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Ferrari's front pullrod suspension. (self.formula1)

submitted ago by terror406

Now that everyone is done circlejerking about how pretty/ugly cars are, anybody have any clue how Ferrari managed to pull off (no pun intended) a pullrod suspension in modern raised nose design?

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[–]SchumacherDurandal1707 5 points6 points ago

It looks like they were just able to package everything in the bottom side of the nose well and still maintain structural rigidity which is the main problem from what I have read. The link posted shows that they managed to get the mounting point for the pull rod high enough on the front spindle to make it work, after that its just the geometry of the rocker arm inside the bottom of the nose that makes it work.

Although the center of gravity will be lowered, the main benefit is that they cleaned up the air above the upper wishbone to get more clean air over the top of the side pods and down to the rear floor of the car.

http://www.f1fanatic.co.uk/wp-content/uploads/2012/02/ferrari_f2012_2012-2.jpg

[–]Hamiltonsmokinghorse 4 points5 points ago

can anyone explain what pullrod suspension is and why it is advantageous and becoming more common now?

[–]Räikkönentlkuvic 4 points5 points ago

Pullrod suspension is similar to pushrod except the suspension member that actuates the bellcrank that compresses the shock/spring pulls on the bellcrank instead of pushing. Google a pic for clarity. The advantage is a lower center of gravity as the components are lower down (sensible).

[–]HamiltonBadBoyFTW 7 points8 points ago

No offence but you effectively just said;

"That thing you don't understand is like this other thing you don't understand except..."

[–]Alonsoafawgvsev 0 points1 point ago

I understood it.... You really need to see a pic

[–]Räikkönentlkuvic 0 points1 point ago

Thanks, though looking at it not at 2am does show that I wrote that pretty badly. On my phone, nonetheless.

[–]Räikkönentlkuvic 0 points1 point ago

Yeah, that was pretty bad. For anyone who still doesn't get it, read those articles that have been posted. They're pretty decent.

[–]Stefan Bellofzen_tm 1 point2 points ago

http://f1-dictionary.110mb.com/pushrod_pullrod.html

[–]Hamiltonsmokinghorse 2 points3 points ago

thanks for the answers

[–]magicRob 0 points1 point ago

Scarbs wrote about pull-rods a while back. It's the Red Bull variation that they brought back to F1 in 2009 after ~20 years of everyone using push rods.

http://scarbsf1.wordpress.com/2010/10/10/red-bull-pull-rod-suspension-what-is-looks-like-how-it-benefits-aerodynamics/

[–]terror406[S] 2 points3 points ago

Interestingly enough, the final paragraph of that article claims pullrod is not a viable option with todays cars:

Now the front of the chassis is raised too high for a pull rod to work, the angle from the upper wishbone to the chassis is nearly horizontal. This geometry meaning that almost no movement of the pull rod will occur as the suspension moves. Making the set up structurally inefficient.

[–]Räikkönentlkuvic 1 point2 points ago*

In FSAE, we package a pullrod suspension system under the car with less than 1" of ground clearance. It depends on where you mount the bellcranks (AKA rocker arms).

Edit: fuckup spelling

[–]Buttonrabbyt 1 point2 points ago

I assume you mean FSAE? To be fair the rules in FSAE and FS limiting the bulkhead and nose positions etc. are nowhere near as strict as in F1. There are a lot more limitations to where the F1 teams are allowed package their suspension systems.

I think the question was more about how they managed to fit the bellcranks under the front bulkhead and still stay within the rules? I think it's probably due to cunning placement of the pivot point for the rocker, if you could keep the entire rocker assembly above the bottom members of the chassis then it keeps it out of the way aerodynamically. Just a guess though, who knows what magic the Ferrari boys get up to when no one's looking...

[–]Räikkönentlkuvic 1 point2 points ago*

Witchcraft. Just plain Ferrari witchcraft.

On another note, are you on an FSAE team? If so, which one? Always nice to meet a fellow engineering student.

[–]Buttonrabbyt 0 points1 point ago

Of sorts, I worked with Concordia sae last year on exchange in Montreal, but I'm based in Glasgow and am in charge of the Strathclyde formula student gearbox. Formula student is essentially the same comp but with different sponsors cos its outside the US. What team are you with?

[–]Räikkönentlkuvic 0 points1 point ago

University of Victoria, BC

[–]Buttonrabbyt 0 points1 point ago

Ahh no way, I looked at trying to exchange out there, but my university only has links with the business school. It's kinda creepy how close we were to having met! Because if my school had sent me there we'd have undoubtedly been working together!

[–]Räikkönentlkuvic 0 points1 point ago

Haha that's awesome! As it were, I almost ended up going to Concordia for a little while.

[–]Buttonrabbyt 0 points1 point ago

No shit, that's awesome! I met a guy from Uvic who transferred to Concordia, wasn't an engineer though, its unlikely you'd have crossed paths... What comps does your team enter?

[–]Räikkönentlkuvic 0 points1 point ago

One per year, alternating between California and Michigan. This year it's Michigan. Always makes for a good drive.

[–]KobayashiBristolShambler 1 point2 points ago

One thing that interests me, is that most of the stuff ive read seems to suggest pullrods are beneficial because they allow tighter packaging and a lower centre of gravity. So aren't they slightly wasted on a high nosed car like the f2012? would they not be far more beneficial to a design like Mclaren''s, where they are trying to keep it slightly lower?

[–]terror406[S] 1 point2 points ago

Yeah, that is of course the other big question: why?

Durandal1707 suggested a cleaner airflow as another argument, but even that seems marginal to me.

In the past switching to pullrods wouldn't be such a big deal, but today you really have to come up with some new solutions to make it work in a high narrow nose. And with so little testing, it is a big risk Ferrari is taking for what appears to be just a slight benefit.

But of course that is exactly what they announced they would do with this year's car.

[–]Crucial_Xtreme 1 point2 points ago

Two different philosophies Bristol. McLaren like a lower nose, like they've had past 3 years & use the snow plow to help get air to the rear. Ferrari believe the step nose is the best way to get air to the rear for more d/f. The step nose has a higher CoG than the McLaren so Ferrari decided to use pull-rod to help compensate for the higher CoG and bring it down some. Ferrari believes the more air they can get under the nose the better. Simply two different ways to try and get to the same place.

[–]KobayashiBristolShambler 1 point2 points ago

true, but on this guy's blog, he seems to suggest the pullrod layout would be so compromised by the high nose that it wouldnt offer any CoG advantages.

ok, so its just some random guy's blog, but is it a fair point?

[–]gilles27 1 point2 points ago

you're comparing to McLaren though, it's Red Bull and co that they'll have a COG advantage over. they're hoping to have an under-nose airflow advantage over McLaren.

their problem will be the low angle the pull rods have to be set at to achieve a pull-rod set-up (any more horizontal and they'd be push-rods!) Very inefficient and very tricky to set-up.

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