Reducing the drag of a two element wing through stall

[horse]

From telegraph story:

“Basically, if you stall the wing you take all the drag off it and pick up straight-line speed,” Horner explained. “It’s something that’s been done quite a lot over the years but with the wing separators you’re not supposed to do that. Our question ultimately will be: 'Is it clever design or is it in breach of the regulations’?”

Been doing it for years...

[Shaddock]

Well...Umm... Actually i didn't state that as a problem. That's how it's supposed to work, i reckon. The answer to the question " how can such a small amount of air through a tiny scoop can have an impact on the rear wing air flow".

Its not just the air from the snorkel that end up in the blown slot, but the air dlow from the air box as well.

[Shaddock]

I have just knocked this up in Powerpoint



I think it may be a little more complicated than this, but the basic principle might work.

I over simplified this, but it the same thing.

[forty-two]

Pedal controlled rather than knee controlled also sounds interesting. Especially for an air brake, where full-on braking is most likely to be where you need the extra braking performance.

Thanks Horse.

It occurred to me that there are a number of road cars which have an electronic button mounted to the floor under the accellerator pedal which kicks in some sort of "boost" (although I don't know if this somehow boosts the throttle or makes the mix more rich or anything! But in all cases I know of it's on Automatic cars).

This button is only pressed when the pedal is completely pressed to the floor. While this is only suitable for the accellerator on a road car (as the brake pedal never actually reaches the floor unless something is seriously wrong!) on an F1 car, the pedals are essentially potentiometers with springs to counter the foot pressure, so they don't (unless I am way off) have any form of force feedback.

So all I was thinking is that perhaps, following a challenge of legality from other teams, an argument could be made by McLaren that the squashy hose from the snorkel HAD to be run right under the brake pedal because there wasn't any room to run it elsewhere. It probably wouldn't get them off the hook completely, but it might be the difference between losing points already accrued vs keeping them but promising to replace the squashy hose with a stiff one while they think up something else.

Of course, we could all be way off the mark with the whole idea. Maybe the snorkel was only there to provide a suitable inlet to prove a point about the extra inlet above the airbox? In other words, perhaps they were/are planning to re-route the ducting from the snorkel down to the floor of the car, and are somehow using an effect similar to a child's airbrush to 'draw' air up from the floor and chuck it at the rear wing? (aero guys, please advise! Total novice waffling here!).

OR

Maybe McLaren just knew that putting that snorkel there would have us all writing away like crazy so we didnt notice the blooming enormous Dyson they've mounted elsewhere to stick the car to the road.

Whatever they're up to, it sure is fun to speculate and to read everyone else's ideas!

[SLC]

Christian Horner:

“Basically, if you stall the wing you take all the drag off it and pick up straight-line speed,” Horner explained. “It’s something that’s been done quite a lot over the years but with the wing separators you’re not supposed to do that.”

I'm glad to see someone agrees with me

[Shrieker]

Yes that's how it should work i reckon.

Given the system tok-tokkie posted;

The air scoop would be the control port (c1 or c2).

The airbox would be the air supply at the bottom.

[horse]

Christian Horner:

“Basically, if you stall the wing you take all the drag off it and pick up straight-line speed,” Horner explained. “It’s something that’s been done quite a lot over the years but with the wing separators you’re not supposed to do that.”

Yeah, saw this in the Telegraph online. I'm not sure if CH can be trusted as an authority here, although there are people around him who should know (AN, for instance). It the "something that’s been done quite a lot over the years" bit that confuses me. Has it?

[horse]

Yes that's how it should work i reckon.

Given the system tok-tokkie posted;

The air scoop would be the control port (c1 or c2).

The airbox would be the air supply at the bottom.

No, that tok-tokkie system is not the same as you provide just a pulse of air to switch between exits, not a continuous flow. Also you need to pulse from either side to switch back and forth.

I'm sure Shaddock is right though, there is probably a similar system that will take a continuous on/off input.

[Shrieker]

I can't see 'pulse' in the wikipedia article http://en.wikipedia.org/wiki/Fluidics

[horse]

I can't see 'pulse' in the wikipedia article http://en.wikipedia.org/wiki/Fluidics

No, sorry, it's my fault, I'm just assuming it's like a switch, but maybe not. I take it all back, sorry guys. [-X

[Shaddock]

Wiki on fluidics http://en.wikipedia.org/wiki/Fluidics

It includes this diagram of a fluidic amplifier but I would call it a flip-flop valve.


A pulse to the side port C1 causes the flow to flip across to outlet O2 etc...

This system has a symmetrical chamber so pulses of air (from C1 C2) can switch the main flow between two exits. With a snorkel you would have an asymmetrical chamber and one control port not two and a default exit for the main flow. A pressure in C deflects the main flow to the alternate exit, cut the flow into C and it moves back due to the main exit by the nature and shape of the chamber.

[horse]

This system has a symmetrical chamber so pulses of air (from C1 C2) can switch the main flow between two exits. With a snorkel you would have an asymmetrical chamber and one control port not two and a default exit for the main flow. A pressure in C deflects the main flow to the alternate exit, cut the flow into C and it moves back due to the main exit by the nature and shape of the chamber.

Yeah, agreed. I suddenly realised you could run the two port system with continuous flow if you wanted, it's just the balance between the two ports (C1, C2) that is important, provided the flow into C1, C2 wasn't too strong.

[SLC]

Christian Horner:

“Basically, if you stall the wing you take all the drag off it and pick up straight-line speed,” Horner explained. “It’s something that’s been done quite a lot over the years but with the wing separators you’re not supposed to do that.”

Yeah, saw this in the Telegraph online. I'm not sure if CH can be trusted as an authority here, although there are people around him who should know (AN, for instance). It the "something that’s been done quite a lot over the years" bit that confuses me. Has it?

What is up with you people? You don't think Horner is a trustworthy source?

Yes it has been done - for many years. This is not in any way a new concept in F1.

[forty-two]

I can't see 'pulse' in the wikipedia article http://en.wikipedia.org/wiki/Fluidics

No, sorry, it's my fault, I'm just assuming it's like a switch, but maybe not. I take it all back, sorry guys. [-X

OK, this has really got me thinking now....

IF the fluidic valve is behaving as a bi-stable (i.e. once switched by a 'signal' of air from one channel, it stays put until a signal appears on the other port) then that would be one thing... BUT on the other hand, if a constant stream of air is required on one or other port in order to prevent the "valve" from averaging it's output between the two outlet ports, perhaps we are looking at something quite different....

We believe that the snorkel has a corresponding identical panel on the other side, so how about this for a wacky idea:

What if they intend to run two snorkels, one on the left, one on the right, whereby completely depressing the accellerator pedal pinches a pipe which 'has' to be routed under it, thus sending the air from the airbox inlet to meet the hole in the floor which feeds the second deck of the DDD thus reducing D/F and presumably drag. But at the end of the long straight, when the driver removes pressure from the accellerator, the airbox air is sent directly to a hidden vent out the back of the car. When the brake pedal is completely depressed, the left hand pipe is pinched, sending signal air to the "fludic valve" which in turn sends the airbox air to the sharkfin, stalling the wing creating a switchable air-brake?

I know this is off the wall, but if you're going for an extreme idea, you may as well make it pay both for when you're flooring it and for when you need to stop a heavy car quick.

I wonder also if it would be legal for a mechanic to slip a cover over one or other snorkel on the final pitstop as the fuel load has now diminished sufficiently to no longer need the air-brake.


Guys, please tell me if I am filling valuable column inches here with too much nonsense!

[horse]

What is up with you people? You don't think Horner is a trustworthy source?

Well he's not an aerodynamicist, was what I was getting at, and he has said some dubious things in the past. He is a team principle after all.

Yes it has been done - for many years. This is not in any way a new concept in F1.

Fabulous. How did it work in the past?