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[scotty]

A quite amazing video that gives some real insight into the front suspension design approaches made by some teams for this season and why they did what they did (ie pull versus push rod suspension). This one isn't for the faint hearted, it's relatively complex stuff.

[Denthúl]

Nice find, thanks for posting.

[scotty]

Yeah, that is a very good video that really gets into the true reasons behind things and explains everything very well indeed, i wish there were more like that. Scalabroni explained in 10 minutes what it took one of my uni lecturers an hour to explain.

Every F1 fan with a youtube account should sub to Peter Windsor imo... PS if anyone wants to see another great tech explaination like this about Coanda effect, it's on his channel too.

[What's Burning?]

Good find. I was absolutely fine until 6:25 or so, then I had to replay it from there a couple of times. When it finished I was bummed because I had about three questions I wanted to ask him.

[scotty]

Shoot and i'll try to answer your questions... it's good practice for me, i guess.

[What's Burning?]

First is how does the actual pull versus push work on the suspension dampers on the inside. Since you're changing the angle of the rod, you must also be considerably changing the angle or even entire location of the shocks or torsion bars.

Second he spoke about the tradeoff of x degradation of the tires per lap and the additional force applied on those tires via the Mclaren and Ferrari method versus the others, made it seem that the pull rods had less wear and tear on the fronts but didn't exactly say what the tradeoffs was other than the aero. Is the only other trade of being able to get the tires to temperature or are there other benefits? And how would a team make such a decision during the design phase of the car because it seems that's something you have to commit to from the beginning... so what's the break point that a team decides to go push versus pull?

He also spoke about 'roll axis' but I wasn't clear as to what he actually meant was rolling, is that the roll of the tire in the horizontal plane or the roll of the rods themselves?

[bud]

I understood the roll axis to be the centre of gravity.
From what I've read the pull rod allows a lower centre of gravity but also more aero room under the nose.

[scotty]

First is how does the actual pull versus push work on the suspension dampers on the inside. Since you're changing the angle of the rod, you must also be considerably changing the angle or even entire location of the shocks or torsion bars.

The dampers and third spring are mounted completely differently, yes. Basically a pull rod setup is 'upside down' to a push rod. Compare these neat drawings of push and pull. This tells you what each part is.

Second he spoke about the tradeoff of x degradation of the tires per lap and the additional force applied on those tires via the Mclaren and Ferrari method versus the others, made it seem that the pull rods had less wear and tear on the fronts but didn't exactly say what the tradeoffs was other than the aero. Is the only other trade of being able to get the tires to temperature or are there other benefits? And how would a team make such a decision during the design phase of the car because it seems that's something you have to commit to from the beginning... so what's the break point that a team decides to go push versus pull?

Well, firstly note that he implied that the pull rod cars will be harder on the front tyre wear as it puts more stress through the tyre (this is how they heat up faster), not that the pull rod setup reduces tyre wear. The true trade off is aero vs tyre wear vs tyre heating, all three are considered. How the teams reach a decision on this will be (i suspect) based mostly on prior data and knowledge and where they think the biggest gain is to be made relative to what they had before. It is not black and white by any means - a suspension arrangement that increases tyre wear may also allow aero gains that reduce tyre wear overall!

He also spoke about 'roll axis' but I wasn't clear as to what he actually meant was rolling, is that the roll of the tire in the horizontal plane or the roll of the rods themselves?

Lateral chassis roll around the roll centre? I'm not sure which part you refer to exactly cause he also touched on pitch (longitudinal) roll under braking, but i think that is what you are asking.

Hope i kinda answered your questions... disclaimer: pure dynamics aren't really my expertise, plus it's 3am and i've had a buncha beers...!

[What's Burning?]

So scotty this is what you go over in class? It's got to be a pleasure going to school actually. Do you guys have any 'hands on' type of classes where you design scale models or build some types of RC cars etc to understand the mechanical aspect of the cars?

[Jabberwocky]

I just wrote a massive lot of things about this video and them my computer restarted damn you Microsoft updates.

in short nice video... will post the questions again once I have calmed down!

[What's Burning?]

I just wrote a massive lot of things about this video and them my computer restarted damn you Microsoft updates.

in short nice video... will post the questions again once I have calmed down!

Cowpie virus?

[Jabberwocky]

You can see why Mclaren have gone for the Warm your tyres up and burn them out quicker approach. I would imagine that it plays to the strengths of there drivers.

I found that video very good, I had never considered the sine change of suspension travel causing lateral degradation to the tyres. what worries me is that I understood it.

the roll center also affected by none parallel wishbones as well I think

[Jabberwocky]

I just wrote a massive lot of things about this video and them my computer restarted damn you Microsoft updates.

in short nice video... will post the questions again once I have calmed down!

Cowpie virus?

It is a top meal... you should try it.

[scotty]

So scotty this is what you go over in class? It's got to be a pleasure going to school actually. Do you guys have any 'hands on' type of classes where you design scale models or build some types of RC cars etc to understand the mechanical aspect of the cars?

We have touched on this kind of specific thing yeah, but never in what i'd consider to be true all encompasing depth. I try to fill in the gaps sort of thing on my own. There are other areas where i have learnt more in depth things though, setup and stuff. I know more about that. Which is good i guess cause ultimately i don't want to design parts, i want to be given them and i'll get them going as fast as possible. It is fun at uni for the most part, yeah. There's some insanely boring sides to it though, learning about 'pure' engineering isn't very interesting for example. But i am so glad i waited until i was 23 when i KNEW what i wanted to do rather than following through a shitty degree at 18 like most people do, and i nearly did.

There were a series of classes called 'Auto Lab' near the start where we took racing components (gearboxes, engines, etc) apart, and did some suspension setup work on real former racing cars (a couple of which are pictured below). THAT WAS AWESOME. Held 10 grand's worth of USF1 F1 clutch in my hand too!

DSC00025.JPG

the roll center also affected by none parallel wishbones as well I think

Yeah but usually only oval cars have them set like that when static, otherwise it'll create some weird handling...

[bigpat]

Hi all,
To my knowledge, the roll axis is the longitudinal line that runs between the front and rear roll centres. Typically on an open wheeler, the front r/c is at ground level, and the rear 50-100 mm above it. So the roll axis slopes uphill from front to rear.

Why it slopes up, has to due with the centre of gravity at each end, roll centre, roll couple, and ultimately roll stiffness.

As for push vs pull rod setup, I think besides centre of gravity, I think the differences lie better motion ratio available with pull rods with todays anhederal wishbone installations, and secondly, packaging options...

Pat