NOTE: Update on McLarens Snorkel\Rear wing here http://wp.me/sNdA9-235
As McLaren continue to use testing rigs to map their cars aerodynamics, the importance of the snorkel on the top of the chassis is becoming apparent. On Friday The car lapped with an array of sensors attached to the rear wing. However, there was an additional sensor mounted inside the snorkel. Raising the question why would you want to test rear wing and driver cooling simultaneously?
This Snorkel, is an apparently innocuous looking part, which was at first believed to be solely an inlet to cool the cockpit. Several teams add similar inlets in this area to supplement the inlet in the tip of the nose. The cockpit houses the power steering rack, hydraulic lines and electronics boxes, so cooling is often required. However the initially simple inlet has been superceded by at least two more shapely snorkel-like derivatives each with an apparently unnecessarily complex double wall construction creating smooth narrow inlet and a streamlined outer surface. This snorkel has been present ont he car through out all the cold and wet testing sessions, suggestion its purpose goes beyond a simple primary purpose of cooling.
One rumour around the internet suggests the inlet is linked by a duct to the shark fin\blown rear wing. At first appearing to be simply a wild rumour, that the snorkel is blocked by the drivers knee to alter the rear wing airflow. However the presence of the airflow sensor along with the rear wing test rig, suggests there might be a link after all. The rumours suggest the drivers left braking leg, which sits unused on long straights could be used to alter the flow from the snorkel to the rear wing duct, where a valve alters flow through the blown slot to stall the rear wing. This would reduce downforce and also drag, which would allow a higher top speed. Then the driver moves his leg to start to brake for the next turn the valve switches airflow back to normal, the wings airflow reattaches and provides the downforce needed for the turns. This sounds both feasible and far-fetched at the same time.
It would be hard to link the rear wing and snorkel with any certainty, but any input from the driver that would alter the cars aerodynamics as the rumours suggest would certainly be an area of greyness in the rules and liable to protest come Bahrain.
Scarbsf1's Blog 
A valve would surely fall under the whole “moveable aerodynamic device” clause as it is actually defined?
“This sounds both feasible and far-fetched at the same time.”
It sounds crazy to me to rely on the driver to do yet another thing on top of driving, managing tyres, brakes and temperatures. Oh, and operating tiny dials while your eyeballs can’t even focus properly on anything. But somehow, I love the idea of the input that the human body can have on the car. It would be comparable to moto riders hiding behind their windscreen on the straights and sitting up when braking.
Do you see any reason why this should be banned? I don’t. It’s not like there’s the same safety issue that there could have been with flexible wings.
Anyway… I hope we find out more about this… 😉
Who will be the first to get a snap inside the cockpit like the shot of the 3rd brake pedal from 1997?
oh, yeah, well thought of 😉
Couldn’t that airflow pressure also open the gap between rear wing’s upper plate? Which would than decrease the aero efficiency of the wing thus reduce drag.
I’m glad to see you did end up delving a little deeper into this like I suggested Scarbs!
Could you explain in layman terms how stalling a wing can reduce the drag, I though stalling a wing increases the drag on the straights. It’s baffling me and other folks on the AtlasF1 board.
Oh and I don’t think it would fall under MAD rule since it driver’s leg that’s moving, but I thought MAD won’t apply to mass dampers either, and guess what happened.
And since it’s my first comment on this blog: Stellar work, much appreciated.
A wing that has fully stalled loses a lot of downforce, it also loses a lot of drag.
whereas, a wing with some seperation, but not yet stalled, does addd drag.
Could it not be a soft tube the drive press together with the knee and not a valve. This i think will be more legal
Bjørn
That is what I would envisage too, I used the term valve in a loose context as we can’t be sure how this is actually configured.
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to me it seems very strange, I would say impossible, the fact that this inlet is linked with the rear wing. It’s just an unusual way to provide cooling of the car, but I don’t think it has anuthing to do with the rear wing and the fin.
This is of course speculation. I agree it seems far featched. But , I have heard enough to suggest that it is possible.
Equally I have heard the snorkel relates to the suspension and ride height.
Who knows what the truth is..?
I think valve control via braking is not ideal
The important thing is at what speed does the car need to be going in order for the rear wing to stall? and how many long fast corners exceed this stall speed that do not require braking? You do not want stalling in a corner.
If the stall threshold is high enough it wont matter, if it isn’t then I suspect the valve control would be linked to something independent of braking.
I never sugested that it operates under braking. On the straight is the only time the driver would operate this, stalling the wing and adding to the top speed
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