The F-Duct: F1's Banned Aero Trick Making a MotoGP Comeback

In 2010, McLaren arrived at the Australian Grand Prix with something the rest of the paddock had not seen before. Hidden within the bodywork of the MP4-25 was a system of internal ducts that could redirect airflow onto the rear wing -- stalling it deliberately, killing drag, and adding straight-line speed.

They called it the F-duct. The FIA banned it before the following season. Fifteen years later, a version of the same concept is reappearing in MotoGP.

The Aerodynamic Principle

Aerodynamic stall in this context means deliberately disrupting the smooth airflow over a wing surface to collapse the downforce it generates. When a wing stalls it stops producing downforce -- but it also stops producing drag. On a long straight where downforce serves no purpose, eliminating that drag translates directly to higher top speed.

The F-duct achieved this by routing a duct from the front of the car, through the cockpit, and into the rear wing. When the duct was open, it directed a jet of air at the wing surface at an angle that disrupted attached airflow and caused the stall.

The Activation Problem

The duct could not always be open. The driver needed to activate it only on straights and close it before braking for corners, where the wing's downforce was needed again.

McLaren's solution was elegant and deliberately difficult to replicate: the driver activated the system by blocking an aperture in the cockpit with their thigh or knee. The blocked inlet changed the internal pressure balance, which triggered the wing stall.

This meant the driver was manually operating an aerodynamic device at speeds exceeding 300 km/h using nothing but their leg. It was legal because there was no mechanical actuator -- just the driver's body. It was also inherently risky, requiring precise timing and physical control under extreme conditions. The FIA banned it for 2011.

The MotoGP Revival: Aprilia's Approach

Aprilia Racing has brought a version of the same concept to MotoGP but solved the activation problem entirely differently. Their system uses the rider's natural body position to control airflow -- no deliberate input required.

When the rider tucks into an aerodynamic position on a straight, their posture alters airflow through internal ducts in the fairing. The ducts change the pressure balance, reducing drag automatically.

In corners, when the rider shifts weight for stability, the same positional change closes the ducts and restores normal aerodynamic behaviour.

No buttons. No dangerous leg movements. The rider's natural racing inputs are the control mechanism. Old concept. New execution.