Brawn BGP001 - rear diffuser design 09 April 2009
Brawn have a quite different central channel to their diffuser, with the shape of the deformable structure being used to create a sort of double-decker (black arrows) design. However, the most important and controversial aspect is that to work properly this section of the diffuser needs to be fed by air. Highlighted in yellow, you can easily see the hole in the reference plane (red arrow), which actually starts far further forward than is apparent from the drawing, thanks to the small dimensions of the gearbox. The hole increases the speed of airflow as it heads towards the higher rear venturi section, where it expands and creates more downforce. Other teams are arguing that the presence of the hole is against the regulations.