After the fuss over the Red Bull front wing over the last few years and the infamous fluttery wing that Ferrari were seen to be testing last year it appears McLaren have their own more subtle interpretation. The following image is a comparison of the Red Bull, McLaren and Ferrari cars accelerating down the straight from Turns 2 to 3 in Melbourne.
The end plate of the McLaren is tipping back, a small but noticeable amount. This isn't the only image of the effect, there are some from testing showing a dramatic change, it certainly suggests McLaren are doing something. Yet the rules this year are even more stringent on flex across the wing in an attempt to prevent the teams attempting these sort of designs.
It will be interesting to see if this story develops like the Mercedes "F Duct", "W Duct" Super DRS whatever you want to call it!