Scuderia Ferrari SF90

[zibby43]

Yes it did but everything in the article is correct. Ferrari have fundemental problems with understeear. Game over for 2019.

Only through low-speed corners.
T9 was great for Vettel, so aero works just fine. There is nothing wrong with the front wing they have.

Don't think i would agree with this statement.
The main downforce producing area in SF90's front wing is really limited, when you look at it from front view.
T9 is a fast corner demanding lots of downforce. Let's say both W10 and SF90 produce 200kg of downforce from the front wing in that specific turn. Downforce producing area on W10 front wing is more evenly spread across its span though. Both wings generate the exact same downforce, but on SF90's case, angle of attack should be greater to reach that figure from a smaller top view area. What happens to a wing at low airspeeds when it has a big angle of attack? Wing stall. This is not such a big issue when the airspeed is high though!

In short, both W10 and SF90 generate 200kg of downforce on T9, whereas in T10 for example, W10 produces 50kg of downforce and SF90 just 10kg or less. That's where the problem lies in my opinion.

(...)However, the more slowly an airplane goes, the greater the angle of attack it needs to produce lift equal to the aircraft's weight. As the speed decreases further, at some point this angle will be equal to the critical (stall) angle of attack. This speed is called the "stall speed"(...)

This answers my earlier question I posited about whether it was possible that the Ferrari FW worked well in certain corners (i.e., higher-speed ones) but suffered when you start to decrease the speed and introduce other variables that make the details of the design more critical.

[timbo]

Let's forget the fact that the AoA changes in an aircraft as this is not relevant here.
What's relevant is the fact that the lower the airspeed, the higher the AoA you need to achieve a specific downforce figure. In W10's case you don't need such a high AoA simply because your downforce producing wing area is larger. In SF90's case you need higher AoA to achieve the same downforce, which is causing wing stall. This in turn causes imbalance, which is translating in understeer and massive time loss in the tight corners.
Here there is a question that arise. Why Ferrari didn't think about that in the first place? They never thought that other teams would ever achieve the W10's front wing downforce levels they have right now after more than 2 months of development.

Not necessarily agreeing here, because the underlined part is IMO important for consideration.
Yes, it is possible that Ferrari would operate the wing in a different AoA configuration, but if it stalls in the low-speed corners, why wouldn't it stall in the high-speed ones?
The problem is that if you have a wing which is stalling in the low airspeed conditions, it is also likely to stall in the high-speed conditions. In fact, since Reynolds number is proportional to the velocity of the fluid, it is even more likely to stall if the speed goes higher.

[zokipirlo]

i would love to know if the slow speed corner deficit is down to front wing concept or suspension dynamics or maybe more likely to be a combination of both.
apparently a new suspension being tested tomorrow during the test.

think i read on here about a link between the rim/wheel issue in testing and the current issues. possibly ran a more advanced suspension that failed and then had to revert to a dated version?

as a ferrari fan its hugely disappointing for season to be almost over. we need to keep working to understand these issues and get back challenging for wins regardless.

Don't get fooled. You cannot lose 8 tenths just from suspension mechanical grip. There is nearly no downforce generated by this high AoA wing on slow corners.

Look at second laps from Mercedes drivers in Q3. They were nowhere close to the lap time of Bottas (Hamilton made some mistakes). I think that it's all in this new Pirelli tyres, which only Mercedes understand, and even they not always. And simulator can't help you anything here, because if you don't understand a problem it's not possible to create a working simulator.

[One and Only]

i would love to know if the slow speed corner deficit is down to front wing concept or suspension dynamics or maybe more likely to be a combination of both.
apparently a new suspension being tested tomorrow during the test.

think i read on here about a link between the rim/wheel issue in testing and the current issues. possibly ran a more advanced suspension that failed and then had to revert to a dated version?

as a ferrari fan its hugely disappointing for season to be almost over. we need to keep working to understand these issues and get back challenging for wins regardless.

Don't get fooled. You cannot lose 8 tenths just from suspension mechanical grip. There is nearly no downforce generated by this high AoA wing on slow corners.

Look at second laps from Mercedes drivers in Q3. They were nowhere close to the lap time of Bottas (Hamilton made some mistakes). I think that it's all in this new Pirelli tyres, which only Mercedes understand, and even they not always. And simulator can't help you anything here, because if you don't understand a problem it's not possible to create a working simulator.

Exactly. IIRC Mercedes was struggling more than others with tires at the beginning of Pirelli era. They invested a lot in suspension development and came up with FRIC suspension that was later banned, but they cannot forget what they already learned. I think they outdeveloped everyone in suspension area which gives them advantage in finding tires working window. Sometimes they do it better, sometimes not, but almost always better than everyone else. People keep comparing Ferrari and Mercedes in slow corners. Mercedes is faster than everyone else in slow corners, not just Ferrari. Only difference is Ferrari managed to match them on other parts of track so overall laptime difference is smaller (Barcelona Friday analysis):

Picture is taken from Formula 1© official website.
It's obvious Ferrari is matching Mercedes in fast corners and gains on straights, which is kinda indicator of efficient aero combined with powerful PU (but no matter how strong PU is, if car is not aero efficient it won't go fast). Even if Ferrari was wrong to go with high rake concept, it is hard to believe Adrian Newey made such mistake as well. Guy who almost always gets correct aero concept and is always on top of rule changes. RBR suffer less than Ferrari in slow and medium corners. It would be interesting to see where would RBR be with Ferrari's straight line speed.

[enry86]

Just to sum up a bit and to clarify my own expectations for the rest of the championship ( ), i'd like to dig a bit on the possible impact of the new suspension on the struggles Ferrari is experiencing with its car.

As far as I know, in the first week of preseason testing Ferrari run the new suspension, until the rim/suspension failure which caused Vettel crash. Before switching to the old suspension the car showed an evident squatting behavior during brake and acceleration, which, correct me if I'm wrong, is no more visible on the car now.

So, my question is, it's possible that the change in rake and ride height brought by the new suspension it's a fundamental factor in the aero concept of the car? And that losing it by running the old suspension explains the lack of downforce so evident in the last race?

Am I putting too much faith in this device to solve most of the car problems?

[DRCorsa]

Let's forget the fact that the AoA changes in an aircraft as this is not relevant here.
What's relevant is the fact that the lower the airspeed, the higher the AoA you need to achieve a specific downforce figure. In W10's case you don't need such a high AoA simply because your downforce producing wing area is larger. In SF90's case you need higher AoA to achieve the same downforce, which is causing wing stall. This in turn causes imbalance, which is translating in understeer and massive time loss in the tight corners.
Here there is a question that arise. Why Ferrari didn't think about that in the first place? They never thought that other teams would ever achieve the W10's front wing downforce levels they have right now after more than 2 months of development.

Not necessarily agreeing here, because the underlined part is IMO important for consideration.
Yes, it is possible that Ferrari would operate the wing in a different AoA configuration, but if it stalls in the low-speed corners, why wouldn't it stall in the high-speed ones?
The problem is that if you have a wing which is stalling in the low airspeed conditions, it is also likely to stall in the high-speed conditions. In fact, since Reynolds number is proportional to the velocity of the fluid, it is even more likely to stall if the speed goes higher.

Reynolds number is a function of airspeed.
Critical AoA is affected by the separation of the boundary layer, which is a directly dependent on Reynolds number.
Take a look at the following graph. You will see that for higher Reynolds numbers, critical AoA is higher too.
That's the reason why SF90's front wing won't stall at high speeds, but will stall at low speeds.

[DRCorsa]

i would love to know if the slow speed corner deficit is down to front wing concept or suspension dynamics or maybe more likely to be a combination of both.
apparently a new suspension being tested tomorrow during the test.

think i read on here about a link between the rim/wheel issue in testing and the current issues. possibly ran a more advanced suspension that failed and then had to revert to a dated version?

as a ferrari fan its hugely disappointing for season to be almost over. we need to keep working to understand these issues and get back challenging for wins regardless.

Don't get fooled. You cannot lose 8 tenths just from suspension mechanical grip. There is nearly no downforce generated by this high AoA wing on slow corners.

Look at second laps from Mercedes drivers in Q3. They were nowhere close to the lap time of Bottas (Hamilton made some mistakes). I think that it's all in this new Pirelli tyres, which only Mercedes understand, and even they not always. And simulator can't help you anything here, because if you don't understand a problem it's not possible to create a working simulator.

You forgot about Hulk's exit, who brought a lot of debris into the track, and specifically on turns 13 and 14?
Noone managed to get a good lap on Q3 run 2, just because of that.

[zokipirlo]

Don't get fooled. You cannot lose 8 tenths just from suspension mechanical grip. There is nearly no downforce generated by this high AoA wing on slow corners.

Look at second laps from Mercedes drivers in Q3. They were nowhere close to the lap time of Bottas (Hamilton made some mistakes). I think that it's all in this new Pirelli tyres, which only Mercedes understand, and even they not always. And simulator can't help you anything here, because if you don't understand a problem it's not possible to create a working simulator.

You forgot about Hulk's exit, who brought a lot of debris into the track, and specifically on turns 13 and 14?
Noone managed to get a good lap on Q3 run 2, just because of that.

Yes, that's true, but Leclerc drove 2 laps, and the rest of the field 1 lap before going for fast lap to clear some debris... doubt it made such a big impact. But even without that, all of them were slower at S2 already except Vettel. Vettel lost 1s in last sector, Bottas lost 3 tenths and Hamilton lost half a second. And Bottas was first in that trio, Hamilton was last.

[DRCorsa]

Look at second laps from Mercedes drivers in Q3. They were nowhere close to the lap time of Bottas (Hamilton made some mistakes). I think that it's all in this new Pirelli tyres, which only Mercedes understand, and even they not always. And simulator can't help you anything here, because if you don't understand a problem it's not possible to create a working simulator.

You forgot about Hulk's exit, who brought a lot of debris into the track, and specifically on turns 13 and 14?
Noone managed to get a good lap on Q3 run 2, just because of that.

Yes, that's true, but Leclerc drove 2 laps, and the rest of the field 1 lap before going for fast lap to clear some debris... doubt it made such a big impact. But even without that, all of them were slower at S2 already except Vettel. Vettel lost 1s in last sector, Bottas lost 3 tenths and Hamilton lost half a second. And Bottas was first in that trio, Hamilton was last.

HAAS did the exact same sector 3 as Ferrari did.
Remember that Haas runs a conventional front wing, Merc like.
Alfa has the "extreme" wing and it was a disaster in Spain too.
Do the maths.

[Nonserviam85]

I start to believe that Ferrari are facing the same issues McLaren had last year, losing downforce under high yaw angles. This is very tricky to simulate on CFD or on the Wind Tunnel and because of the very powerful Power Unit they probably assessed they will be faster overall with the low drag concept but the track is proving otherwise.

[keroro.90]

Let's forget the fact that the AoA changes in an aircraft as this is not relevant here.
What's relevant is the fact that the lower the airspeed, the higher the AoA you need to achieve a specific downforce figure. In W10's case you don't need such a high AoA simply because your downforce producing wing area is larger. In SF90's case you need higher AoA to achieve the same downforce, which is causing wing stall. This in turn causes imbalance, which is translating in understeer and massive time loss in the tight corners.
Here there is a question that arise. Why Ferrari didn't think about that in the first place? They never thought that other teams would ever achieve the W10's front wing downforce levels they have right now after more than 2 months of development.

Not necessarily agreeing here, because the underlined part is IMO important for consideration.
Yes, it is possible that Ferrari would operate the wing in a different AoA configuration, but if it stalls in the low-speed corners, why wouldn't it stall in the high-speed ones?
The problem is that if you have a wing which is stalling in the low airspeed conditions, it is also likely to stall in the high-speed conditions. In fact, since Reynolds number is proportional to the velocity of the fluid, it is even more likely to stall if the speed goes higher.

Reynolds number is a function of airspeed.
Critical AoA is affected by the separation of the boundary layer, which is a directly dependent on Reynolds number.
Take a look at the following graph. You will see that for higher Reynolds numbers, critical AoA is higher too.
That's the reason why SF90's front wing won't stall at high speeds, but will stall at low speeds.

https://i.ibb.co/LdDr5m4/dPNAs.png

This is a very interesting point.
Also in Sauber, the team principal said that they were facing some problems with the FW design (which is similar to the Ferrari one).
So, I think the combination of the FW design with the old suspension might be one of the main cause behind the performance in the low speed corners.

[cokata]

I also thought from day 1 that this wing design is an mistake.

My thinking was more in the way of wing flex. As we know the wings flex at high speed (some more than others) and i thought that since the effective wing area of the SF90 is so small compared to the Merc wing, at high speed a conventional can be made to flex more as it is generating enough DF (and you don't want the drag, at above say 250kp/h) but in low speed you need all the DF you can take drag does not matter at all.

So in low speed Merc effectively have a bigger wing, this should also mean that at high speed the Merc wing should be less draggy for the same DF as it has a bigger aspect ratio.

Having said that the stalling at low speeds makes more sense, and is probably at least in some parts explains the huge advantage Merc have (keep in mind that RBR have a similar concept, and they were destroyed in S3 too)

What i don't know is how much of a penalty is not having the outwash effect with the more conventional wing, but Merc and RBR have made it work, with crazy badgeboards, but it does work.

[DRCorsa]

(...)
What i don't know is how much of a penalty is not having the outwash effect with the more conventional wing, but Merc and RBR have made it work, with crazy badgeboards, but it does work.

Ferrari did little job during the winter.
Phase 1 of new wing development was Ferrari's concept, just because it was the obvious solution (for outwash reasons) at the time.
Both Merc and RB are currently on Phase 3 or even 4, when not only they have discarded the "obvious solution concept" but they have developed the 2019 wing along with the super complex bargeboards in such a way to be both effective in terms of outwash and downforce.
Ferrari is still on Phase 1 and they know well that they have no hopes of catching up.
I am a Ferrari fan BTW.
P.S. I keep a reserve for what i said above, regarding Haas' front wing. Maybe Haas is the team doing the "dirty" job for Ferrari. Maybe in Monaco we are going to see something very similar on the SF90 too.

[GPR-A]

I had said this about Mercedes, when people were critical of their long wheel base, their front 2019 front wing and lower rake concept that, there is no one single silver bullet for building a great car. You can always choose a different concept and make it work. You just need to have a good team who can look beyond the psychological limiting factors and search to evolve their chosen concept. You don't hear Mercedes saying, they chose a wrong concept. In 2017, their car was much criticized for the longer wheel base and the lack of slow corner performance was attributed to it. But for 2018, they retained it and kept improving it.

Ferrari need to have patience and calm heads in their leadership ranks, otherwise, there would be silent panic across and they would falter again. If they allow the pressure from media and fans to push them, then they are doomed.

There would be some circuits where their car might not work and it probably would need a long time to bring right solution to fix it. But there are definitely circuits that would suit the car and they have to aggressively develop their strengths and make the most of it on those circuits. It has taken ages for Mercedes to develop a car that seems to work for every circuit.

Ferrari definitely have resources to turn it around in quick time, but they first have to protect their core designers and engineers from unnecessary external pressure and continue to allow greater freedom to express their ideas and take educated risks. There would definitely light and it's not all gloom.

[timbo]

Reynolds number is a function of airspeed.
Critical AoA is affected by the separation of the boundary layer, which is a directly dependent on Reynolds number.
Take a look at the following graph. You will see that for higher Reynolds numbers, critical AoA is higher too.
That's the reason why SF90's front wing won't stall at high speeds, but will stall at low speeds.

https://i.ibb.co/LdDr5m4/dPNAs.png

The graph covers many orders of magnitude difference in Re number, this is much much higher than the changes dut to velocity difference between t9 and t10. Also, on the graph, you'd see a highly nonlinear behavior of the Cy/Cx curve, and between some Re number values, the position of maximum may increase or decrease.
Anyway, the effect of the pitch attitude of the car is more important here.