Aston Martin AMR24

[Venturiation]

This was posted by @Luscion in the W15 thread but I think it's important for the AMR24 as well:

Snippet from Formu1aUno article - https://formu1a.uno/ecco-perche-la-nuov ... -stagione/

Mercedes opted to lower the front arm of the upper triangle, thereby increasing the anti-squat to keep the aerodynamic platform of its own car as stable as possible, and consequently those of its customers, such as Aston Martin and Williams. But what stands out quite clearly is the compromise found on the push-rod by the former world champion team. In fact, the push-rod arm is positioned rather horizontally, especially when compared to the competitors' specifications. This is a compromise that tends to favor the aerodynamic effect of the profile over the purely mechanical part, which will be more difficult to control, especially when it comes to shock absorber excursions. However, in the design of any suspension, designers always make important compromises, whether in terms of angles, attachments or positioning of the internal suspension components. For this very reason, the Mercedes rear suspension is the first major new feature of this 2024 F1 season

Dan Fallows said: “We’ve inherited new suspension from Mercedes . . . They give us the gearbox and the structure of the rear suspension, so that has changed slightly from last year as well. So, there’s a change on the rear, but on the front it’s very similar."

I find this language quite interesting. It doesn't sound like he's too happy about the change (but maybe I'm reading too much into it). At what point did Mercedes have to decide on the direction of the rear suspension? I would assume it's fairly early, but how early? And when do they tell AMR? This is a fascinating question to think about, for me, because it has huge aerodynamic implications for the car and a team like AMR has no control over the direction Mercedes will take, so how do you plan accordingly? It seems like a nightmare.

From the W15 thread
Edd Straw & Mark Hughes mentioned that there was a "certain hint of slight frustration" behind Dan Fallows' words about the Merc 2024 rear suspension
There was in some of his language a certain hint of slight frustration, not massively but you just feel that maybe they thought there was a bit more they [Mercedes] could do.
15:42 (bit earlier if you want context)
https://www.the-race.com/formula-1/asto ... t-podcast/

[KimiRai]

When alonso took the wheel it appears closer to the ground, must have been testing ride heights?

[mythr-ran-dire]

When alonso took the wheel it appears closer to the ground, must have been testing ride heights?

https://media.surlyhorns.com/monthly_20 ... 159602.png

https://www.racefans.net/wp-content/upl ... 153713.jpg

Possible, but it looks like Alonso just took the corner more aggressively than Stroll did. Look at the difference in deformation on the outside front tire.

[KimiRai]

When alonso took the wheel it appears closer to the ground, must have been testing ride heights?

https://media.surlyhorns.com/monthly_20 ... 159602.png

https://www.racefans.net/wp-content/upl ... 153713.jpg

Possible, but it looks like Alonso just took the corner more aggressively than Stroll did. Look at the difference in deformation on the outside front tire.

Thanks!

[stonehenge]

This was posted by @Luscion in the W15 thread but I think it's important for the AMR24 as well:

Snippet from Formu1aUno article - https://formu1a.uno/ecco-perche-la-nuov ... -stagione/

Mercedes opted to lower the front arm of the upper triangle, thereby increasing the anti-squat to keep the aerodynamic platform of its own car as stable as possible, and consequently those of its customers, such as Aston Martin and Williams. But what stands out quite clearly is the compromise found on the push-rod by the former world champion team. In fact, the push-rod arm is positioned rather horizontally, especially when compared to the competitors' specifications. This is a compromise that tends to favor the aerodynamic effect of the profile over the purely mechanical part, which will be more difficult to control, especially when it comes to shock absorber excursions. However, in the design of any suspension, designers always make important compromises, whether in terms of angles, attachments or positioning of the internal suspension components. For this very reason, the Mercedes rear suspension is the first major new feature of this 2024 F1 season

Dan Fallows said: “We’ve inherited new suspension from Mercedes . . . They give us the gearbox and the structure of the rear suspension, so that has changed slightly from last year as well. So, there’s a change on the rear, but on the front it’s very similar."

I find this language quite interesting. It doesn't sound like he's too happy about the change (but maybe I'm reading too much into it). At what point did Mercedes have to decide on the direction of the rear suspension? I would assume it's fairly early, but how early? And when do they tell AMR? This is a fascinating question to think about, for me, because it has huge aerodynamic implications for the car and a team like AMR has no control over the direction Mercedes will take, so how do you plan accordingly? It seems like a nightmare.

From the W15 thread
Edd Straw & Mark Hughes mentioned that there was a "certain hint of slight frustration" behind Dan Fallows' words about the Merc 2024 rear suspension
There was in some of his language a certain hint of slight frustration, not massively but you just feel that maybe they thought there was a bit more they [Mercedes] could do.
15:42 (bit earlier if you want context)
https://www.the-race.com/formula-1/asto ... t-podcast/

Interesting. Although I think "they" meant Aston Martin. He's saying the frustration is about getting a pushrod from Mercedes and having to "optimize around that" instead of picking the suspension that you think works best with your concept.

[Apexseal157]

One thing I have noticed is how bulbous the sidepods are (different but similar to the bulbous lower portion of the rb19's pods), you can see in the on track photos how convex the side surface is compared to the AMR23, which had much flatter sides. That's been paired with a much thicker waterslide wall, tbh im not sure exactly how that would effect flow apart from the larger cross section providing more outwash, maybe better attachment as flow spills from the top to the side of the pod.

[Blackout]

Very similar sidepod undercut treatment and shapes, with a large and streamlined undercut + that downward sidepod flanc extension we saw on the Alpine that forms a ridge, a lateral barrier and a bottleneck with the floor that helps managing undercut flow and side flow.

[Apexseal157]

Very similar sidepod undercut treatment and shapes, with a large and streamlined undercut + that downward sidepod flanc extension we saw on the Alpine that forms a ridge to separate undercut flow and side flow.

https://i.imgur.com/Dwttuh6.jpeg

yeah I think most cars will have a similar treatment, the aston is much more aggresive though, that lip is by far the most exaggerated of all the cars so far, the belly bump has much tighter curvuture and the waterslides are significantly deeper, I expect all cars will converge on a letterbox style inlet.

[KimiRai]

[GTO99]

Very similar sidepod undercut treatment and shapes, with a large and streamlined undercut + that downward sidepod flanc extension we saw on the Alpine that forms a ridge and a lateral barrier that helps managing undercut flow and side flow.

https://i.imgur.com/Dwttuh6.jpeg

That AMR sidepod with the sharp bottom, has been modified. It does not match the track car.

[BassVirolla]

https://i.imgur.com/0f4koj7.jpeg

More than an undercut, that's an overpod.

[wiktor977]

I really like all those details that they have made to guide the airflow. Team made a big step forward with a new sidepod (I call it flying sidepod), razor thin inlet, front wing and suspension PLUS all those small details. AMR24 is a beauty.

[PinkFloydPulse]

Should be called floatpod...
The car is beautiful! <3

[edgelo]

https://i.postimg.cc/jSRQsJsy/aston-detail.jpg

I really like all those details that they have made to guide the airflow. Team made a big step forward with a new sidepod (I call it flying sidepod), razor thin inlet, front wing and suspension PLUS all those small details. AMR24 is a beauty.

I wonder if that little fin you marked on the image on the lower zone could do the work of a s-duct intake, taking the boundary layer up and creating a slim zone of low pressure behind, that attach the faster air to the body

[Ashwinv16]

Few details I noticed and how I see them, most of it has been noticed today, but I'd like to expand on the performance influence of it all.

https://i.ibb.co/tPwvn1t/GGIQWb-DXs-AApx-B.jpg

The scale of raising the lower inlet lip should absolutely not be underestimated (red lines), this is a direct performance enhancement in two ways: it leads to more air for the undercut and directly into diffuser and it reduces inlet opening drag. It takes multiple small steps to achieve it (as RB19 evolution shown), but AMR did it's job and I don't think there is room to raise it further. Even if so, they are definitely in the zone of diminishing returns. The curvature (purple) of the lip is significant and this is what speeds up the airflow (as long as it stays attached), reduce pressure locally and draws more air from the top layer inside (white arrow). 7 years ago, when Ferrari SF70H was shown, I was certain the approach we see on AMR24 was the way to further improve those cars at the time, but somehow teams chose to stay conservative and abandon the idea altogether by 2021.

What's interesting here is the clear existence of a sort of wing tip of that inlet lip, which will inevitably generate a vortex (blue arrow). This likely plays a role in generating additional downward velocity vector to draw even more air locally and it may be very helpful in yaw. The final piece of making it all work together is the negative twist in the mirror stay (yellow oval, also present on real car), resulting in downwash flow, even ahead of it. Again, not a huge thing on its own, but a lot of details will add up to an extreme solution working as intended in the end.

The interesting thing is the lack of mirror shrouds (orange oval). These generate more drag, but can be helpful in containing the wake losses downstream. It's safe to say AMR decided against them to cut the drag as much as possible at the moment.

https://i.ibb.co/tsx6CBG/GGIXkx5-Xc-AAayd-D.jpg

Now for some more details head on, to me it seems a lot of them are focused entirely on flow conditioning to ensure these extreme inlets (yes, even more extreme than RB19) are working properly. Top wishbone arms are even more curved now and quite visibly (green lines). Both top and bottom (rose oval, white lines) front arms seem to be very much aligned with front wing trailing edge, especially compared to launch spec AMR23. In my view, this is an important feature. Rear arms seem to be further inclined, with all 4 arms and the push and steering rods working together to maximise local downwash for improved floor and sidepod flow conditioning.

Quite possibly the biggest concept change is the front wing. Not only is the nose joint with the second flap (red circle), but the whole spanwise flow of the front wing is very different and aligned with RB19 philosophy. The nose detail likely increases drag (since there are now two stagnation areas locally), but it also generates more downforce overall due to the exposure of the front flap. There is a clear step away from strong outwash generation (orange oval) and I'm sure AMR figured out how to make sure they don't lose performance this outwash brought, likely with strong interaction of the vanes under the brake ducts. Impossible to say how the drag of front wing and front wheel combined is vs AMR23, but front wing alone is a lot lower drag generator now. And make no mistake, they are using mid-downforce rear wing, so this front wing is not low drag solution by any means.

https://i.ibb.co/stRP7kX/GGIagb-CXAAAte-Vc.jpg

Hoping this bit won't spark too much controversy, since this might be interpreted as eyeball-cfd Nevertheless, I've marked down what I see happening under the sidepod inlet and this is the same principle RB19 successfully utilised to extend the undercut compared to RB18 - and most likely reduce the drag a bit as a result. As the airflow compresses locally, pressure increases step by step. Right before the local throat section it reaches the peak - before it start accelerating inside the throat itself. I've illustrated this crudely with different coloured lines and also different number of them, though I believe the flow compression bit is quite obvious.

This resulting pressurisation drives the local outwash effect without an actual outwash geometry. Last year, AMR23 featured quite a strong outwash geometry but ultimately it was a draggy solution (as Ferrari noticed in 2022) so this new solution reduces drag by decent reduction of local frontal area. The problem here is to keep pressurisation just high enough, which requires smaller throat but also generates more drag. It's quite a tricky balancing act I would say.

On the top side, the whole top surface is slightly bellow ambient pressure, resulting in overall lift generated on the sidepod as a whole. So no, the sidepod does not generate downforce overall, which is also quite evident by it's geometrical angle between leading edge and diffuser joint - a positive, lift-generating, angle.

Overall, AMR24 shows clear signs of drag reduction and clear improvements of their AMR23 concept. For the 2nd best car in H1 2023, this is the right way to go.

PS
To provide some substance for those eyeball-cfd observations, you can also take a look at my crude AMR23-like sidepod CFD and compare it to Ferrari's CFD results of launch-spec SF-23. Note for comparison, on my plot the ambient pressure is yellow and everything towards red is above ambient. Ferrari's ambient pressure is grey (transparent) and everything above ambient is red, while yellow and rainbow colours towards purple are bellow ambient.

https://i.ibb.co/f1MZfwC/amr23-yaw-0-iso1-cp-sl.jpg

https://imgur.com/MinzNqj.png

This is a nice insight. To add a a bit, the vortex generation from the inlet helps flow attachment that became a problem with the drag reduction upgrade it brought in USA and Canada. The shape of the side pods though does show a lot of outwash towards the back (see the post above for the yellow trace line). There is a lot of parts in the side pods focussed on flow attachment not seen in any cars previously, except the Red Bull.