Torsional stiffness of the engine in 2022

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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Zynerji
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Torsional stiffness of the engine in 2022

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In Dr. Mario Theissen's paper that BMW published about their F1 engines several years ago, he clearly states his surprise at how much he misunderstood the torsional requirements of the engine at first. He thought the chassis would want an ultra- stiff engine, but he quickly learned that was not the case. I don't recall that he ever stated exactly why the chassis wanted a more compliant block, so I wanted to poll the audience.

Does anyone know why? And is it possible that the return of tunnels and compensating suspension geometry would benefit from a different stiffness?

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DiogoBrand
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No idea what's the right answer, but as far as I can tell the first generation of BMW engines in 2000 were quite heavy. So perhaps the benefit was the lower weight, and not the decrease in stiffness that resulted from it.

Hoffman900
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Re: Torsional stiffness of the engine in 2022

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Do you have the quote and the context it was presented in? I'm curious what was said and how it was said.

Chassis will resonate, and I believe he might be getting at that. I personally know an example that went into resonance on a shaker rig, and almost flew off. Yikes!

Remember, Formula cars and the like only operate at a couple mm of suspension travel, they're very sensitive to these things.

That said, it could be a weight thing, but you don't want any critical dimmensions inside the engine flexing AT ALL. That's a seized engine or a lot of blowby.

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Zynerji
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Re: Torsional stiffness of the engine in 2022

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Hoffman900 wrote:
Wed Feb 23, 2022 5:09 am
Do you have the quote and the context it was presented in? I'm curious what was said and how it was said.

Chassis will resonate, and I believe he might be getting at that. I personally know an example that went into resonance on a shaker rig, and almost flew off. Yikes!

Remember, Formula cars and the like only operate at a couple mm of suspension travel, they're very sensitive to these things.

That said, it could be a weight thing, but you don't want any critical dimmensions inside the engine flexing AT ALL. That's a seized engine or a lot of blowby.
https://redirect.viglink.com/?format=go ... BMW_F1.pdf

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Zynerji
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I found the pdf, and it wasn't exactly how I was remembering it. He just states that his concerns weren't warranted.

Mods can delete post. Thanks!

Can Google Fmoteurs_BMW_F1.pdf if u want to read for yourself.

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Holm86
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Re: Torsional stiffness of the engine in 2022

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Hoffman900 wrote:
Wed Feb 23, 2022 5:09 am
Do you have the quote and the context it was presented in? I'm curious what was said and how it was said.

Chassis will resonate, and I believe he might be getting at that. I personally know an example that went into resonance on a shaker rig, and almost flew off. Yikes!

Remember, Formula cars and the like only operate at a couple mm of suspension travel, they're very sensitive to these things.

That said, it could be a weight thing, but you don't want any critical dimmensions inside the engine flexing AT ALL. That's a seized engine or a lot of blowby.
I also read at one point that when they tried carbon fiber frames in motorcycles they were way too stiff, and the harmonics caused problems. So they actually preferred the more twisty metal frames, until they discovered how to layer the carbon, to get the rigidity in the right directions

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Holm86
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Tommy Cookers
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this is what is necessary for the frame to do the suspension's job

if the suspension had to do the job of suspension the resulting vehicle wouldn't look like a motorcycle

Hoffman900
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Re: Torsional stiffness of the engine in 2022

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Everything on a motorcycle is different. They started figuring out the too-stiff frame thing in the early 1990s. The chassis + swingarm is a significant part of the suspension at lean. How you even design the engine to work is different, a lot more part throttle work than a car and power has to be tractable.

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Zynerji
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Re: Torsional stiffness of the engine in 2022

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I believe American Sprint cars are also a twist-by-design anomaly...

Tommy Cookers
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Re: Torsional stiffness of the engine in 2022

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Zynerji wrote:
Wed Feb 23, 2022 10:23 pm
I believe American Sprint cars are also a twist-by-design anomaly...
of course ...
torsional stiffness needs to be a v.high multiple of suspension stiffness only to adjust cornering 'balance' by ARB effect