2022 cars 'porpoising' at high speed

[djos]

So this is an interesting suspension system for a Venturi tunnel car to prevent the car bottoming out and choking the under Floor air flow.

Rod Millen used a 3rd spring/ damper config to maintain a minimum ride height - you can see it at ~20:30 in this video.



Is a 3rd conventional spring and damper setup legal in F1?

[Stu]

That is a great video of a fantastic car! (I watched it this morning).
I saw it and heard it being given the hill-record treatment at Goodwood FoS a few years ago.
It also explains quite nicely (and basically) how they went about developing the aero package.

Yes, the third spring is what the teams are doing (I think that the first race-car with such a system was the Penske PC23 back in the early nineties- CART/Indycar*). The only real difference between this year and last is that all springing has to have a mechanical link to the suspension, previously hydraulic linking was allowed.

If I am reading that correctly, it also means that any external reservoirs must be physically connected (piggy-back style) to the damper.

It all makes packaging what they want, where they want it that but more complicated, as the shots of the Red Bull gearbox showed.


* correction corner….
Now that I think about it Shelby modified a GT40 rear ARB for use at the Daytona 24hr race in the late sixties - they fitted a short bracket with an offset rubber buffer that was adjustable in the centre of the ARB; the ARB worked as normal during cornering, but on the banking the car would squat down and the ARB became a heave spring.

[mzso]

I have no idea how well the data has been captured. https://www.formula1.com/en/latest/arti ... dlwQE.html

How did they even capture it? There's no mention of it.

[AR3-GP]

I have no idea how well the data has been captured. https://www.formula1.com/en/latest/arti ... dlwQE.html

How did they even capture it? There's no mention of it.

It would have to be from GPS data otherwise these results are impossible to get.

[Stu]

Would GPS be capable of that kind of register? We are talking of a vertical movement in the region of 50-60mm.

[vorticism]

The FIA might have access to ride height telemetry. I doubt it is GPS elevation change data, seems too fine a measurement for that. If they are monitoring POU effects for example, they might need such data.

[dialtone]

Cars have accelerometers to deal with crashes medical requirements and they probably use that data stream.

[Jolle]

The link doesn't work anymore, but if it's about ride hight, the FIA has a couple of tire tests where they collect a lot of data from cars of course.

[johnny comelately]

Some (arguable) relativity here, from watching this video it belatedly occurred to me about the aero for these land speed record cars.

[vorticism]

Some of these trucks porpoise, others do not.




Sometimes the porpoising is not strictly vertical, more of a pitching movement; eventually the front and rear suspension can create a feedback loop causing steep approach angles right into a road incline, lead to flips:

[SiLo]

Some of these trucks porpoise, others do not.

https://www.youtube.com/watch?v=PK0lTgmz0rY


Sometimes the porpoising is not strictly vertical, more of a pitching movement; eventually the front and rear suspension can create a feedback loop causing steep approach angles right into a road incline, lead to flips:

This is far more to do with the frequency at which they are driving over big bumps and ramps than anything else. If they hit the bumps at maximum travel its going to be impossible to damp correctly.

[djos]

Agreed, they aren’t ground effect vehicles using Venturi tunnels like the Pikes Peak Tacoma I posted earlier.

[vorticism]

Some of these trucks porpoise, others do not.
https://www.youtube.com/watch?v=PK0lTgmz0rY
Sometimes the porpoising is not strictly vertical, more of a pitching movement; eventually the front and rear suspension can create a feedback loop causing steep approach angles right into a road incline, lead to flips:

This is far more to do with the frequency at which they are driving over big bumps and ramps than anything else. If they hit the bumps at maximum travel its going to be impossible to damp correctly.

You've actually described F1 porpoising fairly well there. The principals are largely the same. Variable downforce acting upon suspension and tires, with some suspensions able to cope with the variable vertical loads, and other not. Just like the modern F1 cars. Notice the majority of the content of the first vid is vehicle bodies hovering over intense suspension articulation i.e. floating over instances which would otherwise cause more severe vertical load variations.

The second vid is the 'bucking bronco', see-saw effect, which may be a component of some current F1 porpoising as well; yet to be confirmed or disproven. Mainly these videos were posted to get people to think about the underlying principals.

Agreed, they aren’t ground effect vehicles using Venturi tunnels like the Pikes Peak Tacoma I posted earlier.

It has a flat floor and a diffuser. Any CART and Group C or LMP (etc.) with a third spring from the past thirty years would have been equally relevant. Venturi typically means to imply and hourglass profile beneath the car. The silhouette Tacoma is a ground effect vehicle in so far as any car with ground proximal aero devices is a ground effect vehicle; in the classic F1 sense it doesn't fit the description; no skirts, no venturi tunnels, no known instances of porpoising (on the mountain).

[SiLo]

You've actually described F1 porpoising fairly well there. The principals are largely the same. Variable downforce acting upon suspension and tires, with some suspensions able to cope with the variable vertical loads, and other not. Just like the modern F1 cars. Notice the majority of the content of the first vid is vehicle bodies hovering over intense suspension articulation i.e. floating over instances which would otherwise cause more severe vertical load variations.

The second vid is the 'bucking bronco', see-saw effect, which may be a component of some current F1 porpoising as well; yet to be confirmed or disproven. Mainly these videos were posted to get people to think about the underlying principals.

Agreed, they aren’t ground effect vehicles using Venturi tunnels like the Pikes Peak Tacoma I posted earlier.

It has a flat floor and a diffuser. Any CART and Group C or LMP (etc.) with a third spring from the past thirty years would have been equally relevant. Venturi typically means to imply and hourglass profile beneath the car. The silhouette Tacoma is a ground effect vehicle in so far as any car with ground proximal aero devices is a ground effect vehicle; in the classic F1 sense it doesn't fit the description; no skirts, no venturi tunnels, no known instances of porpoising (on the mountain).

Well that's only part of the problem really, they can still try and solve it aerodynamically as well.

[vorticism]

Yes, the 'variable downforce' part I wrote. If that can be solved, then no need for suspension tricks. Yet, we don't know if it can be fully omitted it based on the current regulations.