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27 Sept 2013

Once again I feel compelled to write about a matter that's circulating around several sites about Red Bull and moreover the use of Traction Control.  The sudden re-ignition of interest in this topic is mainly because of the percieved margin of pace that Red Bull had over the rest of the field at Singapore.  Following on from that, Minardi also threw their ring in the hat not saying it but insinuating that something wasn't quite right and the pace must be indicative of the team doing something that's prohibited.

A traffic spike to the piece I wrote back after the Montreal GP reminded me of the a similar furore we had when fans pointed at the staggered lines that Webber's car produced as he exited the chicane at the Circuit Gilles Villeneuve.

I think there are several things we must consider rather than just taking a blinkered look at the difference in pace from Sebastian to the rest of the field
  • Singapore is a street circuit and thus high downforce, we know that Red Bull excel when they visit this type of circuit
  • Vettel was only 0.091 quicker than Rosberg in qualifying, of course we have to factor in a small percentage of track evolution whilst Vettel bit his finger nails in the garage and not going for another run.
  • By not doing two runs in Q3 Vettel saved a set of fresh Option tyres, this for me is the biggest reason we see the disparity in times at the end of the GP when the track was at it's best and he had a fresh set of tyres.
  • Clear air running is a massive factor in any drivers victory, this is heightened at street circuits as not only is it more difficult to pass, which will inevitably lead to tyre graining and/or increased degredation. You also have the issue of heat/inefficient air, running in the wake of another car means that not only does the car ahead disturb the aerodynamics of the trailing car but it effects performance.  The engine must breath in order to create power and should you be following another car not only is the engine and it's components receiving a reduced quantity of airflow it's also agitated and pre-heated.
  • Post Safety Car Rosberg was struggling with Front Wing issues (Tyre marbles stuck in between the flaps) this causes understeer and although some of it can be dialed out by changing diff settings this of course compromises corner entry, apex speed and corner exit.
  • In terms of upgrades for Singapore the team didn't have anything monumental that would suggest such a huge differential in pace but the team ran their Rear Wing DDRS for the first time at Marina Bay in 2012 that went un noticed until the following races.
Discounting the small raw pace difference to Rosberg in Qualifying and the issues faced by the drivers of following others around a street circuit what makes the Red Bull intrinsically faster than the rest?

Firstly I think we would do well to look at some of my past articles (and links to others) in which I and others have talked about Red Bull's dominance:

Cylinder Deactivation: Not a phenomenon that's unique to Red Bull or indeed Renault but it is something that is believed to be of greater potential to those using Renault power.  Put simply it is the reduction in use of cylinders, this can be used to best effect in the braking and turning in phase as it will allow the engine to act as an air pump as the car reduces speed.  It will of course also allow for the engine to recover quicker as the driver picks up the throttle again on corner exit.  By allowing the engine to deactivate cylinders during the off throttle moments it means the exhaust is still feeding energy to the car and therefore the Floor and Diffuser.

Change of Pirelli's tyre construction back to 2012 specification:  The change of tyre construction from Silverstone saw a return to the specification used by the Italian tyre manufacturer in 2012.  The obvious area this has effected has been the midfield with both McLaren and Sauber able to make ground on Force India.  The change came at a pivotal time in the season as decisions were being made up and down the paddock as to whether the teams start to shift focus to their 2014 challengers.  These decisions were not exclusive to 2014 though with 11 races left the development programme for the rest of the season must also be set out.  From Round 13 onwards we are in the 'fly away' zone and so the pre planning of upgrade/track specific upgrades are mapped out by the teams well in advance.  (A team can only chase so many avenues of development otherswise they lose focus)
Red Bull were one of the teams chasing the FIA for the changes to the Pirelli tyres and for obvious reasons, I don't feel they wholeheartedly dropped the development aspect of the 2012 tyre model and with them possessing one of the quickest cars at the tail end of 2012 they clearly understood how to best extract performance from it.  The RB8 and RB9 are incredibly similar vehicles whereas Ferrari, Lotus and moreover McLaren made changes in order to make large leaps in performance.

German GP 2012 Torque Map Clarification: The torque map used by Red Bull at the German GP was so drastically different to those used in the preceding GP's that it came to the attention of the FIA's race stewards.  From then the teams had to decide on a map from the first 5 races they wanted to use as a baseline, +/- 2% of this map would be acceptable by the FIA for changes at each GP.  At the start of the 2013 season Renault (and perhaps others) believed there would be a reset on the baseline map helping teams to make the necessary changes they required to increase performance for their car.  The rule clarification made after Germany has in my opinion had an impact on the development of the 2012/13 cars. Although the the torque map is totally different to the engine map they are intrinsically linked, migrating too far from the bodywork a team ran in the opening 5 rounds of 2012 has to be done with compromise.

Exhausts and moreover the Red Bull Cross Under Tunnel: With all teams now utilising a Coanda styled exhaust, be it a ramped design or Semi-Coanda design it's clear that during this regulation set gaining performance from the Diffuser is pivotal in increasing the downforce yield.  As I mention above it is a rob Peter to pay Paul scenario where you must give up something in one area in order to make further gains in others.  If we take Red Bull's 3 closest protagonists Ferrari, Mercedes and Lotus all three weren't using Coanda style exhaust systems in the first races of 2012 with Ferrari introducing their Semi-Coanda arrangement at Round 5 in Barcelona.  Even Red Bull had tried various exhaust configurations throughout the early stages of the season as all the teams grappled with over heating the inner shoulders of the rear tyres.
Even though Red Bull struggled to correlate what was being seen in the Wind Tunnel/CFD with on track results with the cross-under tunnel their main stay however was the adoption of the downwash ramp.  Now used by Lotus and Sauber too the cross-under acts much like the Semi-Coanda's counterpart but uses the surface of the bodywork to guide the exhaust plume.  The tunnel allows for the airflow to migrate inbound and exit the car more centrally allowing for a cleaner distribution of the exhaust gases into the gap between the floor and the tyres edge.  Furthermore it also allows for a much tidier flow into the svelt Coke Bottle region.
Moving back briefly to 2012 and we know that both Lotus and Mercedes ran most of their early campaign with the exhausts in more neutral positions maximising engine performance rather then aero performance.  When they made the switch later in the season to Semi-Coanda exhausts they did so with a compromise, as their torque maps (and therefore their correlation to their engine maps) were most likely less efficient than that of Red Bull.
Ferrari's 2012 exhaust carried the nickname the 'Acer Duct' due to the sponsorship displayed in that region, although it utilised a layout akin to the Semi-Coanda configuration they now use it also provided the Sidepod's cooling outlet aft of the exhaust position.

Taking both the torque map and exhaust solutions being used in combination, I'd suggest that although the FIA and teams believed they were curtailing an advantage that Red Bull were creating (in Germany 2012) what they actually did was cut off their nose to spite their face.

Helmholtz / Resonator Chambers: Not an item exclusively used by Red Bull, Helmholtz chambers are used in Formula One in order to change the way in which the exhaust produces power and also aid in smoothing the exhaust plume transition.

Ride Height / Rake: We have seen for years now that Red Bull run with a more extreme rake than most of it's competitors.  As explained in the links ride height and rake form an important role in the increase of downforce extracted from the Diffuser.  Get it wrong and the Diffuser will lose performance and is predominantly why teams have progressively chased the use of interlinked suspensions over the last few seasons. The floor on the RB9 has seen significant revisions from it's predecessor with tyre squirt slots on the outer periphery and the use of 2 vertical floor strakes just off from the centre-line of the exhaust.  These are being used in combination with the plume itself to strengthen the Vortex that curls up and under the outer portion of the Diffuser. Feeding airflow into the gap between the Diffusers edge and the tyres sidewall is what we call 'sealing the diffuser' this helps create a low pressure region at the diffusers edge and increases the downforce yield.

You cannot take what I have mentioned here in isolation and must look at the whole package of the RB9, all of the components create the perfect storm and even more so when allied to Sebastian Vettel's driving style.  Mark Webber prefers a car that moves around allowing him to feel his way in and around corners, Vettel however is able to apply a counter-intuitive style that allows him to commit to the corner when most would back out.  This is done by feeding the Diffuser with exhaust gases which in turn creates the downforce required to pull the car through the corner.

Lastly IF (and thats a BIG IF) we were to seriously consider that Red Bull were using a form of Traction Control they would be in clear breach of article 9.3

9.3 Traction control :
No car may be equipped with a system or device which is capable of preventing the driven wheels from spinning under power or of compensating for excessive throttle torque demand by the driver.
Any device or system which notifies the driver of the onset of wheel spin is not permitted. 
In my opinion the only possible form of TC that could viably be utilized would be via KERS. 
The problem for most people is that when we talk about KERS they only think about the discharge of power (ie the roughly 80bhp for a maximum of 6.67 seconds) but that energy must first be captured. (That's because to the average viewer they see the charge refilled in the on screen graphic at the end of each lap and don't think about where it came from).
In its first year (09) many teams/drivers struggled initially as recovering the energy altered the balance of the car.  
Harvesting to use its correct terminology is done in the same way as the release of energy via the unit attached to the crankshaft. Nothing in the regulations stipulates that this energy has to be recovered under braking but it is the most obvious time you would do so. This is because harvesting intrinsically slows the engine speed and aids in the slowing of the car. I'd suggest it is plausible you could modulate harvesting throughout the acceleration phase in a way that could simulate traction control but I'm quite sure all of the teams already do this to some extent.

In Summary

Let's not get carried away with what appeared to be dominating pace around Marina Bay.  The circuit likely provided the opportunity for a perfect storm, whereby Vettel's driving style accentuated the RB9's high downforce configuration and some if not all of the traits I've mentioned above.
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3 comments:

  1. Matt - compliments on your analyses. Your hypothesis about using the kers to modulate or control engine output reaching the wheels is consistent with what I saw and heard last year here in Austin. The Red Bulls were significantly different in exhaust sound from every other car. Their exhaust was muted and controlled to the point of being slightly muffled while in turn 11, but much closer to all the other cars on approach and 100 meters or so after exit of the corner. Ferrari, McLaren and Lotus were together in a class of exhaust sound that was somewhat controlled. They were clearly not as controlled as Red Bull, but somewhat more muted than the rest of the field. The rest of the field were clearly tuning exhaust for max engine output with little or nothing impeding the exhaust gas exit (and sound). Force India stood alone in seeming to change fuel mixtures between practice and qualy. They started off with rich mixtures that popped on overrun and then tuned that out when they began running in earnest. So, your hypothesis fits with what we saw/heard last year.

    The hypothesis also fits on controlling wheel spin. Back in the 60's I drove one of Shelby's 260 cid Cobras for about two years (the car had been wrecked in California; I put it back together as best I could on a college student's budget and ran it locally). The early Cobras generated their incredible (for then) acceleration from storing the excess energy in the transverse leaf springs and the flexing (really flexing) of the ladder type frame. They then paid that energy out as the springs unloaded producing an even acceleration loading on the rear tires. The flexing was so bad that the doors would pop open if they were not properly tied, but they had to be fixed loosely or they would break the tubes around the latch. The acceleration was dependent on the tire friction being maintained withing the range the flexing could take. In the wet or if you broke the tires free, the whole thing got very messy very fast. Driving an early Cobra in the wet went beyond brave into stupid or desperate. The whole point to the Cobra was energy management in a very crude but effective way.

    I have seen video of Adrian Newey driving a Cobra at Goodwood Revival. I will speculate that Mr. Newey has working knowledge of the Cobra and could very well be applying that using the KERS. My physics and calculus are 50 years out of practice, but if someone will run the numbers using today's tires, then I will bet that KERS can be configured to charge during cornering and acceleration in a way that will produce the wheel hop seen in Canada. I will also bet that they are tuning KERS to produce less unbalancing on braking since they may top out the batteries without it.

    Just some thoughts from Austin. Bill Campbell

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  2. I had the opportunity to drive an original Cobra a few years ago. I then compared the experience with my Factory Five Cobra replica. I know exactly what Mr. Campbell describes regarding the frame, suspension flex and responding traction event of the original Cobra. For lack of better terms the Original would twist, coil up, and expel its energy as traction out of a corner...

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