Just think of it as driving a car in reverse ...things do happen faster.
Wes
----------
> From: john robinson <john@engr.wisc.edu>
> To: Jon Hobden <Jon.Hobden@rdel.co.uk>
> CC: Land-speed@autox.team.net
> Subject: Re: Rear wheel steering
> Date: Wed, 07 Jun 2000 11:07:32 -0500
>
>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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