There's a couple of places where chat about the porpoising is taking place, but I just made a post in the aero sub-forum about it, so here's a link if you're interested to read it (rather than repost the whole thing here?)
click here!
You could do like McLaren and use the channel built in to create some lift at the leading edge. Or like RB did and make a smooth shaped bow. From what I can tell Mercedes went full axe head on their bib, very sharp angles. A smoother shape would have more of a hover craft effect that would keep the plank from bottoming out, or at least dampen the downward motion.vorticism wrote: ↑02 Apr 2022, 18:08Your post makes me think of the air cushion effects of flat surfaces in close proximity. If you tip over a finely machined surface, a block of metal or plastic, onto a smooth surface, like a granite plate or something, or if you allow a sheet of plywood to fall to a floor, it never slams. Likewise lifting it back you up you will notice a vacuum resistance.
On one hand the plank may be drawn down by low pressure and the downward force of gravity and the downforce applied by the other bodywork. Conversely, when it raises back up it will require an exaggerated force to overcome the vacuum beneath it. Like when trying to separate two mirror smooth surfaces. If that upward force needed to detach the plank from the track comes from undamped forces like the tires or bodywork flexibility, that might set up porpoising/skipping.
Running zero rake might make this more of a risk. Some rake would keep the bib riding on the track, while the plank stays elevated. Think that before now the teams never combined a low-rake plank with ground effect tunnels. For a while it was flat floors plus rake, and for RB, usually a lot of rake.
I think they would balance the wheels, fat more precise than the average tyre mechanic on our street cars.
I was thinking back to last years slo-mo of the tyres almost having standing waves under some acceleration and curb hopping. I did not mean them being out of balance as that would only 'shake' that corner of the car, not move the whole 'body'
Probably just the hydraulic inerters reflecting damping back into the tire under high speed oscillation. Instead of being transmitted to the body the vibrations stayed in the tire. All waves are traveling waves, standing waves are traveling waves that have both destructive and constructive interference, and produce a standing pattern. The standing is only in appearance.Big Tea wrote: ↑02 Apr 2022, 19:37I was thinking back to last years slo-mo of the tyres almost having standing waves under some acceleration and curb hopping. I did not mean them being out of balance as that would only 'shake' that corner of the car, not move the whole 'body'
I don't think they're standing waves, the sidewall ripples rotate with the sidewall. They arise from the buckling of the sidewall which is result of the tensile strength of the sidewall and the constant vertical and torsional loads delivered through the wheel. At least not any more than a leaf spring deflecting under a constant load is considered to be a standing wave. The porpoising frequency looks quite slow (maybe 1-4 hz), vibrations from sidewall buckling if felt by the car would be much higher (number of ripples times wheel RPM), hundreds or thousands of Hz.
(not doubting your explanation or the others, but) I have a 'boiler' with a fan that runs at (guess) 5k RPM and the side panel resonates at maybe 200-250 Hz. I don't know this 'shift' in frequency is transferred, I was thinking airflow through the flu, but probably mounts( I put a magnetic knife rack on the cabinet side and it silences it )vorticism wrote: ↑02 Apr 2022, 21:13I don't think they're standing waves, the sidewall ripples rotate with the sidewall. They arise from the buckling of the sidewall which is result of the tensile strength of the sidewall and the constant vertical and torsional loads delivered through the wheel. At least not any more than a leaf spring deflecting under a constant load is considered to be a standing wave. The porpoising frequency looks quite slow (maybe 1-4 hz), vibrations from sidewall buckling if felt by the car would be much higher (number of ripples times wheel RPM), hundreds or thousands of Hz.
I would argue that it's still better to bottom out on the bump stops, than on the floor. You don't have any suspension when riding on the floor eitherdjos wrote: ↑04 Apr 2022, 11:16I got shot down for suggesting that idea a few pages ago.
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