During the Formula 1 auto racing season of 2010, team McLaren developed an aerodynamic device called an F-Duct. This device was an ingenious way of out-thinking the regulations of the Federation Internationale de l'Automobile (FIA) by providing a means of notably controlling car performance. More specifically, the F-Duct is a device that allows a driver to alter air flow over the car's rear wing in order to gain higher speed on long straight sections of the race track (up to 10 kmph). In general, Formula 1 teams do not share technological details about their cars in order to keep an advantage over other teams. Available public information is vague in nature and does not provide any technical details. This thesis studied the existing F-Duct system and its requirements, including the location of key components and their functions. First, a working concept was proposed, and a simplified model was prepared to test the concept. Wind tunnel testing was performed on a physical model and the data analyzed. Continuous improvements were made to achieve drag reduction through passive flow control. Finally, an improved model was prepared, drag reduction was observed, and wind tunnel data presented.