McLaren MP4-28 - serrated rear wing 20 July 2014
McLaren rushed through a new rear wing assembly for Germany. The endplates feature more louvers on the lower edge and these are increased in length to allow the low-pressure area behind the rear tyre to help scavenge the underfloor for downforce. The small turning vanes on the outside of the endplate (two red arrows on left) help the airflow on its outer surface to travel upwards, reducing the vortex that is created at the upper rear corner of the wing. This vortex creates drag, so these additions will make the wing assembly more efficient. Perhaps more interesting is the serrated slot gap between the rear wing main plane and the flap (two red arrows in centre). This concept has been used before, but as a serrated gurney flap on the trailing edge of the inset Williams assembly from 2004. The serration, primarily on the trailing edge of the main plane, will set up small vortices that when the wing is closed will travel up the undersurface of the rear wing flap, reducing the risk of airflow separation. These small vortices will also help to re-attach the airflow on the underside of the flap when the rear wing closes from its DRS open position, something that can be critical for rear-end stability at the end of a DRS straight.