These thoughts are definitely intrigueing, and
certainly border on the "mysterious". If front
wheel steering is generally accepted as best, why
haven't boats rudders been moved to the bow? If
the boat's rear steering is best, then all of our
questions about "Why haven't teh sterring wheels
been moved to the back?" are quite valid. Having
raced both, it does seem to me as though the rear
steering on a boat is slower than the front
steering on a car, and thus should be better for
a land speed car, but....?
Dick J
--- john robinson <john@engr.wisc.edu> wrote:
> Howdy,
> I think the main difference in a Rear
> Wheel Steer vehicle while
> doing course corrections, is the lack of
> perceived motion in the desired
> direction; because the rear of the vehicle is
> going in the opposite
> direction (vehicle tail goes left while the
> driver wants the direction of
> the vehicle to be going right), which is
> opposite to the "normal" driving
> feel. The comment of driving to a correction
> indicator is not bad, a long
> painted line on the hood in conjunction with a
> pressure probe attached to
> the nose which would effectively lengthen the
> nose of the vehicle, giving
> the driver a long pointer to view the actual
> direction of the vehicle,
> especially if the driver is as far back in the
> vehicle as possible. I
> believe a RWS vehicle comes down to driver
> adaptability/skill, more than
> the dynamics of FWS vs. RWS..
>
> (the rear wheels skid to the outside of the
> turn in a "normal" Front Wheel
> Steer) while in a RWS
>
> At 09:55 AM 6/7/00 , you wrote:
>
> >A picture is worth a thousand.......
> >
> >Having thought about this some more, Jon,
> you're right about kid's toys and
> >what you are brought up on, as I said a few
> days ago, boats (and for that
> >matter most aeroplanes) manage by steering
> from the wrong end.
> >
> >The problem with rear steer is that it
> requires anticipation (and a blind
> >faith in the future) on the part of the
> driver. Consider a car off the
> >desired centre line, within the limitations of
> the character set (you'll
> >need to select a monospaced font for this like
> Courier or Lucida):
> >
> >(For the example we'll assume a simple reverse
> tricycle for the rear steer,
> >I can't cope with trying to get offset rears
> to look right)
> >You start a fair way offline, and turn towards
> the line:
> >
> > | |
> > | |
> > +-------+ | +-------+ |
> > | / / | | | | | | |
> > | | | | | |
> > | | | | | |
> > | | | | | |
> > | | | | | |
> > | | | | | |
> > | | | | | | \ | |
> > +-------+ | +-------+ |
> > | |
> > | |
> >
> >
> >Once heading back towards the line you
> straighten up
> >
> > / | / |
> > / / | / / |
> > / / / | / / / |
> > / / | / / |
> > / / | / / |
> > / / | / / |
> > / / | / / |
> > / / / | / / / |
> > / / | / |
> > / | / |
> >
> >
> >This is where it gets to be different.
> >With a front steer you basically get to the
> line and point the wheels down
> >it (obviously there's a progression, but you
> get the idea).
> >With rear steer, you need to correct BEFORE
> you are aligned (like turning
> >the back of a boat in against the dock).
> >
> > | |
> > | |
> > / | / |
> > / | / / |
> > / | / / / /
> > / / / /|
> > / / / / |
> > / / / / |
> > / / / / |
> > / / /| / - / |
> > / / | / |
> > / | / |
> > | |
> > | |
> >(sorry about the "-" for the rear wheel, but
> there's nothing between that
> >and "/" in the character set - I'm sure you
> get the idea)
> >
> >
> >Once you're back online, everything's hunky
> dory:
> >
> > | |
> > | |
> > +-------+ +-------+
> > | | | | | | | |
> > | | | |
> > | | | |
> > | | | |
> > | | | |
> > | | | |
> > | | | | | | |
> > +-------+ +-------+
> > | |
> > | |
> >
> >
> >Except that you have to effectively anticipate
> the correction to each minor
> >deviation in the same way. I'm sure you
> could condition yourself to it,
> >but at the end of the day is it worth learning
> a whole new driving style?
> > It's also worth noting that neither boats
> or planes are so concerned
> >about accurately following a line; they
> concern themselves only with the
> >next waypoint, so maybe in today's non-SA GPS
> era the solution is in
> >driving to a correction indicator rather than
> what you see out of the
> >window.
> >
> >It's all very well my saying all this - the
> likelihood of ever having to
> >prove it is zero. Good luck to any of you
> guys who have the ability,
> >money and commitment to actually try any of
> this out.
> >
> >
> >Jon Hobden
> >Horley, England
>
>
> John Robinson, Mechanician
> Mechanical Engineering University of
> Wisconsin
> 1513 University Ave.
> Madison, Wi. 53706
> 608-262-3606
> FAX 608-265-2316
> Current World Land Speed Record Holder
> Bonneville Salt Flats
> H/GCC 92 cu.in. 1980 Dodge Colt
> 131.333 MPH set 1995
> 136.666 MPH set 1996
>
>
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