Reducing the drag of a two element wing through stall

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Ganxxta
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Re: Vodafone Mclaren Mercedes MP4/25

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There was no inspection so far, Charly Whiting had problems with his flight...

A13EX_f
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Re: Vodafone Mclaren Mercedes MP4/25

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I'd laugh if this was all a diversion tactic like lotus did many years ago. I think they kept covering their gearbox up even though they had done nothing with it instead they had discovered ground effect?

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ringo
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Re: Vodafone Mclaren Mercedes MP4/25

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The inlet is not split, it's actually blocked half way with a piece of Carbon.
They were probably testing if they could reduce the opening area. When they found out they could they then changed it to the smaller opening here:

http://f1.gpupdate.net/en/photolarge.ph ... 8&catID=10
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ringo
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Re: Vodafone Mclaren Mercedes MP4/25

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Pup wrote:
n smikle wrote:When I imagine the construction of the knee activator, with no moving or flexible parts, I can only see a solution with a hollowed out wall or some hollow duct in the side of the chassis with a hole in it.

The driver puts his knee over/in the hole to activate it (driver activated device). A problem is that the driver might not seal the hole properly with the side of his knee. Then again this depends on what you want to happen in the duct. If you want to stop air loss in the duct, then the drivers knee must seal the hole. If you want to decrease airflow in the duct the drivers knee only has to go inside the hole, into the ducting to block off most of the flow. Just some thoughts. Not saying it can not work even though it seems illegal anyway..but I think the air can be controlled without the driver and the weird ducting. (we still have to establish if the air int he duct is powerful enough to divert the bigger flow).

From scarbsf1
Image

Imagine making a duct for this in the side of the chassis... I don't know.. I have to think hard on it.
Here's one way this could work:

You see that the scoop is split into two chambers. Also remember in the diagram of the fluidic valve that there are two control points. Add pressure to one or the other, and the main flow switches sides. I've been reading up on fluidics a bit, and I gather that the control can be either a continuous stream of air, or it can just be a puff one way of the other, and the main flow will swap sides and remain stable until you 'puff' it the other way.

OK, so if the scoop has two chambers, imagine two flexible hoses then running from the scoop to the rear of the car, connected to the fluidic valve. Now imagine that the hoses are pliable enough that the driver could easily cut off the flow off of one by pressing his knee against it - pinching it closed. Since cutting off the flow of one is equivalent to increasing the pressure of the other, you could effectively switch the main flow back and forth by pinching one hose or the other. Or, if there needed to be a default state, perhaps it could be set up so that the driver would need to maintain pressure on one of the hoses to keep the flow switched.

I'd think this would be a tricky thing for the driver to do, but I figure I'd throw it out there for the sake of conversation. I do think this would be easier to accomplish than having the driver try to cover some hole with his knee. Personally, however, I still think there would be a way for this to all be done without driver input.
[-X , remember regulation states the construction must be rigid with no relative degree of freedum to the sprung mass. Hoses with air affecting the aerodynamics are clear violation. The inspectors would just rip them out. :lol:
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autogyro
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Re: Vodafone Mclaren Mercedes MP4/25

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How about this.
They started by using the shark fin to bring air from near the engine intake to blow from the slot to improve flow on the rear upper wing section, so as to increase DF.
This worked but also gave a downside, which was to much drag at high speed.
To cure this problem, they are now channeling air from an air intake snorkel on the nose near the footwell, with an adjustable flap to vary the amount of air going in.
The flap is driver adjusted but to meet regulations 'not' when the vehicle is moving.
The air from the snorkel is blown at an angle into the airflow in the shark fin and acts as an air valve. When sufficient side flow from the snorkel is established it diverts the main flow in the fin away from the slot outlet where it is then used for another purpose.
The adjustable snorkel flap, varies the speed at which the flow over the rear upper wing section losses bleed air and stalls and so is adjusted to suit different tracks and conditions.
If this is not the case I would be pleased to make one for any teams without one.
Last edited by autogyro on 06 Mar 2010, 22:07, edited 1 time in total.

volarchico
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Re: Vodafone Mclaren Mercedes MP4/25

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ringo wrote:The inlet is not split, it's actually blocked half way with a piece of Carbon.
They were probably testing if they could reduce the opening area. When they found out they could they then changed it to the smaller opening here:

http://f1.gpupdate.net/en/photolarge.ph ... 8&catID=10
The image you linked to doesn't show the inlet. And I think the previous image shows the inlet blocked by a piece of carbon AND split vertically.

James
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Re: Vodafone Mclaren Mercedes MP4/25

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How about at certain angles of adjustment, air from the font wing feeds into the snorkel but when its lowered, less air enters the snorkel

myurr
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Re: Vodafone Mclaren Mercedes MP4/25

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If the snorkel is related to the fin then it would be a passive system - the fluidic valve that has been discussed is very interesting and I'd imagine the most likely system. The snorkel could simply be carefully tuned so that upon reaching a certain pressure - ie. speed - it activates the fluidic switch, enabling the stalling of the rear wing. The car slows below that speed and the pressure reduces and the switch returns to its default state.

Think of it as being like a transistor - should the input reach a certain level, then the transistor allows current to flow through it's other input and output. Likewise this system allows air to pass through to a particular vent once the input pressure reaches a set point.

timbo
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Re: Vodafone Mclaren Mercedes MP4/25

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myurr wrote:If the snorkel is related to the fin then it would be a passive system - the fluidic valve that has been discussed is very interesting and I'd imagine the most likely system. The snorkel could simply be carefully tuned so that upon reaching a certain pressure - ie. speed - it activates the fluidic switch, enabling the stalling of the rear wing. The car slows below that speed and the pressure reduces and the switch returns to its default state.
There's no need for it to be at the nose. Imagine all the piping losses etc.
It would be more rational to put it closer to the thing. If it has to do anything with the wing though, it most certainly involves driver's control.

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djos
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Re: Vodafone Mclaren Mercedes MP4/25

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You guy's are forgetting one major thing - a Driver controllable system would be classed as active aero and is therefore banned (the only exception is the front wing)!

Besides, the only way for this to work properly and reliably is if it is tuned for a certain speed like the old bendy rear wings where.
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FGD
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Re: Vodafone Mclaren Mercedes MP4/25

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I'm having a very hard time believing this little inlet has anything to do with the rear wing. The most obvious purpose, in my mind, would be that they've got a hot spot within the cockpit that needed some cooling.

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ringo
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Re: Vodafone Mclaren Mercedes MP4/25

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volarchico wrote:
ringo wrote:The inlet is not split, it's actually blocked half way with a piece of Carbon.
They were probably testing if they could reduce the opening area. When they found out they could they then changed it to the smaller opening here:

http://f1.gpupdate.net/en/photolarge.ph ... 8&catID=10
The image you linked to doesn't show the inlet. And I think the previous image shows the inlet blocked by a piece of carbon AND split vertically.
Sorry about that, I now see the vertical split.
This pic, with the yellow arrow, does seem to testing of how small they can get the opening to be though.

I don't believe the snorkel theory but if it's real it's probably something like this:

ImageImageImageImage
All rigid parts , no degree of freedom. Only moving part is the knee, which is not bodywork construction. In this case the knee has to be the main switch. Nonetheless this is just part of the solution, i don't know what's going on behind the from this pipe to the fin; ie if it's real.
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djos
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Re: Vodafone Mclaren Mercedes MP4/25

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FGD wrote:I'm having a very hard time believing this little inlet has anything to do with the rear wing. The most obvious purpose, in my mind, would be that they've got a hot spot within the cockpit that needed some cooling.
Same, it has nothing to do with it, its obviously to cool something else.
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Ganxxta
Ganxxta
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Re: Vodafone Mclaren Mercedes MP4/25

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djos wrote:
FGD wrote:I'm having a very hard time believing this little inlet has anything to do with the rear wing. The most obvious purpose, in my mind, would be that they've got a hot spot within the cockpit that needed some cooling.
Same, it has nothing to do with it, its obviously to cool something else.
+1, this thing is to small to produce an airstream to the rearwing, the airbox channel idea is more likely used...

volarchico
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Re: Vodafone Mclaren Mercedes MP4/25

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Somewhere on this site I saw an "x-ray" view of one of last year's cars (I think BMW?). That was from the side, but I'm wondering if anyone has an above view scaled with where a person's leg might rest. I guess my gut feeling is that there isn't a whole lot of room for left/right swinging of a knee to alter the airflow through that inlet, but I have no proof. I like ringo's drawings and idea, but I'm not sure if they'd work in the confines of the actual car.