Do you know what that L-shaped tube on an F1 car, which looks like an antenna, is used for? And what about its variation, the so-called “aero rake” that we often see—how does it work? In today’s F1 science explainer, let’s uncover the mystery behind these aerodynamic measurement tools.
Let’s start with the basics. That L-shaped tube is officially called a Pitot tube, also known as an airspeed tube. As the name suggests, its core function is to measure airspeed. But what is airspeed, and how does it differ from the speed we usually talk about, such as those measured by GPS or wheel sensors?
Airspeed refers to the speed of the car relative to the surrounding air. Imagine two F1 cars both running at 300 km/h ground speed on a straight. If one car happens to have a 10 km/h tailwind, its airspeed would only be 290 km/h, while the other car in still air—or even in a headwind—might have an airspeed of 300 km/h or higher. For teams, knowing the real-time airspeed is extremely important when analyzing the actual aerodynamic performance of the car, validating CFD simulations and wind tunnel results, and guiding future development and setup strategies.
The Pitot tube itself has a long history, dating back to the early 18th century when French engineer Henri Pitot invented it while working on hydraulic engineering projects. Today it is widely used in aerospace. With aerodynamics becoming central in F1, Pitot tubes also became standard equipment on racing cars.
While the design may vary across teams, the working principle is the same. At the very tip of the Pitot tube is a small hole facing directly into the airflow. As the car speeds along, the incoming airflow rushes into this hole and is brought to zero velocity inside the tube. The pressure measured here is the total pressure, which includes both the static atmospheric pressure and the pressure caused by airflow speed. Small side holes measure the static pressure of the surrounding air, unaffected by direct impact.
Inside, the tube is connected to precision pressure sensors, which continuously record total and static pressure values. Based on Bernoulli’s principle, total pressure equals static pressure plus dynamic pressure. By subtracting the two, engineers can calculate dynamic pressure. Using the formula for dynamic pressure and factoring in air density (which itself depends on temperature, atmospheric pressure, and humidity—monitored by other sensors), the teams can precisely calculate the car’s airspeed.
But there’s a catch: a single Pitot tube can only measure the airflow directly in front of it. This is useful, but when a car is cornering or hit by crosswinds, the fixed orientation limits its accuracy. Also, teams often want to understand not just one point’s airspeed but the entire airflow field around the car. This is where the aero rake—nicknamed the “barbecue rack”—comes into play.
We often see these in pre-season testing or practice sessions after major upgrades, like last week’s Spanish Grand Prix, where teams such as Williams and RB used them to evaluate new front wing performance. Technically called an aero rake, it is usually installed in critical airflow zones such as behind the front wing, near the sidepod inlets, around the diffuser, or in front of the rear wing.
Structurally, an aero rake is a metal frame fitted with dozens, or even hundreds, of Kiel probes—an advanced form of Pitot tube. Each probe has a shroud that makes it less sensitive to flow direction, allowing it to measure airflow within about a 60-degree range. These probes are connected to sensors via cables, transmitting data in real time. Engineers then generate pressure distribution maps across key cross-sections, visualizing how airflow passes over the car’s surfaces, locating high- and low-pressure zones, and identifying turbulence that affects performance.
To improve efficiency, different teams use various shapes of aero rakes. Ferrari even applies 3D-printed titanium parts that integrate the probe lines into the frame, reducing disturbance to the airflow and allowing more flexible layouts to capture comprehensive data.
And that’s today’s F1 science explainer on Pitot tubes and aero rakes. If we’ve missed anything—or if you’d like to add your own insights—feel free to share in the comments!
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