Why Mercedes-AMG fell from the top of Formula 1 Car News

If Formula 1 were to award a word of the year, the winner in 2022 would be “porpoising”, a phenomenon responsible for bringing Mercedes-AMG’s eight-year dominance of F1 to a screeching halt.

The repeated bouncing motion of a porpoising F1 car is familiar to anyone who has worked on race cars with strong ground effect on the ground venturi tunnels. The name comes from the aquatic mammal’s reputation for leaping in and out of the surface of the water during its journey, a movement taken up by the oscillation of the up and down motion of a car.

This is the result of downforce increasing rapidly as speed increases and increasing low pressure under the floor sucking the car closer to the ground. The aero under the floor then stalls, either due to high-speed airflow separation or due to the ground hitting the track surface hard. It can even be triggered by hitting bumps. The car then rises, as the downforce is briefly reduced, then sucked up again when the subfloor is working as expected again. The cycle then repeats itself, hence the rebound movement.

All these new F1 cars suffer more or less from porpoising. But porpoising down the straight isn’t necessarily a problem, provided it’s controlled and not so wild that it damages the car or the driver. It’s about how quickly the porpoising stops when you reach a turn and what compromises you make in the setup to control the phenomenon.

The dynamics of a car on corner entry are essential, doubly so for a car whose performance is dominated by aerodynamics. This requires a compliant and consistent mechanical platform and a change in aero balance on corner entry that is both controllable and reliable. A bouncing car is unpredictable.

“You can’t really stop it; the only thing you do is turn off the gas and drive slower,” said seven-time champion Sir Lewis Hamilton. “But when the car goes up and down it bounces, and if you’re going 200mph and the car is loaded and unloaded, you can imagine it can be quite unstable.”

Hamilton was talking about how the car handled the high-speed left-right turns 9 and 10 in Australia, which followed the long flat-out explosion where the porpoising was most evident.

The Ferrari was actually scoring more vigorously there than the Mercedes, but Charles Leclerc was able to qualify on pole position and win. This is because Ferrari had to make much smaller set-up sacrifices and the effect it produced in turn nine was much less – although it could be felt. On the other hand, the Mercedes drivers obviously have to be more conservative in the fast corners to let the car settle at least partially.

Mercedes has to make far greater compromises on its setup in terms of ride height. That means sacrificing downforce – and therefore lap time – throughout the lap, as its porpoising problem kicks in at a lower speed than the Ferrari. This also comes at the cost of increased drag. That’s why its strongest circuit so far this season was Bahrain, with its vastly slower corners that allowed the Mercedes to ride a bit lower than in Saudi Arabia or Australia.

So why is it so difficult to prevent porpoising? Well, it’s not, but it costs performance. And therein lies the problem: you can increase the ride height to alleviate porpoising, as this reduces the effectiveness of the aero “seal” and therefore the overall level of downforce of the car by effectively “venting” the low pressure , especially at the point where which grows rapidly as the ground gets closer to the ground. And downforce is performance, with the grip it produces eclipsing what is mechanically achievable.

Simulating porpoising is difficult, because you can’t roll the car too low from the treadmill in the wind tunnel or it will damage it. And as efficient as CFD is, the complexity of its calculations multiplies alarmingly and plummets when simulating objects very close to the ground. The data collected by Mercedes has helped it build better models, but only by running the car can it fully explore the problem and its potential solutions.

The combination of F1’s cost cap, set at a baseline of $140m (£107m) in 2022, and the lack of testing means Mercedes has neither the money for corrections to Endless trial and error or track time.

The solution probably lies in a combination of aero modifications in terms of floor design and potentially even floor structure. Indeed, the flexing of the ground can aggravate the problem. The new F1 regulations also simplified the suspension systems, eliminating inerters and hydraulic assistance which would have made it easier to control porpoising.

So fixing it is going to take time, with team principal Toto Wolff repeating his mantra that…