Flexible wings 2011

[marekk]

I was a bit skeptical about richard's idea of drag induce bend, until i've found we are missing one element in our discussion.

RB7's endplates are quite big, vertical airfoils. They generate significant amount of drag and inward facing lift components just at the very rearward edge of the wing.

[shelly]

I was a bit skeptical about richard's idea of drag induce bend, until i've found we are missing one element in our discussion.

RB7's endplates are quite big, vertical airfoils. They generate significant amount of drag and inward facing lift components just at the very rearward edge of the wing.

I do not agree with you on this, especially as far as inward facing lift is concerned.
Endplates are shaped as a consequence of the flow created by wing, flaps and wheels.

[Richard]

For simplicity, lets say the centre of pressure is likely to be centre of the wing cascade, ie 650mm from centre line.

3.17.1 allows 20mm deflection under 100kg load at a point 795mm from the centreline. However the wing endplates are 900mm from centreline, and lets say pylons are 200 from the centreline. Assuming a linear extrapolation from test point to endplate, the test allows 23mm at the endplate, ie 20*(900-200)/(795-200)

We can pro-rata the lever arm of the test load and aero load (A):

Aero Deflection = 23 x (A x (650-200)) / (100*(795-200))

Say 800kg total load on wing, ie 400kg on one side = 70mm deflection at endplate.

Ref for 800kg - http://www.f1fanatic.co.uk/2010/10/18/t ... grand-prix
or ... viewtopic.php?f=6&t=7641 (630kg total back in 2005)

The underside of the wing on a flat car is 75mm above ref plane, and that is 50mm above the plank underside. So that’s 125 to underside of plank, or 55mm from deflected wing to underside of plank

We can see that RB run a steeper rake than others, plus their endplate has much more pronounced torsion than others. That torsion means the end plate corner dips closer to the ground, rather like an athlete dipping for the tape.

So the challenge for the other teams is to have a higher rear, and to twist their endplates.

edit -
Looking at the head on pics the pylons are probably 400 apart, say 200 from centreline. I've updated the numbers above to be tidy, but it makes no difference to the answer!

[marekk]

I was a bit skeptical about richard's idea of drag induce bend, until i've found we are missing one element in our discussion.

RB7's endplates are quite big, vertical airfoils. They generate significant amount of drag and inward facing lift components just at the very rearward edge of the wing.

I do not agree with you on this, especially as far as inward facing lift is concerned.
Endplates are shaped as a consequence of the flow created by wing, flaps and wheels.

If you look at the RB7's wing from the top, there is an vertical airfoil meant to direct incoming flow around the tyres. Center of pressure for this element is aft of where end plate curvature starts, and lift component will be horizontal facing car's center line.

[kalinka]

What puzzles me most, beside of the exact technique producing such a wing is that Ferrari and McLaren are nowhere there...
I think both teams are very much capable of producing it, especially beacuse it's not some kind of hidden-under-engine cover trick. We saw McLaren didn't attepmt do go this way in 2010, Ferrari yes, but not so much like RBR. This year it's McLaren's wing that's bending a little bit more, but somehow I can't buy this "we don't know how it works" saga. Maybe their car is not so much depending on it ? For sure McL is a radically different car from other 2 teams....
Other thing: If it's true that RBR's system is very much depending on that high rear rake, then it wouldn't be such easy to implement it on other cars. I mean there is no way Ferrari and McLaren can just say : let's lift a rear -> FW goes lower -> we make it bend -> here we are. That's not the way they can do it if they doesn't design a car around it....?

[shelly]

I was a bit skeptical about richard's idea of drag induce bend, until i've found we are missing one element in our discussion.

RB7's endplates are quite big, vertical airfoils. They generate significant amount of drag and inward facing lift components just at the very rearward edge of the wing.

I do not agree with you on this, especially as far as inward facing lift is concerned.
Endplates are shaped as a consequence of the flow created by wing, flaps and wheels.

If you look at the RB7's wing from the top, there is an vertical airfoil meant to direct incoming flow around the tyres. Center of pressure for this element is aft of where end plate curvature starts, and lift component will be horizontal facing car's center line.

The endplate has a shape similar to an airfoil, but the inward face of it can not generate lift as it is subject to the much higher prssure of the mainplane and flaps

[marekk]

The endplate has a shape similar to an airfoil, but the inward face of it can not generate lift as it is subject to the much higher prssure of the mainplane and flaps

I doubt the pressure increase above slotted flap (we have to look basically only at the last flap) is bigger the pressure decrease behind this curved part of endplate. Usually pressure increase under the wing is much smaller then pressure decrease above.

And if you look at it from the side, less then half of this curved part is above the flap.

Only if both surfaces of this vertical element work, one can bend incoming flow around the tyres IMO. If stalled, it will only generate turbulences.

[marekk]

What puzzles me most, beside of the exact technique producing such a wing is that Ferrari and McLaren are nowhere there...
I think both teams are very much capable of producing it, especially beacuse it's not some kind of hidden-under-engine cover trick. We saw McLaren didn't attepmt do go this way in 2010, Ferrari yes, but not so much like RBR. This year it's McLaren's wing that's bending a little bit more, but somehow I can't buy this "we don't know how it works" saga. Maybe their car is not so much depending on it ? For sure McL is a radically different car from other 2 teams....
Other thing: If it's true that RBR's system is very much depending on that high rear rake, then it wouldn't be such easy to implement it on other cars. I mean there is no way Ferrari and McLaren can just say : let's lift a rear -> FW goes lower -> we make it bend -> here we are. That's not the way they can do it if they doesn't design a car around it....?

I think the simple answer is front downforce alone is worth nothing. If you add more DF on the front of the car, you have to add about the same amount on the rear. Mclaren can do this to some extent, because they got more rear downforce with channeled sidepods. Others still struggle.

[volarchico]

@shelly and marekk, I think the front wing is quite complicated to try to predict forces on the vertical endplates just by looking. With the multiple elements and the extremely complex shapes and cut-outs on the endplates it would seem difficult to know.

To some extent, I would guess that since the job of these endplates is to direct the flow outside and around the tires, there must be some inward force.

Maybe we can have ringo do a quick integration of the pressures on the endplates of one of his CFD models and let us know the resultant forces?

[Ferraripilot]

For simplicity, lets say the centre of pressure is likely to be centre of the wing cascade, ie 650mm from centre line.3.17.1 allows 20mm deflection under 100kg load at a point 795mm from the centreline. However the wing endplates are 900mm from centreline

I would place the endplates at around 1300mm as the wing is 1400mm wide in total. Testing directly under the centre of pressure is probably the best area IMO, but for teams with a cascade it might be difficult fashioning an adapter to fit under so the Fia testing ram can adequately test. The Fia probably chose the current testing area based on teams ability to configure an adapter without getting into the mess of the outer wing bits as some can be complicated.

[Richard]

[marekk]

I will venture this picture:



There are 62mm longitudal beetwen test/support line and center of pressure, based on the rule of thumb (CoP at 25% chord length), more or less.
For 2 x 4000N this will give about 500Nm torque. Not bad.

[Ferraripilot]

Kind thanks for posting that Mr Leeds!

[atanatizante]

Some questions:

1.Why RB has cascade winglets/flaps at the point where the FW is flexing?
2.Where is the point with maximum drag or pressure on the FW?
3.Could they put ballast/weight underneath or above the FW?
4.Where is the best place to put it?
5.Could this ballast/weight (alone or in addition to the cascade winglets/flaps) increase the effect of flexing the FW?
6.Could they put ballast/weight after the FIA tested the FW?

Thanx in advance!

[scotty86]

Sorry if this has been mentioned (cba to read through 38 pages of argument to check, in all honesty), but exactly how possible is it that Red Bull use heat affected materials and the principle of aerodynamic heating to achieve the resulting wing bending that they do? I don't claim to have vast material knowledge, so am wondering if such a material can even be realistic in F1, not to mention the fact that the speeds they reach (relative to air and spacecraft) aren't necessarily high enough to even generate enough heat...