Ferrari's SF71H- An In Depth Aero Analysis
Ferrari's 2018 Championship fighter has been known for its aggressive aerodynamics. By having a great chassis and hybrid power unit that is able to recover more energy by putting more pressure inside the engine they are able to put the car ahead of their championship rival Mercedes-Benz AMG Petronas. I wish I could do a general mapping of the Ferrari F1 engine but F1 teams are extremely secretive about their engines so it's pretty much impossible to get actual pictures of the power unit. However, what I can do is analyze the Ferrari's aero in depth and explain how the SF71H works the air around it.
A Formula 1 car is the exact opposite of an airplane. Usually an airplane tries to generate lift which helps to keep the plane in the air. However, a Formula 1 car generates negative lift or downforce to push the car down to the ground and give better grip from the tires. However, the problem with having lots of downforce is that you get massive amounts of drag which means that when you are designing the chassis you have to play with the delicate balance between downforce and drag. The SF71H has the second best chassis on the grid with red bull leading. I thought of doing an aero analysis on the Red Bull but their livery basically doesn't let anyone look in depth into their aero elements. Regardless of that, the amount of aerodynamic development going on at Ferrari has been impressive this season and they continue to bring in valuable upgrades which helps produce more downforce or makes the car more aerodynamic.
The Front Wing
The front wing is an important part of the car as it produces front downforce which helps glue the front wheels to the ground during a corner. It is essential that the front wing produces a lot of downforce because that will help the car turn better and prevents the wheels from locking up. A lock up is caused when the tires aren't completely glued to the ground or they are in a temperature range where they don't work very well. During a lock up the tires just lock and don't rotate so the driver has to do some cadence braking to stop the lockup as soon as possible. This usually negatively impacts lap times which is why front wing downforce generation is important to create a car that is drivable and quick. Another important role that the front wing plays is that it helps to deflect air away from the surface of the wheel which I will explain soon.
Most of the air that passes through the front wing contacts the big ridges in the front wing as shown by the air flow about the front wing in figure 1. The air then gets pushed towards the outer edge of the wing because the ridges are curved to allow the air to go there. This tries to create a large area of air contact which creates downforce as it forces the wing down which forces the front tires to the ground as well and it also directs air away from the front tires. This helps reduce turbulent air which in turn reduces drag or loss of downforce. The air that contacts the front wing through the outer sides come into contact with curved slot gaps as shown in figure two which help to deflect and speed up the air to the outer edges of the wing. Most of the air that passes through the front wing goes to the outer back side of the wing. As shown in figure 2 most of the air that contacts with the lower ridges of the front wing escapes through gap 1. Meanwhile the air that comes in contact with the higher ridges and the slot gaps deflect the air towards gaps 2 and 3. Piece 1 which is shown in figure 2 further speeds up the air and directs the air away from the front tires. After the air has passed through the front wing vortices are created as shown in figure 1. If it were not for the gaps shown in figure 2 there would be even larger vortices being generated which would channel turbulent air to the aero elements towards the back side of the car which reduces downforce production.
Functions Of the Deflector And Bottom Bargeboard Area
Although it might feel like this is it in terms of aero work there is a lot more still to go. By looking closely at Figure 1 you can see that some of the air passes straight through the gaps between the ridges and the structure that extends the wing in front of the tires. Most of this air and some of the air that passes right over the front wing but within the inside of the tyre gets channeled into a deflector that redirects the air and speeds up the air such that it later sticks to the structure of the car. The deflector which is shown in detail in figure 3 has tiny slot gaps as highlighted by yellow markings to assist in speeding up the air. The reason why air must be sped up at this stage is because air traveling at a higher velocity sticks to the car's body more effectively which helps the car slice through the air. The deflector also helps to channel air into the bottom bargeboard area (figure 1) by curving outward compared to the body of the car which further helps speed up the air by forming "tunnels" which I will explain soon.
The Upper Bargeboard Area
If you look closely at figure 1 you can see the upper bargeboard area consists of 3 slots. The slot that is closest to the car is actually an inlet for a radiator that cools down the power unit and the other two slots present towards the outside of the car are there to speed up the air that doesn't contact the front wing or the deflector. This air goes inside these two outer slots and gets sped up. This sped up air sticks to the curvy body of the car as shown in figure 4 and the air eventually reaches the underside of the rear wing which will be used for creating downforce. Another reason why its good that the air sticks to the car's curvy profile is because it directs air away from the rear tires which reduces unnecessary drag. In the end the upper bargeboard is there to use the air around the car to produce downforce more efficiently.
The Engine Cover And Rear Wing
The engine cover which is shown in figure 5 helps direct the air that passes over the upper bargeboard area towards the underside of the rear wing by sloping down which then helps that air gain some momentum and go up the underside of the rear wing. When the air goes up the underside of the rear wing it creates an area of low pressure which sucks the car down to the ground. The air that passes through the surface of the front wing helps create an area of high pressure above it. This contrast of pressure above and below the rear wing creates massive amounts of downforce.
Effects Of A High Rake Design
A high rake design is where the front of the car is significantly closer to the ground when compared to the rear of the car. A high rake design helps the front wing to work the air harder and produce more downforce because it is closer to the ground than when the car has a low rake design. This type of design also helps the air that passes underneath the car to stick to the floor of the car and go up underneath the diffuser which creates another area of low pressure which creates more downforce. The diffuser helps the air to move up underneath the car after exiting the floor by curving upwards just like the underside of the rear wing as you can see in figure 7. As shown in figure 6 we can see that the SF71H's front end is significantly lower than the rear end of the car which suggests that it follows the high rake design philosophy.
What I have covered in this article is actually more of the basics to be very honest. There are so many more aero elements that most people don't know about. But what is most amazing is the level of attention to detail that is given. There is no aero element that's there for no reason. Every single piece has a purpose to it. The work needed to accumulate all these elements into a car to help shave off a few tenths of a second is gigantic. None of us have any clue how many hours has been spent by aerodynamicists at the wind tunnel to come up with solutions that put them ahead of their competition. In the end, Ferrari engineers have worked together to create a competitive car with optimism to clear a 10 year drought of championships this year with 4 time world champion Sebastian Vettel and 1 time world champion Kimi Raikkonen.
