Red Bull is no longer what it once was in F1. In the first two years under the ground effect regulations, it dominated the field. Then something broke. Nevertheless, several technical solutions introduced by the Milton Keynes team are still being used, as they remain by far the most efficient and rewarding route. Ahead of the Saudi Arabian GP weekend we present a detailed technical analysis of a crucial area of the car, with much to discuss.
The importance of the side extractor on the RB21
The Austrian team’s solution for the floor is currently the ultimate evolution of concepts already introduced last season. Over time, the design has evolved from a less developed macro-component to the much more complex one we see today. Let’s qualitatively explain how airflow wraps around this element and how the former world champion team uses it for various purposes.
The image below encapsulates virtually all the concepts applied in this area. In recent years, cars have suffered from general understeer, as the rear end generated a lot of downforce. The center of pressure—that is, the aerodynamic balance—would shift to the rear, causing a lack of rotation. F1 teams have since worked in various ways to mitigate this tendency.
They have slightly flattened the rear downforce peak, working extensively on the amount of downforce the floor generates in its front section. The main idea is to insert a side extractor that expands the flow laterally, thereby generating downforce, just like a diffuser. This creates a strong peak that helps move the center of pressure (CoP) forward.
In Red Bull’s case, there are five channels to extract air mass from underneath the car. These channels are fed by airflow previously directed at the vertical fences at the entry of the Venturi tunnels. It’s easy to see how crucial these appendages are, especially for proper aerodynamic load generation. That’s precisely why they are frequently updated.
The separation of airflow between sidepods and floor
However, other things also happen during airflow extraction. The channel walls act as wing profiles that generate additional downforce and are precisely oriented in space to align with the local flow direction. So, in addition to extraction—which already creates downforce—there is a notable surplus due to the profiling of these elements.
The “total” downforce is shown by the red resultant (R). A strong vortex is released from this side extractor, sealing the floor when used correctly. Its position is crucial, and even more so is its dynamic behavior. As the car moves, the flow structure changes constantly depending on various angles. Also, it’s known that the floor operates under low pressure.
This effect tends to pull air from the upper surface of the floor toward the component itself. This reduces the amount of clean air that would otherwise flow around the sidepod. To prevent this, Red Bull’s engineers designed the extractor with a specific profile. This configuration allows for both efficient extraction and local pressure increase.
This setup helps create a sort of wall along the edge of the floor, which in turn improves the airflow’s path toward the rear of the car. Essentially, it’s a low-pressure area that better separates what happens near the sidepods from what occurs along the edge of an F1 car’s floor. F1 is complicated—but at the same time, utterly fascinating.
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