rec.autos.simulators

  GPL Replay Analyzer (which is marvelous) has the ability to graph "slip
angle."  My question is, is this really slip angle in the vehicle dynamics
sense or is it actually yaw?  From a physics point of view, they're two
different things.  I was just curious which one I'm actually looking at
when I use GPL RA.  If it's actual slip angle, which corner of the car is
it?

Thanks,
Bill

--
                    | "Instead of letting the moon be the
Bill Mette          |  gateway to our future, we have let
Enteract, Chicago   |  it become a brief chapter in our

Hi Bill,

Well, you tell me! :) I've seen many definitions of slip angle, but
the one we use is(from the readme):

"The slip angle available in the graph is defined as the difference
between the direction the car is traveling and the direction the nose
of the car is pointing. This means we don't (yet) take into account
the angle of the front tires."

It's for the rear,

Cheers,

/Martin

Hi Martin,
  Thanks for answering so quick.  Guess if I would have been thinking, I
would've gone back and read the README again.  Technically speaking, I
think what you guys are grabbing is yaw.  But from a pure engineering
point of view, even that would only be true for the difference between the
driection of the car's center of mass and the direction the nose is
pointing.  Slip angle (as I've read it) is basically the difference
between the direction a tire is pointing and direction that the *** at
the contact patch is travelling.  Caroll Smith's books do a really good
job of explaining it.
  Anyway, as long you guys define it yourselves in the README it doesn't
really matter.  I was just curious about what information you're
grabbing from GPL.  Keep up the great work with Replay Analyzer!
--
                    | "Instead of letting the moon be the
Bill Mette          |  gateway to our future, we have let
Enteract, Chicago   |  it become a brief chapter in our

Yes, I read that too. But then I read the definition we use and a
couple of others.

Thanks!

BTW, the slip angle (or whatever) we use isn't stored in the rpy-file
but has to be calculated from the driving lines and orientation of car
(which is stored).

/Martin
.