N21 wrote: ↑05 Jul 2022, 18:10
I still don’t fully understand what the floor flexing does to gain performance. Can someone explain in simple terms?
Also if 2mm is allowed and 6mm is observed; are these not such small measurements that it won’t matter that much? Or is the 4mm in between the difference between a car porpoising or not-porpoising?
My personal hypothesis is that the floor/plank twists about an x axis. I think it may be possible to run suspension that is softer in roll than on a car with a floor that is stiffer in that axis. At high speed, low ground clearance, when the car rolls in a corner the outer plank will strike the road and reduce the load on the outer tyres. To avoid this it is necessary to run the suspension stiff in roll.
The benefit of this would be that the car could be run with more ground clearance when straight ahead and when it rolls the outer tunnel will reduce its ride height and so generate more downforce.
Of course there needs to be a mechanism that applies the forces that twist the floor. I hypothesise that these forces come from the bib and the skate on cars equipped with them.
It’s just a guess based on observation. The tests on the floor apply forces normal to the reference plane and symmetrically. They would not uncover reduced stiffness to offset forces that would twist the floor.
The latest change to the test, observing the deflection surrounding the test holes probably suggests this is not what the FIA is concerned about. Instead they may think the plank area is being pushed up into the reference plane reducing ride height at speed.
We’ll see.
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus