flywheels yet again

[darryl]

Physics- motions and reactions with flywheels- we all know the flywheel effect, spin a wheel and try to tilt it- you get a reaction. But does this spinning wheel have any reaction in the axial direction? Have a wheel spinning horizontally, and lift it up and down without tilting it. Is there a difference in what you feel between lifting it when it's rotating to lifting it when it's still?

[boslab]

I like this one

https://youtu.be/aZeQJclDuDE

he did some good ones like his linear motor, the magnetic river etc
mark

[old mart]

Only changing the direction of the axis of rotation will cause precession, not radial or axial movements alone. I have never fully understood precession, the demonstrations with the flywheel on the end of a long shaft do look like antigravity, but further experimentation has disproved this, unfortunately. So no flying saucers using flywheels.

[mklotz]

One of the most fascinating things about precession to me is the gyrocompass. Take a gyroscope and, figuratively, hang a weight on it and it will point north, and geographic, not magnetic north at that. Blows my mind.

This Sperry treatise...

https://ed-thelen.org/SperryManual-05.pdf

explains the gyrocompass clearly and succinctly.

Also, if you search the PDF for the phrase "Reason for Precession", you'll find a nice intuitive description of how the magic happens.

[old mart]

I believe you have to align a gyrocompass with whatever direction is required they don't point north by magic.

[A.K. Boomer]

I believe you have to align a gyrocompass with whatever direction is required they don't point north by magic.

Hmmm - the earth is rotating too you know, might have something to do with it?

[BCRider]

I believe you have to align a gyrocompass with whatever direction is required they don't point north by magic.

You do set them. But that doesn't mean that you're aligning the cage internally. I'd want to look into that idea by reading the Sperry page. Which, by the way, is giving me an error message when I click on it.....

[The Artful Bodger]

Hmmm - the earth is rotating too you know, might have something to do with it?

Of course it does, the earth is a gyro too rotating about the north-south axis and it is also moving around the sun all the while keeping the NS axis pointing (more or less) to the region of Polaris. So we can see the earth gyro is aligned with the universe and this is true of all gyros and I suspect that any movement in 'direction' observed on a gyro is due to our (the observer's) movement in relation to the universe.

[JRouche]

The Perry class frigate I was on had a Sperry Gyro (I think sperry made our whole system), a few of them actually. Our system had its own, maybe two, I forget. We had to learn about them in class. Never remember having to align them with anything. Unless maybe it was already aligned with the ship during the build out. I also always found gyros very interesting. JR

[The Artful Bodger]

I believe you have to align a gyrocompass with whatever direction is required they don't point north by magic.

It is not magic of course but considering that the gyrocompass is attached to the earth which is spinning on it's axis I can well be persuaded that the gyrocompass may tend to align it's axis with the earth axis, i.e. north south.

[The Metal Butcher]

Only changing the direction of the axis of rotation will cause precession, not radial or axial movements alone. I have never fully understood precession, the demonstrations with the flywheel on the end of a long shaft do look like antigravity, but further experimentation has disproved this, unfortunately. So no flying saucers using flywheels.

You're driving down the road, going straight, fast. You turn sharp. You slide. The car wants to remain going the direction you were going, regardless of the angle.

You're driving down the road, going straight, fast. You road turns sharp. You cannot follow the road as you can't redirect your car fast enough. The car wants to remain going the direction you were going, regardless of the angle.

You're driving down the road, but it's a track with the wheels positively retained, going straight, fast. The track turns sharp. You turn with it, but feel an immense force to follow that curve. The car wants to remain going the direction you were going, regardless of the angle.

You're driving down the road, but it's a track, circular, the diameter of earth, with the wheels positively retained, going straight, fast. The track rotates suddenly underneath you, orthogonal to its axis.. You turn with it, but feel an immense force with the turn. The car wants to remain going the direction you were going, regardless of the angle.

Now shrink everything down. The earth becomes small, the car becomes heavy. Now the car has enough force to change the direction of the track, not vise versa. Now consider the track is the wheel, and the car, an arbitrary point on the wheel. You can turn it, but it doesn't want to turn.

Maybe that helps. Maybe it doesn't.

[genea]

. . .

Maybe that helps. ❌ Maybe it doesn't ✅

[A.K. Boomer]

Quick --- everybody flush their toilets and tell us the direction the water swirls ---- CCW or CW and then where you live mine is CCW and I am in USA...

I think the toilets jet design overrides any mild Coriolis effect but still might be interesting experiment just to kill some time... come to think of it - draining a sink that was stagnant creates a directional vortex in the drain --- now that might be influenced by the Coriolis force...

[BCRider]

Quick --- everybody flush their toilets and tell us the direction the water swirls ---- CCW or CW and then where you live mine is CCW and I am in USA...

I think the toilets jet design overrides any mild Coriolis effect but still might be interesting experiment just to kill some time... come to think of it - draining a sink that was stagnant creates a directional vortex in the drain --- now that might be influenced by the Coriolis force...

Yep, the key is still water... I wouldn't call it stagnant unless you leave it for days and it takes on a bit of an odor ... The toilet has flush holes around the rim and often a directed swirl jet that will set up the water to turn however it wants. But a sink with still water will always swirl when draining the same way due to the coriolis effect.

But if we start up a slight circular motion in the other direction and pull the plug it will swirl the other way and not stop. Speeds up in fact. Something to do with the water running into the drain pulling on the rest I guess. I want to say "surface tension" but that's not it. Related though....

[boslab]

The telephone exchanges years ago in the U.K. had sperry high speed gyro generators, these were big, like 1/2 ton things in a vacuum tank spun up by motor, the things activated in a power failure, the drive motor becomes the generator, I was told they could power the telephone network for 12 hours or more, these things were regarded as dangerous enough to embed in steel reinforced concrete, I saw a photo but never got a one to one look, the idea seemed brilliant to me, makes me wonder if these things are still about, seems like a good idea for back up power
mark