Well, it has to happen sometime right? It can't be all the time that McLaren gets a beating or is blamed for something. This time they've done something ingenious and everybody, in true F1 style, has either decided to accept that McLaren came up with a damn good idea and have to copy it or make a lot of noise and try to get it banned.
I still don't understand what the device is. Explanations range from "works by the drivers blocking a pipe in their cockpit with their knees" to "the drivers themselves - who are not classified as an aerodynamic device, moveable or otherwise - who operate the flap by using their right knee to cover the flow of air into the cockpit tunnel. This in turn effects the flow of air to the rear of the car and 'stalls' the rear wing."
It's believed that the advantage accrued from the device amounts to approximately an extra 6mph on the straights when the cars are running at top speed. Which is all well and good. That is what F1 is all about. Coming up with engineering ideas to solve difficult problems and gaining an advantage.
James Allen has a very clear analysis about the McLaren wing, how it works but I still don't get it. There is a close up photo of the rear wing with a drawing as well which clearly shows the detail of the rear part of the car. It is no normal shark fin engine cover I can tell you. Click here to read more.