F-duct

The F-duct was a driver-controlled aerodynamic system used in Formula 1 racing that allowed drivers to reduce drag on their car's rear wing during straightaways, resulting in higher top speeds.

In Formula 1, cars use wings similar to airplane wings, but upside down. These inverted wings push the car down onto the track, creating what's called downforce. This downforce helps the car grip the road better through corners, but it also creates drag—a force that slows the car down. While downforce is essential for taking corners at high speed, it becomes a disadvantage on straight sections of the track where maximum speed is desired.

The F-duct system solved this problem by allowing drivers to temporarily "stall" or deactivate their rear wing when driving in a straight line. The system consisted of a duct—essentially a tube or channel—that ran from an opening at the front of the car to an outlet near the rear wing. By redirecting airflow through this duct to the rear wing, the system disrupted the normal airflow pattern over the wing, reducing both downforce and drag.

To activate the F-duct, drivers would block or unblock a vent inside the cockpit, typically using their hand or knee. When the driver covered the vent, air would be redirected through the duct to the rear wing. When they uncovered it, normal airflow would resume. This gave drivers manual control over when to reduce drag, which they would do on straights to gain speed, then deactivate before corners to restore downforce for better handling.

McLaren introduced the first F-duct system on their MP4-25 car at the start of the 2010 Formula 1 season. The innovation provided a significant performance advantage, with cars gaining approximately 3 to 5 miles per hour in top speed on straightaways. This extra speed made overtaking easier and improved lap times. Other teams, including Ferrari and Renault, quickly developed their own versions of the system once they understood how it worked.

The F-duct existed in a gray area of Formula 1 regulations. Rules prohibited movable aerodynamic devices—parts of the car's bodywork that drivers could adjust to change aerodynamic performance. However, the F-duct technically didn't move any external parts; it only redirected internal airflow. This clever interpretation of the rules allowed teams to use the system during the 2010 season.

Despite its innovative design, the F-duct was banned by Formula 1's governing body, the FIA, after just one season. Officials determined that driver-controlled aerodynamic adjustments violated the spirit of the regulations, even if they technically complied with the letter of the rules. The ban took effect for the 2011 season.

To replace the F-duct and maintain the exciting overtaking opportunities it provided, the FIA introduced the Drag Reduction System, commonly known as DRS. Unlike the F-duct, which drivers could use at any time, DRS can only be activated in designated zones on the track and only when a car is within one second of the car ahead. This system remains in use in Formula 1 today, providing a controlled way to reduce drag and facilitate overtaking.