As the fight at the front of Formula 1 has got more intense, the key to success has been in bringing the best upgrades without hitting a snag.
The missteps taken so far this year by Ferrari, Red Bull, Aston Martin and Mercedes are in contrast to a McLaren team that has so far nailed all the developments it has brought to the MCL38.
As rivals ponder just why McLaren has managed to get things so right, and others have got them wrong, an interesting theory has gathered some momentum.
It is that the story of the 2024 season is a simple one. It is about who has got the best wind tunnel.
The link between McLaren doing so well with its car and having the newest of the current generation of wind tunnels has not been discredited by paddock insiders as a pure coincidence.
Indeed, as Red Bull tries to get to the bottom of why the development of its RB20 has gone astray this year, it is understood to be increasingly convinced that its problem originates from its own Bedford wind tunnel – its modernised facility that was originally built during the Cold War.
It was telling when Red Bull boss Christian Horner let slip after the Italian Grand Prix about the issues the team is facing with its car: "It's disconnected front and rear. And we can see that. Our wind tunnel doesn't say that, but the track says that."
Any problem with the wind tunnel can be a real challenge for teams because, with development being driven by the data coming out of the wind tunnel, any wrong information makes it almost impossible to know for sure if new parts are an improvement or not.
"It's not unusual that when something's not working on the car, you end up with different readings from your simulation tools, and they don't converge," said Horner.
"Then you get three sets of data: you get CFD, you get wind tunnel and you get track. Obviously, the one that really counts is the track data, but to develop it, it's like telling the time with three different watches.
"You've got to focus on the tool that's going to give you the most valuable input, and of course, the track data is the most reliable."
The current situation means Red Bull cannot count down the days quick enough until its new state-of-the-art wind tunnel is up and running at its Milton Keynes base.
Yaw and rolling floor materials
The situation among the top teams is not just about having a wind tunnel that does not give you wrong data.
Instead, it is about how much better the data coming out of your wind tunnel is than your opposition's.
With the current generation of ground-effect cars so sensitive to ride height and under-floor aerodynamics, the more accurate your readings, and the closer the correlation is to the real world, the better the hit rate to develop your car will be.
Higher quality data can be helped by a more advanced wind tunnel, with teams pursuing several key features these days – some of which have been implemented by Ferrari after it shut its wind tunnel down for several weeks this summer for a refurbishment.
As part of the lessons learned from the high-speed bouncing problems that caught it off guard with its Spanish GP upgrade, the team committed to making some improvements to its wind tunnel.
Sources say that originally this was mainly to do with better yaw angle simulation – to help mimic the airflow over a car as it turns through a corner.
After all, when teams require cars to produce downforce, they are not travelling in a straightline, they are rotating, pitching and yawing against the airflow as they transition through a bend. So tunnels have to be able to replicate this as much as possible.
But having committed to shutting down its tunnel for an upgrade, Ferrari is understood to have also decided to go all-in and take things further than originally planned – with a revamp of its rolling floor also being completed.
This is something other teams have done too. So, where once the standard was for a shiny smooth metal surface to offer a consistent aero platform to check on aerodynamics, the current cars ask for something different.
With underfloor air flow absolutely critical to the performance of ground effect cars, and them so sensitive to the track surface beneath them, teams have realised that their tunnel learnings are better with a floor that simulates real life. And F1 cars do not race on shiny metal surfaces.
Instead, the preferred solution now is for rubber-type materials to be used for the rolling floor. These have rough surfaces – so better simulate the disrupted airflow that is generated by real-world asphalt.
As one senior team figure explained, every bump of stone, and gap in the asphalt, helps create a small vortex under the car as it passes over the top – and it is managing these tiny airflow imperfections as they travel down the floor that is essential to deliver performance in the real world.
Teams are understood to have gotten so far advanced with their use of these rougher rolling road surfaces that they have different types that simulate the varying track surfaces that are encountered on the calendar.
The airflow under a car at a rough venue like Bahrain will be very different to the smoothness of somewhere like Montreal.
One engineer suggested that some teams may even now be 3D printing rolling road track surfaces so they accurately recreate individual tracks…
Better sensors
There are other areas where the latest wind tunnels are better too, and that comes down to measuring the data.
Aston Martin's engineering director Luca Furbatto talked recently about a potential advantage that McLaren has coming from more advanced sensors – which help provide more precise and better feedback on what is happening in the tunnel.
"If I'm not wrong the last wind tunnel that was developed in F1 was 20 years ago, so there's a lot of technology change," he said. "So imagine, in terms of flow visualisation, there are tools nowadays that didn't exist 20 years ago.
"You could take a wind tunnel 20 years ago and upgrade it with new technology, but it's never the same as if you start with a brand new one and think: how would you do it [from scratch], and what's the best out there?"
He added: "Today it is possible to scan the flows in different areas of the car. It is something more modern than the tools such as simple scales that were used years ago. The addition of sensors allows us to check the quality of the flows in many parts of the car."
It is little wonder that Aston Martin itself is excited about the prospect of its own new wind tunnel coming on tap in time for the development of its 2026 car.
The human element
It is clear the potential benefits that teams see from having the latest and best wind tunnels, which is why Ferrari was prepared to shut its down mid-season to get it revamped ahead of this winter.
Few outside McLaren know exactly what technology is inside its new Woking tunnel, and even a reveal video the team did explaining the facility last year said it could now show off any of its internal workings.
Team boss Andrea Stella makes no bones of the new wind tunnel at Woking being a help with what is happening on track right now, however, he suggests it is not the complete answer – because he thinks that a key element that cannot be ignored is the human element of making use of the data coming out from it.
"I think in terms of the wind tunnel, it does help the fact that we can lean on a new wind tunnel to the latest technology, because we are dealing with complex aerodynamics," he said.
"I think the evolution of these cars has led to some challenges for physics, and I think that's where other teams, including McLaren, are kind of struggling to easily generate developments.
"However, I think more than the wind tunnel, ultimately, if we have a competitive car on track it is merit of the entire aerodynamic team.
"There's no tool that does the job itself. A tool is a tool as such, because it's used by humans.
"So for me, the praise goes to the aerodynamic team that since we started the work last year, they have been able to achieve such a success rate in terms of development."
