rec.autos.simulators

So which way is it? Loose car- ie.rear-end hits the wall before the
front ;o/- more rear weight bias or less??

I believe it should be more but I keep seeing advice to use less. Is
this a sim issue with the sim being different than actual racing? Or am
I just interpreting the weight transfer wrong?

Thanks,
AKH

More rear bias. When your car accelerates, it forces weight to the rear of
the car. If more weight is in the rear to begin with the effect is less
dramatic.
It also depends on if your car is loose entering or exiting turns. Shocks
and tire pressures as well as cross weight can also cause the car to be
loose. What track r you at ? Need more info to help u.

Don Clawson
DonC - Hawaii

I get the impression that the Papyrus sim doesn't take into consideration
that more load on a tire generates more lateral force, but instead only
model the change in the center of mass when you move weight around.

For a more detailed explanation of setting up a car, see:

  http://www.sequoia-dev.com/Hawaii/Features/setupguide.html

Dave (davids) Sparks
Late Night League
http://www.sequoia-dev.com/Hawaii/latenite.html

I get the impression that the Papyrus sim doesn't take into consideration
that more load on a tire generates more lateral force, but instead only
model the change in the center of mass when you move weight around.

For a more detailed explanation of setting up a car, see:

  http://www.sequoia-dev.com/Hawaii/Features/setupguide.html

Dave (davids) Sparks
Late Night League
http://www.sequoia-dev.com/Hawaii/latenite.html

  I don't normally post, but this one hit home for me.  I have puzzled
over this point for about a year now.  Since NCR came out, I have used
thought I was running fast until hawaii went open...

  Last June I went to the 3 day skip barber school, had a great time and
learned some things.  The lesson that applies here really was about weight
transfer, but I applied it to the F/R bias. Bruce McGinnis (great guy) was
always talking braking once and accelerating once per turn. Why are you
lifting at the exit of the turn?? The reason you are lifting is not to
slow down enough to make the turn, it's because when you lift weight is
transfered to the front giving more cornering force. Yes you do slow some
which fits the speed=radius*grip(G), but the extra load on the front is
what keeps you from dropping two wheels or slapping the wall. I learned
this lesson the hard way, I spun my formula car on the first day after
doing a pedal snap when the car got a little out of shape. The other
lesson I learned was "if you spin, both feet in", it works!

  I'm not very good at creating setups from scratch, but a friend put
together a good Atlanta setup for me.  While I could  manage 185-187mph
race laps, I was still getting passed in the middle of the turns.  For
some reason the weight-transfer lesson came to mind about two weeks ago.
After changing the Rear bias from 50.4 down to 49.5, I can now run 175mph
in the middle of the turn instead of the 171-2 I was doing before.

  I have since moved my atlanta setup to every single track, and with the
exception of the road-courses and phoenix, I run faster than I ever have
before.  Even at Marty with the gears same as Atlanta, I can run 99mph
after a few laps. Tally was about the same speed, but the TRI became very
drivable.

  I don't know if other people can drive the setup with the same results,
but I'll email the basic building block to anyone who wants it.

John Mullins
jmullins/vortex on hawaii

Folks - these are two different things... In fact, weight transfer has the
*opposite* effect of static weight distribution.

Here's why: (For in-depth explanations see the *** to Win series by the author
whose name I'm blanking out right now)

- Static weight: All other things being equal, shifting the center of gravity
of the car should have no effect on the balance - you've got increased lateral
force required, but you've got the same amount of vertical force; should be
a wash. What actually changes the balance is the effect of the extra weight -
The weight deforms the tire, which in turn deforms the contact patch... As
a result the coefficient of friction of the tire goes down... Thus, more front
weight for a tighter car, more rear weight for a looser car.
- Weight transfer: Weight transfer, on the other hand, is a dynamic effect
which operates only in one axis - By decelerating, more normal force is
applied to the front contact patch, but the center of gravity is not shifted
forward. As a result, no additional lateral force is needed to turn that
end of the car, and the front grips harder (despite the fact that the tire
deforms as a result of the extra force). The rear wheels, of course, are
"lightened" by the equivalent amount, and thus may start sliding.

-- Ulrich

Weekend Racer.  Gotta Lovitt
work hard and spend your money
racing.

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