Lewis Hamilton's crash in Monaco allowed Mercedes' rivals to see his bottom. Credit: Getty Images/Jeff Pachoud
The crashes of Sergio Pérez and Lewis Hamilton at the Monaco Grand Prix last weekend gave us some great underbody shots of Red Bull and Mercedes cars.
Mercedes had an upgraded package, but , given Red Bull's performance advantage, it would be very interesting to see what they do with their flooring and diffuser.
It is not always easy to get a completely clear picture from the pictures taken by “spy photographers”. We're looking into the black hole a bit because of the shadows that make it hard to see the surfaces properly.
However, there's still a lot to learn.
What can we see from the Red Bull RB19?
Seeing the Red Bull under the bottom in the air in this form, all the aerodynamicists of the team, especially Mercedes, learned about the number of significant differences between the W14 and RB19.
The most striking thing is how the bottom of the RB19 rests against the diffuser at the rear of the car, this is a very complex detail. They push the “mouth” of the floor quite far back, but then it accelerates at a sharp upward angle before flattening and then bouncing on the trailing edge.
Sergio Perez's car went off the track after a qualifying crash. Photo: Imago/Erlhof
It's kind of like the old IndyCars, which were real ground effect cars. Perhaps Adrian Newey, who worked in the United States in the 1980s, approached it from this angle. Sealing the edges of the floor is critical to the performance of the diffuser and Red Bull has achieved this along the edges of the floor near the front of the rear tires.
When you do this, you can make it harder to work under the floor in this area. You're not just creating an area of low pressure that gets bigger and bigger, you're also accelerating the flow of air in one particular area. Because this area is behind the center of the car, it also creates rear downforce.
What does it help?
With these ground effect rules, having a stable center of pressure is key. These cars run with a couple percent plus or minus anyway – 60 percent rear downforce and 40 percent front downforce. You want the center of pressure under the floor to reflect this (i.e. be 60 percent closer to the rear) and not fight the unstable center of pressure under the floor by rebalancing the front or rear fender.
The Red Bull's center of pressure seems almost perfect. It is not too far forward, so the center of pressure does not shift and does not make the car unstable when braking and at different high-speed corners. That's where Mercedes currently seems to be struggling.
It also helps with tire wear on longer trips. The car can tolerate imbalance for a while, but the imbalance causes the front or rear wheels to overheat when you work too hard on one end of the car.
What's different about Mercedes?
If you were going to draw the original concept from the wording of the rules, what we see on the W14 diffuser is what you're probably aiming for. This is a homogeneous diffuser with nothing “tricky”.
This can be the basis for developing even more complex designs, where you can slightly change the shape of the floor, increase the work of individual sections or shift the center of pressure. Ultimately, however, it is a very simple design, especially when compared to the RB19.
0306 Secrets of the Mercedes W14
Mercedes seems to have used this “original version” and said, “Look how much downforce we can create. ”, but the downforce must be in the right place. I'm not sure if this is the case and wouldn't be surprised if the center of pressure shifts forward with speed and braking on their underground.
The key to this is that their front wing flap assembly flexes at speed more than any other team. You do this to get rear stability at high speed, because something else in the car is causing downforce to move forward, and it might just be the bottom.
Maybe it's a little more complicated than the pictures. show, but the RB19 just has a different generation of underbody compared to the Mercedes.
The vanes also provide another clue to the complexity
The turning vanes start at the leading edge under the floor and fulfill a similar role to the old bargeboards that became so important during the previous regulations.
They direct the air flow outwards and then the aerodynamic pieces around the side of the floor try to create vortices that then theoretically isolate the floor further back and create more downforce. This complicates the work of the diffuser, and also helps to better position the center of pressure.
Again, Red Bull is much more difficult than Mercedes. There will be a lot of people on other teams looking at Red Bull under the floor and thinking, “God, this is hard.” Does increasing complexity make things better? Yes, if you entered the data correctly. It makes no sense to complicate for the sake of it.
Ultimately, it's all about making the parts of the car work as a whole. The Red Bull works so well that as a unit you could probably take the fenders off the car and still drive pretty fast.
Can Mercedes just copy the Red Bull floor?
Mercedes isn't that far off, but finding the last piece of performance is incredibly hard. It's not just the case that you look at images of the bottom of a Red Bull and try to copy it.
You never want to just copy someone else because the finer details and philosophy of their car will almost certainly not suits yours. Aston Martin, for example, has a philosophy very similar to Red Bull, but it comes from the fact that Dan Fallows moves from one team to another and knows their aerodynamic approach and direction.
Mercedes needs to follow its own aerodynamic philosophy. So many hours of research and development have gone into making Red Bull what it is. If you just look at pictures and try to replicate it, you will be puzzled in a wind tunnel and will never come close to improving your own car, let alone catching a Red Bull.
If you don't know why you do something, it's a big problem. You need someone to tell you why a certain action will make your car better. Then you go out and try to reach it.