Reducing the drag of a two element wing through stall

[Giblet]

Thanks for eloquently stating what I was trying to, maybe a bit too hard.

The main thing is when the valve is open, where does the air come from? We know it's not from the as it is too small. The DD inlet on the floor?

If this is how it works, then feeding the wing with air from the diffuser is really smart, partially stalling the diffuser by stealing air, and feeding the blown wing, upon activating the pressure switch with the knee.

If the wing is only fed from the front airbox opening, then what would be the point? the blown part of the wing will always be a at a speed relative to outside airspeed, making the wing not dynamic, which would be the whole point of the exercise.

[Giblet]

His knee will be braced by his foot? His foot can only brace his knee if it's braced itself. And what can he brace his brake foot against other than the brake pedal?

The floor of the car.

Slide back foot, knee goes up. It's the simple geometry of our bodies, and that part makes sense. Legs are not telescopic and do not retract into themselves. The space is so tight anyways, it doesn't have to move far.

Like Dave said, a block could be there to. There are many ways to brace a leg, if it designed that way fro, the get go.

[volarchico]

The F2007 doesn't have an intake in the nose ? Maybe that's why they put the intake where it was (I thought someone else already mentioned this) ?

Yeah, someone already mentioned that, but I was trying to see if there was actually a more definitive answer. This board seems to have lots of well-informed people, so I figured someone must know for certain the purpose behind the F2007's intake...not just a guess. Same as everyone else on here says about the McLaren intake...if it's just for cooling, why mount a duct asymmetrically?

[volarchico]

The floor of the car.

Do they really remove their foot from the pedal? I'm no F1 driver, but that seems like an extraneous motion. Well, unless you need to do that to block/activate the fluidic switch...

[ringo]

I'll keep modifying until i get something. I think i can change some of the geometry of the ducting and the slit it self.

Hey ringo,
Do you know what would happen if you changed the tube that comes from the roll structure a little? I think if you add a nozzle, you could increase the speed of the air coming into the rear wing at some pressure cost.

The tube was effectively a nozzle, it sped up the air near the end, but it was behaving like a compressor because of the restrictive exit. Friction in the tube and bends will also prevent it prom speeding up too much.
I have a new design anyway so i am going to change it up.

I am also aware that Mclaren's wing function would be time dependent, vibration and other factors. That tube could even be some kind of resonator, who knows?

[Raptor22]

Hi guys, just been trough 16 pages of posts and just wanted to add my view. It seems to me that we are divided into two categories on this subject:
1. McLaren have found a way to stall their wing to get less drag
2. Mclaren are using a very effective blown wing resulting in low drag

I'll count myself to the second category. (Pardon my English, but I'm from Belgium so my phrase construction is not always correct).

To me the wing is just an upside down Fowler flap (with only two elements). The slot in the main plane is just to get more air at the suction side of that plane to increase the stall margin (a bit like adding an element to the flap). Because of this very effective Fowler flap, they can work with a rear wing with lower angle of incidence, therefore having a higher finesse (L/D) and higher top speed.

The reason I don't "believe" in the stalled hypothesis is that I have a background in aeronautical and aerospace engineering (MSc thesis in experimental turbo-machinery) and that I have always been taught (and seen) drag = bad. I don't have a lot of experience in low Mach aero, so I'll keep an open mind about reducing the induced drag trough stall.

What troubles me with the stalled hypothesis is not only the size of the wake created by the stall (which could or could not be smaller), but the fact that flow velocity in that wake is going to be very low, causing low static pressure air, which is going to cause a huge form drag. I know induced drag on those stubby wings is huge, but I would be surprised they could off-set the loss in form drag with reduction in induced drag.

Just a thought, great input from all of you, it has been a fascinating read. Cheers.

+1

[Tristan]

Hi guys, just been trough 16 pages of posts and just wanted to add my view. It seems to me that we are divided into two categories on this subject:
1. McLaren have found a way to stall their wing to get less drag
2. Mclaren are using a very effective blown wing resulting in low drag

I'll count myself to the second category. (Pardon my English, but I'm from Belgium so my phrase construction is not always correct).

To me the wing is just an upside down Fowler flap (with only two elements). The slot in the main plane is just to get more air at the suction side of that plane to increase the stall margin (a bit like adding an element to the flap). Because of this very effective Fowler flap, they can work with a rear wing with lower angle of incidence, therefore having a higher finesse (L/D) and higher top speed.

The reason I don't "believe" in the stalled hypothesis is that I have a background in aeronautical and aerospace engineering (MSc thesis in experimental turbo-machinery) and that I have always been taught (and seen) drag = bad. I don't have a lot of experience in low Mach aero, so I'll keep an open mind about reducing the induced drag trough stall.

What troubles me with the stalled hypothesis is not only the size of the wake created by the stall (which could or could not be smaller), but the fact that flow velocity in that wake is going to be very low, causing low static pressure air, which is going to cause a huge form drag. I know induced drag on those stubby wings is huge, but I would be surprised they could off-set the loss in form drag with reduction in induced drag.

Just a thought, great input from all of you, it has been a fascinating read. Cheers.

+1 here too.

[timd]

Yes you would remove your foot from the pedal you dont want to be dragging the brakes theyre very sensitve and strong. You wouldnt want your foot or any weight on it. Youd have overheating issues in the brakes as well as the slight slow down.

Either you move your foot to the left or back. I think these pedal box's are so small they probably move their foot back anyway. Bracing their foot would not be a problem either as there is already a nack required when driving high powered / stiff setup cars over bumps so you dont jump on and off the throttle. This is why the fitness helps them as they can brace while still keeping a sensitive touch to their inputs.

Surely we have someone on here who can comment on the spaces of F1 pedal box's?

Personally i am not so sure there is a switch, in fact i think not.

I would laugh if it was just to cool some advanced CPU for monitoring the car. Remember they have to use the FIA ECU so might be restricted to much for testing / monitoring purposes on tests.

If this wing is set to stall i would have thought it would just be achived thru the whole aero package's airflow at certain speeds / yaw and you'd just have to get it right per track or at least a couple options.

[forty-two]

Not sure if this is old news, but F1SA have the following two news item on their site today:

McLaren FIA Inspection delayed, new Formula 1 innovation spotted:
http://www.f1sa.com/index.php?option=co ... Itemid=219

McLaren taking alternate Formula 1 rear wing bodywork to Bahrain:
http://www.f1sa.com/index.php?option=co ... Itemid=219

Looks like the guys at F1SA don't want users to copy and paste from their site, so instead I thought I'd just leave the hyperlinks there if anyone wanted to click them?!? (Sorry F1SA if you don't like this happening)

It would at least appear that McLaren are either sweating the legality of this innovation, or are simply happily lapping up all the extra publicity that this issue is getting their car!

Thoughts anyone?

[Just_a_fan]

Not sure if this is old news, but F1SA have the following two news item on their site today:

McLaren FIA Inspection delayed, new Formula 1 innovation spotted:
http://www.f1sa.com/index.php?option=co ... Itemid=219

McLaren taking alternate Formula 1 rear wing bodywork to Bahrain:
http://www.f1sa.com/index.php?option=co ... Itemid=219

Looks like the guys at F1SA don't want users to copy and paste from their site, so instead I thought I'd just leave the hyperlinks there if anyone wanted to click them?!? (Sorry F1SA if you don't like this happening)

It would at least appear that McLaren are either sweating the legality of this innovation, or are simply happily lapping up all the extra publicity that this issue is getting their car!

Thoughts anyone?

I love the way that the site is referring to the knee being used to operate a device. Do you think they have someone reading this forum...?

[autogyro]

I suddenly thought of something.
Do you think Hamilton has got hollow knees?

Or perhaps Jenson has got hollow legs, which is more likely.

[forty-two]

Not sure if this is old news, but F1SA have the following two news item on their site today:

McLaren FIA Inspection delayed, new Formula 1 innovation spotted:
http://www.f1sa.com/index.php?option=co ... Itemid=219

McLaren taking alternate Formula 1 rear wing bodywork to Bahrain:
http://www.f1sa.com/index.php?option=co ... Itemid=219

Looks like the guys at F1SA don't want users to copy and paste from their site, so instead I thought I'd just leave the hyperlinks there if anyone wanted to click them?!? (Sorry F1SA if you don't like this happening)

It would at least appear that McLaren are either sweating the legality of this innovation, or are simply happily lapping up all the extra publicity that this issue is getting their car!

Thoughts anyone?

I love the way that the site is referring to the knee being used to operate a device. Do you think they have someone reading this forum...?

Hehe, my thoughts exactly!

I wonder how often ALL the teams check this site to see what's being said about them and their rivals. My guess, fairly frequently!

[forty-two]

I would laugh if it was just to cool some advanced CPU for monitoring the car. Remember they have to use the FIA ECU so might be restricted to much for testing / monitoring purposes on tests.

Did I dream it, or did I read some time ago that the "FIA ECU" was actually designed and manufactured by McLaren Technology?

If so, I doubt they'd have too much trouble running a "Custom" version if they needed some extra instrumentation for testing. I'm not sure if that would be legal or not, but providing they only use it during winter testing I imagine it'd be ok??

[outer_bongolia]

And again, for those of you who think the McLaren slot is acting as a blown flap (and thus helping to prevent stall) are incorrect. This is what the Williams and Sauber wing are doing, and indeed what the McLaren 2009 wing did, but this has nothing whatsoever to do in terms of applied aerodynamics to the 2010 wing.

Hey SLC. Thanks for this interesting bit. Would you be able to share something more, or should we rely on the little riddle that you leave us with?

As far as the rest of the little rant goes, we are just normal people and some engineers trying to understand what's going on. I usually encourage people to talk and think about stuff that they do not know so that I can guide them, instead of just telling that they are wrong so why don't they just shut up and let the grown ups talk. If you are not satisfied with the discussion here, please keep it to yourself or attend a conference or two.

[Ciro Pabón]

I suddenly thought of something.
Do you think Hamilton has got hollow knees?

Or perhaps Jenson has got hollow legs, which is more likely.

Well, maybe they should connect the hose to their brains... ha, ha.