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Discussion Starter #1
I can't help but wonder if Electric Evette is a hoax. It has a small
caster in front instead of the usual steerable front wheels. Tom
Sines claims that this arrangement works as well as or better than
the usual four wheeled automobile. That's an extraordinary claim
which demands extraordinary proof to be believable.

Count me among the skeptics. I expect others are skeptical too, but
are too polite to say so.

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Discussion Starter #2
From: Tom Shay
> I can't help but wonder if Electric Evette is a hoax. It has a small
> caster in front instead of the usual steerable front wheels. Tom
> Sines claims that this arrangement works as well as or better than
> the usual four wheeled automobile. That's an extraordinary claim
> which demands extraordinary proof to be believable.

My BEST students built a very similar vehicle about 3 years ago. It had two 26" bike wheels left and right, and a shopping cart caster under the front. The body was a 2' wide x 5' long sheet of 3/4" plywood. The "seat" was actually a 4" piece of fabric-covered foam on top, with a short backrest at the rear edge. Each wheel was belt driven with separate PM motors.

They planned to skid-steer it like a Bobcat, by just switching one or the other motors on/off or forward/reverse. Since PM motors tend to run at constant speed, it should go straight with the motor both in parallel.

Well, it sort-of worked. At speed, there tended to be enough inertia for it to go (mostly) straight. But at low speeds, any small bump or hole made it veer drastically off-course. It was barely steer-able.

They adde bolts to the free-wheeling caster to seriously restrict its turning to about 10 degrees -- that helped. They added a piece of rubber hose to connect the shafts of the left and right motors together, so it tended to go straight unless the differential motor torque got high enough to make the rubber slip (kind of like posi-traction). But in the end, they added a tiller that directly steered the caster. That provided much better steering control.

--
I would not waste my life in friction when it could be turned into momentum. -- Frances Willard
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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