Newsgroups: rec.autos.simulators
Path: news.jprc.com!dca1-feed2.news.digex.net!digex!news1.radix.net!tor-nx1.netcom.ca!news.maxwell.syr.edu!newshub.northeast.verio.net!logbridge.uoregon.edu!news.acsu.buffalo.edu!freenet.buffalo.edu!bd427
From: Doug Milliken <bd427@freenet.buffalo.edu>
Subject: Re: Understeer in open wheeled sims are gonna get better
In-Reply-To: <36630C28.4014@mci2000.com>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Message-ID: <F39p47.Bpt@freenet.buffalo.edu>
Sender: nntp@freenet.buffalo.edu
NNTP-Posting-Host: freenet.buffalo.edu
Organization: Buffalo Free-Net
References: <738nn8$fei$1@nnrp1.dejanews.com> <F2usLo.2zD@freenet.buffalo.edu> <73g7sh$2oq$1@nnrp1.dejanews.com> <365C2E74.672E@mci2000.com> <F342s1.GDE@freenet.buffalo.edu> <36630C28.4014@mci2000.com>
Mime-Version: 1.0
Date: Tue, 1 Dec 1998 03:45:24 GMT
Lines: 53
Xref: news.jprc.com rec.autos.simulators:61146



On Mon, 30 Nov 1998, Pat Dotson wrote:

> Doug Milliken wrote:
> > 
> > >      |         ---
> > >      |        /   \
> > >      |       /     -------------
> > >      |      /
> > > LF   |     /
> > > lbs  |    /
> > >      |   /
> > >      |  /
> > >      | /
> > >      |/
> > >       ---------------------------
> > >          SA (degrees)
> > 
> > at the front and rear of the print.  Crudely like the plot below, where SA
> > is to the same scale as the plot above.
> > 
> >  AT     |     /\
> >  lb-ft  |    /  \
> >         |   /    \
> >         |  /      \
> >         | /        \
> >         |/          --\
> >          ---------------\====\---------======
> >            SA (degrees)        \------/
> 
> 
> Ah, so peak AT does coincide with the onset of
> peak LF.  Cool.  That means that FF effects
> should mirror real life steering forces,
> doesn't it?

No -- look again.  The peak AT happens at something like 1/2 the slip angle
for peak LF (but not exactly 1/2).  By the time you get to peak LF, the AT
is down near zero.

> Does AT change depending on over/understeer?

Not as such...it's a tire property, so it changes with load, traction/
braking, camber, etc., and of course, slip angle.  Of course if your car is
wildly oversteer at the limit, you may have to spin out to get the front
tires to a high enough slip angle to be at their peak LF...! 

I think I'm cutting into book sales by now...so I'd better quit this
thread.

-- Doug Milliken

