Why is this tech considered such a flex?

Hello and welcome along to round 2 of the Formula OverAnalysed papers- Why are flexi-wings so sought after in the 2021 grid?

To quickly introduce this topic to the unaware, the FIA announced that it will outlaw flexi-wings from the French GP. Why is that? And what are flexi wings in the first place?

For beginners, flexi-wings are the rear (and in some instances, front; but this article focuses on rear, since that is the primary concern in 2021) wing attachments that flexes under loads brought about by acceleration or breaking. This 'flex' is merely the changing of the length of its horizontal width and vertical tilt under applied forces during the races especially, since the performance gain in qualifying (over just one lap) is almost not significant. (Its like running full wets when the dry track has only just started to get wet from the rain; the conditions are not as demanding). 

Referencing the second law of Newtonian motion, it can be connoted (simply) into the following statement: forces can be said to be applied on a thing(body) when either the body's mass and/or the speed* of the body changes over a period of time. This change of speed over a period of time is also called acceleration, which may be to speed up on the straights or slow down (decelerate) under breaking. The mass change (reduction) also refers to the car burning off fuel during the actual grand prix. However it may be, there is always a force that acts on the rear wing. This force can also be brought about by the air passing, since the speed of the rear wing with respect to its surroundings (air, which is at rest [assume no wind, thus not moving and hence, speed of air is zero]) increases from, for example, 110 Km/h at the slowest point in Baku's T1 to approximately 200 Km/h on the run up to T2. This force will be talked about later.

*it should by right be velocity, but it can be taken as speed since we do not require to measure the rate of distance travelled from a certain point

I would like to quote from the 2021 technical regulations' pdf found online in article 3.9, 

"...Bodywork (in this case, the rear wing) may deflect no more than 15mm vertically when a 1000N load is applied vertically to it...Bodywork may deflect by no more than one degree horizontally when a load of 1000N is applied simultaneously to its extremities in a rearward direction...". 

What this means is that when a mass of approximately 100 kilos is hung from any 2 symmetrical points of the rear wing, its height should not reduce by more than 15 mm, or 1.5 cm. Pretty strong in my opinion! Similarly, when pulled backwards with a force almost equal to that of a 100 kilos, the rear wing should not deflect by more than one degree backwards. Pretty strong again!

However, the loophole that teams like Red Bull has found and exploited brilliantly is the fact that the conditions here in the test is very different from that of race conditions; The air is pushing on the rear wing, The rear wing itself undergoes acceleration and experiences forces when the car is accelerating or decelerating. Another factor that matters is the actual ideology behind the construction of the car: is it meant to be high or low downforce? As many F1 fans may know, Red Bull has -almost historically- been and still are high downforce runners. Their car generates a lot more downforce than the Mercedes, as can be proven by the front crash structure (FCS). Red Bull's FCS is a lot shorter and steeper than Mercedes, indicating that they are a lot more downforce oriented than the latter as the steeper (and shorter) the FCS, the more effective downforce. 

"Therefore, the flex-wing has the ability to have its height and angle changed under racing condition. Ok, fine; but why is it even adopted in the first place? And why is it sought to be disbanded by the FIA?", one may wonder. 

Well, like mentioned before, under racing conditions, the force that acts on the rear wing may be able to flex outside of the FIA test conditions are, when it is engineered to behave that way by the way the carbon fibre was used to construct the wing (see: ChainBear). This gives the team an advantage over the competition to them. This advantage here is the ability to control the downforce that acts on the car. So, it may be justified to think of them as the active suspension concept for rear wings. To explain simply what active suspension was able to do, I would like to quote Paddy Lowe, from his Beyond The Grid podcast episode,

"An active (suspension system), (is when) you're applying energy...via hydraulic* pump, to (make an easier job of driving around) each corner. (This is to) maintain a certain ride height and grand clearance**..."

*the use of water/oil to apply forces and energy

**the space between the road and the lower end of the car

This system, with the aid of moving suspensions that aid cornering and straight line acceleration, helps to increase overall competitiveness and downforce on the car, since the downforce derived on the car is more consistent over a lap with the height of the car from the ground kept as consistent as possible. 

This is similar to the flexi-wing, as this too controls as much downforce as possible: through the corners, the wing flexes 'upwards' as the amount of force that acts on the rear wing reduces, since the speed of the air decreases to zero (again, assuming that there is no wind blowing). 

As such, this allows the wing to flex back to its normal position, improving downforce and grip through corners, as shown by the first picture above, as the Alfa Romeo negotiates T2 in Spain, with the yellow line present to prove the flex when accelerating down a straight. 

When on the straight, since the air is again pushing against the rear wing, the wing is able to flex as much as is shown in the picture. This allows the car to have a reduced downforce effect, which is essentially is useful drag. With lesser drag, the car is able to reach a higher speed with the 'compressed' wing when compared to the same car with the standard, FIA-compliant wings, regardless of the surroundings. 

This is deemed to be illegal by the FIA since this is, in its essence, similar to a banned concept talked before, the active suspension system. To again quote the FIA to show where the active suspension -and thus the flexi-wing- is able to be deemed as illegal, the FIA have mentioned, on Formula1.com, that 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". This means that the cars will be deemed to be running illegal technology or concepts that have the body parts move when racing but not when the FIA tests them. Secondly, this falls slightly outside of what the FIA is aiming to do: tighten the field to each other as much as possible. With this technology, some teams may pull it off brilliantly and be able to recover as much as 5 tenths per lap, as many of the TPs claim. However, there will most likely also be teams that are not able to pull it off as spectacularly or not at all. This would then further spread the field further from each other due to the performance deficit between the fastest and slowest car increased.

So there you have it!; the reasons why the flexi-wings are being banned and what they are in the first place. I feel like I did a fair job of explaining the ideology and conceptualisation of flexi-wings. What are your opinions? Should the FIA let teams run flexi-wings? Should I change my approach to writing these articles? Let me know in the comments, thoughts and suggestions in the comment section below and I would massively appreciate any bit of interaction here. This is only my second article ever so please be merciful if you disliked any part of the article :)) Anyway, until next time, I wish you and your world well.