Susp rates

Niels_at_home said:
Not quite true however! Telemetry has the suspension position which is actually the spring length. When motion ratio is 1, and each corner has 2000N of sprung load, with a 50.000N/m spring, the 'suspension position' telemetry will be 40mm with the car at rest. It is wrongly named in telemetry. I also think it is measured on the pushrod so it doesn't measure wheel displacement.
Click to expand...

But then again, if my pushrod is vertical as you suggested (and since mult are for force, not for displacement) i can assume the movement i see in Motec is a wheel kynematic movement (which, for rF is then equal to spring movement because of the geometry in use), right?
 
Niels_at_home said:
Not quite true however! Telemetry has the suspension position which is actually the spring length. When motion ratio is 1, and each corner has 2000N of sprung load, with a 50.000N/m spring, the 'suspension position' telemetry will be 40mm with the car at rest. It is wrongly named in telemetry. I also think it is measured on the pushrod so it doesn't measure wheel displacement.
Click to expand...

In what case would it not true?

I guess technically I should have said the body moves, but it is a bit: Tomaytoe, Tomahto. I find it easier to visualize as the wheel movement since it isolates that particular corner. Wheel moves up, body moves down, same relative motion.

If you consider that the soft limits of suspension travel are defined as the vertical position of the wheel, it seems to follow that the telemetry being dumped for suspension travel would be a component of that. Why would rf bother to calculate spring compression? Spring compression is abitrary when you don't have location, and other defining parameters. What is being dumped as telemetry are things that are already being used for calculation. rF doesn't care about how compressed your springs are. rF does however do things differently (bumpstops) at a certain vertical wheel displacement.
 
I didn't say it makes sense the way it is done, just that it is done this way. :)
 
Happy new year everyone!

just looking for a confirmation about a doubt i have.

Talking about dampers, for example:

BumpStage2=0.025
ReboundStage2=-0.025
SlowBumpRange=(3000.0, 250.0, 21)
SlowBumpSetting=14
FastBumpRange=(1500.0, 250.0, 21)
FastBumpSetting=6
SlowReboundRange=(4000.0, 500.0, 21)
SlowReboundSetting=12
FastReboundRange=(2000.0, 500.0, 21)
FastReboundSetting=6


Is it fair to assume that all the forces that could be calculated by the values specified here are to be then multiplied by the DamperMult value?

so if, for example, i would have a force equal to y at a speed equal to x than it would mean the real force at the wheel would be equal to y*DamperMult...is it a fair assumption?

what about the "damper" speed? do the multipliers work somehow on them as well or they are simply considered to be the speed at which the wheels move vertically?

Thanks!
 
Take whatever value have for damping and multiply it by what you have for DamperMult. THEN, rF takes that through suspension geometry (if you told it to do so and how with AdjustSuspRates parameter).

Again, DamperMult and SpringMult are basically a simple simulation of pushrod levers.

In other words, if you have spring 100N/mm and SpringMult=0.6, then it's the same like you'd have spring 60N/mm and SpringMult=1.0
 
Just following up on Niels' method of putting the pushrod at the centre of the wheel.

Bristow says "=1 means the wheel rates are adjusted only for the location the lower end of the pushrod relative to the inner and outer mounts of the wishbones."

So we have a discrepancy. According to Bristow to get spring rate=wheel rate you should attach the pushrod to the outer end of the wishbone, not the wheel. Indeed, if Bristow is right you might get a motion ratio larger than 1.0 if you put the pushrod on the centre of the wheel, i.e. outboard of the end of the wishbone.

I will try to do some testing with wheels set far away from some fairly short wishbones, but wondered if this has already been tested.

Also I assume the physics engine uses the lower wishbone only, that you can't attach the pushrod to the upper wishbone.
 
what Niels meant was that, if you attach the push to the wheel center and you make it vertical and very long, Motion Ratio is approximately = 1.
 
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