degradation.

Ironically, this appears to be the behaviour the team is trying to rid itself of.

LOTUS

Choosing not to run the revised 2015 specification nose this time, Lotus embarked on an aero evaluation of the frontal aerodynamics in free practice.

Both cars were rigged up with aero rakes and sensors around the front tyres.

The aero rake chosen was a commonly-used type, mounted low down ahead of the sidepods.

It will pick up the wake of the front wing and tyre as they approach the floor's lower leading edge.

But the sensor on Pastor Maldonado's car was more interesting, being mounted to the brake ducts and facing the tyre's inner sidewall.

This device is a camera that measures the tyre's sidewall profile as it bulges from bumps, aero load and turns.

Understanding the tyre profile is critical as the airflow passing off the front wing is heavily influenced by the changing shape.

Without a tyre-specific change for 2015, this work will be useful in the development of front wing details for next year.

McLAREN

Like Lotus, McLaren had an aero programme planned on Kevin Magnussen's runsheets on Friday.

The car started free practice with a pair of tall aero rakes fitted behind the front tyres.

Whereas aero rakes are a common sight, they tend to be asymmetric, only fitted to one side of the car.

For McLaren to use a pair was therefore unusual. It could be so that the steering effect on airflow can be directly measured on both sides of the car simultaneously, rather than making assumptions from a single sensor when measuring left and right steering effect on only one side of the car at a time.

The rake's position was broadly aligned with the inner face of the front wheels, therefore encompassing the wake from the front wing, inner brake ducts and tyres.

This is one of the more critical airflows in the boundary between the clean airflow close up to the car's bodywork and the more turbulent flow passing outside the front tyres.

It's now expected that McLaren will bring a new front wing to the Abu Dhabi GP, influenced by its new head of aerodynamics, the ex-Red Bull man Peter Prodromou.

Considering how little time Prodromou has officially been at McLaren, it is surprising his influence could be seen in a component with as long a lead time as the front wing.