for what little it is worth.....Rear steer??
Don't airplanes turn primarily with the ailerons and the rudder????? Oh
yeah don't they also move in 3 dimensions during a turn??? Don't they
have a lot of sky to turn in ??? Rudder on the front?? aren't they
actually doing thrust vectoring from the prop more than ruddering as in
a sailboat. if you put the prop in front with the rudder might work just
fine as long as you went slow enough to keep it in the water. My
powerboat turns in 2 dimensions other than very slow at the dock when in
fact it is usually easier to back in than turn into the slip. BTW
everyone I know that has a twin engine boat can get more steering from
differential power that the rudder..And larger boats have thrusteres in
the bow so they can steer precicely. I think the reason they use rear
steer is it is the end most likely to stay in the water!!!!!My car on
the other hand turns in 1 dimension has very little pitch roll or
yaw...maybe you need a racecar with a hard chinned bottom to make this
all work LOL
What was the downside again to turning the driven wheels???if you have
to have front wheel drive.....If you have to have front wheel drive
strctly for areo i think someone needs to go back and get their
calculator out and figure out how much of the road load is areo and how
much is rolling resitance.. me thinks you are fixing the wrong part in
the first place. Even the drive train loss is in many cases more than
the aero
Dahlgren
Dick J wrote:
>
> 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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