FWAS

[vorticism]

The regs state that the FWAS (Front Wing Adjuster System) must fail into Corner Mode, the high-downforce mode, just like DRS did. Obviously, this is the safest option.

However, as we've seen so far, teams are not choosing flaps that pivot at the trailing edge of the flap with a leading edge that pivots up. Instead we see front-hinged flaps with trailing edges that lay back. Apparently they are relying upon an interpretation of "fail safe" as a mechanical one, not an aerodynamic one. Presumably a spring force or worm gear locking maintains Corner Mode, while a hydraulic or electromechanical force overcomes this to move the flap into Straight Mode. Thus, if the hydraulics or electronics ever fail, the passive spring force, whether mechanical or pneumatic, forces the flap to stay in Corner Mode.

Which leads me to: was rear wing DRS ever strictly an aero-based fail safe design? Sometimes this appeared to be the case with the high pressure side of the flap presenting enough angle to be necessarily forced back down when the actuator counter force was relieved. Other times, the flap pivoted so far upward, that it would seemingly require actuator counter force in the opposite direction to get the flap back down to high downforce mode i.e. hydraulic or spring force re-seated the flap, not aerodynamic force. I think we even saw rear wing DRS flaps being torn off at times, which would imply there was aero pressure forcing the flap open, not closed.

Distinct from rear wing DRS is that these lay-back FWAS flaps find their stop in the opposite orientation--on their topsides, which they are pushed against, and the passive spring force (or worm gear locking) alone bears aerodynamic downforce, whereas RW DRS flaps fell on to their stops, with the inherently passive stop bearing aerodynamic downforce, with perhaps some actuator imbued force pushing down upon it as will to prevent flutter.

A mechanical fail safe does not seem like a perfect fail safe. I say an aero fail safe would be safer, but if they've gotten on with a mechanical fail safe for 10+ years I suppose it's not an issue.

As for general arrangements, there are four options as I understand it.
4-element: two split flaps
2-element split: one split flap
2-element continuous: two continuous flaps
1-element: one continuous flap

FWAS update:
4-element: VCARB, Ferrari, Haas, RBR
2-element split: Mercedes
2-element continuous: RB (rendering) & some pre-season renderings made by various people
1-element: no one

[Cuky]

DRS opening was mandated by the rules, for me those two rules are the most interesting in that regard:

3.10.10.b. The axis of rotation of the RW Flap must be fixed and located no more than 20mm
below the upper extremity and no more than 20mm forward of the rear extremity of
RV-RW-PROFILES at all times.

It specifies where the axis for rotation is placed basically placing it up and rearwards.

and then

3.10.10.g. At all points along the span, when the DRS is in the state of deployment, the two
sections the rear wing profiles (as defined under Article 3.10.1) must have a minimum
gap of between 9.4mm and 85mm. This will be measured with a spherical gauge.

Which basically says that there has to be a gap opened between two rear wing sections and gives minimum and maximum gap for the opening.

[michl420]

was rear wing DRS ever strictly an aero-based fail safe design?

I think the flap will almost ever go down because of the aero load. But a spring against the hydraulik cylinder make it even saver and have almost no downsides.

choosing flaps that pivot at the trailing edge of the flap

The reglement say pivot on the leading edge (FWAS).

[vorticism]

choosing flaps that pivot at the trailing edge of the flap

The reglement say pivot on the leading edge (FWAS).

It specifies a forward placement limit (no closer than x to the leading edge) which means it can be placed anywhere aft of that point.

[johnnycesup]

It specifies a forward placement limit (no closer than x to the leading edge) which means it can be placed anywhere aft of that point.

Per the regulations, “Point A” and “Point B” (which define the pivoting line for the primary flap) must be:
i. within the volume of FW Primary Flap.
ii. no more than 25mm from the forwardmost point of FW Primary Flap at their respective Y
positions.

Similarly for "C" and "D" in the secondary flap, so the limit is not how close it is to the leading edge but how far, and therefore the flaps must pivot from the front.

[vorticism]

It specifies a forward placement limit (no closer than x to the leading edge) which means it can be placed anywhere aft of that point.

Per the regulations, “Point A” and “Point B” (which define the pivoting line for the primary flap) must be:
i. within the volume of FW Primary Flap.
ii. no more than 25mm from the forwardmost point of FW Primary Flap at their respective Y
positions.

Similarly for "C" and "D" in the secondary flap, so the limit is not how close it is to the leading edge but how far, and therefore the flaps must pivot from the front.

I think I took "their respective Y positions" as a limit for how far a hinge could be from an edge of the flap to ensure proper support. It's been a few months since I glanced through that section--didn't spend much time on the FW in general. Earlier on in the press, maybe some hobbyist modellers, has shown DRS type movement (nose up), which probably colored my perception. Either earlier revisions of the regs allowed that, or those depictions were wrong.

What do you make of the fail safe methodology?

[johnnycesup]

What do you make of the fail safe methodology?

Well, it's going to have to be through a spring, or another type of energy storage system.

I guess nothing is completely fail safe right, so as long as the scrutineers are happy that the system will revert to the up position unless something really catastrophic happens, it'll be fine I think. Although there's a bigger chance of something catastrophic happening to the front wing than the rear, thats for sure.