Sidepods are a very important part of an F1 car, and they come in various shapes and sizes. They’re crucial for the aerodynamics of the car, and they also play a key role in keeping things cool. But how do F1 car sidepods work?
Sidepods on F1 cars help manipulate airflow both over and around the car, and they also help channel air into the radiators to cool the car’s internals. They have long been an important feature for downforce production, and teams can take very different approaches to the designs of their sidepods.
Below, I’ll go into more detail about how an F1 car’s sidepods help with downforce production, and how they help keep things cool as well. I’ll also answer questions about sidepod design, covering undercuts, cooling slats, scallops, and more!
What Is A Sidepod In F1?
A sidepod on an F1 car is the bulge in the body of the car at either side of the driver, moving back to varying degrees alongside where the engine sits inside the car. Sidepods are used to cool the internal components and guide airflow over the car.
Sidepods have been around in Formula 1 since 1970, when Colin Chapman and Maurice Philippe’s Lotus 72 made its debut. It was the first car to feature ‘coolers’ on each side of the car.
The sidepods on a Formula 1 car are used to cool the engine and other internal components. However, it’s more than just the engine that needs cooling, as there are several other elements, including:
- Electronics (including the ECU)
- Gearbox
- Battery
- Hydraulics
- Clutch
- Hybrid system
Each Team Has A Unique Design
How teams structure their sidepods has a major impact on the cooling of the internals and on the airflow over the car. With teams using different engines, gearboxes, chassis and other parts, different cooling requirements and chassis dimensions mean teams must use unique sidepod designs.
This means some teams must run larger air intakes on their sidepods, and we’ll often see various shapes that are more rounded or others that are squarer. Some teams may not opt to use cooling slats (more on them below), while others may require them depending on their engine and other internals.
The chassis dimensions may also require sidepods to be of various shapes, sizes, and overall designs (such as scalloped or undercut designs, more on these below too), in order to maximize downforce and properly channel the air over and off the car.
Other Purposes Of Sidepods
The sidepods on an F1 car also serve a few other purposes, including housing various electronic components, and also the side impact structures, which are important safety features. But the focus of this article will be on their cooling and aerodynamic functions.
I’ll talk more about how sidepods help with cooling soon, but let’s first talk about the role they play in downforce production, as that has been subject of much discussion in the last few years in particular.
How Sidepods Help With Aerodynamics In F1
The sidepods on an F1 car play a key role in the aerodynamics and downforce production capabilities of the cars. They are used to help generate some outwash (more on that soon) and to manipulate the airflow over and to the back of the car. They do this using ‘flow fields.’
Many of the teams use wide sidepods to create a flow field going towards the rear tires, which serves two purposes:
- Pushing the front wheel wake away from the car to avoid disturbing the aerodynamics at the rear
- Creating less pressure buildup at the rear tires, resulting in less drag
This helps the cars maximize downforce production at the rear of the car, helping with traction and overall performance. But to get a better understanding of how sidepods produce downforce and why they look the way they do, we can turn to the rule changes that came into force in 2022.
How The 2022 Regulations Affected Sidepod Design In F1
The 2022 regulation changes completely altered the way many parts of an F1 car look and operate. The sidepods and surrounding areas were a particularly striking example of this. It also yielded many interesting designs that got F1 media and fans alike excited about how each team approached things.
For example, we had the scooped designs of Ferrari compared to the massive undercut on the Red Bull (see the image a bit later on). But there were several reasons the sidepods changed so much in 2022 and beyond.
No More Bargeboards
Noticeable components missing from the current F1 cars when compared to the years leading up to the rule changes are the complex bargeboards. These were intricate structures used to manipulate airflow and improve downforce production, but the 2022 rule changes banned them. This meant the sides of the cars began to look very different.
The new regulations essentially allow the teams to have longer sidepods to reduce some of the aerodynamic losses as a result of the bargeboard ban (although that’s not the only reason teams might use longer sidepods). Bargeboards generated a lot of outwash, which helped manage the wake off the front wheels and seal the underfloor for improved downforce production.
Differing Designs
With bargeboards gone, teams now had to rely somewhat on their sidepod design to deal with the front wheel wake and ‘feed’ the underfloor to produce downforce. For example, Ferrari designed the underside of the inlet of their sidepods to create a high-pressure area that helped push the front wheel wake outwards very early, and it also helped feed the underfloor.
On the other hand, Mercedes used the bargeboard-like strake of the inlet of the underfloor and a downwashing wing in front of their sidepod inlet, which generates some outwash (but less than Ferrari’s solution). We saw how much Mercedes struggled compared to previous years, and how Ferrari’s design helped them win races at the start of the 2022 season.
Key Fact: Things obviously changed for Ferrari when Technical Directive 39 came into play
This illustrates that sidepod design plays a key part in the performance of the car, but there are lots of other things to consider that can prevent teams from just copying what works for other teams. They need to think about the packaging of other parts of their car, how other components affect airflow, and of course the costs of the development race.
No More Y250 Vortex Either
But going back to how the 2022 rules changed things, they drastically reduced the teams’ abilities to create outwash to keep the front wheel wake away from the car and to seal the underfloor aerodynamically (especially with the absence of the Y250 vortex). This vortex is gone as a result of the elimination of the gap between the nose and the inner edges of the front wing.
The longer sidepods we now see and various components that generate ‘edge vortices’ are used to stabilize airflow under the car and to seal the floor.
So, the sidepods changed drastically in 2022 largely to help generate some outwash and keep the front wheel wake and other sources of turbulent air away from the cars’ various aerodynamic devices.
What Does Undercut Mean On F1 Sidepods?
Undercuts on F1 sidepods are essentially areas where the sidepods are cut out below the radiator intake, or towards the rear of the sidepod. This results in a shape where the sidepod is narrower towards the floor of the car, as if the underside of the sidepod has been ‘cut out.’
Many teams employ an undercut sidepod design, the extent of which varies between the cars. Red Bull are one team that use a clearly visible undercut, which you can see in the image below, with the white arrow illustrating where the undercut begins. This helps channel the airflow to the rear of the car for better downforce production, but there are lots of different ways to approach undercuts, and teams use them to varying extents.
What Are Scallops/Bathtubs On F1 Sidepods?
Scallops on F1 car sidepods are essentially areas of the sidepod that dip down to create a depression in the sidepod, reflecting the shape of a scallop. These ‘scooped out’ sections serve a purpose of redirecting airflow in various ways over the rear of the car.
The first example of scallops on F1 car sidepods under the new regulations came when Ferrari first released images of their 2022 car. The Ferrari’s sidepods were sort of scooped out and curved as the sidepods run towards the rear of the car.
Ferrari’s Scalloped Sidepod Design
The Ferrari F1-75’s ‘bathtub’ sidepod design worked with the diffuser ramp’s upper surface to form an area of high pressure at the back of the car. This added rear downforce directly to the floor, but it also increased the pressure at the rear of the sidepod, decreasing drag. Lower drag and increased downforce is the ideal combination!
However, this again illustrates just how much is at play on an F1 car when we’re talking about performance. It’s not all down to the sidepods, otherwise you might expect Ferrari’s sidepods to have won them every race! Part of the beauty of Formula 1 is the complexity and how there is no one solution to every problem, which is why we see so much diversity in the car designs.
How Do Sidepods Help With Cooling?
Sidepods help with engine cooling as they direct airflow into the internals and the radiators. In order to keep the engine cool (along with the various other hot components that I listed earlier), the radiators need air to be funneled onto them, just like radiators in your average road car. Sidepods do this funneling.
Road cars have their radiators placed directly behind the grill on the hood of the car where it can catch as much fresh air as possible. Radiators provide an interface for cooling fluid within the radiator with air outside the radiator. Coolant flows through and around the engine, absorbing some of the heat energy, and then it flows back through the radiators.
How A Car Radiator Works In Simple Terms
The cool air passing over the radiator when the car is travelling at speed absorbs some of the energy from the coolant within the radiator, and the large surface area of radiators allows for a relatively large amount of heat transfer from the hot coolant to the cool air outside.
This allows the coolant to remain ‘cool’ (relatively speaking) and continue to perform its job – keeping the engine temperature within an ideal operating window. The radiators in F1 cars do the same job as radiators on your average road car.
F1 Car Radiators
However, there is no space for radiators on the front of a Formula 1 car. That’s where the aerodynamic, downforce producing front wing goes. In addition, the engine sits at the rear of the car right behind the driver. It’s always better to have the radiators as close as possible to the engine, which is why they are built into the sidepods. The front wing and the nose help funnel air into the sidepods for cooling.
Key Fact: F1 car radiators have a much bigger surface area than a road car’s, due to the massive cooling requirements of these high-speed machines
Ejecting The Hot Air
The air that rushes into the sidepods cools the engine, but quickly heats up due to the high engine temperature. That air still needs to be sent out of the car to prevent it from overheating the engine. Hot gases from the combustion process inside the engine are sent through the exhaust pipe, which ejects the hot air out towards the back of the car, like the exhaust on your average road car.
But what about the hot air that has passed through the sidepods and radiators?
There have been some rule changes in the past that affected how teams could implement outlets on their sidepods. They’re a must for letting the air flow out of the sidepod after interacting with the radiator, but doing this in different ways can help or hinder a car’s aerodynamics.
One rule change came in 2009, when teams had to use ‘closed sidepods’ with limited areas where they could use outlets. But now we see teams employ various strategies, with cooling slats or ‘louvres’ being used on the sidepods of many of the cars (although these are also often found on the engine covers).
Cooling Slats On F1 Cars
The hot air that is ejected from these cooling slats doesn’t have a lot of usable ‘energy’ (even though it is hot, we’re talking about energy in terms of its use for downforce production), meaning it can be extremely disruptive to the aerodynamics of the rear of the car if it is not carefully controlled (see our guide on dirty air for more on this).
Managing the hot air that comes out of the sidepods when teams use cooling slats is therefore a very important aspect of the 2022 F1 car designs.
Note: If you want to learn more about the ways F1 cars manage their temperatures, check out our full guide to cooling in Formula 1
Final Thoughts
Sidepods on F1 cars serve two very important purposes. They are important aerodynamic components, and they help produce a lot of the car’s downforce. They also house the car’s radiators, and so they also play a key role in cooling the internals, like the engine and hybrid unit.
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