Mercedes W13

[siskue2005]

Rear wing hi-res:

Doesn't look like they have used chainsaw or a grinder. It looks very elegant and clean. Maybe they didn't have smaller Petronas sticker, hence the sticker is jutting out ?

[atanatizante]

From AMuS:

The engineers now understand the car better. But it will be a while before the bouncing disappears and the team is no longer forced to make such major compromises when it comes to setup. Mercedes is aiming for a cure by the start of the European season in Imola. That would already be the end of April, and should happen through a better understanding. Hamilton fears: "We have a fundamental problem. It will take a while."

To put it in numbers: Mercedes is half a second behind on one lap. The gap grows over the distance because the Silver Arrow works the tires harder. An example: after 34 laps, Hamilton was 28.8 seconds behind. That corresponds to eight tenths of a second per lap. The engine is no longer life insurance for Mercedes. There seems to be some performance missing. Suboptimal after the combustion engine was frozen in early March. However, it must be mentioned that Mercedes added a lot of dirty downforce via the rear wing and beam wing. That reduced the top speed.

I'm not too sure on the race pace just yet, the first stint he was tucked up behind Sainz for all of it until his tyres let go, then he fell back behind Perez and dropped away. After that they went to the Hard tyre which was a bad choice, the Medium was much better which Perez went for and the others ahead went for another stint on the softs if I recall correctly. So a good chunk of that 28.8 second deficit was not entirely true. If the car was 8 tenths a lap slower, how was lewis able to hang on to Sainz for so long, and also on the back of Perez after the safety car until Perez had issues.

At the end of the race, which was practically a 7 laps sprint race after the SC phase, HAM was 9.8 sec. behind LEC, which means he was 1.3 sec./lap slower ... not to mention that LEC slow down a couple of laps after the VER retired from the race ...

[GrizzleBoy]

From AMuS:

I'm not too sure on the race pace just yet, the first stint he was tucked up behind Sainz for all of it until his tyres let go, then he fell back behind Perez and dropped away. After that they went to the Hard tyre which was a bad choice, the Medium was much better which Perez went for and the others ahead went for another stint on the softs if I recall correctly. So a good chunk of that 28.8 second deficit was not entirely true. If the car was 8 tenths a lap slower, how was lewis able to hang on to Sainz for so long, and also on the back of Perez after the safety car until Perez had issues.

At the end of the race, which was practically a 7 laps sprint race after the SC phase, HAM was 9.8 sec. behind LEC, which means he was 1.3 sec./lap slower ... not to mention that LEC slow down a couple of laps after the VER retired from the race ...

Depends whether Ham continued to push too though. Could easily have instantly decided to coast home for the podium as the prospect of overtaking any car in front was basically zero for the entire race.

[NathanOlder]

From AMuS:

I'm not too sure on the race pace just yet, the first stint he was tucked up behind Sainz for all of it until his tyres let go, then he fell back behind Perez and dropped away. After that they went to the Hard tyre which was a bad choice, the Medium was much better which Perez went for and the others ahead went for another stint on the softs if I recall correctly. So a good chunk of that 28.8 second deficit was not entirely true. If the car was 8 tenths a lap slower, how was lewis able to hang on to Sainz for so long, and also on the back of Perez after the safety car until Perez had issues.

At the end of the race, which was practically a 7 laps sprint race after the SC phase, HAM was 9.8 sec. behind LEC, which means he was 1.3 sec./lap slower ... not to mention that LEC slow down a couple of laps after the VER retired from the race ...

Well if you didn't notice, Lewis was stuck behind a wounded Perez for all of those laps. So the last stint after the SC was not a good indication on how fast the car was.

[atanatizante]

I don't know, the shape just seems so suboptimal aero wise.

It could also be that the shape produces unwieldy amounts of peak downforce that they simply cannot control without raising the ride height.

I'd love to know the level of downforce increases with the reduction in ride height and what the shape of the graph looks like. I'm sure someone could put some real numbers too it.

Here's a graph for a generic ground effect device showing how the downforce (-Cl) varies with distance from the ground (ride height represented by the dimensionless relationship h/L because it's not just the distance from the ground but also the size of the device (the floor in this case) that determines ground effect - a large body will be "in ground effect" at a greater height than a small body).

https://www.researchgate.net/profile/Jo ... l-with.png

You can see how the downforce changes a lot with a small change in ride height near the peak.

This is obviously a simplified device but it shows the effect.

I don't understand the role of the CD curve in that graph? Is somehow related to the angle of the rear axle when they rise the ride height of the car? In that case, then it`s missing the angle numbers on the horizontal axis of that graph ...

[atanatizante]

...

They are carrying more wing because they are having to run the car higher off the floor to reduce the porpoising.

...

Carrying more rear wing was to reduce porpoising or to compensate for the loss of downforce due to rising the car`s ride height? So now for the fact that they are bringing a trimmed RW for here in Jeddah implies they`ll run lower the car perhaps isn't it?

[bonjon1979]

From AMuS:

I'm not too sure on the race pace just yet, the first stint he was tucked up behind Sainz for all of it until his tyres let go, then he fell back behind Perez and dropped away. After that they went to the Hard tyre which was a bad choice, the Medium was much better which Perez went for and the others ahead went for another stint on the softs if I recall correctly. So a good chunk of that 28.8 second deficit was not entirely true. If the car was 8 tenths a lap slower, how was lewis able to hang on to Sainz for so long, and also on the back of Perez after the safety car until Perez had issues.

At the end of the race, which was practically a 7 laps sprint race after the SC phase, HAM was 9.8 sec. behind LEC, which means he was 1.3 sec./lap slower ... not to mention that LEC slow down a couple of laps after the VER retired from the race ...

LeClerc did put on fresh tyres though, and Hamilton was fighting with/stuck behind perez so not a true comparison. They were more like 6-8 tenths a lap slower through the race.

[Just_a_fan]

It could also be that the shape produces unwieldy amounts of peak downforce that they simply cannot control without raising the ride height.

I'd love to know the level of downforce increases with the reduction in ride height and what the shape of the graph looks like. I'm sure someone could put some real numbers too it.

Here's a graph for a generic ground effect device showing how the downforce (-Cl) varies with distance from the ground (ride height represented by the dimensionless relationship h/L because it's not just the distance from the ground but also the size of the device (the floor in this case) that determines ground effect - a large body will be "in ground effect" at a greater height than a small body).

https://www.researchgate.net/profile/Jo ... l-with.png

You can see how the downforce changes a lot with a small change in ride height near the peak.

This is obviously a simplified device but it shows the effect.

I don't understand the role of the CD curve in that graph? Is somehow related to the angle of the rear axle when they rise the ride height of the car? In that case, then it`s missing the angle numbers on the horizontal axis of that graph ...

The Cd line shows that the drag increases as ride height reduces and the Cl increases. That's to be expected.

This is for a generic diffuser object, not a specific car. The object is kept parallel to the road surface as ride height changes, the rake is altered. That would be a very different graph.

[Just_a_fan]

...

They are carrying more wing because they are having to run the car higher off the floor to reduce the porpoising.

...

Carrying more rear wing was to reduce porpoising or to compensate for the loss of downforce due to rising the car`s ride height? So now for the fact that they are bringing a trimmed RW for here in Jeddah implies they`ll run lower the car perhaps isn't it?

They ran a big rear wing because they had to run the car higher off the ground than it was designed to be run. It compensated for the downforce lost by running higher off the ground.

At Jeddha, they need to reduce some drag because it's got a very long section of high speed gentle turns. If they run the Bahrain rear wing, they'll be too slow on the fast sections at Jeddha. It's a compromise between downforce for the real corners, and lower drag for the high speed section. At Jeddha, the compromise favours less drag.

[pursue_one's]

Upper bodywork affecting W13's underfloor aerodynamics
In a way, it is a strange phenomenon that can be explained by the fact that the upper bodywork of the W13 dramatically affects the aerodynamics underneath the car.

The result is that with certain combinations of speed, lateral acceleration and ride height, the car suddenly loses downforce due to the fact that the airflow passing on top of the upper bodywork suddenly detaches from it, especially in the area between the sidepods and the engine cover.

In a nutshell, we can say that the airstream detaches at this level and does not continue towards the rear end.

Furthermore, the shape of the sidepods generates a sort of spillage through the floor sides, reducing the efficiency of the floor with sudden pressure changes underneath.

Mercedes set to bring updates for their car to Imola
This is not a phenomenon that can be managed with set-up changes. As far as we know, a first aero overhaul of the W13's current concept is expected for the fourth round of the 2022 season at Imola, and its final step will be introduced two races later at Barcelona.

Though several observers suggested that Mercedes' power unit was inferior to those of Ferrari and Red Bull, the team does not appear too concerned by this, as their data suggests that they were not able to deploy all their engine's performance due to their car's lack of stability.

https://racingnews365.com/why-mercedes- ... th-the-w13

[f1jcw]

Thats not sounding good, sounds like they have gone in the wrong direction.

[214270]

365 have a poor reputation for factual news.

That said, I hypothesised that they might struggle. The aero features available to manage airflow have been greatly reduced with the new rules; I think this is the reason wide sidepods have featured so prominently in competitors designs. I reckon Merc will have to follow suit.

[izzy]

Thats not sounding good, sounds like they have gone in the wrong direction.

Yes, if it's correct, but is it? Where did Paulo Filisetti the technical journalist get this info? These would have to have been missed by Mercedes aero's in their wind tunnel, which does do yaw presumably.

[Just_a_fan]

Upper bodywork affecting W13's underfloor aerodynamics
In a way, it is a strange phenomenon that can be explained by the fact that the upper bodywork of the W13 dramatically affects the aerodynamics underneath the car.

The result is that with certain combinations of speed, lateral acceleration and ride height, the car suddenly loses downforce due to the fact that the airflow passing on top of the upper bodywork suddenly detaches from it, especially in the area between the sidepods and the engine cover.

In a nutshell, we can say that the airstream detaches at this level and does not continue towards the rear end.

Furthermore, the shape of the sidepods generates a sort of spillage through the floor sides, reducing the efficiency of the floor with sudden pressure changes underneath.

Mercedes set to bring updates for their car to Imola
This is not a phenomenon that can be managed with set-up changes. As far as we know, a first aero overhaul of the W13's current concept is expected for the fourth round of the 2022 season at Imola, and its final step will be introduced two races later at Barcelona.

Though several observers suggested that Mercedes' power unit was inferior to those of Ferrari and Red Bull, the team does not appear too concerned by this, as their data suggests that they were not able to deploy all their engine's performance due to their car's lack of stability.

https://racingnews365.com/why-mercedes- ... th-the-w13

Hmm, sounds like a bit of made up space filling. The flow over the bodywork detaches as the ride height changes. Really?

[matteosc]

Thats not sounding good, sounds like they have gone in the wrong direction.

Yes, if it's correct, but is it? Where did Paulo Filisetti the technical journalist get this info? These would have to have been missed by Mercedes aero's in their wind tunnel, which does do yaw presumably.

I agree, its seems highly unlikely that detached flows from the upper surface of the car went unnoticed in simulations and wind tunnel. In my opinion it is way more likely that the car is set to run very low, but they cannot do that because of porpoising. I think that in Mercedes case rising the car height causes a loss of downforce higher than in other cars.

There is always the possibility that they stuck too much to previous years concepts and miss out some new opportunities that the new regulations offer, but it is too early to say. I guess we will have to wait at least until Imola/Barcelona to know who was right.