Suspension Ideas and Questions

[747heavy]

How did this car steer, looks like that part is missing.

In the second photo you see the steering rod & steering arm better.
back at this time, not every F1 car had their steering rack infront of the front axle.

[DaveW]

Informative & well illustrated post, Ciro. I think you must be in quite good shape....

I would like to comment on a couple of things. The first:

...on hard suspensions, as God intended for race cars to have, it's minute....

Yes.. but compromise is key for a "good" suspension set-up. Tightly sprung race vehicles "work" their tyres, limit sprung mass movement, & make the vehicle respond quickly to driver inputs. However, race vehicles normally encounter vertical disturbances from track irregularities, kerbs & driver inputs. These result in stored disturbance "energy" that must be dissipated efficiently whilst minimising vertical tyre load disturbance (which can also cause loss of grip). That is one function of dampers, & they can perform only if they are allowed to move. It is a fact that, when the ratio of tyre/suspension deflection exceeds unity, increased damper settings are likely to reduce damper work done per cycle. It follows, I think, that an upper limit exists to (average) spring stiffness for a "good" mechanical set-up, & that will depend upon tyre stiffness.

The second:

...I guess that's one of the reasons why good F1 drivers start at kart races, because the suspension of an F1 car, at 600 kilos, and with such large tyres, moves very little...

It is certainly true that F1 vehicles use very stiff springs - at the front axle, & in heave. Suspension stiffness is, in my experience, rather different at the rear axle, & in roll at both axles - at least it is for "mechanical" corners when rear axle heave stiffness is usually amongst the lowest to be found amongst open wheel aero race vehicles in a similar condition.

I have no experience of karts, but I suspect that they do have a suspension - the chassis. I also suspect that they have an adaptive "mass damper", that happens to wear a helmet....

[riff_raff]

DaveW is correct about karts. While they do not have a conventional suspension, they still have many chassis adjustments that can be made to change handling. The spindles can be changed for caster, kingpin, camber, offset, etc. Tire pressures can be changed. Wheel spacers can be used to alter track. And some classes use an interchangeable rear chassis bar to alter torsional stiffness.

[KSP]

I want to apply more realistic values for one of the F1 mods of rFactor. So my question is - what are the typical average values for some of F1 suspension parameters:
- kingpin inclination
- kingpin offset
- caster, camber, toe
- wheel rated stiffness of front/rear ARB, springs, 3rd springs, their 4-way dampers
- damper speed when slow value change to fast?
Any info about any of these parameters please!

[Jersey Tom]

Why bother when the tire model (which has the absolute biggest impact IMO) isn't realistic?

[KSP]

I've already done tires at a fairly reasonable level.
So what about suspension parameters?

[Belatti]

DaveW is correct about karts. While they do not have a conventional suspension, they still have many chassis adjustments that can be made to change handling. The spindles can be changed for caster, kingpin, camber, offset, etc. Tire pressures can be changed. Wheel spacers can be used to alter track. And some classes use an interchangeable rear chassis bar to alter torsional stiffness.

Front and rear

http://www.f1technical.net/forum/viewtopic.php?f=6&t=6311&start=30

[Jersey Tom]

I've already done tires at a fairly reasonable level.

How exactly have you done this?

[KSP]

I've already done tires at a fairly reasonable level.

How exactly have you done this?

I answered you in PM, but haven't yet received a response. Maybe I asked too much? Can you just correct my mistakes there?

[delacf]

Other matters: I do not know if this is the right place.

I have been thinking about studying the possibility of using some kind of "plastic" to the pull rod. The pull rod would be changed for each race. What do you think about this? The problem I see is the low Young's modulus of these materials. Maybe if I have this in mind for the design of the suspension ¿?

Regards,

delacf

[DaveW]

Interesting idea, delacf, & it has been done before, though not deliberately (look closely at this). If "mechanical" control is important, then the requirement to install a damper across the "spring" might outweigh any theoretical benefits.

[C09]

Hey, I'm working on an interesting and promissing radiacl suspension geometry configuration, I'll post it when it's finished.