Porpoising

Porpoising is a repetitive bouncing motion that occurs in racing cars at high speeds, where the vehicle rapidly moves up and down like a porpoise jumping through water, caused by an imbalance in the aerodynamic forces underneath the car.

This phenomenon became particularly noticeable in Formula 1 racing when new regulations in 2022 brought back ground effect aerodynamics. Ground effect is a clever way racing cars create downforce by using the air flowing underneath them. The car's floor is designed like an upside-down airplane wing, with special tunnels that speed up the air and create a low-pressure zone that literally sucks the car down onto the track.

Porpoising happens because of a cycle that repeats itself over and over. When the car goes fast, it generates lots of downforce and gets pulled closer to the ground. But when it gets too close, the smooth airflow underneath suddenly becomes turbulent and stops working properly—this is called an aerodynamic stall. When this happens, the car loses its suction and bounces upward.

Once the car rises slightly, there's more space between the floor and the track again, so the airflow recovers and starts working normally. This pulls the car back down, and the whole cycle starts again. This continuous bouncing can happen multiple times per second, creating a very uncomfortable and potentially dangerous situation for the driver.

Several factors make porpoising more or less likely to occur. The ride height, which is simply how far the bottom of the car sits above the ground, plays a huge role. Teams want to run their cars as low as possible to maximize downforce, but this increases the risk of porpoising. The car's suspension setup and the specific design of the floor also affect whether porpoising will happen.

The impacts of porpoising are serious. Drivers experience violent shaking that can cause physical discomfort, back pain, and extreme fatigue during a race. It also makes the car harder to control, especially when braking or going through fast corners. The constant bouncing can reduce the car's grip on the track and wear out tires faster than normal.

Teams have several ways to reduce or eliminate porpoising. The simplest solution is raising the ride height, which gives the airflow more room to work without stalling. However, this also means less downforce and slower cornering speeds, so teams must find a careful balance. Engineers can also adjust the suspension to be stiffer or modify the floor design to make the airflow more stable.

Interestingly, porpoising isn't new to motorsport. It was a common problem in the late 1970s and early 1980s when ground effect cars first appeared in Formula 1. The issue largely disappeared when regulations changed, but it came back in 2022 with the return of ground effect aerodynamics. Racing authorities have since introduced new rules requiring teams to monitor porpoising with sensors and have made technical changes to help reduce the problem, including raising minimum ride heights and strengthening certain parts of the car's floor.