Flexi - Wings are the hot topic today

Why F1's flexi wing tricks are a never-ending problem for the FIA
By: Matt Somerfield
Co-author: Giorgio Piola
May 12, 2021, 5:59 AM
https://www.autosport.com/f1/news/why-f1s-flexi-wing-tricks-are-a-never-ending-problem-for-the-fia/6507108/

The FIA's clampdown on Formula 1 teams exploiting clever 'bendy wings' to boost straightline speed is the latest skirmish in a war that has raged for decades.
Image Unavailable, Please Login
On the one side are the teams who are constantly trying to push the boundaries of the regulations when it comes to flexible bodywork.

Then, fighting them is the FIA which is constantly having to find ways of policing the matter to ensure that teams aren’t exploiting the rules.

The FIA’s latest move, to impose stricter tests from the French Grand Prix, has come off the back of concerns that teams have indeed gone too far.

For despite pretty tough pullback and vertical load tests to check that wings were as rigid as possible, evidence points towards some clever designs.

In a note the FIA has sent to the teams, it said there were concerns that teams – and that is plural – had designs that passed the static tests but: “nonetheless exhibit excessive deflections while the cars are in motion.”

It added: “We believe that such deformations can have a significant influence on the car’s aerodynamic performance.”

This is not a new problem for the FIA, but history shows that flexible wings is a really tricky area of the car to police because there can be no such thing as a zero tolerance approach.

The nature of physics mean parts have to bend, otherwise they shatter as soon as a load is applied.

For teams, such aeroelasticity offers opportunity for aerodynamic benefits. So it is no surprise this area has been a constant battle ground for more than two decades.

Flexi wing history

In the lead up to and during 1999, there were a number of high profile accidents with teams trying to create an effect whereby the rear wing would tilt rearwards under load - giving required downforce at lower speeds but reducing it and, more importantly drag, as speed built up.

Image Unavailable, Please Login
Rear wing load test

Photo by: Giorgio Piola

In response, the FIA incorporated a stringent load test on the rear wing during scrutineering in order to detect any adverse rear flex on the wing.

Image Unavailable, Please Login
Rear wing flap pullback test

Photo by: Giorgio Piola

Straightline speeds began to increase again during the 2005 and 2006 seasons with it becoming clear that teams were once again using aeroelasticity to make gains.

This time it wasn't being done in the same way as before and teams had designed their rear wing planes in such a way that the gap between the main plane and top flap would close up.

This had the effect of 'stalling' the rear wing, as the airflow couldn't circulate around the wing in the usual manner. This served the same purpose of reducing downforce, drag and increasing straightline speed. As the car slowed, the gap would reopen and downforce would be restored.

Image Unavailable, Please Login
SLIDE SHOW McLaren MP4-22 2007 Canada rear wing

Photo by: Giorgio Piola

Formula 1's technical working group had already conceived a method to prevent this sort of manipulation, and had proposed it be introduced in 2007. But, with an explosion of the practice causing concern it may get out of hand during the 2006 season, the FIA introduced slot gap separators from the Canadian GP (as seen on the illustrations from 2007, above).

These separators were seen as a simple way of preventing the gap from closing as more load was applied.

Image Unavailable, Please Login
Front wing deflection test loads

Photo by: Giorgio Piola

The next big F1 talking point regarding flexible bodywork seemed to have Red Bull in the dock at every conceivable turn.

The Milton Keynes-based outfit often seemed to be the ones singled out over flexi wings, as it appeared to have the best handle on how to best apply aeroelasticity to the front wing, while also being able to defeat the FIA's load tests.

Teams began looking at ways to circumvent the load tests in a way that allowed the outer tips of the front wing to reach towards the ground.

This effect would magnify the downforce being generated and, as a consequence, also change how the airflow was pushed across and around the face of the tyre, altering the shape of the wake created.

Consequently this would improve downforce over the rest of the car. For example, the floor was now able to produce more downforce, as the wake wasn't impinging on its performance as much.

Image Unavailable, Please Login
Revised front wing deflection test

Photo by: Giorgio Piola

The rules were changed throughout the next few years as the FIA tried to peg back any advances being made by the teams, all of which were set against losing any ground to rivals.

There was no one size fits all way of banning flexi wings though, although the practice did hit more of a snag when the regulations regarding the width of the wing were altered for 2014, as this obviously magnified how the loads were put through the wing at the measuring point.

Image Unavailable, Please Login
2014 Regulation change overview, using Red Bull RB9 to compare

Photo by: Giorgio Piola

The front wing's entire make-up and load profile were altered further still for 2017, as F1 ditched the conventional straight leading edge design of the main plane in favour of the arrowhead design.

This altered the wing's relative position with the nose, and also the distance from the leading edge of the front wing to the front edge of the floor – an important area for connecting up air flows.

Undeterred Red Bull appeared to have found another way around the changes, as its front wing footplates were seen to be rotating at a different rate to the rest of the wing and thus altering the effect on the vortex shed from it.

Image Unavailable, Please Login
Red Bull RB15 top view

Photo by: Giorgio Piola

In the end, the teams' push on flexible bodywork appears to have been stalled by the simplified front wings used since the 2019 regulation changes.

The issue of flexi wings occasionally popped up since then, but it revved up significantly this season as Mercedes and Red Bull became locked in a tight fight for victories.

On board footage of the Red Bull cars, in particular, appeared to show the rear wing flexing down at high speed, before popping back up into position when the car slowed at the end of straights.

And while Lewis Hamilton may have brought the matter into the spotlight when he suggested Red Bull was running a ‘bendy wing’, it is clear from the FIA’s latest action that it has been looking at the matter for a little while.

But what is uncertain for now is if the tough tests coming for the French GP will draw a line under the matter completely, or become just another move in a battle that can never be won.

Image Unavailable, Please Login
Lewis Hamilton, Mercedes W12, Max Verstappen, Red Bull Racing RB16B

Photo by: Charles Coates / Motorsport Images

 

BBC- https://www.bbc.co.uk/sport/formula1/57086036

Formula 1's governing body has launched a clampdown on flexible rear wings amid suspicions teams are bending the rules.

The move comes after Lewis Hamilton claimed Red Bull used a "bendy" wing, increasing straight-line speed.

The governing body has written to teams saying it had "become aware" some rear wings passed tests but had "excessive deflections while cars are in motion".

The FIA has told teams it will introduce new load-deflection tests from 15 June.

In addition to new, more targeted static tests, the FIA plans to use on-board cameras to monitor the behaviour of wings while cars are in motion in an attempt to spot any excessive movement of bodywork.

Teams will be required to put a series of markings on their wings to facilitate this process.

Article 3.8 of the F1 technical regulations states that bodywork must be "rigidly secured to the entirely sprung part of the car" and "remain immobile in relation to the sprung part of the car".

This is a ban on so-called 'moveable aerodynamic devices', which has been in place for many years.

But it is a difficult area of the rules because all surfaces flex under load to some degree, and historically some teams have tried to exploit this in search of an aerodynamic advantage.

If a wing or other bodywork part can be made to deflect or rotate in relation to others above a certain speed, it can reduce drag on the straights and make the car faster. The bodywork would then snap back into optimum downforce-producing position before the corners.

FIA single-seater technical head Nikolas Tombazis wrote in a note to teams that the deformations the FIA was referring to "can have a significant influence on a car's aerodynamic performance and hence could be deemed to contravene the provisions of article 3.8".

He did not name teams or give specific examples of wing behaviour.

"We will be looking out for any anomalous behaviour of the deformation of the rear wing," said Tombazis.

"In particular, we will not tolerate any persistent out-of-plane deformation that may be contrived to circumvent the symmetrical loading applied in the load deflection tests.

"Should we observe any characteristics that indicate exploitation of this area, we will introduce further load deflection tests as necessary."

Teams are being given a month to comply with the new tests so they have enough time to strengthen their wings if necessary.

There will be a tolerance of 20% built into the test in the first month of its operation.

Red Bull team principal Christian Horner said at the Spanish Grand Prix that Toto Wolff, his opposite number at Mercedes, had spoken to him on the issue.

Horner insisted his car complied with the regulations, saying: "The car's scrutineered thoroughly and there are pull-back tests, all kinds of tests it has to pass," he said. "The FIA are completely happy it has passed all the tests that are pretty stringent.

"I was surprised to see his comments, but it is something Toto has mentioned to me previously. So I doubt it was Lewis' opinion. It probably came from elsewhere."

The first race at which the new tests will come into force is the French Grand Prix on 25-27 June.

Before then, F1 is scheduled to race in Monaco on 20-23 May, Azerbaijan on 4-6 June and Turkey on 11-13 June, although the Istanbul race is in doubt following a surge in coronavirus cases in the country.

 

The ‘flapping’ phenomenon behind F1’s latest flexi wing intrigue
By: Matt Somerfield
May 12, 2021, 11:24 AM
Formula 1 is as much an aero contest as it is a fight between drivers, so it’s no surprise that it has become the focus of the latest Red Bull versus Mercedes battleground.
Image Unavailable, Please Login
The subject become a hot talking point at the Spanish Grand Prix, when Lewis Hamilton suggested Red Bull had been running a ‘bendy’ rear wing to boost straightline speed performance.

In the wake of these allegations, and no doubt following some prompting from teams, the FIA has reviewed what some outfits are up to and agreed that action needs to be taken.

For while all the current rear wing designs are able to pass the static load and deformation tests, they appear to exhibit excessive deflections while the cars are in motion.

As a consequence, the FIA has invoked article 3.9.9 of the technical regulations that permits it to introduce further load/deflection tests on any part of the car it deems fit.

As such, new tests will be introduced from 15 June in an attempt to curb the practice whilst also giving the teams the necessary time to prepare designs that comply.

This gives the teams until the French Grand Prix to fall in line, although a 20% tolerance will be given during the first month of the new tests to aid in the transition.

The load and deformation tests that focus on the rear wing are designed to prevent the structure from being over flexible. Teams are well aware that the ability to lean the wing back as speed builds will result in drag being reduced, giving the driver a straight line speed boost.

Image Unavailable, Please Login
Rear wing load test

Photo by: Giorgio Piola

There’s long been a battle between the teams and the FIA on this front, with the loads and amount of deflection applied during the tests regularly updated to prevent them being defeated during the static test.

However, the teams know that there’s still performance to be found if they can pass those tests but still find a way to have the wing lean back while out on track.

The current regulations focus on the uniform deflection of the entire structure with the checks focused on vertical and horizontal displacement.

However, the new checks will focus on the rotation of the wing around the cars centreplane, with just one degree of tolerance permitted as the loads are applied.

The new rotational tests will prevent the wing from ‘steering’ around the centre plane, a trick that the FIA may be focusing on as being used to circumvent the symmetrical loading applied in the deflection tests.

This is a notable feature in the onboard footage from the rear facing T-camera of the Red Bull, for example.

Close examination of the moving images shows the top rear wing element ‘flapping’ laterally, moving side-to-side with the relative vibration of the endplates, which owing to their design also find themselves oscillating.

This could explain how the wing ‘bends’ rearwards under load, as the wing pivots around the central axis, with one side of the wing moving incrementally rearward before the other.


Red Bull Racing RB16B rear wing comparison

Photo by: Giorgio Piola

Interestingly, Red Bull arrived in Spain with a new high downforce rear wing that it tested throughout Friday’s free practice sessions before making the switch back to it medium downforce arrangement for FP3, qualifying and the race in order to be quicker down the straights at the expense of a loss in the corners.

This new high downforce wing featured all of the usual architecture of its medium downforce wing, albeit with the flap arrangement adjusted.

The height and geometry of the top flap, its trailing edge Gurney flap and cutouts were all altered, whilst the most visually obvious alteration came in the form of a change to the shape of the mainplane’s leading edge, which features an upturn in the central portion of the wing.

Meanwhile, the medium downforce wing features a gentle spoon-shaped spanwise curvature to the mainplane to offset the drag ordinarily created by the interaction of the outboard section of the wing and the endplate.

Image Unavailable, Please Login
Red Bull Racing RB16B rear wing comparison

It appeared to be this change of wing concept that sparked the debate, with Hamilton making reference to it after qualifying and then again before the race.

“Yeah, considering the Red Bull’s are really fast, with that nice, erm, wing that they have” chuckled Hamilton in response to the line of questioning from Sky F1 about the change in wind direction for race day.

In a post-qualifying interview, Hamilton made reference to it being a ‘bendy wing’.

It’s certainly not the first, nor the last time, that flexible wings have been a topic of debate in Formula 1, with Jenson Button recalling on Sky the time when his BAR006 was first fitted with a flexible rear wing.

“Actually, BAR-Honda were the first people to do it back in 2004, we had that, I remember Hockenheim being the first race and it made a good difference,” he said.

While BAR-Honda wasn’t actually the first to do it, it had taken the lessons of previous attempts and found a way to make it work under the prevailing regulations.

During that period, many of the teams were pushing the regulations in interesting ways in an attempt to reduce drag.

BAR-Honda tried various solutions, including fins mounted to the mainplane, paired with the slightly splayed leading edge to the endplate. This has become commonplace again as teams are no longer permitted to use louvres.


BAR 006 2004 rear wing

Photo by: Giorgio Piola

It will be interesting to see if the new load/deformation tests have an impact on the competitive order when we head to the long straights at Paul Ricard.

Any team making changes to its wings, to ensure they comply to the rules, will also need to juggle the potential consequences that could have on them hitting the budget cap limit.

There could also be intrigue beforehand though, because teams could yet decide to lodge protests against their rivals should they believe they’re using a rear wing assembly that contravenes the current regulations, even before the new tests come in to force.

Image Unavailable, Please Login
Red Bull Racing RB16B rear wing

Photo by: Giorgio Piola

https://www.autosport.com/f1/news/the-flapping-phenomenon-behind-f1s-latest-flexi-wing-intrigue/6507256/

 

Why is F1 doing everything they can to stunt technology these days? Better racing? If so, clearly it is not working. F1 used to be a test bed for new technologies that would make it down to road vehicles. Why bendy wings are not allowed baffles me.

 

Allow in and out steering wheels, but not bending wings??

 

How is this any different when the front wings flexes under loads??

 

The DAS was legal then banned the next year because the FIA could ban it. Given COVID, the teams that could produce one opted not to given cost and time. That was my understanding of that. Not related to this of course.

On topic - interesting to see RedBull with practice Wing and Qualy wing. Like a motor with practice mode and hyper mode for quali. Clever people!!

 

Because they don't want a spending war re: aeroelasticity.

 

Understood, but I don't agree with that either. Vehicle manufacturers spend a ton of money each year in R&D, why can't one of those vehicles be F1? There are many other "spec" racing series around the world, F1 should be the one to allow more tech advancement, and remove spending caps.

My apologies to all for the discussion diversion....

 

I see the point given F1 always like to say as you do -- Best drivers, tech etc. The rules will have limits on all this as we see again with aero today.

 

Not the first time this happens, but when FIA changes the rules in the middle of the game I feel suspicious, knowing how inept (if not corrupt) they are.

 

The FIA opened a pandera box when they allowed DRS.

Previously they didn't tolerate any moving part.

The "flexy wings" present them with a new dilemma.

Maybe they should think about simply allowing " variable geometry" in F1.



Jim Hall and his Chaparrals were really ahead of their time !!

 

This.

Red Bull produced a legal car and it passes all tests. Now that they're a bit too quick suddenly Mercedes seeks to change the rules mid season so that their main rival is slowed down?

 

Both wings flex, but RBR much more so,

 

Red Bull top speed throughout the weekend was the lowest as well. Lewis claim that Red Bull was faster on the straights is straight up fantasy (backed up by the fact that RBR lost 2 tenths on the straights every time!)

 

I'm thinking that maybe the problem is that they still test the wings with weights. With the current tech, they could put cameras, laser beams or whatever to check if the wing is really moving or not.

 

This reminds me of something...Something about 2019, a red car and a motor that passed all the tests. Couldn't have happened to a nicer team ;^)

 

'Teams' are being noticed with more flex in the press. Not just RedBull it appears. Too quick? They were not quick enough in Spain. If the tests are changed then it applies to all teams. They only worried teams will be those that have more flex.

Again if this were RedBull complaining via Max - as Max did calling Ferrari cheaters loudly in the press in the past - what would be the opinion here? RedBull have nothing to worry about if the FIA take a look at the teams with respect to this issue. They have been warned and all this will be in force in France.

 

FIA still bending over to protect Toto's agenda.

 

Good point. Binotto should stroll down the paddock, sniff the rear wing, and tell Horner it smells like grapefruit juice (in Italian of course).

But I'm truly hoping FIA doesn't do anything to slow RB down as watching Vintage Max challenge ham is the most competition we've seen at the front in awhile.

 

Unfortunately I suspect that the duel between Lewis and Max is just a mirage..

 

They race results and current points tell us everything we need to know. It’s only an a perception of competition.

 

The FIA is realizing that the test setup (see pics in OP) is insufficient to restrict the intent of the rule. They are only testing for flexure under form drag, and even then are not measuring changes in airfoil shape/incidence as a result of that flexure. Also it does not tell them about flexure due to normal forces acting on the airfoils (wings), and resulting changes in lift/drag.

But yeah, you can't go changing criteria in the middle of the season just because a competitor may be at a disadvantage.

 

In fact, they let Mercedes use the DAS in 2020 to ban it in 2021. You will have to explain to me the consistency of all this.

 

Aerodynamic things are not to be adjusted during the race. A wing that bends is self adjusting.

That is the rule was poorly written and now has to be poorly enforced. The only other thing FIA could do would be to allow DRS on every straight without a time specification.