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Author Topic: Shop made gyroscope  (Read 1716 times)

Iacopo

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Re: Shop made gyroscope
« Reply #30 on: September 25, 2022, 04:15:07 AM »

I found the patent for an air gyroscope, (not made like the Kruger fountains), I don't know if this could be stable enough to maintain its orientation sufficiently to show the rotation of Earth, but the inventor says:

"Another object of my invention is to provide a gyroscope which may act as a true space fixed reference and in which precessional errors due to friction are greatly minimized".

This is the patent. There are two drawings also:

https://patents.google.com/patent/US2729106


If someone is interested, I found an air gyroscope for sale, ($ 450), Kruger fountains style:

https://www.pureunobtanium.com/product-page/air-gyroscope


It is not frictionless anyway; from a video, (of an air gyroscope like the one in the video below), I could calculate that it loses 5 RPM in 18 seconds, from 140 to 135 RPM.  It's a spin decay similar to that of my tops, in that range of speeds.
And I have no idea at all if during the precession it sinks down like normal gyroscopes, or it rises like tops, or it stays stable.
The nutation seems maintained quite longer than in gyroscopes with normal bearings.

An air gyroscope in action:

https://www.youtube.com/watch?v=XyLC_1KW1-A
« Last Edit: September 25, 2022, 04:38:52 AM by Iacopo »
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Bill Wells

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Re: Shop made gyroscope
« Reply #31 on: September 25, 2022, 01:18:21 PM »

If someone is interested, I found an air gyroscope for sale, ($ 450), Kruger fountains style:

Interested, yes, but not enough to spend $450.

My interest is in the experimenting. I am behind in reading and viewing all the recent replies on this topic. Presently learning from failed trials - that is how we progress.
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Bill Wells

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Re: Shop made gyroscope
« Reply #32 on: September 25, 2022, 02:07:49 PM »

...it seems to me that the magnets of the motor do act like a compass. Maybe a solution could be to use two equal electric motors mounted in opposite positions, trying to neutralize the magnetic field.
Jorge had the same concern. I confirmed this by suspending a large two magnet 12V motor. It definitely aligned with Earth magnetic field  :-[ .

I will try the two electric motor scheme, with two Super Precision gyros. Interesting that the gyros connected together completely cancel each other, no gyroscope effect. This can be remedied by changing polarity of battery connection. Then gyroscope effect is doubled.
 

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ortwin

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Re: Shop made gyroscope
« Reply #33 on: September 25, 2022, 02:47:13 PM »

...


If someone is interested, I found an air gyroscope for sale, ($ 450), Kruger fountains style:

...
We talked of possibilities making one here for showing the "intermediate axis theorem", "Kovalevskaya top" or "show the T handle effect with clarity". Did you continue with anything in that project? I must admit I have not.
You said you calculated the braking of that top is in the same range as your tops in some corresponding speed range. That would be just so great to have a top with that low a friction and at the same time the freedom of movement that a ball gives plus the possibility of choosing the different relative moments of inertia by moving weights inside the ball.
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Iacopo

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Re: Shop made gyroscope
« Reply #34 on: September 25, 2022, 03:52:34 PM »

Interesting that the gyros connected together completely cancel each other, no gyroscope effect. 
 



When you tilt the axis with the two gyros attached and spinning in opposite directions, do you feel a resistance to tilting ?  Or there is no resistance, as if the flywheels were not spinning ?  I am not sure about it.

Did you continue with anything in that project?

No I didn't, mainly for lack of time.  I keep it as a project in the drawer. 
I thought to some details, how I could make them. 
I observed carefully the video and it seems that there is no tendency of the air gyro to rise/fall while precessing. I like this fact.
Probably one day I will make it.  Maybe with the T handle effect too. 
I would buy the one I found, but $ 450 is too much.   
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ortwin

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Re: Shop made gyroscope
« Reply #35 on: September 25, 2022, 05:59:10 PM »

...
When you tilt the axis with the two gyros attached and spinning in opposite directions, do you feel a resistance to tilting ?  Or there is no resistance, as if the flywheels were not spinning ?  ...
My answer, although you did not ask me, is, there is no resistance, it is as if the flywheels were not spinning!
At least if you tilt it around the center of the connection between the two gyros and the gyros are at the same speed. Bill will tell us first hand what he observes with his gyroscopes, I had the chance to feel it in experiments designed directly for that purpose in science centers similar to this experiment here or this one.
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Bill Wells

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Re: Shop made gyroscope
« Reply #36 on: September 25, 2022, 11:51:56 PM »

When you tilt the axis with the two gyros attached and spinning in opposite directions, do you feel a resistance to tilting ?  Or there is no resistance, as if the flywheels were not spinning ?  ...

There is no resistance, as if the flywheels were not spinning.
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ortwin

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Re: Shop made gyroscope
« Reply #37 on: September 26, 2022, 06:20:57 AM »

@Bill: if you pick up the connected gyros (spinning in opposite directions) with a string, does it matter where you have the string? Does it matter if it is in the red or in the blue (center) position?



 
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Iacopo

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Re: Shop made gyroscope
« Reply #38 on: September 26, 2022, 07:00:37 AM »

My answer, although you did not ask me, is, there is no resistance, it is as if the flywheels were not spinning!
At least if you tilt it around the center of the connection between the two gyros and the gyros are at the same speed. Bill will tell us first hand what he observes with his gyroscopes, I had the chance to feel it in experiments designed directly for that purpose in science centers similar to this experiment here or this one.

There is no resistance, as if the flywheels were not spinning.

Thank you. As for the position of the string, I suppose there is no difference, there should be no gyroscopic motion in any case, but Bill can see it with his eyes.
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Bill Wells

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Re: Shop made gyroscope
« Reply #39 on: September 26, 2022, 12:44:52 PM »

@Bill: if you pick up the connected gyros (spinning in opposite directions) with a string, does it matter where you have the string? Does it matter if it is in the red or in the blue (center) position?
I can check this today, but pretty sure blue/red are the same - as if gyros not spinning. Seems they cancel each other out.
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Bill Wells

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Re: Shop made gyroscope
« Reply #40 on: September 27, 2022, 11:42:45 AM »

@Bill: if you pick up the connected gyros (spinning in opposite directions) with a string, does it matter where you have the string? Does it matter if it is in the red or in the blue (center) position?


Sorry, took me a while to find blue string  ;D
With the gyros spinning opposite, it is like they are NOT spinning. No gyroscopic effect.

My current experiment with earth rotation is much a challenge of making/assembling/handling components. Then floating them in a boat. Several times the boat capsized. Dealing with eddy current (again). Dealing with Earth magnetic field (it does affect alignment of even small DC motors).
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Bill Wells

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Re: Shop made gyroscope
« Reply #41 on: September 27, 2022, 11:57:07 AM »

I found the patent for an air gyroscope...

You know we will make one of these.  Seems that just a decent fan underneath would suspend a sphere.
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ta0

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Re: Shop made gyroscope
« Reply #42 on: September 27, 2022, 01:01:46 PM »

Practically, if our small boat has its flywheel axis horizontal, and oriented east-west, as Earth rotates a bit, the axis of the flywheel cannot maintain its orientation relatively to the stars because it is constrained to follow the rotation of Earth; the rotation of Earth would cause a torque on the flywheel axis in the direction to make the east side of the axis to sink down and the west side to rise up.  Because of the gyroscopic effect, the movement happens with a 90 degrees delay, this makes the flywheel and the boat to rotate on the plane of the water.  The speed of the rotation of the boat would be the same of the rotation of Earth, so, on Earth, the boat would appear to be steady.

I think that this also depends on the direction of spinning of the flywheel;

if the flywheel axis is horizontal, and oriented east-west, and the flywheel spins with its upper part moving towards south, the gyroscope will rotate in sync with Earth, practically maintaining a stable orientation relatively to Earth.

But, in the same situation, if the flywheel spins in the opposite direction, (its upper part moving towards north), this should make the gyroscope to behave differently. We will see the gyroscope, and the small boat with it, to rotate clockwise on the plane of the water, (at a speed twice that of Earth, i.e. 0.5 degrees per minute).
I don't know if I follow your reasoning.
I think the only difference regarding the direction of the rotation of the gyro is that in one case one end of the gyro axis ends up pointing north and in the other case the opposite side.
If there is no gimbal to let the gyro rotate with respect to the boat, it will drag the boat with it.
If it's free to rotate in the horizontal direction, it will rotate with respect to the boat (stationary with respect to the earth) but the rate of rotation will depend on the spin.
In a commercial gyrocompass, it is fully gimballed, but it's maintained horizontally with weights (like a balanced arm scale).
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Iacopo

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Re: Shop made gyroscope
« Reply #43 on: September 27, 2022, 04:12:10 PM »

I don't know if I follow your reasoning.
I think the only difference regarding the direction of the rotation of the gyro is that in one case one end of the gyro axis ends up pointing north and in the other case the opposite side.
If there is no gimbal to let the gyro rotate with respect to the boat, it will drag the boat with it.
If it's free to rotate in the horizontal direction, it will rotate with respect to the boat (stationary with respect to the earth) but the rate of rotation will depend on the spin.
In a commercial gyrocompass, it is fully gimballed, but it's maintained horizontally with weights (like a balanced arm scale).

You are right, Ta0, I was misunderstanding how the gyro compass works.
I found a better article about it and now I understand it a bit better;
the gyro compass points north, not because it precesses at the same speed of the rotation of Earth, but because it stops precessing when it points north.

I try again.
The small boat with the flywheel fixed horizontally in it, is a simplest kind of gyro compass.
It works well onlybest at the equator.
In the drawing below, the small boat is at the equator, we see it from North Pole.
The flywheel spins, with its axis oriented east-west, (A), and it tries to maintain its orientation, but Earth rotates and in position B a torque from the small boat wanting to align itself to the sea makes the flywheel to precess, so the boat rotates on the plane of the water.
The boat rotates until the position C, then it stops rotating, and the flywheel remains with its axis oriented north-south.
The reason that the precession stops at this point is that now the flywheel axis is exactly parallel to the rotation axis of Earth, and, from here, the rotation of Earth does not change the situation of parallelism, so there is no more torque, and no more precession.

This works best at the equator because at the other latitudes, especially near the poles, the axis of this flywheel, horizontal, would never be parallel to that of Earth, and the flywheel would tend to continue to precess, the leverage for making the flywheel to precess becomes progressively less efficient, until, at the North Pole, the gyro compass doesn't follow the rotation of Earth anymore.     



Still the experiment with a small boat and a simple horizontal flywheel without gimbals maybe could be worth.
Depending on the direction of spinning and the orientation of the flywheel, before to point north, a clockwise or a counterclockwise rotation of the boat on the water could be seen, showing that Earth rotates.
« Last Edit: September 28, 2022, 02:02:17 AM by Iacopo »
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Iacopo

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Re: Shop made gyroscope
« Reply #44 on: September 27, 2022, 04:36:20 PM »

You know we will make one of these.  Seems that just a decent fan underneath would suspend a sphere.

I started looking for the materials for making the mine. Even if I don't know yet when I will make it...
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