Adjustable Rear Wing (DRS)

[ringo]

Actuation seems to be in the middle of the wing.
This cuts down on the weight of having 2 devices at each end plate.
I like the ferrari middle strut better, as it reduces the length and bends of piping required, since there can be a direct line from the gearbox going to the middle strut of the wing.



The force required is much larger this way, but the upper element doesn't carry more than 500lb of force.
Also as the element turns up, high pressure from the main element that overlaps with the front underside of the upper element will ease the required force as well.



Looking at the renault the pipe is probably 1/4 inch on the inside. 85 psi can give a force of pi*(1/4)^2/4 x 85, that's only 4lb; too little.
There has to be an expansion at the end of the pipe, as it seems to be flaring as it connects to the beam wing.

For about 500lb of force, the area has to be about 6 inches square.
That force is higher than what's on the element though.

http://motorsport.nextgen-auto.com/gall ... medium.jpg

for an elyptical airfoil shaped strut, then 6inch2 = pi *A*B ; A and B being the minor and major axis.

This all depends on the force required and the moment arm of the actuator and the element centre of pressure.
If we know the power of the system, we should be able to figure out how fast it deploys.

[Giblet]

With a wing on a pivot, at speed, would not the wing be trying to move to a flatter position on its own?

Wouldn't the actuator have more work keeping it down?

[ringo]

It would want to stay flat. The actuator would have to lift it then hold it.



Don't mind the hydraulics, just for sake of putting something there.
Sauber's seem to be a hydraulic motor instead of a ram.

Though technically, it should be making less downforce in the open position, so the force should be less to hold it at that max opening than when it starts to move initially.
The relationship is not linear.

The air foil has a pitching moment as well, this has to be inferred from the polar graph of the airfoil.

for example:


as the angle of attack decreases, the lift coefficent goes down obviously, but the pitching moment increases slightly.
This wing wont be stalled completely though, as there is a point where reducing downforce wont make any difference to the drag. The hydraulic will hold the wing at this position. In the case of this airfoil it would be at Cl of 0.4 at 1.5 degrees angle of attack.

[Shrek]

Can they move the wing's trailing edge down instead of moving the wing's leading edge down

[ringo]

I think it's against regulation.
It's a failsafe, if the adjuster fails having the pivot on the trailing edge would mean the wing would return to a high drag possition.
If it were in the front, a system failure would lead to wing flutter and possibly a major loss of downforce on the back.

video of the sauber wing:
[youtube]http://www.youtube.com/watch?v=YUaAb-W5ITw[/youtube]

It adjusts pretty fast!

[horse]

It's a failsafe, if the adjuster fails having the pivot on the trailing edge would mean the wing would return to a high drag possition.
If it were in the front, a system failure would lead to wing flutter and possibly a major loss of downforce on the back.

Do you think there are some bump stops or something as well? If the actuator lets go then I guess the flap will want to do a 180 and reverse. At worse I guess it could hit the main element and close the gap. Hopefully that won't then bust the main element...

[ringo]

I think there are notches in the end plates that would stop the element.
If the wing closes fully, it will gain back the downforce, but the drag will be extremely high.

[hud]

does FIA regulate how much the flap can move or how big the flap should be or how many percent drag coefficient should change? it seems like ferrari has bigger flap-to-main plane ratio compare to renault, which i think will reduce the drag coefficient very much when being activated.

[imightbewrong]

Looks like RBR are not pivoting on a axis on the wing, but slightly displaced.

[forty-two]

And their actuator must be plumbed or wired via the endplates as no central column.

Of all the mechanisms I've seen so far, the Ferrari one appears to be the slimmest in terms of drag.

[forty-two]

Looking again at this image, it looks like the pipe circled is actually off centre, and there even appears to be a hole for a return pipe!

[Richard]

These pics do make you wonder why others have those large pylons & actuators, and why RB have that lump in the middle of their wing.

[Ferraripilot]

[quote="richard_leeds"]These pics do make you wonder why others have those large pylons & actuators, and why RB have that lump in the middle of their wing.[quote="tomazy"]

I don't quite 'get' the large pylons at the back as actuators. Wouldn't such a mechanism be counter-productive to the other aero at the back of the car?

[horse]

I don't quite 'get' the large pylons at the back as actuators. Wouldn't such a mechanism be counter-productive to the other aero at the back of the car?

I think it's just a matter of making a choice about which compromise you are going to make. The Mercedes system is very neat in the centre of the wing but it looks likes they are loosing a cm or so at each end-plate which Ferrari, for instance, do not with their system.

I guess there is some differences in methodology as well. The Mercedes system is most likely electric whereas I think some others might be pneumatic. There may also be some different variations in the loads on the mechanisms as well with an end hinged system compared to a centre "hinged" system (2 contact points compared to 3).

I don't know of the relative reliabilities of all these technologies, but I guess each must be fairly close for so many different variants to have appeared.

[ringo]

I don't quite 'get' the large pylons at the back as actuators. Wouldn't such a mechanism be counter-productive to the other aero at the back of the car?

I think it's just a matter of making a choice about which compromise you are going to make. The Mercedes system is very neat in the centre of the wing but it looks likes they are loosing a cm or so at each end-plate which Ferrari, for instance, do not with their system.

I guess there is some differences in methodology as well. The Mercedes system is most likely electric whereas I think some others might be pneumatic. There may also be some different variations in the loads on the mechanisms as well with an end hinged system compared to a centre "hinged" system (2 contact points compared to 3).

I don't know of the relative reliabilities of all these technologies, but I guess each must be fairly close for so many different variants to have appeared.

Pneumatic is not as accurate. Hydraulic is easier implemented on the F1 car as well.
Mercedes solution uses some of the wing span and who knows how fast it is.
But they seem to have more experience using it since abu dhabi driver tests.