| daestrom 2005-10-14, 10:21 am |
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"Scott A Crosby" <scrosby@cs.rice.edu> wrote in message
news:oydvf02mi6m.fsf@bert.cs.rice.edu...
> On Wed, 12 Oct 2005 20:28:20 GMT, "daestrom"
> <daestrom@NO_SPAM_HEREtwcny.rr.com> writes:
>
>
> If we tried this, the gyroscope will precess until it its axis of
> rotation is oriented on a north-south axis. At which time, it will
> remain unaffected by earth's rotation.
Yes, I identified this issue in the paragraph you snipped. One would have
to stop the spinning rotor, and reset the axis, then spin the rotor back up
again. Nice of you to simply parrot what I've already discussed. Or didn't
you bother to read the whole message?
> Also, the gyroscope will be
> slowed down by one rotation per day, aka, $x$ rotations forward per
> day and one rotation backward from earth's rotation. And conservation
> of energy tells me that that one rotation difference/day is where the
> energy it produces comes from.
Nope. Come now, apply some analysis to the situation. Spin the rotor at
10000 RPM. That is 1.44e+7 revolutions per day. From this, you subtract 1
and think it is some significant amount? Besides, as I've said before,
you'll have to stop the rotor and reset the axis when it reaches N-S and
restart the rotor after resetting the axis. At the very best, this is not
even 12 hours, so you've really only 'lost' 1/2 revolution. (start the axis
tilted towards the south and allow it to precess to the north).
All the time the foundation, mounted firmly to the planet, is exerting a
force in the east-west direction and moving around the planet doesn't
account for some work done on the system by the planet?? In such a system,
one must set a frame of reference outside the planet, not use the ground for
the reference. Conservation of energy tells me that work done on the
mechanism by the planet means simply that the planet will lose kinetic
energy. A point that has been mentioned several times.
>
> This situation also fully converges angular momentum from earth's
> rotation, spin the gyro up. extract energy from precessing, spin down
> a slightly slower gyro, and you get back exactly the energy you put
> in, and the earth doesn't change rotation velocity.
>
The forces applied to spin the gyro up are not in the same plane as the
earth's axis. Spinning up the gyro while mounted vertically on the equator
does *not* increase/decrease the spin of the earth. If anything, the force
will act to precess the planet since the torque to spin up the rotor is at
right angles to the earth's axis. But stopping the rotor to reset it will
require a torque that *is* aligned with the planet's axis (since the gyro's
axis has now rotated)
The question becomes one of how efficiently one can spin up/down the rotor
so as not to waste as much energy resetting the axis as was extracted in the
past while the axis was moving.
> Unworkable.
>
Theoretically, or practically? I've already conceded that 'practically' it
probably can't be made to work. But the theory is still valid.
daestrom
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