rec.autos.simulators

Hey, did any of you ever notice that the ackerman (sp?) effect
is backwards in ICR2. Turn your wheels and take a look at them. Notice
that the outside tire turns further than the inside tire. Now, if you're
going around a corner, the inside tire must go around a tighter turning
radius than the outside tire, so why does the outside tire turn further
than the inside tire. Looks like Papyrus needs itself some engineers or
mechanics working for them 'cause this is the first thing that my brother
and I noticed. Actually, it kind of annoys me, how about including this
in the patch file Papyrus?

-Dan? (the Skinny Puppy)

        The night lifted,
        Leaving behind it a grayish light the color of stagnant water.
        Soon there was only a tattered fragment of darkness,
       *** in midair,
        On the other side of the window.
        Fear caught my throat.
        The tattered fragment of darkness had a face.
        Looking at it, I understood the reason for my fear.
        The face was my own.

Boy do you have a lot of time on your hands when you race.  What are
your lap times anyways.  Lord, you can't be going too fast to look at
your tires.  Anyways, I am just glad to see somebody actually racing an
indycar.  Most everyone who posts to this newsgroup can't even see their
tires spin, if you know what I mean.  I guess you're right though.  If
you're gonna make a simulation, you better make it real.  Later! :)

Gary

: Hey, did any of you ever notice that the ackerman (sp?) effect
: is backwards in ICR2. Turn your wheels and take a look at them. Notice
: that the outside tire turns further than the inside tire. Now, if you're
: going around a corner, the inside tire must go around a tighter turning
: radius than the outside tire, so why does the outside tire turn further
: than the inside tire. Looks like Papyrus needs itself some engineers or
: mechanics working for them 'cause this is the first thing that my brother
: and I noticed. Actually, it kind of annoys me, how about including this
: in the patch file Papyrus?

Amazingly enough, this is probably correct.  Racing cars use
reverse-Ackermann steering geometry in order to increase the grip
of the outside tyre at the expense of the inside tyre.  Tyres "slip"
when cornering (actually an elastic distortion of the tyre causes sideways
motion).  Tyre grip peaks at a certain slip angle - 3 or 4 degrees
in a racing tyre.  By turning the outside wheel more, you increase
its slip angle (and decrease the slip angle of the inside tyre),
putting the outside tyre, which takes most of the load, closer to
its maximum grip.

Reverse-Ackermann steering is not used on road cars because it
increases rolling resistance in corners, and there is a lot less
weight transfer at normal road speeds.

Looks like Papyrus _do_ have some engineers or mechanics working for
them (or at least someone who's read a racecar engineering textbook:-).

For those who want to know more about reverse Ackermann, see "Tune to Win"
by Carroll Smith.  It's just one viewpoint, but it's thought provoking, as
Smith usually is.

                      bob