humble sabot wrote: ↑07 Mar 2022, 19:37
This wouldn't describe well the member in question. You can see in the close up shots that it's thinnest through the chassis section, particularly through the point where the pivot would normally be. Whether it's being used as a spring rather than as a flexure would require seeing what's going on where the pull rods enter the chassis. Since we're dealing with composites here the whole layup schedule has to be taken into account, from the fibre selection, orientation and especially the matrix. If they're using it primarily as a flexure then it's relatively trivial to use the earlier keel style technology; but if they're using it as a spring I would expect that this has been a long term project for the team because a lot of factors have to be controlled for to achieve the desired behaviour, whereas a little machined titanium torsion spring is a very easy thing to simulate and have perfect correlation.
One might even say that if it's a flexure it'll probably be safely the same design all year, but if it's a spring they'll bring new ones every weekend, between adjusting spring rates for specific tracks and getting a handle on how to build this spring for this particular car and its aero behaviour.
I was thinking along similar lines. The more I look at the RB16 lower arm photos, the more I think they are employing the bar with two outboard mount points. Looking closely at the RB16 photo, it appears the bar is sandwiched between two flexible mounts. This leads me to think they are using the arm as a spring, where compression of the suspension allows the bar to flex in the center section, between the mounts. I am not seeing the same on the RB18, but with the covers off we don't know if we are seeing all that is relevant, or the entire as run setup.
If the other elements of the steering secure the wheel hub from movement, then the "flexing" of the arm is merely compression, displaced where they want it to be. This gets rid of the problem with the arc of a single mount point and spring flex as has been discussed.
Though on road cars it's a spring augmenting two somewhat normal A arms usually in modern use the spring is attached on full droop. Any further compression simply pushes the spring together, and the tension between the mounts results in more or less a slight "S" curve as the length is displaced. On a Corvette, the outboard attachment points usually adjust ride height, And with minimal wheel/hub travel on a F1 car, it's not much length to displace.
Essentially the RB16 turned upside down in a sense.