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Re: Reducing the drag of a two element wing through stall
Posted: 04 Mar 2010, 14:27
by impaero
Either 'stall' means something different in F1 compared to convention or I've got things mixed up.
This makes much more sense to me:
Well, the airlow travelling along the back face of a foil has a tendacy to detach itself at the thickest part of the section - limiting the maximum downforce for a given foil profile and AoA. However, if you introduce a thin layer of turbulance at that thickest part of section the flow will stay "attached" for much longer increasing the max downforce for the same profile and AoA.
So in a nutshell McLaren can run less wing (less drag) yet still get decent levels of downforce.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 14:38
by hollus
You cannot protest the legality of a car until there is a race. That will be the 12th of march, I guess, or maybe the 14th. Hence the clarifications instead of protests. Have you all forgotten when the Browns got challenged last year?
Re: Reducing the drag of a two element wing through stall
Posted: 04 Mar 2010, 14:51
by hollus
impaero wrote:Either 'stall' means something different in F1 compared to convention or I've got things mixed up.
This makes much more sense to me:
Well, the airlow travelling along the back face of a foil has a tendacy to detach itself at the thickest part of the section - limiting the maximum downforce for a given foil profile and AoA. However, if you introduce a thin layer of turbulance at that thickest part of section the flow will stay "attached" for much longer increasing the max downforce for the same profile and AoA.
So in a nutshell McLaren can run less wing (less drag) yet still get decent levels of downforce.
That is correct. If they have gotten a very efficeint blown wing that is always on, they get a better lift to drag ratio in all conditions, and that would explain by itself the higher maximum speeds. I think something like that brought BMW back to competitive times lst year.
But, then, it doesn't disprove that there may be ALSO some sort of active control to stall the wing in the straghts.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 14:57
by hollus
While far from proven, I think many people here like me are coming to a consensus that this might all be controlled by squeezing a tube fed by the snorkel, somewhere, somehow, likely by the driver.
Does anybody have insight from the rules on whether that (squeezing a tube) would be considerd "movable aero"?
Bieng internal is not an argument, Renault's mass dampers weren't even in teh airflow and got banned.
I can see how squeezing a tube in the cockpit is not conceptually different to turning the steering wheel. Both are actions by the dirver that alter the geometry of some object in the airflow (air even runs through certain parts of the steering wheel, not just around).
I have the feeling that this will come down to semantics as finely cut as last years "slots" that were not holes to feed the double decker difussers.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:08
by ing
pete555 wrote:Red bull may more relaxed about this as they are already running a fin which is integrated into the design.(meaning less work to evolve the concept)
Whereas Ferrari have to
A: Develop a fin that works in tandem with their race spec bodywork
B: Then make the blown wing work
They all have to increase the scoop size if they want to feed the slot that way but the roll structure has to be homologated before the 1st race.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:21
by timbo
ing wrote:pete555 wrote:Red bull may more relaxed about this as they are already running a fin which is integrated into the design.(meaning less work to evolve the concept)
Whereas Ferrari have to
A: Develop a fin that works in tandem with their race spec bodywork
B: Then make the blown wing work
They all have to increase the scoop size if they want to feed the slot that way but the roll structure has to be homologated before the 1st race.
They can add intakes a la Williams
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:27
by Pedro
axle wrote:It's not the slot in the wing that's being questioned...it's the way it's fed/controlled.
Williams, Sauber and McLaren are all using the slot idea but the feed of the McLaren is the unique part.
What would be so questionable about feeding it via sharkfin? Seems nothing irregular to me.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:47
by thestig84
Pedro wrote:axle wrote:It's not the slot in the wing that's being questioned...it's the way it's fed/controlled.
Williams, Sauber and McLaren are all using the slot idea but the feed of the McLaren is the unique part.
What would be so questionable about feeding it via sharkfin? Seems nothing irregular to me.
As axle just said its not the feeding via the shark fin that is questionable its more how its being controlled. Williams and Sauber cant control their feed to the slot.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:49
by forty-two
thestig84 wrote:Pedro wrote:axle wrote:It's not the slot in the wing that's being questioned...it's the way it's fed/controlled.
Williams, Sauber and McLaren are all using the slot idea but the feed of the McLaren is the unique part.
What would be so questionable about feeding it via sharkfin? Seems nothing irregular to me.
As axle just said its not the feeding via the shark fin that is questionable its more how its being controlled. Williams and Sauber cant control their feed to the slot.
And nobody has any proof that McLaren can either.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:52
by thestig84
forty-two wrote:
And nobody has any proof that McLaren can either.
No, but one would assume that is the reason. As like has previously been said Williams and Sauber versions seem to be fine.
Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:55
by Hangaku
Indeed, how do we know that all these discussions about the snorkel, what it feeds, and how that is controlled, isn't the very thing that caused Ferrari and Red Bull to ask for clarification in the first place?

Re: Vodafone Mclaren Mercedes MP4/25
Posted: 04 Mar 2010, 15:59
by Confused_Andy
This was going to be disputed sooner or later, i just hope whitmarsh aint signed anything as stupid to say they can use a controlled system and it just turns out to be uncontrolled.
We dont need another sequel to FIA vs McLaren.
Re: Reducing the drag of a two element wing through stall
Posted: 04 Mar 2010, 16:22
by horse
Hi guys,
I thought I might to have a go at explaining what I think is happening. I think it very much relies on there being two elements to the wing. To illustrate, consider the two element wing, operating not in stall:
My idea here is that the two elements have a combined chord line, which produces a steep angle of attack. Hence, the forces generated by the wing combine to produce both down force and drag. Now consider the situation where only the top element is in stall:
Here, the elements can be considered separately. We see the force vector of the main element is producing mostly DF and the flap in stall is producing mostly drag. I think the argument goes that because the flap is small compared to the main element, then the combined drag of this system will be less than the drag from the wing operating as one seen in the first figure. That's my guess anyway.
Please note that the length of the vectors are just for illustration.
Please be nice.

Re: Reducing the drag of a two element wing through stall
Posted: 04 Mar 2010, 16:34
by hollus
I think that is the idea. If the wing had just the first element, it would behave much like that of a plane. But the second element just has a monster angle of attack, and there is no way the second element will produce downforce without also produding a lot of drag.
So you can have the second element (or the whole wing, it is the same for discussion purposes) working nicely, with attached flow, producing masses of downforce and a lot of drag, or you can stall it, produce very little downforce and moderate drag. The word "moderate" being relative, of course.
I see it pretty much the same way as you.
Re: Reducing the drag of a two element wing through stall
Posted: 04 Mar 2010, 16:35
by pgj