From: bill@Celestial.COM (Bill Campbell)
Subject: Re: driving in snow (or other low traction conditions)
Organization: Celestial Software, Mercer Island, WA
Date: Fri, 18 Dec 1992 20:38:01 GMT

In <47460@ogicse.ogi.edu> hakanson@bogart.cse.ogi.edu (Marion Hakanson) writes:

:In article <1992Dec17.045418.22907@eskimo.com> wix@eskimo.com (Dennis Wicks) writes:
:>Of course, if you are driving way over your head, or too fast for
:>conditions, and everything comes unstuck, hang on and pray to
:>whatever diety you prefer!

:In an earlier article,  mrc@Ikkoku-Kan.Panda.COM (Mark Crispin) posted
:a very good summary of vehicle dynamics, understeering, oversteering,
:etc -- good advice for how to avoid the situation described above.

:But once you do lose it totally, you can do something else while
:you're praying and hanging on.

:According to Sam Posey, in a Road & Track (Magazine) Performance
:Driving video I have, such a situation is one time that you should
:lock up the brakes.  The reasoning is that once you've spun the car,
:if the brakes are locked you are at least decelerating, and you will
:continue in a straight line in the direction you were last traveling
:(note that this may not be in the direction the car is pointing!),
:even if the car continues spinning around.  This is preferable to
:having the car shoot off at full speed in whatever direction the car
:happens to be pointing when the tires regain adhesion.

The first time I read about locking the brakes when there wasn't
an immediate opportunity to recover was an article by Denny Hulme
that appeared around 1972, I believe in Autoweek.  He pointed out
that locking the brakes when the car was going in a relatively
safe direction would cause it to continue in that direction where
it might decide to go someplace else entirely if the steering
takes effect again.  It may continue to spin, but it will travel
in a straight line if the brakes are locked.

:I think the idea is that unless you're Mario Andretti (or sons) in a
:properly balanced vehicle, you probably won't be able to recover from
:a spin without coming to a complete stop, and this is the safest way
:to accomplish that.

Shortly after I read the Denny Hulme article, I had an
opportunity to test the theory at Watkins Glen.  I was driving a
Formula Ford in an SCCA national race and came into the turn at
the end of the main straight with the car off balance because I
had just passed another car and tried to get back to the left
side of the track too quickly.  I lost it as I turned in (about
125MPH at that point) and realized that I couldn't recover.  If I
locked the brakes at that point I would have gone off the outside
of the track sideways, probably rolling the car.  Somehow I
remembered Hulme's article, and I grabbed a handful of RIGHT hand
lock (it was a right hand corner) which made the car spin faster.
Once it was spinning I then declutched, locked the brakes, and
downshifted from 4th to 1st.  The car was spinning down the
middle of the track at this point rather than off on a tangent
(the guy I had passed had a very strange look on his face that I
noticed as I went through 180 degrees :-).  When the car had spun
about 270 degrees I released the brakes and turned the front
wheels left into the spin straigtening out at about 70MPH and
continuing on the track.  I only lost about 3 seconds on that lap
and my pit crew thought someone had spun in front of me.

I had several opportunities to try similar maneuvers over the
years and it worked effectively each time.  It really was a crowd
pleaser when I did this right in front of the stands on the
Pocono short course coming out of the infield onto the main
straight.

:Note that this piece of driving strategy will not have to be called
:into play if you are able to follow Mark's advice and avoid spinning
:the car in the first place.

True enough, and generally easy to do on the street.  Few people
really have any idea what their car is capable of doing though
and over-react causing spins and accidents that could be easily
avoided if they knew what they were doing.

Bill
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