[Momentus (OP)]

https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=80399.0;attach=31024;image

I made a complex, and hence a useful model many years ago. It was designed as an automotive transmission. This is a much simplified version, to demonstrate a new form of motion.

The experiment goes like this:

1. Run the gyroscope motor to bring the gyroscope rotors up to a modest speed. As the rotors are are touching, they counter rotate. Equal and opposite. Now let the motor freewheel.

2. Run the reaction motor. This rotates the Gyroscopes about their precession axis, accompanied by equal and opposite torque orthogonal to the spin axis. There can be no torque exerted by the reaction motor along a precession axis, therefore no substantial movement of the reaction flywheel.
 
3. Increase the speed of precession until the precession axis changes to the spin axis. When this happens the reaction motor will meet resistance as it tries to increase the spin speed of the system and there will be movement of the reaction flywheel to counter this. At this point let the reaction motor freewheel.

 4. As the spin axis of the gyroscopes is now aligned with the Reaction motor, precession has changed to what was the spin axis and the gyroscope motor can be used to brake the precession to a halt.

6. Both gyroscope rotors are now rotating about the reaction motor axis.

 I called have this manipulation of momentum, Dark Motion. I have made other devices that demonstrate equal and opposite reactions as in the above with similar outcomes.

I am going to post this without further explanation at this point, to see what develops.

Ideally some model maker with an interest in science will duplicate the device. Or a mathematician may be able to model it. Or a computer program could be written. I do not have the skill set to do that.

[evan_au]

I made a complex, and hence a useful model

Complex does not mean correct.

The geocentric model of the Solar System was quite complex, with epicycles upon epicycles - but it wasn't really useful as it kept giving wrong predictions about the motion of the planets.

If you are trying to design something at a comparable level of mystery to Dark Energy and Dark Matter, we have a special section of the forum called New Theories.

[Momentus (OP)]

I did not say the model I posted is complex. If you read the post again you will see that the drawing refers to a simple model.

When manipulated as per instructions the model will create Angular Momentum. I do not claim this as a novel theory. It is a machine built for a specific purpose. I do not have your experience or status on this forum. I thought that a machine would best fit in Technology. If that is incorrect then perhaps it should be moved to a more acceptable place.
Moving it does not change its validity, or purpose.

It is not new science. The analysis of the machine can be carried out using the bog standard formulae from any good gyrodynamics textbook.

I am not trying to design something, I have designed and built something that works. I expressed the hope that this design could be built by others, or analysed by a Forum King.

The link that I see is that of anomalous motion, a better description for the actual observations of the phenomena of dark energy/matter.

Your observations on the complexity of medieval science are relevant to the current situation with Dark Matter and Dark energy.

I have posted the design of a simple device which will create Angular Momentum, It is the device and its operation I want to have analysed, preferably from an informed source.

[Colin2B]

I did not say the model I posted is complex. If you read the post again you will see that the drawing refers to a simple model.

I don’t think @evan_au was specifically referring to your simple model.

The link that I see is that of anomalous motion.....

What do you see as being anomalous about the motion.

[Momentus (OP)]

Colin2B

The rotation of certain Galaxies is too fast when calculated using the observed matter and Conservation of Momentum. To explain this anomalous motion, Dark Matter was invented.
The universe is expanding too fast, to explain this anomalous motion, Dark Energy was invented.

As you can see when you analyse the motion of my model, I trust that you have done that, Momentum is created. That is also anomalous motion. I call it Dark Motion.
I notice that you have not commented on the Model itself. Is this because you have not understood how it works?

[Colin2B]

I notice that you have not commented on the Model itself. Is this because you have not understood how it works?

I was less interested in how it works as why you consider the motion anomalous.

[Momentus (OP)]

I was less interested in how it works as why you consider the motion anomalous.

At least You have shown some interest, but no understanding. How is creating momentum anything other than anomalous?

I really need some help with this, some feedback.

This post has been treated like a challenge to intelligent Design. Conservation of Momentum is ordained and should not, make that cannot, be questioned. There is no evidence that will convince otherwise. To suggest it can be otherwise is Heretical.

Best way to treat a toxic post like mine is to ignore or trivialise. I got both.

The fact remains, the model works and I need help with Dark Motion.

It may be that I have underestimated the difficulty, the complexity of the model. That which I see as a very simple model may not appear so to others.

I did not go to university, I do not have a degree, I do not speak mathematics. I hesitate to give simplistic explanations for fear of being ridiculed.

So here is a simplistic explanation of this Dark Motion Model. Feel free to mock.

Take two pencils. Equal in length and weight, but opposite in colour. I will use red/blue. Place them side by side. Pointing in equal and opposite directions. Next, rotate each pencil through 90 degrees, rotate the red pencil clockwise, rotate the blue pencil widershins, that is do it in equal and opposite directions. They now both point in the same direction.

Spin and momentum are vector quantities. The pencils can be said to represent the spin/momentum of the gyroscopes in the Dark Motion model. It is trite but true that the counter-intuitive behaviour of a gyroscope is easily explained by saying “changing the vector of its momentum.”

The direction of the virtual vector sum of the precession spin and the gyroscope rotor spin is moved through 90 degrees by the sequential operation of the motors.

There is nothing about the construction or operation of the Dark Motion model that cannot be calculated by a competent design engineer. It is not some weird new exploitation of hitherto unknown and mysterious properties.

No new forces. Just a new understanding of the existing ones. Sir Isaac made a trivial error in framing the wording of “to every action”

May I finish with a further plea for help?
I have not mastered the art of inserting a picture. If there is mathematical member lurking out there who can translate my pencil example into proper physics diagrams with symbols, it would be much appreciated.

This is far to big and important for me to carry on with on my own. Please help. If you can see that I am mistaken tell me how the Dark Motion model will behave differently.

[Halc]

1. Run the gyroscope motor to bring the gyroscope rotors up to a modest speed. As the rotors are are touching, they counter rotate. Equal and opposite. Now let the motor freewheel.

You've created a system with rotating parts but zero net angular momentum.  Viewed as a black box, it will behave like a rock with the same mass.  Net angular momentum is zero.  It disturbs me to see those axle clamps in the picture, which allows external torque to be applied if the apparatus at any point would have otherwise twisted to the side.  Better to consider the thing in space.

2. Run the reaction motor. This rotates the Gyroscopes about their precession axis, accompanied by equal and opposite torque orthogonal to the spin axis. There can be no torque exerted by the reaction motor along a precession axis, therefore no substantial movement of the reaction flywheel.

It is not labeled, but I presume the reaction motor is that grey thing that spins up the red wheel. Also not labeled is whatever you consider the precession axis. There is the one main axle in the whole setup which is the rotation axis of the red wheel.  There is no precession axis
since there's only the motor producing spin and counterspin. So the red wheel spins one way, and the contraption to the left spins the other way.  Still zero net angular momentum.
 

3. Increase the speed of precession until the precession axis changes to the spin axis.

You seem to think there is a precession axis that is different than the spin axis.  There is only the latter.  The contraption to the left acts as a whole as a rock, and thus does not precess.  Internally, sure it does, but the precession forces produced by the wheels inside exactly cancel each other, putting significant internal stress on the bars and bearings and such, but exactly cancelling and so having no external effect.  In other words, if you put a shroud around the yellow wheels and the thing was quiet enough, you'd not be able to tell by just holding it if the wheels were spinning or not. They won't resist any external change in orientation.

When this happens the reaction motor will meet resistance

The contraption to the left has a certain moment of inertia which is the same whether the yellow wheels are spinning or not.  That moment serves as the reaction mass that counters the torque on the red wheel.  If the red wheel has the same moment as the contraption, then the two will spin at equal and opposite rates, at any speed, whether or not the gyros inside are spinning.
If you spin it fast enough and the gyros have sufficient angular momentum, the internal stresses on the contraption will make it fly apart, but until then, the contraption as a whole acts like a rock.

4. As the spin axis of the gyroscopes is now aligned with the Reaction motor

The spin axis of the gyroscopes is always perpendicular to the spin of the reaction wheel. It is drawn that way and you're provided no mechanism where that can change without deformation of the parts.  Unless we're all missing something and the picture just doesn't convey some hidden secrets or something.

I see no point in going on. You seem to be basing conclusions on the existence of a separate 'precession axis' which is allowed to change. There is no such axis, and the picture doesn't show one.

Both gyroscope rotors are now rotating about the reaction motor axis.

That they are, in equal and opposite directions.  Net angular momentum is still zero. No anomaly. Class dismissed.

I am going to post this without further explanation at this point, to see what develops.

You're essentially planning not to answer questions is what you mean. Your replies have been really hostile towards requests for clarifications.
I'm watching your posts in David's topic and you seemingly have much to learn about angular momentum. There are direct replies pointing out your trivial errors, but you deny them, and then wonder why your mathematics comes up with supposed anomalies.  It doesn't if you do it correctly.
For instance, you say "For angular momentum to be conserved the tangential velocity [of a ball on a string] must remain constant. " which is just wrong. If radius is shortened (such as the skater pulling her limbs in), the tangential velocity must go up to maintain constant angular momentum. L=rmv, making it a function of radius, not just speed. This was pointed out in the first reply to your post there, and you ignored it. You don't seem to want the help that you ask for.

Ideally some model maker with an interest in science will duplicate the device.

Why?  It is uninteresting. Ideally, you will realize that a conclusion of angular momentum being created in a closed system implies that you've made an error somewhere. Be open to that possibility.

You have shown some interest, but no understanding. How is creating momentum anything other than anomalous?

It would be anomalous.  Your device doesn't do that. Only your assertions do.

I really need some help with this, some feedback.

You seem to be ignoring the help in the other thread. Are you going to listen to it here?

This post has been treated like a challenge to intelligent Design. Conservation of Momentum is ordained and should not, make that cannot, be questioned. There is no evidence that will convince otherwise. To suggest it can be otherwise is Heretical.

All the trolls say that. But the math does not bear out your description.

The fact remains, the model works and I need help with Dark Motion.

Angular momentum is conserved with your model. I don't see any computations, so I don't see how you figure it works, but you describe a precession axis which just plain doesn't exist. The left part does not precess at all since it has no net angular momentum.

I did not go to university, I do not have a degree, I do not speak mathematics.

And yet when you make a mistake, you assume it is with the people who do have the degree and speak mathematics. Consider the possibility that this thing which you've not actually built behaves differently than what you imagine it does.

I hesitate to give simplistic explanations for fear of being ridiculed.

You're not being ridiculed, except possibly for being completely closed to the feedback you asked for.

Take two pencils. Equal in length and weight, but opposite in colour. I will use red/blue. Place them side by side. Pointing in equal and opposite directions. Next, rotate each pencil through 90 degrees, rotate the red pencil clockwise, rotate the blue pencil widershins, that is do it in equal and opposite directions. They now both point in the same direction.

I learned a new word today. Thanks!

Spin and momentum are vector quantities.

Angular momentum in this case. Both momentum and angular momentum are vector quantities, yes, but they're different things and separately conserved.

The pencils can be said to represent the spin/momentum of the gyroscopes in the Dark Motion model. It is trite but true that the counter-intuitive behaviour of a gyroscope is easily explained by saying “changing the vector of its momentum.”

But add the vectors of the two pencils. They add up to zero, so the system has zero angular momentum.

The direction of the virtual vector sum of the precession spin and the gyroscope rotor spin is moved through 90 degrees by the sequential operation of the motors.

An object with zero angular momentum doesn't have a direction to it, so it cannot be rotated or precessed meaningfully.

Just a new understanding of the existing ones. Sir Isaac made a trivial error in framing the wording of “to every action”

More likely a misunderstanding of the existing ones by you. When I consider a model and find some violation of a conservation law, my first reaction is to assume I've made a mistake, and not a mistake with a law that has withstood centuries of verification.

If you can see that I am mistaken tell me how the Dark Motion model will behave differently.

I did above. No momentum is created if the forces are kept internal. When you brake all the wheels, there will be no remaining net rotation of the thing. There is no 'dark motion'.

[Colin2B]

I learned a new word today. Thanks!

Ah, widdershins. Obsolete, but very useful for taking the lefthand way around a bonfire, or stirring a concoction on Walpurgisnacht.

You have shown some interest, but no understanding. How is creating momentum anything other than anomalous?

It would be anomalous.  Your device doesn't do that. Only your assertions do.

When I was assessed as having no understanding, I realised nothing I could say would be heard, so dropped out.
Like you I saw the anomalies in the ‘precession axis’ and in the overall description of the so called anomalous motion, but as you say, neither of those are correct.i

Will you be listened to??

A video of the device would be good.

[Momentus (OP)]

Halc

Thank you for your detailed analysis of my Tandem Rotor device.
It does sound much more complicated than I had assumed it to be.

My big problem is that I have a device which works. I thought that I had figured out how it works, which is why I posted.

You've created a system with rotating parts but zero net angular momentum

So far so good, we are in agreement. The “Axle clamps” are in fact pillow block bearings It is OK to “consider the thing in space.”

There is no precession axis

A gyroscope has 3 orthogonal axes. They are the spin axis, at right angles to this is the torque axis and orthogonal to both is the precession axis.

To translate this to the model the spin axis is the left to right axis, the torque axis is the vertical axis the precession axis is the one that is left,

the one main axle in the whole setup which is the rotation axis of the red wheel.

So that is the set up. Two contra rotating gyroscopes, producing equal and opposite torques and precessing about the main axis of the red wheel.

Precession/torque in a gyroscope is instantaneous. Applying precession to a gyroscope along an axis at right angles to the spin axis the same thing as applying torque at the other, orthogonal axis. Its counter intuitive, but that is what a gyroscope does.

So with the model, there is no torque present to be reacted by the red Flywheel. The rotation of “the contraption” is driven by the gyroscope torque reacted within the frame.

Since this description varies radically from the one that you propose and leads to a different outcome. I ask for your comment before continuing.

[Halc]

It does sound much more complicated than I had assumed it to be.

It's actually more simple than you assume it to be. The yellow wheels have no net angular momentum so they’re effectively just mass, making it a trivial system.

My big problem is that I have a device which works. I thought that I had figured out how it works, which is why I posted.

Maybe then a short video clip of the device in action.
Those pillow block bearings are not frictionless, so they’ll contribute external torque to the entire device. But I take it you claim that the device behaves differently with the yellow wheels spinning than if not.

A gyroscope has 3 orthogonal axes. They are the spin axis, at right angles to this is the torque axis and orthogonal to both is the precession axis.

To translate this to the model the spin axis is the left to right axis, the torque axis is the vertical axis the precession axis is the one that is left

Left to right is the spin axis of the red wheel, the main rod held by the bearings. The torque axis of that wheel is the same axis, and so the precession axis is as well. All three are the same, so it shouldn't precess since there is no orthogonal torque applied to it.
The spin axis of the yellow wheel is not fixed since you intend to spin the device. Most of the torque applied to each yellow wheel will come from the other.
Your description here of these three fixed-direction axes contradicts your OP where you imply that the precession axis slowly changes as the red wheel speeds up. That makes no sense to me, so not sure what you mean by those words.

So that is the set up. Two contra rotating gyroscopes, producing equal and opposite torques and precessing about the main axis of the red wheel.

If they produce equal and opposite torques, they don’t precess at all. That was my point. No net torque, so no precession.
Similarly, a classic wheel spinning at the end of a rod will precess and not fall, but two wheels spinning  in opposite directions on the end of the rod will fall like they’re not spinning at all. The first case would violate a-m conservation if it fell, but the latter does not.

So with the model, there is no torque present to be reacted by the red Flywheel.

Yes there is. The device on the left has a moment of inertia, wheels inside spinning or not. It is that moment of inertia that takes the reaction torque from the red wheel spinning up. If the rest of the device had zero moment, the red wheel could not spin at all, having nothing against which it can apply torque.

[Colin2B]

Those pillow block bearings are not frictionless, so they’ll contribute external torque to the entire device.

As @Halc says these are not frictionless. Friction is a major problem with gyroscope models as the theory assumes zero friction. Your ball races with cages and lubricants is enough to provide external torque so not behaving as free space. Most toy gyros have cone/cup bearings to reduce friction, but these are unlikely to be able to take the load you are creating, ceramic unlubricated, or graphite composite bearings might give less friction.

A gyroscope has 3 orthogonal axes. They are the spin axis, at right angles to this is the torque axis and orthogonal to both is the precession axis.
To translate this to the model the spin axis is the left to right axis, the torque axis is the vertical axis the precession axis is the one that is left

Left to right is the spin axis of the red wheel, the main rod held by the bearings. The torque axis of that wheel is the same axis, and so the precession axis is as well. All three are the same, so it shouldn't precess since there is no orthogonal torque applied to it.
The spin axis of the yellow wheel is not fixed since you intend to spin the device. Most of the torque applied to each yellow wheel will come from the other.
Your description here of these three fixed-direction axes contradicts your OP where you imply that the precession axis slowly changes as the red wheel speeds up. That makes no sense to me, so not sure what you mean by those words.

To add to what @Halc says
If the yellow wheels are fixed flywheels, and assuming only one exists, then turning the reaction motor axis would cause the yellow wheel to try to precess perpendicular to both the gyro axis and the reaction axis. This is the only precession axis in the model and it is not the reaction motor axis. Again, if the other yellow gyroscope were the only yellow wheel it would try to precess in the opposite direction. As @Halc says the two together produce considerable stress on the frame.
So your comment “So that is the set up. Two contra rotating gyroscopes, producing equal and opposite torques and precessing about the main axis of the red wheel” is incorrect as they would not try to precess around the reaction axis (main axis of the red wheel).

The assembly of the reaction motor and reaction flywheel is unclear. I had assumed the motor frame is fixed to the flywheel and the rotor shaft to the gyro frame. Have you measured the moments of inertia of the flywheel and the gyro frame? If the gyro frame is less than the flywheel it will turn with only small movement of the flywheel until at higher speed the flywheel will begin to turn.

I have to ask again, why do you think the motion of this assembly is anomalous.

[Halc]

The assembly of the reaction motor and reaction flywheel is unclear. I had assumed the motor frame is fixed to the flywheel and the rotor shaft to the gyro frame.

Does it matter?  All that seems to matter is the moment of the part that turns one way vs the moment of the part that turns the other way, and even then it doesn't matter since we're not comparing the number of revolutions of each.

Related: Most prop airplanes put the propeller on the engine shaft, but the Sopwith Camel used a rotary engine with the shaft mounted to the chassis, giving considerable angular momentum to it, resulting in gyroscopic effects that made it difficult to steer.

[Colin2B]

Does it matter? 

Just helps with my lack of understanding 

As an aside, I wonder what techniques the OP has used to measure all the angular momenta and all the energy inputs/outputs.

[Momentus (OP)]

Tooth abscess, very painful, has kept me quiet for a few days. Thanks to modern antibiotics I am functioning again.

I find myself not where I want to be. The postings are “I'm right, no I'm right”. Repeating the same thing, louder. That does not work in real life, not going to work here either.

But this is not a political debate where the most skilful orator would prevail. No alternative facts.
It is a machine.

There is a point at which the views diverge. I will try to find that point.

Starting with a tower gyroscope, children's toy. Set it in motion and it does not tumble over, it rotates, defying gravity hooray.

I can use it to illustrate some points which are relevant to how I think the machine works.

The orthogonal axes are internally referenced, as the spin axis revolves about the tower, so does torque and precession, always orthogonal

Gyroscope Spin has a vector, precession spin has a vector. The vector sum is is a resultant spin axis between the spin axis and the precession axis.

The model has twin rotors so we need to modify the toy to have two gyroscopes, hinged either side of a central pole. This demonstrates that with equal and opposite gravity torque and gyroscope spin direction both precess in the same direction.

The rotors in the model are constrained by the frame so that they only have two freedoms of movement. Locking the hinges of the toy gives the same result.

When a torque is applied to the vertical axis of the toy, the gyroscopes respond by precessing at right angles to the applied torque. This motion is prevented by the locked hinges. A reaction torque results which precesses the twin gyroscopes about the vertical axis. This is an instantaneous reaction.

This appears to remove the inertia of the gyroscopes. As any attempt to apply a torque about the vertical axis is instantaneously reacted by the gyroscopes as precession about the vertical axis. Counter intuitive, which is the source of false claims that “gyroscopes become weightless”
 I think that I will pause my explanation at this point, because this may well be where Halc’s view is different.

So the red wheel spins one way, and the contraption to the left spins the other way.  Still zero net angular momentum.

To relate the toy to the model, the axis of the red wheel corresponds to the vertical axis of the toy. The motor shaft is attempting to apply torque to the frame to turn the spinning gyroscopes. The toy demonstrates that there cannot be a torque along that axis. Therefore no reaction torque, no movement of the red reaction flywheel.

In the real world, there is some rotation of the red wheel. Bearing rolling resistance must be overcome just for a start and the frame has inertia.

More in my next post.

[Halc]

Tooth abscess, very painful, has kept me quiet for a few days.

Well that bites. Good to hear you are functional again.

The orthogonal axes are internally referenced, as the spin axis revolves about the tower, so does torque and precession, always orthogonal

We already diverge, because those axes are not always orthogonal.  I spin up a dreidel and it is close to vertical on my table, but not quite. The spin axis and precession axis are only 14° different. OK, the torque axis is perpendicular to the precession axis in this case, but not to the spin axis.
I will acknowledge from your drawing that you've set up a device where these forces are orthogonal. I'm just saying that it need not be built that way, so this blanket statement implying that they must be orthogonal simply isn't true.

Gyroscope Spin has a vector, precession spin has a vector. The vector sum is is a resultant spin axis between the spin axis and the precession axis.

They're different things, so not sure why you'd want to add those two vectors, but OK. Your device (as a whole or as a half) lacks angular momentum and thus does not precess, so there is no precession axis or precession vector. The child's gyroscope and the dreidel both do have angular momentum and thus do precess due to the torque exerted by gravity.

The model has twin rotors so we need to modify the toy to have two gyroscopes, hinged either side of a central pole. This demonstrates that with equal and opposite gravity torque and gyroscope spin direction both precess in the same direction.

Good example of a system with zero angular momentum that nevertheless precesses. But change it to one common axle (instead of two independent gyros whose axles coincidentally line up) and the thing will not precess. Do you see the difference?
Closer to your device: Picture two independent gyros on opposite sides of the same tower, but with identical spin vectors this time. Left alone, they precess in opposite directions, but we instead constrain that motion via a barrier connected to the tower. Each gyro now exerts precession pressure on that barrier, but cannot move. Nothing precesses. This adds stress to the barrier, but no net force or net torque, and thus no motion. The wheels spin without any precession. That's closer to what's going on in your device, where the precession is constrained by having both ends of the yellow spin axles constrained, resulting in equal and opposites stresses that cancel any precession.

The rotors in the model are constrained by the frame so that they only have two freedoms of movement.
 Locking the hinges of the toy gives the same result.

Not sure what your toy looks like. I picture a top leaning to the side of a tower upon which it rests, or just a top on a table.

When a torque is applied to the vertical axis of the toy, the gyroscopes respond by precessing at right angles to the applied torque.

You mean the gyro moves up and down?  I've not seen many toys that work with torque being applied vertically like that. Usually the torque is supplied by gravity, which can only result in torque along a horizonal axis, resulting in precession along the vertical axis. Maybe a link showing such a toy would help me visualize what you have in mind. Unclear where the hinges are and what motion is allowed/prevented when locked and not locked. Don't say vertical. Say up or down, since that tells me which way the torque vector points.

This appears to remove the inertia of the gyroscopes. As any attempt to apply a torque about the vertical axis is instantaneously reacted by the gyroscopes as precession about the vertical axis.

You're contradicting yourself now. You said the torque and precession axes are orthogonal, but here you have them both vertical, which is parallel.  A vertical torque cannot produce vertical precession, only a change to vertical angular momentum.

Counter intuitive, which is the source of false claims that “gyroscopes become weightless”

Of course that's wrong and not even intuitive. I've seen heavy ones, and they're definitely not weightless when spinning. If it weighs 100 newtons stationary, it weighs 100 newtons while spinning.  If the weight changed, you could get cargo into space easier by spinning it first.

I think that I will pause my explanation at this point, because this may well be where Halc’s view is different.

You haven't really said much with which I disagree except the reaction to vertical torque.
Your model depicted in the OP runs on these bearings which have friction in real life, so torque is applied through these bearings and you cannot expect the device to retain its angular momentum of zero. That's why I envisioned the device in space with no external forces possible. It can have all the internal friction it wants up there, and it isn't going to gain any momentum from it.

To relate the toy to the model, the axis of the red wheel corresponds to the vertical axis of the toy.

OK, so you are putting the equivalent of vertical torque on it, but the yellow wheels to not precess in the same direction as the torque like you assert. One is spinning east and the other west and they are constrained from precession, so there is no precession of the yellow wheels.  The two wheels attempt to precess, but the frame holding them prevents it, and those forces are equal and opposite, so there is no effect: no resistance other than the same regular angular moment that it had when nothing was spinning.
I don't know what your toy looks like, but if precession is constrained, then there will be no precession, just spin without resistance.

The motor shaft is attempting to apply torque to the frame to turn the spinning gyroscopes. The toy demonstrates that there cannot be a torque along that axis.

You can apply torque along any axis you like, so not sure what you mean by this statement.

Therefore no reaction torque, no movement of the red reaction flywheel.

You're saying the red wheel stays stationary when you turn on its motor? That can't be right. It would violate angular momentum conservation to spin one side and not the other in an equal and opposite way.

[Momentus (OP)]

Hi Halc

For me today's new thing is Dreidel.  But I am familiar with spinning tops, so I can see your point clearly. The precession axis and the spin axis of a nearly vertical spinning top are not orthogonal. I have no explanation for this. Spinning tops are complex beasts and usually have several chapters devoted to their behaviours in most text books.

The orthogonal nature of the gyroscope is the orthodox view. It is not my idea. When you work from first principles using the laws of motion, you get orthogonal spin precession and torque.
Your example is however quite compelling, so I checked. It has not changed. My memory is not at fault, although it is a long time since I first looked at Professor Leonard Maunder’s 400 page tome on Gyrodynamics. I do not know how to reconcile your example with the standard view of gyroscope behaviuor.

so this blanket statement implying that they must be orthogonal simply isn't true.

No
orthogonal rules!!!

 May I suggest you check your own gyro-dynamics reference work?

Good example of a system with zero angular momentum that nevertheless precesses. But change it to one common axle (instead of two independent gyros whose axles coincidentally line up) and the thing will not precess. Do you see the difference?

Zero angular momentum describes a system where the wheels are not spinning. No net angular momentum describes a system where the wheels are contra rotating. I see that as the difference. There is kinetic energy stored as as angular momentum in a gyroscope, two contra rotating gyroscopes would store twice the energy. So must have twice something that the static, zero momentum system does not have. A spinning wheel reacts torque in a different way.

One common axle is an accurate portrayal of the “toy” and it will sit with contra spinning rotors without precessing. Now you intervene to change that state. You turn the vertical shaft, and note the effort required to turn it.

When you turn the vertical axis, the motion that results is precession, by definition of what a gyroscope is, also it is accompanied by an instantaneous torque, again because it is a gyroscope.

Nothing happens until you try to turn it, then it reacts as a gyroscope must, it produces orthogonal torque and precession. From the direction you turn it, the torque will try to bend the bar either up or down. The faster you turn it, the greater the orthogonal torque, the greater the speed of precession.

Your intervention does not apply torque to the vertical shaft. It precesses the twin gyroscopes.

Your subsequent points in your post are all affected by this. I shall refrain from detailed analysis as I shall only be repeating myself.

The motor shaft is attempting to apply torque to the frame to turn the spinning gyroscopes. The toy demonstrates that there cannot be a torque along that axis.
You can apply torque along any axis you like, so not sure what you mean by this statement.

Torque can only be applied where there is an equal and opposite torque to react the torque you are determined to apply. The stubborn nut gives way suddenly and you bark your knuckles. You tried to apply a torque along an axis you liked. In the example I gave there is no reaction torque along the red axis. It is the absolute nature of a gyroscope that it reacts torque at right angles to the precession axis.

You're saying the red wheel stays stationary when you turn on its motor? That can't be right. It would violate angular momentum conservation to spin one side and not the other in an equal and opposite way.

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I am saying that if you do this, then that is what happens. I give my reasons, couched as best I can using orthodox, standard, accepted, laws of motion.

Yes the Frame is spinning and the red wheel is not, but if you try to harvest the stored momentum by reversing the red wheel motor, you will simply stop the precession of the rotors in the frame.  And return to two rotors contra-rotating, all as before.

You need to progress on to the two pencil vector part of my post to see how the angular momentum can be harvested.

Which if you have followed so far I will repeat in my next post.

[Halc]

Zero angular momentum describes a system where the wheels are not spinning. No net angular momentum describes a system where the wheels are contra rotating. I see that as the difference.

OK then, you have that system with two opposite spinning wheels like you describe. Your toy apparently has this.  How much angular momentum does the system have?  Because I don’t see that as a difference.  This seems to be the root of your problem: that you cannot add.

There is kinetic energy stored as as angular momentum in a gyroscope

Momentum is not energy, so this cannot be correct. There is kinetic energy in the gyroscope, but it isn’t stored as momentum, angular or otherwise. This continued equivocation of the two is causing you to make all sorts of nonsense statements like this.

So must have twice something that the static, zero momentum system does not have.

Both have zero momentum.  It the spinning one doesn’t have just twice the kinetic energy, because the other one has zero kinetic energy, and nonzero is more than twice zero.

One common axle is an accurate portrayal of the “toy” and it will sit with contra spinning rotors without precessing. Now you intervene to change that state. You turn the vertical shaft, and note the effort required to turn it.

This description violates conservation of angular momentum.

When I was assessed as having no understanding, I realised nothing I could say would be heard, so dropped out.

Considering it. Trying to pare down the text to the critical mistakes.

Will you be listened to??

Nope.  Not unexpected actually.
He seems to be in it for the view count, not for learning anything.

[Momentus (OP)]

To add to what @Halc says
If the yellow wheels are fixed flywheels, and assuming only one exists, then turning the reaction motor axis would cause the yellow wheel to try to precess perpendicular to both the gyro axis and the reaction axis. This is the only precession axis in the model and it is not the reaction motor axis. Again, if the other yellow gyroscope were the only yellow wheel it would try to precess in the opposite direction. As @Halc says the two together produce considerable stress on the frame.
So your comment “So that is the set up. Two contra rotating gyroscopes, producing equal and opposite torques and precessing about the main axis of the red wheel” is incorrect as they would not try to precess around the reaction axis (main axis of the red wheel).

The stress in the frame is due to equal and opposite gyroscope couples, orthogonal to precession. The reaction motor axis becomes the precession axis. The spin axis and couple axis maintain their orthogonal relationship as the device rotates.
When the reaction motor is switched on, the device rotates about the reaction motor axis. As you would expect. It is what happens. Out there in the real world.
A gyroscope that is rotating about one orthogonal axis produces a couple at the other axis.
@Halc
Thank you for keeping this thread alive. 800+ views, there was always the chance that someone who has an understanding of gyroscope behaviour was looking in.

Both have zero momentum.  It the spinning one doesn’t have just twice the kinetic energy, because the other one has zero kinetic energy, and nonzero is more than twice zero.

Difficult to argue with that!!!!

One common axle is an accurate portrayal of the “toy” and it will sit with contra spinning rotors without precessing. Now you intervene to change that state. You turn the vertical shaft, and note the effort required to turn it.

This description violates conservation of angular momentum.

Even more difficult to see !

Mod edit: Fixed embedded quote

[Momentus (OP)]

 If a gyroscope is rotating about any axis, other than the spin axis, then that is precession and Orthogonal to that axis is the couple.

For clarity, let the red axis be along the red flywheel axis, The yellow axis is the gyro axis and the blue axis is orthogonal to these. In the model the red axis does not move, the yellow and the blue axes move but remain orthogonal to red.

In the model we have forced precession along the red axis, with equal and opposite torque about the blue axis and spin about the yellow axis. This is the starting condition.

The spinning gyroscope rotor is forced to precess about the red axis as that is the only axis that permits rotation orthogonal to the yellow, gyroscope spin axis. This simultaneously induces a torque about the other orthogonal axis, the Blue axis.

When the frame containing the spinning gyroscopes is rotated by the red motor, That rotation induces an orthogonal couple at the blue axis. As the spin of the gyroscopes are equal and opposite, these torques, induced by the precession about the red axis are equal and opposite.

This is the condition you describe in your early experiments with bicycle wheels. The two torques were still there in your manipulation of the counter rotating bicycle wheels, but as they were balanced, they had no external effect. The torque did not disappear. No external torque does not mean the same thing as a balanced internal torque. Because you could not longer feel the torque generated by the wheels does not mean it was not present.

I will bang on about this some more. Take a bicycle, with the frame securely clamped to hold it off the ground. With the front wheel not spinning move the handle bars. There will be some slight resistance due to the inertia of the wheel about the vertical axis, but not very much.

Now as you have already guessed, spin the wheel and do it again, move the handlebars. It feels much the same. However you know, from previous experience that is not the same, there is a torque being reacted by the forks supporting the front wheel. If your clamps are loose, the frame will move.

My conclusion.

The conditions for the flywheels to act as gyroscopes are fulfilled. A spin axis of the rotor, Yellow, A torque axis, Blue and a precession axis, Red.

Momentus