Mercedes F1 W13 - a jewel in the rough or an overambitious design?

Mercedes F1 team produced a striking car for the 2022 F1 season, taking by surprise both their opponents and their previous Technical Director, Ross Brawn - who admitted his team of engineers (who came up with the 2022 regulations) did not anticipate Mercedes solution among thousands of designs tested. Much has been said about the car in various F1 media and there is no need for another lengthy article that can't offer anything new.

In short - the car was a monster in the wind tunnel, yet it can't be tamed on the track and is consistently falling short of the pace of Ferrari and Red Bull cars. The team was fighting aerodynamic bouncing (caused by unstable ground-effect floor design) for most of the early season. The bouncing looks to be mostly sorted in the last few races, yet the pace deficit remains. The team was adamant the car and its zero-pods sidepod design was not at all to blame for the lack of speed, but is this really the case?

While at one point it looked like suspension and/or maybe tyre management is their biggest problem in the first 5-6 races, taking a look at things after 11 full races and seeing the same pace deficit most of the time gives a different perspective. If at one point the team claimed they couldn't understand the car and set it up properly, this wasn't mentioned for a while, but the deficit is there. The only place Mercedes seemed closer on pace was Silverstone and it was, arguably, coming more from Hamilton being fast, Ferrari's Sainz struggling with his pace and slowing down Leclerc who was already hurt by front wing damage. Changing the floor from Barcelona helped Mercedes with bouncing, but this did very little to remove the lap-time deficit to Ferrari and Red Bull.

From aerodynamic perspective alone, there are two clear disadvantages of their concept:

• higher drag, shown in pre-season via CFD, confirmed in first few races by the team and demonstrated in every race since, where they used less rear wing (so to offset drag they lose downforce) than Red Bull and Ferrari just to come close to their top speed; this higher drag comes from mid-wing ahead of sidepods and rear tyre drag demonstrated via CFD with a narrow "sidepoded" model
• incapability to induce strong floor sealing vortex due to having elongated inlets going down to the floor, which take away some of the air Red Bull, Ferrari and other teams use for floor sealing; I've mentioned this several times on different topics on F1 Technical forum and Gary Anderson also mentioned this a couple of weeks later; this problem can be offset with lower ride-height, but this leave the car vulnerable to bouncing and sudden downforce loss with bumps on the track.

Advantage of Mercedes' zero-pods is introducing more air for the beam wing and diffuser with mid wing, but both Red Bull and Ferrari are doing the same job with their wider designs. In fact, Ferrari has by far the slimmest rear end, as their sidepods taper inwards and their engine cover is the slimmest in the field. In the wind tunnel, W13 might be the fastest car, but the wind tunnel model is still just a model - and it can't reflect the actual car with 100% fidelity. With these rules, this problem was demonstrated with very different wind tunnel model floor stiffness compared to actual floor stiffness and was one of the reasons most teams didn't experience aerodynamic bouncing in wind tunnel or simulations, while they were designing their cars.

From this perspective, Merc design has a clear disadvantage with such a big exposed floor surface. This low stiffness, coupled with potentially smaller ride-height operating window (potential suspension problem, but definitely not as big as it seemed early in the season), leaves the car set-up options compromised. Low floor stiffness reflects on bouncing sensitivity by providing unstable and unpredictable mechanical floor sealing and sudden gain and loss of extra downforce. If bouncing is sorted with more advanced aerodynamic floor design, bumps on track and roll while cornering still affect the predictability of downforce, as floor deflection and vibration increase and decrease mechanical floor sealing and thus increase and decrease downforce. I'm still not convinced Hamilton and Russell crashed in Austria Q because they pushed too hard and not because of mid-corner downforce loss due to sudden loss of floor sealing.

To take care of this low stiffness, the only sensible solution are rod stays, since cable stays don't prevent upward deflection (i.e. floor edges are still prone to vibrations, just limited in downward direction). Rod stays are a big drag penalty, unless concealed within sidepod bodywork, which is what Red Bull was doing from the day 1. Somehow Ferrari manages things with cable stays alone, but their floor is significantly less exposed in the critical area (ahead of rear wheel) than Mercedes. And with wide bodywork, you can fit as many stays as you want, which you can also use to reduce floor weight while increasing overall stiffness.

Zero-pods would have been a clear conceptual winner in 2021 F1 season, as all teams were going towards it and Mercedes has been working towards it for a long time and won the last 8 World Constructor Championships in a row. With new rules, top two F1 cars in 2022 are completely different than their predecessors. This is not a coincidence. This also does not mean Merc couldn't somehow regroup and extract 100% of that concept potential, while RB and Ferrari get stuck at 95%, making it a better car overall. But can anyone really see this happening, especially from methodical Red Bull with their mighty Honda engine and taking 2022 budget cap into account?

Can we make a definitive verdict about the Mercedes W13? In my view, after half a season, we can. Conceptually, Mercedes missed the trick with wider sidepod design this season and will have to make up a lot of ground to Red Bull and Ferrari. It's not that W13 is inherently slow - in Silverstone, Hamilton was quick as he always is, but he can't drive the car faster than it can actually go. The problem is car set-up, which so often seems to be compromised because of instability of floor downforce. Even their seemingly higher chassis drag can be taken care of with mid-wing redesign and repackaging of engine components to reduce airbox frontal surface. But is all of this worth it to keep their original and innovative design and risk another season with an unpredictable car? Time will tell.