Mclaren Mercedes MP4-25

[Pup]

...it is my understanding that a blown flap will delay the onset of stall. It's as simple as that. How can a blown flap enduce stall (unless the direction of the blow is opposite to the direction of flow? lol)

I think the idea of a stalling blown wing is that it prevents the wing from stalling everywhere but the straight. On the straight, the flow is either cut off, as SLC suggests, or disrupted in some other way, as I think happens - and the wing stalls.

It's actually very similar to a few years back, when the teams were running flexible rear wings. The upper element would flex on the straight, closing the gap between it and the lower element. The two wings become one, and the whole thing stalled - precisely because the lower wing was no longer providing a stream of air to the rear of the upper one. Actually, this would be better, since it would be continuous, and not periodic, like the closed gap concept (where the upper wing would close, then open as the wing stalled, close again, etc.)

The other theory, of course, is that the wing never stalls, and the blowing simply allows for a higher AoA, meaning either greater downforce, or the same downforce with less wing/less drag.

Of course, unless the team issues a press release about it, we'll probably never know for sure which it does.

BTW, some smart people for years here have been saying that stalling the wing is good, which is why I don't dismiss the idea out of hand. It is certainly a counterintuitive concept.

[Pup]

I was referring to the "been working on it for 3 years" bit.

Ah. Well there's the convenient bit - I can't say where I know this!

And, well, that's the suspicious bit. You say you work for an F1 team, and I can believe that. But, if you work for McLaren, you wouldn't come online and say, "Hey everybody, we're cheating and here's what we're doing!"; and if you work for someone else, you wouldn't exactly be in the loop on McLaren's secrets.

[Pup]

dont know if its already said, but i saw those slits from another view(on the sidepods) And i came to an conclusion, it keeps the flow attached to the sidepod(dunno if such an object can stall though).

It was some sort of wing in front of the wing wich allowed it to be run at larger angles to stall, i think that is what it does on the sidepod.

I was thinking the same thing myself. The sidepods slope fairly severely, and these could help in keeping the BL attached.

So yes now we can talk about stalling sidepods.

[astracrazy]

Camera has been moved from front wing mount to engine cover

But looking at this next pic its still on the wing mount


so has one always been on the engine cover?

[dougskullery]

I'm no F1 analyst, but it seems to me that Mclaren have superb one lap pace, but are perhaps lacking a little in consistency over a race distance. Ferrari the opposite.

[Pup]

so has one always been on the engine cover?

It's new. Hope it doesn't stay there - I doubt Mobil would be pleased.

[jason.parker.86]

Now Merc have dumped Macca; They seem to be thinking alot more outside of the box. They have never been this "inventive". Merc probally been holding them back

[SLC]

I was referring to the "been working on it for 3 years" bit.

Ah. Well there's the convenient bit - I can't say where I know this!

And, well, that's the suspicious bit. You say you work for an F1 team, and I can believe that. But, if you work for McLaren, you wouldn't come online and say, "Hey everybody, we're cheating and here's what we're doing!"; and if you work for someone else, you wouldn't exactly be in the loop on McLaren's secrets.

I don't work for McLaren.

The paddock is like a swirling high school rumour and gossip pit - people like to brag. After a while everyone pretty much knows everything.

Oh and it's not cheating - this system (although yes, I don't know any specifics) is almost certainly 100% legal, at least according to the letter of the law.

[Pup]

Fair enough. So when you say it would be legal, is that because there are no moving parts?

[PlatinumZealot]

The only problem I have with the stalling idea is this:

And please note SLC I'm not flaming you or attacking you, I'm simply stating wat I know and would like to be enlightened if possible.

I've got a BEng(hons) in Aerospace Engineering, so I do know about aerodynamics, tho I DO NOT have the knowledge that SLC has.

But it is my understanding that a blown flap will delay the onset of stall. It's as simple as that. How can a blown flap enduce stall (unless the direction of the blow is opposite to the direction of flow? lol)

Furthermore, fundamentally, if I wing is stalling it increases drag, simple as.

Obviously there could be far more complex things going on here than I understand, hence my asking. (For example imagine my suprise when I first learn of compressible flow, when a divergent nozzle actually INCREASES flow velocity lol)

But to my knowledge those two point I make, make the whole concept of deliberatly stalling a wing seem not only pointless to an F1 team but also counter-productive.

The angle of attack doesn't change, so maybe the behaviour is not similar to a plane wing. Those airfoil graphs have angle of attack on the X axis right? So you see what I'm saying? Something to think about.

[Pup]

The angle of attack doesn't change, so maybe the behaviour is not similar to a plane wing. Those airfoil graphs have angle of attack on the X axis right? So you see what I'm saying? Something to think about.

I think the only time an aircraft wing resembles anything like an F1 wing is during landing - flaps and slots fully extended and the wing cambered like crazy. Even then, the angle of attack is nothing like that of an F1 wing. And yes, in F1 you don't have the luxury of flattening out the wing and reducing the AoA as you go faster, like in a plane.

So that's why I say that it has to be the wing's induced drag that creates the counterintuitive condition of a stalled wing having less total drag. If you think about the AoA of an F1 wing, it likely produces more induced drag than downforce. I mean, if a wing produces 100lb of force at a given speed, and has an AoA of 70°, then it's only giving you 34lb of downforce, but 94lb of induced drag. OK, so the direction of lift isn't 1:1 with the AoA, but still. So, in theory, a stall wouldn't create enough added form drag to counter the fact that the wing is no longer working against you. Net win.

This should probably all go into Horse's thread in the Aero section, too.

[autogyro]

The angle of attack doesn't change, so maybe the behaviour is not similar to a plane wing. Those airfoil graphs have angle of attack on the X axis right? So you see what I'm saying? Something to think about.

I think the only time an aircraft wing resembles anything like an F1 wing is during landing - flaps and slots fully extended and the wing cambered like crazy. Even then, the angle of attack is nothing like that of an F1 wing. And yes, in F1 you don't have the luxury of flattening out the wing and reducing the AoA as you go faster, like in a plane.

So that's why I say that it has to be the wing's induced drag that creates the counterintuitive condition of a stalled wing having less total drag. If you think about the AoA of an F1 wing, it likely produces more induced drag than downforce. I mean, if a wing produces 100lb of force at a given speed, and has an AoA of 70°, then it's only giving you 34lb of downforce, but 94lb of induced drag. OK, so the direction of lift isn't 1:1 with the AoA, but still. So, in theory, a stall wouldn't create enough added form drag to counter the fact that the wing is no longer working against you. Net win.

With those figures for DF and induced drag, surely they are doing something wrong!

[Pup]

With those figures for DF and induced drag, surely they are doing something wrong!

Well, my high school math teachers would have a different theory.

But while I wouldn't place any bets on my numbers, I do suspect that the overall theory is sound. That is, that F1 designers are more than happy to trade off drag for downforce. Let the engine guys worry about the drag.

Except, that is, when the downforce isn't doing anything for you; i.e., on the straight.

[ringo]

@Ringo, perhaps I am wrong about the condition of the flow behind the wing? If it is already separated at the injection point, then my ideas don't really hold and perhaps injection into the flow (but not in a blown flap sense) would have a positive impact. I'm well out of my league now though.

EDIT: This might be a better attempt. Dashed lines show the resultant in the direction of interest.

The jet would not add to the drag, since it's not the same thing, The jet vector should also be in the opposite direction, since it's the reaction force on the wing that counts. That is a different thing altogether still.
My idea was more about pressure; pressure is not a vector quantity. However it can act on surfaces to create motion in a direction. I was thinking more like a hydraulic cylinder, the plunger will move toward the side with lower pressure. Equal pressure on both sides and the net force on the plunger is zero.

[ringo]

Stall one element and the whole wing, including the lower wing stalls.

Stall teh entre wing and the diffusor chokes resulting in a rapid increase in pressure under the car and this makes it extremely unstable.

Someone tried to debunk my effect being similar to removal of the rear wing and missed the point. The oint is that both cases result in a sudden and massive disruption in flow around the car. Thats why when the wing falls off, cars spin off the road or at lest gives the driver more than hand full of fish tailing to contend with. Downforce at high speed is vitally important. If this stalling concept was so fantastic why do they not run stalled wings at Monza...? I rest my case.

You want enough downforce to keep the tail down, and maintain aero balance near the COG that's it. The diffuser does not choke either. When a wing breaks off and the car fish tails, that has many reasons:

the endplates go as well with the wing.
The end plates provide yaw stability with their surface area.
Just like the vertical tail on an plane.

The car has a raked floor, when the wing goes, the tail lift's more, the splitter floor is pitched down into the boundary layer and Ground effect is disturbed.

And to add to this, note the MP4 25 has a fin too, to add more area for yaw stability at high speed.

At Monza they run a wing closer to no wing at all, that is what I am looking at. Stalling is not my main argument.

Ringo, shooting a hole in the wing does not result in a pressure equalisation. for that to occur, you would need to shoot enough holes into the wing so that the surface area of the wing is reduced sufficiently to not suspend the mass of the aircraft so its not a good analogy. even if I drill a hole through the M4/25 rear wing, the wing will still produce massive downforce because.
- the pressure equalisation does not occur
- there is a still a massive vertical displacement of air /sec.

I also tested this out one of my park flyers. I drilled holes into the wingeverywhere this morning and took it for a flight. Hey its still flies... it requires a bit of up trim but it still flies. So how do you explan this? The airflow over the wing is fast enough for pressure equalisation not be significant.

Your park flyer doesn't stall because of the Reynolds number, micro scale flying is completely different concept than high Reynold's number. Take a Moth's wings for instance, they are rough, dusty, fuzzy and tattered, this works at that small scale but we can't apply rough and fuzzy wings to commercial airliners to increase performance. We do the opposite and polish them down.

When i said a hole, i meant more like a huge rip along the wing, sorry about that. The pressure equalization will occur, in the same way that an engine will lose vacuum if there are any leaks, it will try to equalize with the atmosphere; adhering to the law of entropy.

and no I do not believe in the stalled wing concept and I never will. Its science fiction and I think it was created by James Allen.

We don't know if it's science fiction yet.
Touch screen computers were science fiction in the 70s with star trek. Now we have this I pad thing and I phones.

No body that would like to move through the air wants to "Stall", not even bee's.
If Stall was desired, mother nature would have invented it. Wait, actually she did, when birds land they essentially stall their wings and use it as an airbrake.
Other useful applications of stalled wings are airbrakes on aircraft.
Stall is useful for slowing things down, not speeding them up.

right now I'm off to the Hobby store to buy new wings for my Wilga

Ahh!!! gimme a sec..... *runs to dig up some Nat. Geographic videos*

[youtube]http://www.youtube.com/watch?v=j3mTPEuFcWk[/youtube]

Perfect example of RAW straight line speed! Stalling can be good in nature

The problem we are having is the use of the word stall. I am of the opinion a wing can be "stalled" where lift and drag is reduced. Similar to this bird, pressure is equal on both sides of the bird's wings, she is not not moving to the left or right, just down.

video narator: "When it comes to raw speed no creature on earth can match the MP4 25!! "