2022 cars 'porpoising' at high speed

[atanatizante]

Regarding the suspension, heave, dampers and stuff that could influence porpoising:

[Big Tea]

So is it possible that Scarbs April 1 quip about non Newtonian colloids was not all bull?
It would seem a good way to produce the effects he says are required?

[saviour stivala]

All ‘heave’ springs in use are progressive rate. If ‘Bump-stops’ to restrict ultimate travel are used the car will feel like bottoming when bump-stops are hit. The banned ‘hydraulic trick suspension’ systems would have eliminated most of these problems.

[atanatizante]

After riding but most of all attacking so good the kerbs here at Imola, there are rumours saying RB18 have developed a passive solution with the suspensions, dampers, heave and other stuff that acts together like an active suspension. This solution was primarily designed for lowering as much as possible the floor, but secondly, it aids the car to ride and attack kerbs better than the opposition. Could they achieve that with the 2022 regs?

[Ozan]

I think all teams should agree to bring back FRIC or some kind of a hydrolic suspension to solve this porpoising problems, it's dangerous and uncomfortable for drivers, also damaging the cars and power units thus creating more financial problems for teams.

[Stu]

No, no, no!

When a legal solution is possible, and some teams are proving that it can be better controlled (but probably not eliminated), rules should be left as they are.
Not possible to simply fit FRIC without major chassis redesign.

The same arguments were made in 1994 after active suspension was banned.

[vorticism]

FRIC was not necessarily for tuning out low frequency oscillations, it was more about relatively static pitch and ride height control iirc. The wording which may be catching them out is the forbidding of certain types of damper valving

[vorticism]

Alonso's water pump failure chalked up to porpoising--of a certain type. Sounds like a side effect of repeated ground strike. Might be important to keep in mind that porpoising sometimes means bottoming out the ICE repeatedly on the track cushioned only by the plank. When considering RB's fuel line failure mode, perhaps we consider that instead of the relatively less intense non-contact porpoising heaves initiating a resonant mode. Ultimately these '22 cars ride lower to the ground. In previous seasons (past decade plus) the higher rake on the cars meant the ICE struck the ground less often if at all (they primarily rode on the t-tray).

https://www.motorsport.com/f1/news/alpi ... /10144829/

[testing]

Possibly interesting bit of video about "pumping" of our two-wheeled friends, when the suspension bottoms out:



Back to four wheels: it seems that the suspension simply bottoms out as the downforce created by the floor increases.

Teams are probably trying to fix this by
1) changing the linkage geometry and rates of the heave springs
2) trying to design a floor that stalls as the car squats like it did in previous years

Both of which are obviously easier said than done...

[vorticism]

Packing up might be a problem if the rebound rates are incompatible with the porpoising frequency, the desert truck vids I posted earlier might help illustrate this further. If it is simply, as you say, a peak downforce issue pressing the car to the road, how does this explain the oscillation? The return of ride height. If downforce is consistent, or at least slowly varying, until bottoming out of the suspension, then the compressed tires nor the compressed suspension have a need to return energy against the consistent high downforce.

Enter the aero component. Something is causing a net downforce fluctuation. Would we define that as:

-Onset and/or sustain mode is sudden loss of downforce
-Onset and/or sustain mode is sudden gain of downforce

The suddenness is important because this relates to the suspension spring and damping rates, and potentially the tires. Adding or removing ~500N (total guess) from the car slowly may pose no problem, but adding or removing such a force within 0,1 - 0,5 s is another matter.

[djos]

No, no, no!

When a legal solution is possible, and some teams are proving that it can be better controlled (but probably not eliminated), rules should be left as they are.
Not possible to simply fit FRIC without major chassis redesign.

The same arguments were made in 1994 after active suspension was banned.

Exactly, Mclaren, Haas and red bull don’t have porpoising so why should they be penalised for getting it right!

[mzso]

It’s pretty much been said by all those who actually have a clue and spoken publicly; Jean-Claude Migeot, Peter Wright, and James Allison that choke flow is NOT the issue. I am not sure why people are yammering on about it still. Every single person in the media talking about this have no idea. They are journalists and pundits, not aerodynamicists, not engineers, and none have designed even something as simple as a Formula Ford.

No-one ever said that choked airflow doesn't cause porpoising, only that it's not necessarily the cause.
In a ground-effect car it obviously does, no airflow, no downforce. It doesn't exclude other phenomena from causing a loss of downforce before choking can happen, causing an oscillation.

[mzso]

No, no, no!

When a legal solution is possible, and some teams are proving that it can be better controlled (but probably not eliminated), rules should be left as they are.
Not possible to simply fit FRIC without major chassis redesign.

The same arguments were made in 1994 after active suspension was banned.

Yeah, and only one champion died in 1994 thanks to the ban...

Also, I don't think it's healthy that straightforward solutions to problems are banned for no good reason, forcing engineers to come up with contrived, complicated and usually more fallible solutions.

[Hoffman900]

It’s pretty much been said by all those who actually have a clue and spoken publicly; Jean-Claude Migeot, Peter Wright, and James Allison that choke flow is NOT the issue. I am not sure why people are yammering on about it still. Every single person in the media talking about this have no idea. They are journalists and pundits, not aerodynamicists, not engineers, and none have designed even something as simple as a Formula Ford.

No-one ever said that choked airflow doesn't cause porpoising, only that it's not necessarily the cause.
In a ground-effect car it obviously does, no airflow, no downforce. It doesn't exclude other phenomena from causing a loss of downforce before choking can happen, causing an oscillation.

James Allison:
“The mechanisms that cause it, while not completely understood yet, are rather different from what the commentators are providing on the web and on your tv screens”

Peter Wright cited Karman Vortex street turbulence as the cause.

Jean-Claude Migeot:
“ Migeot explained that the cause of porpoising was not in a cyclical stall function, but down to the aerodynamic forces within the underbody at high speed inducing movement in the car close to its natural heave frequency.”

Jean-Claude and Peter Wright, two aerodynamicists who were there in the last ground effects era cited the same phenomenon, cited the same issue, while James Allison discounted the stalling theory that commentators have been harping about.
But sure, I’m the arrogant one.

[mzso]

@Hoffman900
You're not actually discrediting what I said though.