McLaren MCL39

[Hoffman900]

You all just discovered bump steer

[De Wet]

Since you are using private material and other people's intellectual property, you could disclose the authors of the article and illustrations

Apologies. Will do so in future.

[Brahmal]

Most other teams have open vents in this part of the caliper cover, dumping air from the brake disk into the drum cover. McLaren is clearly piping that air somewhere specific. That first duct looks like it vents into the body of the wheel disk, not sure about the bigger duct underneath.

Gotta think this is part of their tire-temp system. I'm pretty sure the other teams don't have something like this.

[mwillems]

There is more to it than what can be seen. What if McLaren have found a mechanical equivalent to DAS that is induced and managed by anti-geometry? Watching the latest tech talk made me think this is possible, considering the front axle usually tows out when the chassis is loaded. There is a geometry that can effectively tow in when under load which may be what McLaren went after

How would this impact braking through corners if the tyres toe under load? Could it explain the lock ups Mclaren are getting here?

Is it possible that under too much load it is ultimately reducing the contact patch on the loaded tyre⁰?

[Farnborough]

There is more to it than what can be seen. What if McLaren have found a mechanical equivalent to DAS that is induced and managed by anti-geometry? Watching the latest tech talk made me think this is possible, considering the front axle usually tows out when the chassis is loaded. There is a geometry that can effectively tow in when under load which may be what McLaren went after

How would this impact braking through corners if the tyres toe under load? Could it explain the lock ups Mclaren are getting here?

Is it possible that under too much load it is ultimately reducing the contact patch on the loaded tyre⁰?

Toe in if moved to excess (what that level is you'd need to define) primarily changes the response speed of driver input. Too much and its like a mad squirrel in its alacrity and effect. It can overwhelm the chassis dynamic in making that phase alarming to drive.

The question for me is "which way is it changing in response to suspension movement? " ie, is it moving to more as suspension lifts or the opposite. That's IF they're using a design that is specifically changing this.

DAS in MB appeared to have normally accepted toe intended for cornering dynamic, with that cancelled by pulling wheel to "effectively" make near zero toe away from that setting.

This McL layout SUGGESTS something else to me (I put that in post such that others may offer critique) that without more intimate specific design detail, can't fully be observed.

This response we see communicated by the drivers and possibly Stella, do suggest there's something in this discussion. That paired with their "radical " projection prior to season.

[mwillems]

Seems we need to watch this space. It feels to me that the grip curve that determines how much you can brake in a corner is different on this car than on others, and I'm wondering if it is more dynamic.

I get the impression that you need to be really alive to what the car is telling you is an acceptable amount of braking through a corner or that it changes either quicker or in unexpected ways, due to the way the ftont is operating.

Feels possible they have given the car more pure grip and speed in corners, but braking is messy.

This is just my speculation, but this seems to be what is surfacing in China.

[Hoffman900]

Again, you guys are talking about bump steer, a well understood phenomenon.

Typically on a standard formula car (Formula Atlantic, Formula Ford, etc) some bump understeer on both ends is what is designed in; the front will toe-out in bump and the rear will toe-in. With some roll, the outside tire will toe out while the inside tire is toeing in at the front, and be reversed in the rear. This is all relative to what you set the toe when static (on the ground, all fluids, driver, etc.).

There is another term called “roll steer” which is used with solid rear axle or beam front suspension designs (think dirt Sprint Cars, Formula Vees) where the whole assembly tilts one way or another (as viewed from overhead) through the suspension’s travel. It’s something that people design around as well and you can control the direction and rate.

Just like anti-dive, these are well understood and purposely designed values to hit whatever the performance criteria (lap time, tire life, etc) and have been for over half a century.

F1 gets a little more complicated as the sidewalls are hugely influencial with the aero field, so not sure exactly what they target or what they want as it’s complicated.

[bigpat]

I think hat is regards to suspension movement, because the suspension arms are relatively long in relation to the amount of vertical suspension travel, therefore any effect like bumpsteer would be extremely minimal....

As for the brake cooling, although quite novel, I would assume all the teams would have their own intricate ducting solutions to achieve a similar result.

I would tend to think that the McLaren simply has a more consistent and relatively high aerodynamic loading throughout the speed range, which overall stresses the tyres less, more so as more laps are run on the tyres.

It is noticable that the McLaren runs significantly smaller cooling opening than others on the grid, which increases the cars overall aero efficiency....

[DiogoBrand]

So it looks like after 2022's brake duct woes, McLaren overcompensated and designed the best brake ducts in history?

[Hoffman900]

I think hat is regards to suspension movement, because the suspension arms are relatively long in relation to the amount of vertical suspension travel, therefore any effect like bumpsteer would be extremely minimal....

As for the brake cooling, although quite novel, I would assume all the teams would have their own intricate ducting solutions to achieve a similar result.

I would tend to think that the McLaren simply has a more consistent and relatively high aerodynamic loading throughout the speed range, which overall stresses the tyres less, more so as more laps are run on the tyres.

It is noticable that the McLaren runs significantly smaller cooling opening than others on the grid, which increases the cars overall aero efficiency....

I agree.

[CjC]

So it looks like after 2022's brake duct woes, McLaren overcompensated and designed the best brake ducts in history?

Good point!

[101FlyingDutchman]

So it looks like after 2022's brake duct woes, McLaren overcompensated and designed the best brake ducts in history?

Good point!

James Key inspired ducting

[Waz]

Again, you guys are talking about bump steer, a well understood phenomenon.

Typically on a standard formula car (Formula Atlantic, Formula Ford, etc) some bump understeer on both ends is what is designed in; the front will toe-out in bump and the rear will toe-in. With some roll, the outside tire will toe out while the inside tire is toeing in at the front, and be reversed in the rear. This is all relative to what you set the toe when static (on the ground, all fluids, driver, etc.).

There is another term called “roll steer” which is used with solid rear axle or beam front suspension designs (think dirt Sprint Cars, Formula Vees) where the whole assembly tilts one way or another (as viewed from overhead) through the suspension’s travel. It’s something that people design around as well and you can control the direction and rate.

Just like anti-dive, these are well understood and purposely designed values to hit whatever the performance criteria (lap time, tire life, etc) and have been for over half a century.

F1 gets a little more complicated as the sidewalls are hugely influencial with the aero field, so not sure exactly what they target or what they want as it’s complicated.

Every aspect of race car design will be well understood by F1 teams that have decades of engineering data to reference.

The discussion here doesn't seem to be if the phenomenon is new or not, but rather the manner McLaren are going about the engineering solutions to them.

All teams have "anti-dive", but is McLaren's solution superior and how? I thought the discussion around was interesting.

All teams will have an element of "bump steer", but is McLaren's solution offering a different aspect and how? Developing a passive form of DAS seems more complicated than bump steer, and must surely be trying to achieve a different goal.

Not all of us work in engineering, so it's fascinating to read opinions and concepts presented by others on what seems a trivial idea, but in these tricky regulations can make a substantial difference over a race distance.

[organic]

by n_mode_log on Twitter

[Farnborough]

Again, you guys are talking about bump steer, a well understood phenomenon.

Typically on a standard formula car (Formula Atlantic, Formula Ford, etc) some bump understeer on both ends is what is designed in; the front will toe-out in bump and the rear will toe-in. With some roll, the outside tire will toe out while the inside tire is toeing in at the front, and be reversed in the rear. This is all relative to what you set the toe when static (on the ground, all fluids, driver, etc.).

There is another term called “roll steer” which is used with solid rear axle or beam front suspension designs (think dirt Sprint Cars, Formula Vees) where the whole assembly tilts one way or another (as viewed from overhead) through the suspension’s travel. It’s something that people design around as well and you can control the direction and rate.

Just like anti-dive, these are well understood and purposely designed values to hit whatever the performance criteria (lap time, tire life, etc) and have been for over half a century.

F1 gets a little more complicated as the sidewalls are hugely influencial with the aero field, so not sure exactly what they target or what they want as it’s complicated.

Every aspect of race car design will be well understood by F1 teams that have decades of engineering data to reference.

The discussion here doesn't seem to be if the phenomenon is new or not, but rather the manner McLaren are going about the engineering solutions to them.

All teams have "anti-dive", but is McLaren's solution superior and how? I thought the discussion around was interesting.

All teams will have an element of "bump steer", but is McLaren's solution offering a different aspect and how? Developing a passive form of DAS seems more complicated than bump steer, and must surely be trying to achieve a different goal.

Not all of us work in engineering, so it's fascinating to read opinions and concepts presented by others on what seems a trivial idea, but in these tricky regulations can make a substantial difference over a race distance.

I feel if there's decent moderate input to keep the enquiring nature of topic rolling along, then lucid views can be given. I value the contributions from Ing, Hoffman, amongst others, to bring good insight to these thread.

"All teams will have an element of "bump steer", but is McLaren's solution offering a different aspect and how? Developing a passive form of DAS seems more complicated than bump steer, and must surely be trying to achieve a different goal."

That can be examined to build further picture of what they are doing.
Some initial statement may help (but clarification welcome) generally given, running straight on these car would not involve toe out, perhaps a tiny amount of toe in (wheels pointed inward toward each other) and at full aero compression with it flat out rubbing the ground, seems desirable. That would make lifting the front suspension seem to be the controlling factor in bringing toe in to higher movement, which in turn would promote turn in IF there's substantiated "anti dive" in place.

The effect of the above would be to make the chassis calm turn in a "balls out flat" initiated turn (definitely a good thing) and help to make it less nervous under that condition.
Moving toward a faster more flighty response as front travel moved up in suspension geometry to produce a fast and on the nose feeling. Transient feedback in that maybe interpreted differently by driver (we've had some report of this so far from drivers) but should be tuneable to some extent.

These characteristics would fit with aero balance (having abundance on front at v max to lazy at slow speed and lower suspension compression) also appearing desirable to work with.

Whether that fits in or runs contrary to conventional geometry interpretation im not sure.

I know from setting toe in, in excess, it can make a chassis alarmingly potent at turn in phase. Its a small shift, but with potent effects if left unchecked.