McLaren MCL39 Speculation Thread

[Slahinki]

It's about time they got in top of the weight issues so we can see a full livery again with all the new sponsors. It was encouraging to see all the special liveries in 2024 be a full color car

I would love the Austin livery - with a bit more of the chrome at the front - to be the actual livery. I think it’s really beautiful and merges the main eras of McLaren’s identity into a cohesive single livery.

Completely agree on the livery. It's a very nice blend of the papaya and chrome colours in the Marlboro shapes. Absolutely lovely.

[Emag]

McLaren is in a bit of a weird situation when it comes to identifying major improvement points from last year just because they started out so bad in 2023.

That means half the races from 2023 are irrelevant data points because we would be comparing a literal backmarker to a (at worst) top 3-4 car when it wasn't actually the best.

The other remaining races unfortunately have mismatches in terms of weather conditions. Some just because they have vastly different air and track temps, others because of rain and the rest because the races itself were organized on different periods of the year.

One of the closest comparison points to last year was actually Abu Dhabi, the last race of the season.
Weather conditions when the fastest lap in qualifying was set in 2023 and 2024 are both quite similar with negligible differences, even in terms of wind speed :

(2024 top, 2023 bottom)


From that comparison, the most noticeable improvement is at medium-low speed corners. The 2024 car not only is capable of maintaining higher minimum speed through those, but it also "bleeds" less speed on longer corners. In fact, when compared to the rest of the 2024 field, long medium-speed corners is perhaps the one area where McLaren excelled, with performances in Zandvoort (especially with the strong S2 there) being one of the many examples of their advantage.

This is a contrasting comparison with their 2023 car, because those types of corners were their biggest weakness last year after the Austria upgrade transformed the car. They have showed great understanding of their package and the regulations from that point onward, with upgrades that have clearly addressed the weaknesses that were faced on-track.

Although qualifying is a good indicator of overall improvements because you're judging peak pace, I would argue a significant improvement over 2023 for McLaren was their race-pace and how well they could look after the tires, although this trait of the car could not be exploited by Oscar as often as it was by Lando.

Still, if you look at the 2024 season, their tire wear performance in race pace was probably only second to Ferrari, which paid a significant price in quali-pace for that tire wear advantage.

When looking at the race lap-chart between the 2023 and 2024 car at Abu Dhabi, one can very clearly see how much more consistent the 2024 car is throughout the stint, losing very little pace (comparatively) towards the end of the stints. What's somewhat bizarre is that the 2024 car at some cases even displayed "negative degradation" if one can call it that. Basically, the laptimes were getting faster by the end of the stint instead of getting slower.

2023 :


2024 :


Although McLaren made huge improvements from 2023, there were areas of the car which they did not manage to improve. The biggest of which was drag, or overall straight-line performance. Because a lot of attention was given to rear wing + beam wing configurations throughout 2024, we can assume that downforce efficiency was perhaps vastly improved over 2023 (RW-BW wise), however the overall straight-line speed performance in comparison to the competition was still quite weak.

Since the car also lost some of the high-speed corner advantage in 2024 (which is highly likely to be an accepted compromise for the improved medium-low speed performance), this lack of straight-line performance is perhaps not as simply correlated to high wing levels, but rather a draggy concept.

To sum up, McLaren did an amazing job in 2024 to fix the most damning weaknesses of the 2023 car so quickly, but there is still room for improvement. It seemed like towards the end of 2024, the car was receiving little significant developments, but some post-season articles have hinted towards them holding back certain ideas for 2025.

Development potential aside, the major weakness points that need to be addressed for 2025 (in my opinion) are :

1 - Straightline performance / Drag
2 - Wet weather performance (and actually, in general, improvement in lower temps)
3 - Performance in quick changes of direction

[emp]

^Nice summary Emag. I would like to add the difference in how they used the softer tyres in comparison with the others cars. I noticed that they were maybe the best on the hards, can push more and have better tyre wear, than on the softs in the races. Maybe that could be something to look for with the new car.

[mclaren111]

McLaren is in a bit of a weird situation when it comes to identifying major improvement points from last year just because they started out so bad in 2023.

That means half the races from 2023 are irrelevant data points because we would be comparing a literal backmarker to a (at worst) top 3-4 car when it wasn't actually the best.

The other remaining races unfortunately have mismatches in terms of weather conditions. Some just because they have vastly different air and track temps, others because of rain and the rest because the races itself were organized on different periods of the year.

One of the closest comparison points to last year was actually Abu Dhabi, the last race of the season.
Weather conditions when the fastest lap in qualifying was set in 2023 and 2024 are both quite similar with negligible differences, even in terms of wind speed :

(2024 top, 2023 bottom)
https://i.imgur.com/H5enP76.png

From that comparison, the most noticeable improvement is at medium-low speed corners. The 2024 car not only is capable of maintaining higher minimum speed through those, but it also "bleeds" less speed on longer corners. In fact, when compared to the rest of the 2024 field, long medium-speed corners is perhaps the one area where McLaren excelled, with performances in Zandvoort (especially with the strong S2 there) being one of the many examples of their advantage.

This is a contrasting comparison with their 2023 car, because those types of corners were their biggest weakness last year after the Austria upgrade transformed the car. They have showed great understanding of their package and the regulations from that point onward, with upgrades that have clearly addressed the weaknesses that were faced on-track.

Although qualifying is a good indicator of overall improvements because you're judging peak pace, I would argue a significant improvement over 2023 for McLaren was their race-pace and how well they could look after the tires, although this trait of the car could not be exploited by Oscar as often as it was by Lando.

Still, if you look at the 2024 season, their tire wear performance in race pace was probably only second to Ferrari, which paid a significant price in quali-pace for that tire wear advantage.

When looking at the race lap-chart between the 2023 and 2024 car at Abu Dhabi, one can very clearly see how much more consistent the 2024 car is throughout the stint, losing very little pace (comparatively) towards the end of the stints. What's somewhat bizarre is that the 2024 car at some cases even displayed "negative degradation" if one can call it that. Basically, the laptimes were getting faster by the end of the stint instead of getting slower.

2023 :
https://i.imgur.com/UrNA9nu.png

2024 :
https://i.imgur.com/bRLHiSe.png

Although McLaren made huge improvements from 2023, there were areas of the car which they did not manage to improve. The biggest of which was drag, or overall straight-line performance. Because a lot of attention was given to rear wing + beam wing configurations throughout 2024, we can assume that downforce efficiency was perhaps vastly improved over 2023 (RW-BW wise), however the overall straight-line speed performance in comparison to the competition was still quite weak.

Since the car also lost some of the high-speed corner advantage in 2024 (which is highly likely to be an accepted compromise for the improved medium-low speed performance), this lack of straight-line performance is perhaps not as simply correlated to high wing levels, but rather a draggy concept.

To sum up, McLaren did an amazing job in 2024 to fix the most damning weaknesses of the 2023 car so quickly, but there is still room for improvement. It seemed like towards the end of 2024, the car was receiving little significant developments, but some post-season articles have hinted towards them holding back certain ideas for 2025.

Development potential aside, the major weakness points that need to be addressed for 2025 (in my opinion) are :

1 - Straightline performance / Drag
2 - Wet weather performance (and actually, in general, improvement in lower temps)
3 - Performance in quick changes of direction

Very good summery...

[mwillems]

Maybe it makes sense to start by identifying the strengths and weaknesses of the 38 chassis? Because the data is very contradictory from source to source. The most obvious thing is the high drag, and Stella once said that this is one of the points they are already working on, the Brazilian wing was the first step.

Higher drag and tyre management, for me, are the areas that you can see teams like Ferrari have a good advantage. Vegas is a great example of where other teams can do so much more than us, as well as general cold and wet conditions.

Ferrari's superior tyre management quite clearly came at a large cost though, and with such a tight grid the great tyre management at a cost to qualifying pace (and wet weather performance) is just not a good tradeoff.

Dragginess, cold conditions and general performance at stop-go circuits are the main weaknesses I'd say

Also: similar to comparing tyre wear against Ferrari who themselves probably went too far in that direction, we should be cautious not to judge teams too harshly in how they dealt with cold conditions because in this Merc are the yardstick. However we know they got their working window completely wrong, so perhaps one should be wary of unrealistic targets

The team intend to address the baked in issue of front graining in low downforce and colder conditions that could not be addressed during 2024, it being what they consider now the main weakness of the car.

https://www.motorsportweek.com/2024/12/ ... 24-f1-car/

[bananapeel23]

Yeah I was looking at the Ferrari S Duct just before Christmas and wondering if that is something we might see, but thinking we still didn't see it on the 38, so wondered if we would see it on the 39.

Was the Ferrari S-duct even really an S-duct by the end of the season? It seems to have been implemented into the overall intake design and no longer really acted as a bypass duct, at least going by what it looks like from the outside.

It seems to have become more of a packaging solution than anything else. Only really the SF23 seems to have used the "S-duct" primarily as an aerodynamic device.

Regardless of whether or not it's an S-duct, McLaren clearly hasn't utilized the ability to use the chassis volume for cooling or bypass ducting like Ferrari and Red Bull, so they could conceivably go down that route. The question is if McLaren has decided not to so because it doesn't improve their package, or because it's too expensive to justify only a minor performance improvement, especially if it requires them to rework their entire aero concept.

I feel like McLaren would've incorporated an S-duct in the launch spec MCL38 if they thought it was worth it. It was a well known trick by 2024 and McLaren would surely have pursued such a solution if they believed it would help. Obviously that may have changed for 2024, but I believe that's fairly unlikely.

I'd expect them to stick to a conventional sidepod geometry for 2025. I don't really see them sinking a lot of money into drastic survival cell redesign in the last year of a regulation cycle. Any changes to the survival cell will probably be pretty minor and relate mostly to the attachment points of the impact structures, suspension geometry and weight distribution. At least that's what I think.

[mwillems]

Yeah I was looking at the Ferrari S Duct just before Christmas and wondering if that is something we might see, but thinking we still didn't see it on the 38, so wondered if we would see it on the 39.

Was the Ferrari S-duct even really an S-duct by the end of the season? It seems to have been implemented into the overall intake design and no longer really acted as a bypass duct, at least going by what it looks like from the outside.

It seems to have become more of a packaging solution than anything else. Only really the SF23 seems to have used the "S-duct" primarily as an aerodynamic device.

Regardless of whether or not it's an S-duct, McLaren clearly hasn't utilized the ability to use the chassis volume for cooling or bypass ducting like Ferrari and Red Bull, so they could conceivably go down that route. The question is if McLaren has decided not to so because it doesn't improve their package, or because it's too expensive to justify only a minor performance improvement, especially if it requires them to rework their entire aero concept.

I feel like McLaren would've incorporated an S-duct in the launch spec MCL38 if they thought it was worth it. It was a well known trick by 2024 and McLaren would surely have pursued such a solution if they believed it would help. Obviously that may have changed for 2024, but I believe that's fairly unlikely.

I'd expect them to stick to a conventional sidepod geometry for 2025. I don't really see them sinking a lot of money into drastic survival cell redesign in the last year of a regulation cycle. Any changes to the survival cell will probably be pretty minor and relate mostly to the attachment points of the impact structures, suspension geometry and weight distribution. At least that's what I think.

You know more than I about the Ferrari S Duct, I just came across an article talking about it from the year before last. I didn't know what had happened to it on the Ferrari since, only that if it was really useful then I think it might have appeared on the MCL38 and didn't so it makes me doubt that it will again.

[Vanja #66]

The outlet of the duct is much smaller than the bottom inlet, which means the air scooped up gets accelerated. Ferrari's sidepods at the time where designed to slow the air down, so it didn't make too much sense. However, when you consider how extreme the solution on SF23 was, you realise there is not enough airflow velocity to help with extracting the air through the louvers - so they used the jet stream from S-duct outlet to help with that

The other thing S-duct helped with is airflow attachment in extreme yaw conditions. In those cases, this transition area between sidepod topside and engine cover is susceptible to separation under yaw and through the corner. Having an energised jet stream there will help out with keeping the flow attached like any other slot on a wing does





On Imola spec bodywork of SF24 the S-duct inlet was merged with radiator inlet much like RB20 had it since the launch. S-duct outlet was closed off and a single cobra winglet performed the job of handling the cockpit flow losses over the engine cover shelf. The tight engine cover of SF23A is hardly going to appear now that all teams have taken McLaren/Alpine's original 2022 shelf-route, so the S-duct as a duct is not expected on any car really

[bananapeel23]

On Imola spec bodywork of SF24 the S-duct inlet was merged with radiator inlet much like RB20 had it since the launch. S-duct outlet was closed off and a single cobra winglet performed the job of handling the cockpit flow losses over the engine cover shelf. The tight engine cover of SF23A is hardly going to appear now that all teams have taken McLaren/Alpine's original 2022 shelf-route, so the S-duct as a duct is not expected on any car really

So my assessment that the S-duct intake has turned into more of a packaging solution, rather than a bypass duct is correct?

The purpose of the "s-duct" (even if it isn't an S-duct at all) in 2024 and 2025 must surely be to have the benefits of a full-width undercut while eliminating the boundary layer losses, then?

[MTudor]

McLaren is in a bit of a weird situation when it comes to identifying major improvement points from last year just because they started out so bad in 2023.

That means half the races from 2023 are irrelevant data points because we would be comparing a literal backmarker to a (at worst) top 3-4 car when it wasn't actually the best.

The other remaining races unfortunately have mismatches in terms of weather conditions. Some just because they have vastly different air and track temps, others because of rain and the rest because the races itself were organized on different periods of the year.

One of the closest comparison points to last year was actually Abu Dhabi, the last race of the season.
Weather conditions when the fastest lap in qualifying was set in 2023 and 2024 are both quite similar with negligible differences, even in terms of wind speed :

(2024 top, 2023 bottom)
https://i.imgur.com/H5enP76.png

From that comparison, the most noticeable improvement is at medium-low speed corners. The 2024 car not only is capable of maintaining higher minimum speed through those, but it also "bleeds" less speed on longer corners. In fact, when compared to the rest of the 2024 field, long medium-speed corners is perhaps the one area where McLaren excelled, with performances in Zandvoort (especially with the strong S2 there) being one of the many examples of their advantage.

This is a contrasting comparison with their 2023 car, because those types of corners were their biggest weakness last year after the Austria upgrade transformed the car. They have showed great understanding of their package and the regulations from that point onward, with upgrades that have clearly addressed the weaknesses that were faced on-track.

Although qualifying is a good indicator of overall improvements because you're judging peak pace, I would argue a significant improvement over 2023 for McLaren was their race-pace and how well they could look after the tires, although this trait of the car could not be exploited by Oscar as often as it was by Lando.

Still, if you look at the 2024 season, their tire wear performance in race pace was probably only second to Ferrari, which paid a significant price in quali-pace for that tire wear advantage.

When looking at the race lap-chart between the 2023 and 2024 car at Abu Dhabi, one can very clearly see how much more consistent the 2024 car is throughout the stint, losing very little pace (comparatively) towards the end of the stints. What's somewhat bizarre is that the 2024 car at some cases even displayed "negative degradation" if one can call it that. Basically, the laptimes were getting faster by the end of the stint instead of getting slower.

2023 :
https://i.imgur.com/UrNA9nu.png

2024 :
https://i.imgur.com/bRLHiSe.png

Although McLaren made huge improvements from 2023, there were areas of the car which they did not manage to improve. The biggest of which was drag, or overall straight-line performance. Because a lot of attention was given to rear wing + beam wing configurations throughout 2024, we can assume that downforce efficiency was perhaps vastly improved over 2023 (RW-BW wise), however the overall straight-line speed performance in comparison to the competition was still quite weak.

Since the car also lost some of the high-speed corner advantage in 2024 (which is highly likely to be an accepted compromise for the improved medium-low speed performance), this lack of straight-line performance is perhaps not as simply correlated to high wing levels, but rather a draggy concept.

To sum up, McLaren did an amazing job in 2024 to fix the most damning weaknesses of the 2023 car so quickly, but there is still room for improvement. It seemed like towards the end of 2024, the car was receiving little significant developments, but some post-season articles have hinted towards them holding back certain ideas for 2025.

Development potential aside, the major weakness points that need to be addressed for 2025 (in my opinion) are :

1 - Straightline performance / Drag
2 - Wet weather performance (and actually, in general, improvement in lower temps)
3 - Performance in quick changes of direction

Very good summery...

OMG we lost this,we lost that,that wasn't good enough and yet we won the WCC!!!
Stop embarrassing yourself with these lame analysis!!!

[Vanja #66]

So my assessment that the S-duct intake has turned into more of a packaging solution, rather than a bypass duct is correct?

The purpose of the "s-duct" (even if it isn't an S-duct at all) in 2024 and 2025 must surely be to have the benefits of a full-width undercut while eliminating the boundary layer losses, then?

Well, there was photo evidence in Imola of a merged inlet, so...



The S-duct is a bypass duct, it sent the air from down the undercut on top of the engine cover of SF23A. RB20 never had an S-duct, it was just an inverted L (Г - gamma) inlet. That air along the tub could be quite low on energy (which is why SF23 had a very wide duct inlet!) so it's not that good for cooling either - but obviously if chosen as a solution it can work on different cars. Even W15 had a partial Г inlet by the end of the season.

In my view, McLaren was working toward a different inlet solution on MCL38 so I don't think we'll see this inlet on McL39, but it's not a major design difference so it's not impossible

[bananapeel23]

In my view, McLaren was working toward a different inlet solution on MCL38 so I don't think we'll see this inlet on McL39, but it's not a major design difference so it's not impossible

Isn't it a pretty major design difference since the vertical intake isn't actually part of the sidepod volume, but the chassis volume, meaning you have to redesign (and possibly crash test) the tub in order to incorporate it?

Or have I misunderstood where the vertical intake was actually located on the SF24? Because my take was that the main benefit of having it is that you can ingest the boundary layer that would otherwise disturb the undercut while retaining the full width undercut allowed for by the regs. So while the cooling air isn't all that good, it comes with the benefit of cleaning up the flow over the floor.

[Seanspeed]

Maybe it makes sense to start by identifying the strengths and weaknesses of the 38 chassis? Because the data is very contradictory from source to source. The most obvious thing is the high drag, and Stella once said that this is one of the points they are already working on, the Brazilian wing was the first step.

Higher drag and tyre management, for me, are the areas that you can see teams like Ferrari have a good advantage. Vegas is a great example of where other teams can do so much more than us, as well as general cold and wet conditions.

Ferrari's superior tyre management quite clearly came at a large cost though, and with such a tight grid the great tyre management at a cost to qualifying pace (and wet weather performance) is just not a good tradeoff.

Dragginess, cold conditions and general performance at stop-go circuits are the main weaknesses I'd say

Also: similar to comparing tyre wear against Ferrari who themselves probably went too far in that direction, we should be cautious not to judge teams too harshly in how they dealt with cold conditions because in this Merc are the yardstick. However we know they got their working window completely wrong, so perhaps one should be wary of unrealistic targets

I genuinely am not comprehending this idea that Ferrari had better tire wear than Mclaren last year in the first place. Ferrari had the occasional Sprint/Sunday race with better tire wear, but this was not the norm.