So, it was little wonder that Red Bull team boss Christian Horner, whose team has been dominant in F1 2023 up until now, found himself having to repeatedly dismiss any suggestions that his squad’s struggles were related to new FIA stipulations over the wings.
Backing up his argument is the fact that, with a flexi-wing estimated to be only worth about one-tenth of a second around Singapore, the scale of Red Bull’s pace drop pointed to other factors being at play as the RB19 proved itself difficult to get into the right set-up window around the Marina Bay circuit.
Plus, according to consensus in the paddock, the focus of the FIA push on flexi-wings was not in fact Red Bull, as it was others who had been perhaps pushing the boundaries in this area far more. While it was easy to link a potential shuffling of the order in Singapore - some teams looked better than normal, others had drifted back - with the timing of the much-talked about flexi-wing technical directive (TD), it was actually another FIA document that had gone under the radar in recent weeks which served to fuel bigger intrigue for engineers.
Plank games
At the same time the FIA issued its TD on flexi-wings (TD18) in late August, Motorsport.com has learned it had also sent out a revision to the famous TD39 that was introduced at the 2022 Canadian Grand Prix, which had originally been aimed at bringing an end to porpoising.
One of the factors to trigger car porpoising was suspected to be teams playing around with flexible floors, which is why from last year fresh stipulations came in about the stiffness of floors and the measurements of planks.
The wildest theories at the time pointed to teams running moveable skid block designs, that disappeared into the plank area so did not get worn when the car ran close to the ground and therefore did not wear down beyond the allowed tolerances.
This was possible to do because, at the time, only a small section of the skid block was measured to check on compliance post-race.
However, to stamp out the practice, the FIA declared that measurements would be taken around 75% of the skid block radius - effectively preventing small areas getting protected.
The matter seemed to have gone away, but during 2023 it has emerged that teams have still been playing around in this area and continue to push the limits with floor flexibility because it is such a key performance differentiator.
The focus of this latest push appears to suggest that teams have shifted their focus away from the skid block moving, to it now being the plank that is the moveable component as teams exploit a tolerance within the rules that allows the plank to slightly deflect.
Article 3.15.8 of F1’s Technical Regulations states that: “Bodywork within RV-PLANK may deflect no more than 2mm at the two holes in the plank at XF=1080 and no more than 2mm at the rearmost hole, when the car, without driver, is supported at these positions [for testing].”
It is suggested that this 2mm tolerance has been viewed not as a limitation by some teams but an opportunity to get away with some extra flexibility to help drive performance gains.
One theory that emerged in Singapore was that this could help allow the plank and floor to get sucked down at high speed thanks to this flexibility, delivering a nice downforce boost, while the skid blocks remained static and out of the way so were at no risk of being worn.
The skid blocks were in effect disappearing just like they were in 2022. But while back then they were being moved, this time it was plank around it that was flexible.
If a team was manipulating the floor like this, it would mean the plank could in theory be worn away by running super close to the ground without the risk of damaging the skid blocks for their post-race FIA checks.
Stopping the flexing
This potential exploitation of flexibility in the floor is the focus of the latest TD39 revisions, with the FIA stating in its updated documents that: “We have become aware of design details in the region of the skids…that aim to take maximum advantage of the permitted stiffness in these regions.
“Whilst these designs may comply with the deflection requirements of 3.15.6 and 3.15.8, we would like to remind teams that designs must still comply with the relevant bodywork dimensional constraints.”
The theories about moveable planks drew further credence with the FIA reminding teams that there had to be a continuous surface on the reference plane.
It also added: “Designs must not utilise breaks in this surface to facilitate differences in vertical stiffness across the break or to facilitate differential motion across the break that lead to discontinuities in the surface.”
To ensure teams stopped playing around with any tricks, the FIA said that certain designs were to be outlawed along the ‘reference plane’ – which is in effect the plank. These were:
1. Gaps, cuts or butted joints in the reference plane in the vicinity of the designated holes and/or skids.
2. Frequent or systematic damage, cracks or breakages of the surface of the reference plane or bodywork in the vicinity of the designated holes and/or skids.
3. Elastomeric or very compliant materials on the reference plane.
4. Folded surfaces or bellows type joints, whether elastomeric or not.
Just as had happened with the latest FIA flexi wing affair, from the Singapore Grand Prix teams had to submit their CAD designs and FE analysis for the front skid block, plus drawings of any flexibility around the hole.
Shaking up the grid
Any team that suddenly had to change approach with its floor to fully comply with the new stipulations would face an obvious performance drop, and probably also have to relearn a lot about ride heights and where to position their floor in relation to the track.
But while Red Bull endured a weekend where it seemed a bit lost with set-up, rivals were not yet ready to believe that this was anything more than a quirk of the unique Singapore track. And Horner was crystal clear about how much his team had changed on its car in relation to the TDs. “Zero,” he said.
McLaren boss Andrea Stella was sceptical about the TDs being a factor in what happened to Red Bull, as he said its pace drop was in excess of anything linked to the flexi wing and floor demands.
“I don't know whether Red Bull had been affected or not by the TD,” he said. “But I would say that even if there was an effect, this effect wouldn't be as large as the deficit of performance that meant they were out of Q3. So I would exclude that that's the sole reason: if it's a reason at all.”
For Mercedes, whose own squad back in 2015 endured a massive performance drop with a dominant car in Singapore, the reality is that the Marina Bay circuit can be a bit of an outlier to throw up surprises.
Speaking after qualifying about whether he felt Red Bull had been hurt by the TDs, Mercedes boss Toto Wolff said: “We've been in Singapore with a dominant car and were not able to perform.
“But it's so difficult. We have one set of data now [the Singapore GP] and then we're going to a totally different track where that plays a role. So let's wait.”
Teams are now waiting with anticipation to see what happens in Japan this weekend, with the Suzuka circuit the perfect place to better see the true impact of the TDs on car form up and down the grid.
A return to the status quo we’ve seen for much of the season would serve to draw a firm line under talk that any teams had been operating in a grey area with their wings and floors to gain an unfair advantage.
But if the F1 form book remains as shuffled up as it was in Singapore, then expect the intrigue to step up a gear.
