problem.
It might affect roll couple distribution, though - a high enough rear
RC would be
equivalent to locking up the rear ARB...
Jonny
problem.
It might affect roll couple distribution, though - a high enough rear
RC would be
equivalent to locking up the rear ARB...
Jonny
jonas
The Beckman numbers are correct and were taken from the book by
Giancarlo Genta (uhm, "Modeling and Computer simulation"?). Indeed,
there's a few things missing from these Ferrari numbers, which IS load
sensitivity. There are more examples in the book (5 actually) which DO
include load sensitivity, although these are very small numbers (but
ofcourse, the loads get quite high, in the thousands).
And as for u>1, yeah well, like Gregor & Todd said. :) Even the tires
on your own car will probably go higher than 1. Take a hook around a
bar, pull that; it gets 'more than 1' because it grips, not slips.
Same for materials like ***, which grab hold of the road more than
just sliding. For really slipping materials, I'd think the
Flateral<=Fnormal would be correct, although I don't think such
materials exist on this planet. ;)
Ruud van Gaal
Free car sim : http://www.racesimcentral.net/
Pencil art : http://www.racesimcentral.net/
Good point. Perhaps if he ran a high roll center at the front it would keep
his car more understeer?
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Perform a test where you slowly increase the steer signal
while maintaining a constant speed on level ground.
Does the eventually car spin out? (Final Oversteer)
Or does the lateral acceleration received reach a peak
at some steer angle and then drop off at higher steer angles
(Final Understeer).
Presumably, you have a car that is final oversteer.
If even in this very benign case, the car will spin out.
If so, reduce the torque capability of the front end until
this doesn't occur through changing the tire lateral capability.
(Which can be done with friction coefficients and/or through
load sensitivity - for example: changing Anti-Roll Bars to
change the amount of lateral load transfer betwen the fronts and rears.)
The other test you might do is a step steer test.
Step the steer signal (not necessarily to full lateral G level)
and watch the car respond in yaw and lateral acceleration.
If it doesn't respond as you like (stably and damped) then
you have either (or both) a static stability problem
or a damping problem or ...
Subtle changes in the tire properties can affect the results
greatly.
> jonas
> > Are you sure this is a problem? Typically this is what would happen in a
> > real car, where the after the opposite lock is performed the rotation in
> > the other direction can be even more severe if you don't anticipate for
> > it. I know, it happened to me once :).
> > -Gregor
hmm, not quite.. i can make car setups wich tend to understeer and with
those i can get through the curves ok. the physics feel realistic to me
until the moment i begin to counter-steer in oversteer situations. but
at that point the car begins to spin into the opposite direction and is
much harder to catch again, so that in the end i never manage to regain
control. the problem might somehow by related to the inputs i pass to
my car, but i can't really think of how.
this always depends on how fast i go, and how fast i increase the
steering signal. i'd say i can create both setups. but with any setup i
use i have the problem that once the car spins out for some reason it
is lost.
jonas
actually i just tried decreasing my cars front torque capability, and
it is getting better. i'm not where i want to get yet, but i'll keep
trying. i guess i was just overestimating the effect of
counter-steering versus what can be done by regulating throttle (RWD
vehicle) in my setups.
thanks for the helpful messages everbody sent.
jonas