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Author Topic: Shop made gyroscope  (Read 3589 times)

Bill Wells

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Re: Shop made gyroscope
« Reply #45 on: October 01, 2022, 01:59:51 PM »

In the drawing below, the small boat is at the equator, we see it from North Pole.
Iacopo, your drawings always help.

In the real world, experiments are difficult. Attached are photos of my attempts with floating the gyro in a small boat. As a convenience, I float the boat in the vacuum container used previously in my spin duration trials. Trials can be conducted in partial vacuum or in air.

(1)   It takes a long time for water to stop circular motion. It must be completely still before any gyro effect can be measured. Continuing water movement is always a problem.
(2)  Even with the small motor that comes with the Precision Gyroscope, the motor magnets do align with Earth's magnetic field. I may have solved that by shielding the motor with a steel cylinder.
(3)  I place a laser pointer on top of the boat in hopes of measuring angular motion. In last test, the pointer oscillated back and forth through 30 degrees for over an hour.
(4)  The middle photo, with gyro axis vertical, the Styrofoam block rotates in direction of the flywheel. This is simply due to friction. Rotation is slower when in partial vacuum.
(5)  In all cases, the boat is prevented from hitting wall of chamber by a pin attached to bottom of chamber, which extends up into hole in a Styrofoam block. This works well.
(6)  Gyro motor is driven by battery pack.

All this is very time consuming. May not continue this exercise in frustration. Unless someone has better suggestions.















« Last Edit: October 01, 2022, 02:04:05 PM by Bill Wells »
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Iacopo

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Re: Shop made gyroscope
« Reply #46 on: October 02, 2022, 04:32:14 AM »

It takes a long time for water to stop circular motion. It must be completely still before any gyro effect can be measured. Continuing water movement is always a problem.

I think that it is difficult to have the water really still.
The problem is not only that water moves by inertia, (in which case we could simply wait until it stops moving), it moves continuously in any case because of differences of temperature.
You can put a drop of ink or something in the water to see its movements.
You can use mica, but mica tends to sink so it works well only if the liquid doesn't move too slowly, otherwise it settles on the bottom.
In the photo below, there is alcohol mixed with mica.
If you hold a glass in your hand, with alcohol and mica in it, you will see that the alcohol is not still but it moves continuously, and quite fast !  I was surprised when I saw it the first time.  The little differences of temperature in the liquid, caused just by the mild warmth of the hand at the sides of the glass, and the cooling at the surface of the alcohol due to the evaporation, are sufficient to cause the evident convection currents in it.
 


It's not very different with water.  Warmer water is lighter and wants to move upwards. Colder water is heavier and wants to move downwards.  The evaporation of the water makes its surface colder, (I measured the temperature of water in a bucket and it was about two degrees colder that the room temperature). In these conditions the water moves, and even if it moves slowly, it is still too fast for our aims.

For to avoid the convection currents, the water should have the same temperature everywhere in the tank.
The evaporation should be prevented. Maybe a thin film of oil on the water could help ? I don't know.
I suggested to use oil instead of water;  certainly using oil is more messy, but oil practically doesn't evaporate, so I believe that it would be easier to avoid convection currents with it.  Oil is more viscous, but I suppose that, for very slow movements, it is almost frictionless, so it could work.


motor magnets do align with Earth's magnetic field. I may have solved that by shielding the motor with a steel cylinder.

It seems a good idea.

I place a laser pointer on top of the boat in hopes of measuring angular motion. In last test, the pointer oscillated back and forth through 30 degrees for over an hour.

I have read that the simplest gyro compasses can oscillate back and forth, with a period of 84.4 minutes.
84.4 minutes is also the time that it takes for a theoretical satellite at the level of the sea to complete an orbit around Earth, and the two things are related.
But I can't even begin to imagine the reason of it.
 
« Last Edit: October 02, 2022, 04:47:06 AM by Iacopo »
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ta0

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Re: Shop made gyroscope
« Reply #47 on: October 02, 2022, 10:32:31 AM »

Yes, water seems very difficult to control in an experiment that needs to be very isolated from perturbations.

I have read that the simplest gyro compasses can oscillate back and forth, with a period of 84.4 minutes.
84.4 minutes is also the time that it takes for a theoretical satellite at the level of the sea to complete an orbit around Earth, and the two things are related.
But I can't even begin to imagine the reason of it.
I have no idea, but now I'm curious. I need to investigate this.
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Iacopo

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Re: Shop made gyroscope
« Reply #48 on: October 02, 2022, 12:11:21 PM »

I have no idea, but now I'm curious. I need to investigate this.

It is in the end of this article, (in italian).
But reading it with more attention, it says something different, it says that, according to Max Schuler, if a gyro compass is built so to have a period of oscillation of 84.4 minutes, it will compensate for the errors due to the accelerations of the boat, and it will maintain a more stable orientation. The logicality seems still apparently bizarre, but I know nothing about gyro compasses.

https://it.frwiki.wiki/wiki/Gyrocompas 
« Last Edit: October 02, 2022, 12:15:32 PM by Iacopo »
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