On 06/04/2022, Bigbird <
bigbird.nospam.usenet@gmail.com> wrote:
I thought the explanation on F1.com during testing was simple enough...
and that didn't rely on an analogy to something else that most people
not understanding porpoising already probably wouldn't understand any
better.
https://www.formula1.com/en/latest/article.analysis-what-is-porpoising-and-why-is-it-causing-the-f1-teams-a-headache-at.6O93LlvFMyY81L9LfSutcS.html
While in general the simplest explanation is the best explanation, that
is not the case here. The movement itself is correctly described but the
reason why it becomes so aggravated on the W13 isn't really mentioned.
James Allison from Mercedes mentioned in one video that the media
pundits, such as the one on that video you linked, got it wrong. If the
reason was solely aero and simply caused by the downforce generated by
the underfloor making the car bottom down and then back up, every team
would have about the same levels of porpoising.
There are two main aspects behind it, damping and aero, in that order.
It's a compound problem, the bulk of the issue is probably related to
how well each team is able to control damping. It all starts with the
car being sucked to the ground, but this is a primary porpoising that
every team experiences and can, in most cases, be controlled with ride
height and changes to the design of the floor.
The real issue arises (like explained in the video I linked) from the
way the dampers react to this heave/pitch movement. The primary
porpoising generates a moderate oscillation movement but then the
dampers and general flexing characteristics of some cars, like the
Mercedes exacerbate it, to the point the floor could be damaged. It's a
bit like the natural oscillation frequency of their
suspension/damper/chassis combination happens to be very close to the oscillation frequency induced by the underfloor aero. This leads to a
resonance effect that magnifies the amplitude of the oscillation and
therefore a much harder problem to solve compared to other teams, which
don't happen to have a similar natural oscillation frequency.
The rear suspension seems to be a bit more critical and perhaps a real
fix requires a redesigned geometry. The way the chassis and power unit
flex may also be a significant factor, which again highlights the
difficulty Mercedes is facing.
I'm sorry for the long reply and I reckon the goal of a neat description
wasn't met, however this is a bit more complex and that's why engineers
who know much more than us haven't figured a way to address it properly
yet.
--
Vasco Costa
AKA gluon. Enthusiastic about computers, motorsports, science,
technology, travelling and TV series. Yes I'm a bit of a geek.
Gemini: gemini://gluonspace.com/
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