🚀 go-pugleaf

"Dan Bloomquist" <public21@lakeweb.com> wrote in message 
news:N4oAj.5632$Sa1.5188@news02.roc.ny...
> daestrom wrote:
>>
>> "Dan Bloomquist" <public21@lakeweb.com> wrote in message 
>> news:7tdAj.5709$7d1.5641@news01.roc.ny...
>>> daestrom wrote:
>>>>
>>>> Whilst I don't agree with any of the OP's junk science, if you arrange 
>>>> the gyro's shaft so that it is perpendicular to the earth's axis, and 
>>>> the shaft is limited to a track that is also perpencidular to the 
>>>> earth's axis (on the equator it would be vertical, at other latitudes 
>>>> it would be tilted away from the pole by the degree of latitude), then 
>>>> as the earth rotates each day, the gyro's shaft would make one complete 
>>>> revolution around the track. This revolution of the shaft around the 
>>>> track could be harnessed to draw some power.
>>>
>>> Hi daestrom,
>>> This is about converting angular momentum to energy. But, angular 
>>> momentum is conserved. i.e., you can't slow the rotation of the earth 
>>> from a closed system.
>>>
>>> I'm sure the details would bare this out.
>>>
>>
>> On the 'big picture' I can see what you mean, but if we put the gyro on 
>> the equator with the shaft pointing straight up at noon, six hours later 
>> the shaft is horizontal, six more hours and it points straight down, 
>> etc...
>>
>> If we attach some mechanism to capture that 'revolution' of the shaft 
>> around the track, we transfer some angular momentum (AM) from the earth 
>> to the mechanism (albeit a tiny amount).  Momentum is conserved but 
>> kinetic energy is transferred from one rotating body (the earth) to 
>> another (the mechanism).
>
> Hi daestrom,
> It has been a while and I never finished working through any math. But 
> here is what I recall happens. As soon as you put some force on the axis 
> of the gyro, (restrict precision), you the angular momentum of the rotor. 
> This change will exactly balance the change in the angular momentum of the 
> earth. And, of course, it will take a force to get energy, FxD. If there 
> is any question that the rotor will change velocity with external force, 
> see this toy:
>
> http://www.powerballs.com/
>
> I've been meaning to buy one of these for years. Question is, can I get 
> one cheap enough on ebay to make the cost of fun balance. I'm thinking I 
> can. :)
>
> So, the energy will come from what ever energy it took to accelerate the 
> rotor.

So let me see, (using my earlier example of a gyro mounted with its shaft 
vertical at the equator), as the earth rotates the shaft will turn from 
up-down to east-west orientation if we don't restrict it at all.  If we *do* 
attach some sort of mechanism that retards it in the east-west direction 
(i.e. doesn't let the shaft top end tip to the west freely), then precession 
will try to tip the shaft towards the north-south direction.  Okay, and I 
postulated a 'track' that is oriented east-west' so any precession toward 
north-south is restricted entirely.

A concrete example.  Start with shaft vertical.  Spin rotor such that the 
'northern' side is moving towards the west, and the 'southern' side is 
moving towards the east (i.e. CCW when viewed from 'above').  Since the 
earth is moving towards the east, the top of the shaft tends to move toward 
the west.  We retard this movement somewhat with our mechanism.  Because of 
the particular spin and the force we are applying to the top of the shaft to 
try and get the top to move eastward with us and the planet, the gyro 
precesses and a force is developed by the gyro to move the top of the shaft 
towards the north.  If we let it move towards the north, things would 
continue until it (the gyro shaft) is parallel with the earth's axis.  Then 
all precession would stop. (Congratulations, we have a rudimentary 
gyrocompass.  I used to work on marine gyrocompasses in the navy, they take 
a bit more than this, but we at least have a 'north-seeking' gyro)

But if we don't let it move north (constrained by the 'track'), then 
whatever retarding force we are applying in the east-west direction is 
translated to the north-south direction against the track.  These forces may 
increase friction in 'real' bearings, but let's assume 'ideal' bearings so 
this addtional force against the shaft doesn't slow the spin of the gyro. 
The force against the track in the north-south direction moves through zero 
distance so no work there.  But our retarding force in the east-west 
direction is adjusted to allow the shaft to tilt west at something less than 
one revolution per day so we have a force working through an angular 
displacement and have work.

As I said before, I believe this transfers some of the angular momentum from 
one part of the closed system to another (i.e. from the spinning planet to 
the mechanism that is retarding the gyro shaft's east-west apparent motion). 
Momentum is conserved and energy is transferred.

But my earlier calcs show the amount of power involved is terribly small. 
To measure it experimentally against all the frictions and other losses 
would be pretty hopeless.  Unless you find a planet with a much shorter day 
:-)

daestrom