Mercedes AMG W05 Front Wing Analysis (halfway-season)

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(A small apology for some drawings being of lesser quality; I took some material from my first analysis, at which point I only started with drawing f1 bodywork. Since then I got a lot better at it, resulting in a noticeable difference in quality.)

Foreword

As mentioned a few months ago, Mercedes started winter testing with a very elaborate front wing. I also made a prediction that Mercedes would not change immediately too much on the front wing coming into Melbourne.
Going into that weekend, my prediction was proven wrong the moment pictures showed extensive updates. And after Melbourne updates on the front wing just kept coming, resulting in a wing that, although is clearly based on its predecessor sharing the majority of its concepts, looks and in fact behaves -on some points- very different then the pre-Melbourne spec.

This article will discuss those numerous changes, as well as touching things I didn’t had the chance last time due a lack of photographic material to accurately base upon, especially the underbody strakes.

What changed in Melbourne?


As has been said, quite a few extensive changes were made. However, this wing would not run until Bahrain, and the winter-testing front wing was used for the first 2 qualifyings and races. One possible explanation was that they still had to get their shorter front crash structure through the crash tests, the nose around which the new front wing was designed. They still didn’t have that crash structure in Bahrain, but by then the data gathered in the free practices probably showed the wing was an improvement even with the longer nose.
The one thing immediately hitting the eye was the radical change in endplate design:
In my previous article I talked about the heritage of Mercedes’ double endplate. Counting in the season of Brawn, the concept was used for 5 years straight. It came to an end in Melbourne. My belief is that they planned this before winter testing, but took the old endplate to get a better understanding of the data.

Gone is the curved gap in between the 2 endplates. It’s now a fully continuous endplate. The gap bled off high pressure from the wing elements, preventing airflow separation and stalling and created two independent airflow paths around the front tire, but Mercedes seemly found other means to do so and didn’t need that gap anymore.

The back end of the endplate is much more aggressively curved, bending the air further away from the tire then before. The marginal extra drag from this is most likely offset by the decrease in tire wake.

Mercedes furthermore made drastic changes to their cascades:
First off, they removed the small flick in the endplate. This was a feature from last year and looked to be taken over. It always was a bit puzzling what its true purpose was, and seeing it being removed either tells it never did what it was supposed to do, or it didn’t fit in anymore with 2014-style front wings, perhaps not corresponding well with the outwards-twisted vertical pieces.

I asked Will Tyson on this, and this was his opinion: “The small flick created a tiny set of vortices to shape airflow around the front tyre. The 2014 tyre compounds clearly do not benefit from this additional airflow management technique.” The 2014 compounds are known to be harder, and probably flex and bend less on higher speeds, so whereas in 2013 this flick created a vortex guiding around the tire, the vortex could very well be hitting the tire itself in the present, doing more harm than good.

The j-part got completely reshaped and disconnected from the main cascade. It’s now a larger, separate vane and redirects more air. Interestingly, and not so easy to spot on pictures, is that it features a horizontal strake along its length. It’s guessing to that strake’s purpose, but it could be to smoothen airflow in between the cascade and the j-part, preventing the air getting turbulent above the wing elements.
The endplate of the cascade also got slightly revised as well, being vertically bent, next to it already being bent outwards to the back.
Finally, the support of cascade changed as well, now being bent instead of completely straight, following the line of the cascade endplate. The intent could be to have the air make a smoother transition underneath the cascade, benefitting airflow attachment. It also has its benefits further down the wing, moving the obstruction partly from the high AoA area of the wing more to the lower AoA area, increasing downforce and efficiency.

And finally, we have the wing elements:
The wing elements have been completely reshaped. Most importantly, the slots separating the first 3 elements have been extended completely to the neutral section (don’t mind the smaller neutral section in the older wing; incorrect drawn size). While the top elements have been made a bit thinner, they have a higher angle of attack, with the last element standing vertical at the outwards edge, but decreasing in AoA near the tips. The end result is a wing producing more downforce without stalling at higher speeds.

Round 2: Spain

With the wing effectively used during the whole weekend in Bahrain and the shorter nose finally succeeding the crash tests before being introduced and raced in China, further development could be initiated.

Mercedes immediately went on to do so in Spain:
First, they added a slot inside the third element in the area in front of the wheel (red circle), effectively creating a 6 element wing in front of the tire. It allows a tiny bit of a higher AoA in that area while keeping airflow underneath the wing attached.
Second, they also added slots in the flat part of the footplate, extending the first 4 elements all the way to the bended part. Since the footplate doesn’t bend upwards in that region, it looks to keep airflow attached, not only beneath the footplate but also in the curved sections of the wing elements. Bleeding off some airflow will aid in the outwards bending airflow, increasing outwash and decreasing tire wake. It could furthermore rob the base of the tire from airflow. It’s to be noted that the base of tire creates a turbulent and very draggy vortex. Removing high energetic airflow there, decreasing this vortex in strength, and thus also decreasing its disadvantages. Ferrari tried a similar solution before, so Mercedes might have gotten the idea from them.

Furthermore, they made alterations to the endplate and cascades:
Mercedes introduced a strake on the inside of the endplate (yellow) and right above the flat (but slotted) footplate. It helps in upwashing the airflow, while also creating a vortex at its protruding tip. Curiously, it is at the same plane as its outside and inverted cousin, perhaps implying those 2 strakes work in conjunction to each other, creating a low pressure field behind them both on the inside and outside (blue), sucking in high pressure air. This aids in airflow keeping very much attached to the endplate, following its curve. A lot of thought has gone into this. McLaren, another team who uses strakes on both sides of the endplate, has both strakes bend upwards, intending in clearly upwashing the air. Mercedes seems more concerned here with drawing high pressure air onto the surface of endplate and letting the plate do the work. Again, this is guessing, but either way Mercedes kept the solution so it does work for them.

Finally, Mercedes also made a small change to the cascade:
The cascade support pylon has been minimized. It also bends slightly inwards now. This looks more to be a case of having a minimum impact on the airflow, wishing to keep the elements behind as free from obstruction as possible. The slight bent in it suggest another small solution in airflow attachment. Mercedes clearly looks to have a deep understanding of what is going on in that region, and can have the airflow do what they want.

…And 2 weeks later…

Mercedes is very unrelenting in their development pace. With such a small window in between the 2 races (but importantly, fairly close to the factory in Brackley, UK) they brought another fairly substantial set of updates, including to the front wing.

At Monaco, they reshaped their endplate:
Whereas before the endplate would swoop to above in an elegant curve down from the footplate, it does now in 2 stages, increasing endplate surface and forming a protruding tip near the footplate (red circle). This will create a nice clockwise-rotating vortex. It could just be an optimization of the relative new endplate, having studied the data and found out they don’t need to leak off as much as high pressure air from the last few wing elements, optimizing the endplate for more airflow guidance outside it. There’s a belief that the aforementioned vortex bends around the tire, guiding airflow around it and reconnecting it back at the base of the sidepods, increasing rear downforce and decreasing tire wake. This looks difficult to achieve, but can give a good performance boost if successful, so a fairly substantial alteration. Note that the strake tries to do this as well, so it’s necessarily true.
They also reshaped the outside strake on the endplate, now featuring a lateral bend in it. It looks like this tries to enhance the tip vortex it creates. As mentioned, this vortex too tries to reach around the tire, so any solution to increase its strength is more than welcome.

Some things not mentioned before now

I also like to address some parts that previously couldn’t be due lack of reference material or simply overlooked. To start with, I’d like to discuss the underbody strakes of the front wing. Underbody strakes are the most difficult to photograph due them being well hidden underneath the wing. When the wing is attached to the nosecone, it’s impossible to photograph, unless the car crashes and has to be lifted (and in even most of those cases, the wing is destroyed robbing the opportunity). The only good moment is when the team switches front wings and a mechanic has to lift the front wing, exposing what’s going on at the underside, and this is what I made of it in the case of Mercedes:
Teams have been using underbody strakes for years now. It guides low pressure air, speeding it up or bends it. They also create vortices. The placement of them are very important, for front, global and rear downforce, as well as tire wake.
I numbered the strakes in the top image for easy reference. Strake 1 is the shortest one, starting and ending underneath the second elements. It has an outwards bent in it, which does create a bit of outwash, but more importantly works together with strake 2. The tandem of those two strakes create a venturi tunnel, speeding up airflow, dropping pressure and increasing downforce. The second wing element has very little AoA, but due the placement of the strakes it still creates a fairly amount of downforce for only a very small drag penalty.
Strake 2, 3 and 4 extend completely all the way to the same plane as the edge of the footplate, close to the ground beneath the edge of the front wing. They are straight, except for the ends of 2 and 3, with 3 having the more aggressive bend. They also try to speed up airflow a bit, while trying to bend air away from the tire.
Strake 4 is longitudinal straight, but latitudinal it has bent over its complete length. Important to know is that the strake is position right next to the inner edge of the tire. At the back end of the bent part of the strake, it creates a strong vortex at the tip, shielding airflow. The airflow it’s shielding is meant for the splitter and underfloor, making this a very critical solution. Without it, the rotating tire would send more turbulent air into that region, robbing the floor and splitter of downforce.
This way Mercedes maximizes underflow right in front of the tire for downforce production, while keeping airflow not in front of the tire, away from the tire.

And as a last action, the vortex generators on top of the second wing element:
Basing, on their placement, they create a vortex right above the strakes. Air between the strakes and the underside of the wing tends to stagnate, which creates drag. Creating a vortex in front of the stagnated air re-energizes the air there and speeds it up. They prevent marbles or other dirt from clogging up the slots in between the elements, which would also lead to downforce loss.

So what’s next?

Mercedes didn’t introduced new frontwing parts in Canada or Austria. Both are low to medium downforce circuits, thus the endless pursuit for downforce lessens somewhat during this period. From next week on we have a return to higher downforce circuits, to begin with Silverstone. Expect Mercedes to have used the time between Monaco and coming race weekend to have made further developments.

Again, a big thanks goes to Will Tyson (thewptformula) for bettering this article. He had a big input concerning content and clarifications throughout it.
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