The vital discrepancy creating F1 headaches for Mercedes

The team that has won a record eight consecutive constructors’ championships since the start of Formula 1’s hybrid-engine era is floundering at the start of the 2022 season.

At the time of writing, after the Australian GP, the W13 is an average of 0.847s off the pace in qualifying. Ferrari and Red Bull are in a league of their own at the front, and Lewis Hamilton appears to have no more of a chance of avenging the controversial loss of an eighth world title in Abu Dhabi last year than Max Verstappen’s new rival, Charles Leclerc, did of winning a first at the same point a year ago.

Formula 1’s much-vaunted new rules have caught Mercedes on the hop, and the team is scratching around trying to understand why it is so far off the pace, and what can be done about it. As team principal Toto Wolff puts it: “There are deficits everywhere. We have many parts on the car that don’t work, that we don’t understand, that don’t perform enough. This is not where we expect the car to be.”

Hamilton has been even more succinct: “We need more grip and we need more power.”

So how much trouble is Mercedes in, and how likely is a recovery before this season becomes an exercise in damage limitation, and the championship a write-off?

Before we get into that, it’s worth outlining the context for the situation in which Mercedes finds itself.
The new technical regulations introduced this year to improve the racing are the biggest change in F1 for 40 years. They have presented the teams with a set of challenges that almost nobody currently working in Formula 1 has faced before.

The rules have fundamentally reworked the aerodynamic design philosophy in F1. Since 1983, cars have had flat bottoms between the axles, and underbody airflow manipulation fundamentally started at the rear wheels, where the floor was finally allowed to sweep upwards for downforce generation.

For 2022, shaped underbodies have been reintroduced, and with them a phenomenon known as “ground effect”. The two sides of the underfloor either side of the driver are shaped like an upturned aeroplane wing for their entire length. These are called venturi tunnels. Air is accelerated along these surfaces, creating a low-pressure area, which sucks the car towards the ground.

No clear sign of Mercedes' major weakness with the W13 car became apparent until it hit the track

Photo by: Mercedes AMG

Ground effect has been used in isolated parts of the cars in recent years – for example underneath the front-wing endplates – but this is the first time since 1982 that it forms the basis of the car’s entire aerodynamics.

The time span involved has meant the teams were pretty much starting from a point of zero knowledge as to how to make the cars work, and how to deal with the problems that ground effect throws up. In addition to this, an engine development freeze has come into effect from the start of this season; F1 is in the second season of a budget cap – which this year limits spending on design and development to $140m; and F1 has instigated a sliding scale of restrictions which permit the most successful teams the lowest amount of research and the least successful the most.

At the same time, Mercedes has being going through a period of internal change. Last year, its two most senior technical figures stepped away from their roles. Engine chief Andy Cowell, who masterminded the revolutionary hybrid engine that has set the standard in F1 for eight years, decided to leave the company. And technical director James Allison, one of the most highly regarded aerodynamic designers and engineering leaders in F1, stepped away from day-to-day running of the F1 team when he was promoted to chief technical officer.

Their replacements – Hywel Thomas on engines; Mike Elliott on car design – have been with the company for years, effectively as second in command in their departments. The hope and expectation, therefore, was that the transition would be seamless.

“We are starting to get it [porpoising] under control, but at the moment having to throw away the basic performance of our car as a smaller problem, in order to get the bigger problem, the uncontrollable bouncing, under our control” James Allison

When the new Mercedes W13 was unveiled, it gave the impression of business as usual. Its bodywork continued the trend of the previous years of the team shrink-wrapping the car as much as possible – and that was even before the remarkable update introduced at the second pre-season test, which was dubbed the “no sidepod” car so much had the bodywork been reduced.

On track, though, the car had problems from the start. In testing, Mercedes was among the teams to suffer most severely from a phenomenon known as 'porpoising', an aerodynamic effect that was commonplace in the first ground effect era. The underbody airflow stalls and reattaches in quick succession, causing a sudden loss and then regaining of downforce, triggering high-frequency bouncing on the straights.

“We were caught out by it quite badly,” Allison says, “and the amount of porpoising on our car, especially when we put our first-race upgrade package on the car in the last winter test, has been quite extreme.

“We are starting to get it under control, but at the moment a little bit by having to throw away the basic performance of our car as a smaller problem, in order to get the bigger problem, the uncontrollable bouncing, slightly under our control.”

Mercedes has also appeared down on top speed compared to its rivals

Photo by: Sam Bloxham / Motorsport Images

The Mercedes has also been relatively slow on the straights. In fact, all the Mercedes-engined cars have tended to be towards the bottom of the speed traps.

This has led many observers to the conclusion that Mercedes’ engine development work with the new E10 fuel over the winter has been less effective than that of its rivals, and so Mercedes has been overtaken on performance. If true, this would have potentially large consequences, now that development – other than for reliability reasons – is outlawed.

Mercedes does not believe this is the case. “We need to analyse the drag levels first, before we really make a judgment of whether we are lacking power,” Wolff says. “I don’t think there are big differences in the power units but clearly Ferrari made a big step forward because last year they weren’t totally competitive.”

Allison says he believes “most” of the deficit on the straights “is coming from the size of our rear wing”. He adds: “There will be differences, of course. There may be small differences in the power of the engines. But I don’t think any of us, none of the teams, have got a handle on that, on where the pecking order is, and they are likely to be small if differences at all.”

The car is also over the weight limit – but then so are many cars believed to be because meeting the limit, even at its increased level this year, is not easy as a result of a number of beefed up safety requirements in the rules.

The core problem with the car is its lack of aerodynamic performance, which Mercedes believes is rooted in the porpoising problem.

“The only way to run,” says Hamilton’s team-mate George Russell, “is to raise the car very high. And obviously, with this ground effect car, [then] we lose all the downforce.”

Trackside engineering director Andrew Shovlin describes finding a way to stop the car porpoising so Mercedes can run it at a rideheight at which it can deliver its theoretical performance as “priority number one”.

“Fundamentally,” he adds, “we need to understand the problems better. We’ve got some avenues that I think are giving us a good direction, but it’s taking a bit of time to get those parts on the car. And we’re working very hard. We’re well aware that there are other teams that have got on top of this problem faster than we have, and that’s not the standard we normally work to.”

Shovlin accepts Mercedes has been caught out by the porpoising phenomenon

Photo by: Carl Bingham / Motorsport Images

The problem with porpoising, though, is that it’s not a phenomenon that is easily dealt with by teams’ normal working practices. It does not show up in computational fluid dynamics, nor in the windtunnel. On top of that, most teams have admitted the problem caught them by surprise – which seems odd when it was so common back in the 1970s and early ’80s. But that’s time at play. A graduate out of university in 1982 would be 61 or 62 now.

It is therefore interesting to reflect on the fact that two teams each have one very experienced – and extremely highly regarded – engineer who was around during the original ground-effect era and therefore has first-hand, practical experience of porpoising.

Those engineers are Adrian Newey, Red Bull’s chief technical officer, and Rory Byrne, still a consultant at Ferrari, and one who played a significant role in the 2022 design concept. Can it be an accident that these two teams are by far the most competitive at the start of F1’s new ground-effect era?

Frank Dernie, who had a long and successful career as an F1 aerodynamicist from the mid-1970s until about 10 years ago, thinks probably not. “They probably started off with [porpoising] in the back of their minds in the concept of the car, which is how it should be,” he says.

"You’ve got to make it work using crossflow and vortices and all sorts of other weird and wonderful things" Frank Dernie

Dernie is perhaps most famous as the aerodynamicist at Williams when it broke through to become F1’s most successful team in the early 1980s. And he led the aerodynamic design of two ground-effect Williams cars: the FW07, the team’s first championship winner, and its successor the FW08, which won the last ground-effect drivers’ title with Keke Rosberg in 1982.

Dernie admits he’s “12 years out of date” with regards to some F1 knowledge – such as the latest capabilities of CFD – and in some ways it feels incongruous to be talking to someone about his experiences 40 years ago to try to make sense of a problem in the 21st century. But that just happens to be the timescale involved.

In the late 1970s and early 1980s, F1 cars had ‘skirts’ – bodywork that runs the length of the sidepod to seal off the venturi tunnels. These are not allowed now. But the method of creating downforce via ground effect remains the same.

Dernie talks of two key ways porpoising was typically triggered back in the day – “skirt jamming”, and underfloor flexing. Both have direct relevance today. Skirt jamming was when the sliding skirts got stuck in the “up” position, causing a loss of downforce. While current cars don’t have skirts, Dernie says Mercedes’ issues “could be allied to [skirt jamming], because anyone who has a floor that actually does touch the ground when they’re going quickly – if they touch a bump or the circuit is uneven or it comes up – that will cause a form of porpoising similar to the jammed-skirt syndrome.”

Frank Dernie, alongside Sir Frank Williams and Alan Jones, enjoyed great success with Williams during the last ground effect car era

Photo by: Rainer W. Schlegelmilch / Motorsport Images

Mercedes’ floor edges could be seen touching the ground through medium- and high-speed corners in testing.

“Unless you can keep it touching the ground all the time,” Dernie says, “it is better for it to touch the ground never.”

This is because of the way aerodynamic theory works. Dernie says that the length of an F1 sidepod compared to its width means “a sidepod cannot work as a wing unless it’s got skirts, which effectively make the air think it’s an infinite wing, and the skirt is permanently sealed. And therefore, you’ve got to make it work using crossflow and vortices and all sorts of other weird and wonderful things. Crossflow is the inevitable effect of the fact that the pressure underneath the car is lower than the pressure on the sides.”

This means air will come into the underfloor from the sides. “You don’t have to stop that happening,” Dernie says. “You can’t stop it happening. You have to work with it. You have to make that crossflow do something useful, and it’s not easy.

“The first thing you need to do is understand what of the many things it is which is causing the problem. And after that, you’ve got half a chance of fixing it.

“It will be aero, but it could be aero due to trying to seal the sides – which is frankly stupid because it’s not possible with that sort of car – or it’s not stiff enough, ie it’s an aero-elastic problem. They have either not made the floor stiff enough, or they haven’t got it supported in the right places. It certainly looks like that to me, to be honest.”

If this is the cause, it could be a function of the no-sidepod philosophy of the car, which is aimed at creating down-draft to the edge of the floor.

“It’s just a big expanse of floor, isn’t it?” Dernie says. “They haven’t left room to put stays in it. There’s one stay that goes more or less to the back corner, which is presumably where it was flexing most because it is the least supported. That will have helped, I expect. But the amount of stays we used to have on the floor of our ground-effect cars and how solid they were back in the day was way beyond anything I’ve seen.

“Now, I haven’t seen the detailed lay-up of the floor itself, because that obviously makes a difference, but we used to use a thick aluminium honeycomb for our floor and that was one of the reasons why we were quick.

Mercedes has attached a floor stay to its W13 to create extra support

Photo by: Giorgio Piola

“I did say to Patrick [Head, Williams’ former technical director] on one occasion: ‘What we need to do, Patrick, is get the entire race team to stand in one of the sidepods to see if it’s stiff enough.’ Dernie laughs. “Which actually puts it in some perspective as to how stiff it needs to be.”

A current aerodynamicist with another team backs up Dernie’s theories.

“We don’t really see a stall when we get the car touching the track in CFD or the tunnel,” he says. “The thinking is that this might be to do with different flexibility of parts on track to those we model. It also could be to do with the cars being physically bounced as the car hits the track with the amount of downforce.”

Dernie adds: “If they get to understand it, it might just need a new floor. That could be it. The thing that will take the most time is if they don’t understand thoroughly what’s causing it, they won’t be able to design something that solves it.”

"If we could magically make that issue vanish, where would we actually be in terms of car pace? Is the car fast enough or not?" Andrew Shovlin

One branch of Mercedes’ thinking is that it should sacrifice downforce elsewhere to take some of the aerodynamic load out of the floor – a lower-drag rear wing has been delivered for the Miami race.

“I’ve heard people saying they will have to sacrifice downforce for stability,” Dernie says. “I’m not completely convinced they will. We didn’t do that on the Williams ground-effect cars. If they have taken that as something they will have to do, they will just end up with a car with less downforce. I would be experimenting at the circuit, putting inserts in floors and drilling holes in stuff and putting stays in various paces to see what the effect is.”

The ‘known unknown’ right now is how long it will take Mercedes to get to the bottom of it. Wolff says: “It’s an understanding of how we can unleash the performance we believe to be in the car, or hope to be in the car, before throwing bits at in terms of performance.”

Beyond that, there is another, more worrying question looming in the background: what if it’s not just porpoising that’s the problem? What if the car, fundamentally, is just not very good?

“What we don’t know,” Shovlin adds, “is, if we could just magically make that issue vanish, where would we actually be in terms of car pace? Is the car fast enough or not? And it’s very difficult to answer that question.”

If Mercedes gets on top of its porpoising problem, will the W13 car actually be a frontrunner?

Photo by: Andy Hone / Motorsport Images