Ferrari SF-25

[venkyhere]

The location of the venturi is mandated (among other things like CoG of the actual car):

https://www.racecar-engineering.com/art ... gulations/

There is some freedom, but the rules are a pretty narrow box.

I thought the 'restrictive' part of the floor was mainly in the x-axis, with some restriction on y ; whilst offering relatively more freedom on the z-axis (large upper limits on the entry height and exit height of the tunnels) , so that teams can achieve the flow volume according to the way they package the engine bottom tray, the gearbox etc.

The whole “sealing the floor” thing was pundits trying to imagine / clouded by the skirts of underfloors past. Indy / Cart allowed tunnels the whole time, and they first started using these vortex generators / strakes and induced leakage to help underbody downforce in the 1990s, most notably with the then very successful Reynards.

Bingo.
right from 2022, 'experts' on F1tv and Sky have been talking of the floor edges and the vortex folds on them providing a 'floor seal' as if they were talking of Colin Chapman's Lotus 78. If you ask Sam Collins even today, he will talk about the floor-seal.

[catent]

in the paddock they are saying the plank wear is a flaw of the car, to be fixed, does it need a new suspension?

bar wear is inevitable for this generation of cars, it is extremely important for them to ride low, I am sure almost all cars wear the bar more than is permissible, FIA just checks randomly, what is wrong

Interesting then that both McLarens and Russel’s Merc have no issues with plank wear although they’ve been checked

No issues ... in the particular races they've been checked.

Do you recall Hamilton at COTA 2023?

I'm not suggesting every car, in every race, exceeds plank wear allowances; I am suggesting that many are close to the margins in their attempt to maximize performance. Other teams and drivers have in fact been disqualified for the same reason throughout this regulation set.

This discussion may be pushing the bounds of what is relevant to an SF-25 technical thread.

[zioture]

Ferrari F1 SF25 Mystery: Is the Rear Suspension or Gearbox the Real Problem?

The latest technical controversy surrounding Ferrari ‘s F1 SF25 has sparked debate among journalists, YouTubers, and analysts, particularly in Italy. The focus? Two possible weak points: the rear suspension and the gearbox.

Ferrari F1 – Is the Rear Suspension Really the Issue?
For years, discussions revolved around Ferrari’s front suspension. Now, with the introduction of the pull-rod system, attention has shifted to the rear suspension. Some suggest that its lack of adequate stiffness is causing performance inconsistencies. However, this claim is questionable because stiffness is a setup variable that can be adjusted by modifying torsion bars. If necessary, new components can be designed and tested relatively easily.

Ferrari F1 – The Gearbox Flexibility Debate
A more controversial theory suggests that Ferrari’s gearbox might lack structural rigidity, leading to unexpected deformations affecting the car’s overall stability. The argument states that Ferrari may have reduced the gearbox’s dimensions to optimize aerodynamics, inadvertently compromising its torsional stiffness.

However, this theory seems highly unlikely. Gearboxes in Formula 1 are designed with extreme precision to ensure minimal flex. Any deformation beyond a few hundredths of a millimeter would severely impact gear meshing and mechanical efficiency, something Ferrari’s engineers would have accounted for in their design process.

Read Article here https://www.newsf1.it/category/f1-news-english/

Ferrari’s F1 SF25 has been at the center of a heated technical debate. Is the rear suspension causing instability, or is the gearbox flexing too much? In this in-depth analysis, we break down the latest theories, separating facts from speculation. Watch the full video in Italian with English subtitles enabled to get the complete picture of Ferrari’s technical challenges!

[dialtone]

Ferrari F1 – Is the Rear Suspension Really the Issue?
For years, discussions revolved around Ferrari’s front suspension. Now, with the introduction of the pull-rod system, attention has shifted to the rear suspension. Some suggest that its lack of adequate stiffness is causing performance inconsistencies. However, this claim is questionable because stiffness is a setup variable that can be adjusted by modifying torsion bars. If necessary, new components can be designed and tested relatively easily.

Ferrari F1 – The Gearbox Flexibility Debate
A more controversial theory suggests that Ferrari’s gearbox might lack structural rigidity, leading to unexpected deformations affecting the car’s overall stability. The argument states that Ferrari may have reduced the gearbox’s dimensions to optimize aerodynamics, inadvertently compromising its torsional stiffness.

Both rejections of the arguments in the video start from the Eng. Romanelli saying that the problem is fundamentally easy to solve either with FEA or that the error would be so big as to not be realistic.

While that's obviously a reasonable explanation, we've seen cars with flapping DRSes, RBR with a broken rear DRS flap in Spain '22, and plenty of cars just breaking down in various absurd ways.

Clearly an error was made somewhere, so arguing from the place that error isn't possible is not exactly helpful, and at the end of the video he just goes to say that the error was a setup error but that seems to be equally refutable by saying that they would have tested it and know what their static height is supposed to be to avoid shaving the plank, they are playing with margins.

[kalinka]

was it in Australia when Lewis was complaining about lost gear sync? I don't think it's a smoking gun, and I don't think it was because of gearbox flexing issues, but they may have some genuine issue with the new gearbox anyway.

[zioture]

Ferrari F1 – Is the Rear Suspension Really the Issue?
For years, discussions revolved around Ferrari’s front suspension. Now, with the introduction of the pull-rod system, attention has shifted to the rear suspension. Some suggest that its lack of adequate stiffness is causing performance inconsistencies. However, this claim is questionable because stiffness is a setup variable that can be adjusted by modifying torsion bars. If necessary, new components can be designed and tested relatively easily.

Ferrari F1 – The Gearbox Flexibility Debate
A more controversial theory suggests that Ferrari’s gearbox might lack structural rigidity, leading to unexpected deformations affecting the car’s overall stability. The argument states that Ferrari may have reduced the gearbox’s dimensions to optimize aerodynamics, inadvertently compromising its torsional stiffness.

Both rejections of the arguments in the video start from the Eng. Romanelli saying that the problem is fundamentally easy to solve either with FEA or that the error would be so big as to not be realistic.

While that's obviously a reasonable explanation, we've seen cars with flapping DRSes, RBR with a broken rear DRS flap in Spain '22, and plenty of cars just breaking down in various absurd ways.

Clearly an error was made somewhere, so arguing from the place that error isn't possible is not exactly helpful, and at the end of the video he just goes to say that the error was a setup error but that seems to be equally refutable by saying that they would have tested it and know what their static height is supposed to be to avoid shaving the plank, they are playing with margins.

You are right in pointing out that even small errors can lead to significant issues, and Engineer Romanelli’s point about using FEA (Finite Element Analysis) to detect these problems is valid, but it doesn’t rule out the possibility of a setup error or misjudgment under specific conditions.

According to Engineer Segalini's analysis, the main issue with the Ferrari SF-25 is that the car is too sensitive to setup changes, especially when compared to cars like the McLaren MCL39, which has shown greater stability. Segalini emphasizes that Ferrari's setup errors, particularly concerning the new regulations and technical choices, have made the car harder to balance. These errors are "unacceptable," as he puts it, meaning the team should have followed the rules more carefully and tested the setup better.

As for the static height and plank issue, it’s important to note that Ferrari’s sensitivity comes partly from the aerodynamic balance and the specific suspension setup. Segalini pointed out that while Ferrari has a good rear setup, the front, with its new pull-rod configuration, could be more flexible and difficult to handle, which can affect overall performance and stability.

So, while setup errors may seem like straightforward issues, it’s clear that Ferrari’s car is at a critical point, where better balance is needed, especially with the new changes. Testing the car’s limits is necessary, but the Ferrari SF-25’s balance remains a delicate issue.

You can read the full article here: https://www.newsf1.it/ferrari-f1-strugg ... o-mclaren/

[zioture]

"Bottoming issues? The problem is often at the front. Even with a small rake, it’s the tea tray that scrapes the track and risks wear. So why is everyone always talking about the rear?"

[Farnborough]

"Bottoming issues? The problem is often at the front. Even with a small rake, it’s the tea tray that scrapes the track and risks wear. So why is everyone always talking about the rear?"

https://pbs.twimg.com/media/GnyaR4yXsAA ... ame=medium

The front "T tray" touches, but can bend upward away from track to mitigate wear, the rear has no such facility.

There's a spring unit in all the cars that's only seen with extensive cover removal of floor structure, this immediately above and effective for this function.

It doesn't usually bounce on the front either, primarily the rear.

[zioture]

Contrary to what some Italian media have reported, if there's wear on the floor's skid block, it's more likely to be at the front rather than the rear. I consulted with one of our engineers who collaborates with NewsF1.it, Riccardo Romanelli, a race car designer at Wolff Racing Cars, and here's what he said:

"In general, the issue is almost always at the front. The car, even dynamically, needs to maintain a certain amount of rake, even if minimal. And the area most exposed to contact with the track — and at risk of exceeding the wear limit — is the tea tray."

It would be very interesting to see exactly where the skid block on the Ferrari wore out in China, because it really seems hard to believe it happened at the rear.

[Farnborough]

Contrary to what some Italian media have reported, if there's wear on the floor's skid block, it's more likely to be at the front rather than the rear. I consulted with one of our engineers who collaborates with NewsF1.it, Riccardo Romanelli, a race car designer at Wolff Racing Cars, and here's what he said:

"In general, the issue is almost always at the front. The car, even dynamically, needs to maintain a certain amount of rake, even if minimal. And the area most exposed to contact with the track — and at risk of exceeding the wear limit — is the tea tray."

It would be very interesting to see exactly where the skid block on the Ferrari wore out in China, because it really seems hard to believe it happened at the rear.

I've not any inside information from the team and don't wish to make it sound like I have.

Observation though was that the LH car after China sprint, the car was sitting with negative rake static post race. I know that's not under aero load though.

I've posted over on the team thread about what it seems they are doing with suspension though and particularly the rear in using the skid/plank as ultimately control for final part of suspension travel, this to avoid overload of tyre carcass and subsequently produce "bouncing" by crossing into that tyre response curve. I really don't think people appreciate just how far into contrary behaviour they are running these chassis to function within this rule set.

The plank after race is really worn all over though. Literally every part of it.

[karana]

It would be very interesting to see exactly where the skid block on the Ferrari wore out in China, because it really seems hard to believe it happened at the rear.

From Jo Bauer's report:

The rearmost skid was measured according to the team’s legality documents submission in
accordance with TD039 L, item 1.2 b) i). Measurements were taken along the stiffness compliant
area at three different points of the periphery (inner arc). The recorded measurement were 8.6 mm
(LHS), 8.6 mm (car centerline) and 8.5 mm (RHS).

The rearmost hole where plank wear can be measured is between 22.5cm and 42.5cm ahead of the rearmost edge of the plank.

[Farnborough]

Well spotted Karana

Anyone watching Q today, with the cars running light at v-low fuel, with a whole trail of plank waste clearly visible on the new track surface going into #1 turn ..... they aren't even on the brakes there, so no compromise from that in initial phase of corner. The T tray just has more movement to get out of the way, the rear not.

Large plume of plank debris blown out of diffuser expansion as they came through there.

It seems that there's very conventional views on here that only accept a "classic" reasoning for chassis setup, that's in terms of just how low the teams are running them. They are, in reality, highly marginal in their calls on just how much wear they wish to tolerate on underside of car. They are all really pushing it, hard.

[Farnborough]

More part of this puzzle it seems, with public report of LH referring to a replacement part that SHOULD change the situation.

Most reports appear to reference "stifness" and lack thereof, suggesting they've missed a target in structural somewhere.

Hopefully they'll get a step change with whatever that replacement is. Then we may see more lucid details of exactly what that is.

[sucof]

I was thinking about how could be that Hamilton shall wait a few races so his car will get something fixed, compared to Leclerc's.
This only could be a main part that has a maximum allowed amount per year.
So an other sign towards gearbox.
I usually disregard rumours, but there are too many signs pointing towards a gearbox problem for Ferrari.
Starting with the info that they have a brand newly designed one, which is smaller, then their diffuser changed this year, like it has a smaller gearbox, then the problems in the first races where they had to raise the car to help the gearbox... and so on.
So they are probably waiting for the fix as it is not an easy one, and to be able to change the gearbox without future penalties.

[Farnborough]

I was thinking about how could be that Hamilton shall wait a few races so his car will get something fixed, compared to Leclerc's.
This only could be a main part that has a maximum allowed amount per year.
So an other sign towards gearbox.
I usually disregard rumours, but there are too many signs pointing towards a gearbox problem for Ferrari.
Starting with the info that they have a brand newly designed one, which is smaller, then their diffuser changed this year, like it has a smaller gearbox, then the problems in the first races where they had to raise the car to help the gearbox... and so on.
So they are probably waiting for the fix as it is not an easy one, and to be able to change the gearbox without future penalties.

Yes, not being the thread for unconfirmed detail but this a quote from LH in press record post race

"Asked if Ferrari are confident they can solve the problem, Hamilton replied: “They are aware of it. They don’t know what’s caused it, or why, so when the new component comes it will be gone and it will be the same with both cars."

Shows that something is clear to the team in regard to compromise.