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24 Nov 2014


Both Red Bull cars were found to be infringing the technical regulations in post qualifying scrutineering, flexion of the Front Wing flaps being the culprit.  Followers of the technical side of the sport might be thinking here we go again... however it's not aeroelasticity at blame this time (contrary to Christian Horner's rebuttal with the BBC, although he did later concede they'd thinned the metal used) but a metal component that was 'designed' to deform or spring under load.

Article 3.15 of the technical regulations covers aerodynamic influence:

With the exception of the driver adjustable bodywork described in Article 3.18 (in addition to minimal parts solely associated with its actuation) and the ducts described in Article 11.4, any specific part of the car influencing its aerodynamic performance:

a)Must comply with the rules relating to bodywork.
b)Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom).
c)Must remain immobile in relation to the sprung part of the car.

No part can be infinitely rigid, especially given the forces a Formula One car has placed upon it.  That's why key areas of the car, known to be influenced by the teams to make aerodynamic gains are tested for deflection.  The most well known of these tests is the front wing deflection test, owing to the flex teams were trying to achieve in the preceding seasons.  In those circumstances the teams were trying to either arch the wing back, twisting it about the front wings pylons (longitudinally) or flexing the far tip of the wing, in order for it to be in closer proximity to the ground.  The front wing deflection test has been beefed up over the last few years in order to make it difficult for the teams to 'flex' their wings with it now set at a vertical load of 1000nm over the endplate.

The flaps are not subjected to the load test and so they're free game for the teams to exploit.  We've often seen the Williams front wing deflecting at high speed but theirs is simply being achieved through aeroelasticity, ie the force on the wing is sufficient for it to flex downward as the load increases.  It's been an exceptional tool for Williams this season but doesn't only have a direct effect at the front wing but components downstream too.

In the case of Red Bull they decided to go a step further, rather than just having aeroelasticity doing the job, which is slower to return to the optimum position for downforce, they decided to mechanize their front wing adjuster.  The placement of their adjuster was changed along with a flap arrangement change as far back as China...
Above: Red Bull's cascade-less front wing from Bahrain (note the position of the flap adjuster)
Above: This was at the post race test in Bahrain and as we can see the mechanic is adjusting the front wings flap angle.

This early iteration of Red Bull's front wing had the adjuster placed much further inbound than it's most recent locale, furthermore it also adjusted the whole flap, whereas we can see in the wing used from China onward the flap had been split into two sections, with the outer section of the flaps retaining their AoA and therefore a consistent airflow structure with which to manage the outer tyre wake, whilst the inner most section of the flap moved around the metal structure that defines both sections.
Above: The team changed their approach in China, as we can see the adjuster has been moved alongside the metal hinge that allows the inboard section of the flap to be adjusted.  Note that the adjuster is still made of metal at this point, albeit no longer painted in Infiniti purple, over the next few races the adjuster was treated to some black paint.
Above: This is an RB9 Front Wing but as images of the underside of the wing are difficult to come by it serves the purpose of illustrating how the outer section of the wing can remain immobile but the inner flap sections AoA (Angle of Attack) can be altered.  In this case the smaller circle highlights the position of the adjuster, whilst the metal section to it's left is the separation point.
As we can see from this picture in Montreal there is two definite sections to the adjuster, the metal teardrop shaped head which surrounds the hex bolt, which in turn adjusts the angle of the flap.  Then we have what I believe to be a hard rubberized frontal section.  I believe this to be a fast reset, allowing the wing to be reset to the maximum position, making for a swifter pitstop routine if necessary.
However as we can see in Brazil (above) I'm convinced that this part was altered once more, becoming a singular piece (again Horner unconvincingly told the BBC they'd returned to the Brazil spec wing).  With reports from Abu Dhabi that would suggest the latest design would appear to be made from a much softer rubber (imagine squishing a clown's nose for example) which is believed to have allowed the wing flap to move to it's lowest setting under load (ie when at Vmax) before springing back to it's 'set' position.

As the FIA are allowed to do under article 3.17 (3.17.8: In order to ensure that the requirements of Article 3.15 are respected, the FIA reserves the right to introduce further load/deflection tests on any part of the bodywork which appears to be (or is suspected of), moving whilst the car is in motion.) they used a 'stick test' pushing on the upper flap to determine whether the wing was flexing under load.  Contrary to Horner's rebuttal (again) the test was not only conducted on the Red Bull cars but other competitors too, but the force needed to move the RB10's flap was enough to convince the stewards that this was a blatant attempt to mechanically manipulate the flap, rather than the aerodynamic load deformation seen with other teams.

The FIA in my opinion have done the right thing here, as a dangerous precedent gets set when teams start to push the boundaries of the regulations.  Things like this start off small but then become much larger concepts, nipping it in the bud at the final round means teams won't put huge resource into developing their 2015 challengers with this in mind, although as we know they won't forget it and will find another way.  What may appear to be fairly innocuous at the outset often descends into a complex and expensive chase of performance, take FRIC as an example...

It'll be interesting to see if the FIA devise another deflection test for the flaps going forward and/or how much the teams make an effort in their quest to increase their aeroelasticity.  For me Williams have perhaps showed the way in this regard this season (front wing flap deflection) and have specifically targeted direct and vicarious downstream gains from it.  They clearly lack peak downforce when compared to even some of their close rivals, let alone Red Bull & Mercedes but they've proven there is more than one way to skin a cat, with an extremely efficient car.  The deformation of their front wing flap, falls inline with the compression of the tyres at speed, which in turn changes its wake profile.  This means that the aero structures around the floor and sidepod also change with speed (mass airflow) and so being able to manipulate this flow through flap deformation will have a marked effect on top speed.   Furthermore it also changes the cars centre of pressure and so controlling how this pressure shifts also makes life easier for the driver in terms of balance (under braking, turn-in etc).
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2 comments:

  1. First of all, I think the FIA is right in stopping these developments. But, comparing the banned Red Bull and praised Williams solutions, is banning the Red Bull solution not a case of banning the less expansive one? Should the FIA bring much more stringent deflection tests to stop a spending war on these costly concepts?

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    1. I think you have to look at them as two seperate issues, Red Bull's solution has a flagrant disregard for the regulations. The Williams (and others, singling out Williams as they have done a good job of it, however their nose camera position picks up the flap rotation better than others, infact can you remember seeing other nose cam footage this year? it's been rare) solution is akin to the flex that was being induced on the outer portion of the wings several years ago. In that case the FIA could simply beef up the deflection tests, making life more difficult for the team to 'build in' the flex. The test now stands at 1000nm double (if memory serves) where it used to be, whilst the reduction in wing span to 1650mm will have also made life difficult too (never say impossible with F1 though). I suspect that the FIA will either issue a technical directive over the winter, implying that they read the regulations in a certain way and the stewards will be informed of any infringements they see fit going forward OR they will change the regulations, enforcing the 'stick test'. The stick test although it sounds rudimentary btw does have force measurement, meaning they know how much one wing flexes compared to another. The problem for devising another load test for that region is that not one flap is the same, but for sure it'll be interesting to see how the FIA react going forward as I'm sure they'll want to get on top of it before teams start investing significant development in the region.

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