Still at the ‘unproven theory’ stage is the potential function of the supplementary air intake above the drivers head. This had been presumed to be purely to feed an oil cooler, but closer inspection suggests there may be another primary function for this inlet. Allied with the shark fin, the inlet appears to provide airflow to inside the rear wing. Creating a ‘blown slot’ to make the rear wing more effective. Similar to a concept used by BMW Sauber last year.
It looks like McLaren have opened up a slot in the back of the rear wing, this is visible as a blackline above the normal slot between the wing and flap. This slot is fed with air from the inlet and routed inside the shark fin and rear wing flap. The high pressure air exits through the slot and effectively makes the two element rear wing into a three element device. This allows the rear wing to angled more steeply without fear of stalling, thus creating more downforce.
Clues to support this theory is the way McLaren have closed off the inlet, an access hatch inside the shark fin, as well as the bulbous shape of the fin leading towards the rear wing.
As BMW Sauber set a precedent last year with a flap blown by an inlet in the front of the wing, this is a legal approach to circumventing the restriction on the number of elements allowed in the rear wing.