Analysis: How 'rake' helps make Red Bull Singapore GP favourite

Red Bull's performance always come to the fore when the chassis plays a more prominent role and their power unit deficit is marginalised.

Monaco, Hungary and Singapore stand out as its best opportunities in this instance, and is why they have been earmarked as favourites for Singapore.

While Red Bull has been synonymous with these high-downforce situations for a number of years, it's interesting that it has recently been holding its own at circuits that don't traditionally favour its characteristics.

Just check out the straight line speed it had at Monza, where it was not as far down on the opposition as its power deficit would have you believe.

So, what is it about the RB12 that gives it an edge in these situations? Our colleagues on the Italian edition of Motorsport.com posed that question to Enrique Scalabroni, ex-Ferrari and Williams designer, who had some interesting insight into the 'rake' used by Red Bull.

It's Scalabroni's assertion that Red Bull has a variable rake set-up that allows it to dynamically improve downforce and minimise drag.

Of course Red Bull's philosophy has centred around the nose-down attitude of the car, increasing the size of the diffuser by virtue of the car's angle, since 2009.

However, this is but one part of the story, with many of the avenues used by the team to make this philosophy work having been closed down by changes in the regulations to limit their performance over the years.

Mercedes W04 FRIC system

Photo by: Giorgio Piola

Scalabroni explained that during the earlier incarnations, the team needed to create clever solutions to 'seal' the diffuser - with Red Bull unsurprisingly at the forefront of the exhaust blowing revolution that ran from 2010 up until the start of the hybrid era.

The energy of the exhaust plume was used to populate the area between the tyre's side wall and the diffuser, creating a sort of 'thermal skirt', assisting the diffusers expansion.

Red Bull RB6 flexible front wing

Photo by: Giorgio Piola

Meanwhile, other solutions were being implemented, such as flexible front wings that made further use of the raked attitude of the car.

The flexi-wings, which started another development war, pivoted down from the wing's neutral section to the outer edge to maximise the vortex that could be generated, improving downforce and displacing airflow around the front tyre.

The FIA subsequently increased the load tests done during scrutineering to limit this push on aeroelasticity. Whilst the effects of the trick became limited, they were not been forgotten.

Ferrari SF15T and Red Bull RB9 T trays

Photo by: Giorgio Piola

One of the key components behind the raked attitude of the Red Bull car is the splitter or 'tea-tray', as it is the limiting factor in how much rake can be achieved.

Such is the performance advantage that can be gained from running the splitter beyond the considered zero point, it is an area of the car that the FIA monitor closely.

Down the years, teams have used all sorts of clever mechanisms to circumnavigate load tests conducted on the splitter, and Red Bull has always been under close scrutiny due to the level of rake it runs

The load tests have steadily increased since 2009 to counter any potential developments but perhaps the most interesting change was made in 2014, when the FIA insisted that teams return to the use of Titanium for their skids.

Granted the sparks created by the skids are a plus side, especially at the night race in Singapore, but it was the admission that teams had been using Tungsten previously that got lost amongst this.

Tungsten had become the material of choice for the skids as although it is slightly heavier than Titanium, it doesn't wear as fast. That means the blocks could be exposed to the track surface more often without incurring serious plank damage.

It was no surprise therefore that rival teams suggested one of the motivating forces for mandating the use of titanium was actually to prevent Red Bull being able to run its plank on the floor as much through excessive rake.

Despite the obstacles having been placed in the way of Red Bull, its desire to run with a raked attitude remains, as the performance that can be gleaned makes it worth the effort.

It's a philosophy that requires all of the parts to work together and, whilst exhaust blowing to seal the diffuser is no longer a viable avenue, the team has continued to look at ways of minimising airflow disturbance.

How rake returned

Scalabroni suggests that this begins with a key aero structure 250mm from the car's centreline, where the neutral section of the front wing terminates and the flapped section begins.

This surface juncture creates pressure gradients that collide, creating a highly energetic vortex (Y250) that's directed down the car, past various other aerodynamic devices that control its direction and vorticity.

This helps to understand how the RB12 is such a phenomenal car through the corners, with downforce aplenty. But it doesn't explain how the team are getting the best from the car on the straights given their power unit deficit to the other teams at circuits they'd ordinarily struggle.

This is where Enrique proposes that the team have elected to run with a more softly sprung rear end than is normally the case.

Ordinarily, he said, a team would use around 1500lb springs to maintain aero stability, whilst he'd argue that the RB12 is using around 600lb.

This means that it can achieve the optimum rake through the corners but once on a straight, the downforce being generated continues to pull the rear of the car down toward the ground, changing the car's attitude and, with it, the loaded wing elements. This reduces the downforce and drag it generate, boosting top speed.

Suspension focus

We can't talk about this without giving a nod to FRIC (Front-to-rear interconnected suspension).

In 2014 the FIA banned the use of hydraulic systems to connect the front and rear suspensions in order to improve the dynamic platform of the car.

Whilst it considerably improved the mechanical stability of the car, the more mature systems were also focused on improving the aerodynamic efficiency of the car too.

Mercedes AMG F1 Team W07 suspension detail

Photo by: Giorgio Piola

FRIC may be banned but that doesn't mean the knowledge is discarded, far from it. Instead, the teams have continued to work on solutions that maintain chassis parity, as they search for more mechanical grip and trade it off for aerodynamic performance.

Mercedes continues to lead the way in this respect, with an all hydraulic arrangement at the front of the W07, as we've uncovered previously, allowing it to ride kerbs, take more aggressive lines and generally help with tyre performance and degradation.

Red Bull can attribute much of its relative pace improvement to the fine tuning of its suspension too, although you'd have to argue that the current tyre situation has played right into its hands.

The current high pressures being enforced mean the sidewall is less susceptible to deformation, improving its aerodynamic consistency.

This is because the tyre is an organic item: its properties change around the course of a lap depending on the loads exerted on it.

Control of these changes in shape can have a dramatic improvement on performance, especially as during the corners a tyre's deformation pushes airflow laterally into key airflow structures such as the diffuser and at vMax the tyre will grow, changing its profile and the wake it sheds, likely leading to more drag.

The finite control of tyre pressures and temperatures was one basket where Mercedes had its eggs stored and, so the recent change of protocol will have undoubtedly have had an effect, although it's a cascading one, as others were doing it too, just not on the same level.

Another thing that'll buoy Red Bull is that Mercedes is still unsure of its performance at Singapore compared with last year, where it struggled for pace relative to the other teams.

Such was its despair that it created a separate working group to investigate the issues that befell it during a weekend that prompted some wild conspiracy theories.

A sensitivity to the tyres, given the change of starting pressures in the preceding round, is considered the lead culprit.

Even so, it will be more wary, especially with the use of three tyre compounds this season making setup even more crucial.