What is an F1 aero rake?

Just when you’re expecting to finally glimpse the new season’s F1 cars, teams send them out covered in lightweight scaffolding.

The first day of testing almost always sees the appearance of fence-like structures hanging off the cars. Usually attached just behind the front axle or around the rear axle and diffuser, these fences are known as aerodynamic rakes and measure the air pressure over the car at any one point.

All of the teams will run an aero rake at some point during testing as they look to ensure there is correlation between their wind tunnel simulations and real on-track running.

With a minimal amount of testing allowed, designers rely on simulations to ensure that they are going in the right direction. But it’s only when the cars pull out of the pitlane that they will know whether their data is replicated in the real-world.

If there’s a discrepancy between them, then teams could have spent all winter heading down a dead end and a rapid trip back to the drawing board could be in order.

Here are the full details on how aero rakes work.

What is an F1 aero rake?

Made from special alloys such as titanium, the aero rakes used by F1 teams are capable of registering multiple readings in real time and feeding them back to engineers while the car is out on track.

Multiple Kiel probes are attached to the metal fence. These measure airflow pressure from almost any angle of attack, so are resistant to changes in direction of airflow — unlike pitot tubes.

Because of this, the readings give engineers a clear view of how air is channelled over the bodywork and aerodynamic components.

Rakes can vary from as little as 50mm all the way to 600mm in length.

How does an aero rake work?

The aero fence is comprised of Kiel probes that register the flow of air over each data point.

Each probe is shrouded by a protector shield with the probe itself registering the pressure of the air which is then fed back to teams and engineers live.

Kiel probes are useful for Formula 1 teams because they are less sensitive to changes in yaw angle than pitot tubes, which measure air pressure on aircraft. This is handy when the cars in question are capable of pulling 5g through some corners before immediately flicking into the opposite direction for the next.

All of the captured data is the used to formulate a virtual map of the airflow travelling over the car while it’s in motion.

The accuracy of an aero rake is in the range of 10 microns, or 0.01mm.