Dirty Air vs Slipstream

Have you heard the terms “Dirty Air” and “Slipstream” when watching a Formula 1 race but don’t understand the difference? I’m here to explain. Let’s take a look at car aerodynamics.

(Image credits to Kym IIIman)

Slipstream

Slipstreaming occurs when an F1 car follows closely behind another, providing less aerodynamic drag and allowing the following car to gain significant speed. But how? Well, it all has to do with airflow. Formula 1 cars are built with exceptional aerodynamics; they need to be able to go fast while also maintaining stability on the ground. This is achieved through “drag” or “downforce.” The less the drag, the quicker the car will go. As an F1 car speeds down a straight, the airflow pulls the car along the track. When following an F1 car, there is less airflow pulling the car down, which creates less drag, making the car lighter and allowing it to go faster. This is why you can see a 6-tenth gap go down to 2 or 3 tenths just on a straight.

Dirty Air

Now you may be thinking, “If slipstream is so good, then why wouldn’t you always want to follow closely to the car in front?” While slipstream is very useful, following closely behind isn’t always so great. The term for this phenomenon is “Dirty Air”, which occurs when an F1 car follows closely behind another, but suffers an impact in corners. As I mentioned, downforce is essential for keeping the car on track. When following closely, there is reduced drag, but in the corners, that downforce is necessary to help the cars stay on track and take corners faster. With that reduced drag, the cars are a lot more likely to slide and have no grip, which also results in higher tyre degradation. This is why most of the time you’ll see cars getting super close on long straights, but as they go through the corners, the following car may slide and drop off the back of them. 

Conclusion

Dirty Air and Slipstream are similar, but they occur in different areas: Slipstream in the straights and Dirty Air in the corners, with opposite effects. Both play a huge role in overtaking. Tracks with long straights, for instance, allow for more slipstreaming, which aids overtaking. In contrast, tracks with more corners create more dirty Air, making overtaking more challenging.

Article written by Haley Hall