Question |
| Asked by: |
Blaze |
| Subject: |
Gyro Flywheel in different orientations |
| Question: |
Has anyone built an overhung gyro where the spin axis of the flywheel was NOT the same shaft as the arm of the gyro? In other words the axle of the flywheel is perpendicular to the arm of the system (the arm is the shaft between the flywheel and pivot).
There are two additional scenarios that I can think of.
1) The flywheel axle is vertical and is perpendicular to the gyro arm (the flywheel orientation is flat, like a pancake when the arm is horizontal). In this scenario the gryo arm would have to be able to turn about its long axis as well as precess about the pivot point as it would normally do.
2) The flywheel axle is horizontal and is perpendicular to the gyro arm (the flywheel orientation is like a wheel but rotated 90 degrees about a vertical axis through its center of mass). In this scenario the gryo arm would have to be able to turn about its long axis as well as precess about the pivot point as it would normally do.
It is important that the gyro arm can rotate about its long axis as it precesses for both of the above scenarios.
I predict that scenario one, when released from horizontal, the gyro would start much like a "conventional" overhung gyro and would "hold itself up" as it precessed. This is because the gyro arm would rotate a bit as it precessed and therefore the flywheel would actually not be perfectly flat in orientation as it precessed.
I predict that in scenario two, when released from horizontal, the gyro would fall until it contacted something (the table or whatever surface its pivot was sitting on). It would not precess or hold itself up. However, if one were to hold up the flywheel end and rotate (that is rotate, not precess) the arm a bit, then the gyro would start to precess and would in fact hold itself up as it precessed once it got going. In this scenario, if one were to start the gyro with the flywheel axle not perfectly horizontal, the gyro would start much like a conventional overhung gyro but the distance it falls as it gets up to speed would likely be greater than a conventional gyro especially if the axle angle were very nearly horizontal. This scenario is really just a modification of scenario one.
Your thoughts?
Cheers,
Blaze |
| Date: |
27 February 2013
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Answers (Ordered by Date)
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Blaze - 27/02/2013 02:18:28
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| | Upon further reflection, I believe that neither scenario would actually "hold itself up" as they precessed in a gravity field. They would both continue to fall. However both of these scenarios should work just fine in a gravity free environment. They would precess faster or slower as you rotate (that is rotate, not precess) the arm about its long axis.
regards,
Blaze
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Glenn Hawkins - 27/02/2013 15:43:36
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| | Hello Blaze,
Yes, I have.. I used two paper clips wrapped snugly around the guard of the cradle and extending outward. Actually it was sturdy and worked well. Later for another experiment I welded a straightened clothes-hanger length to the rim guard of the cradle at the knob. Both altered gyros performed the same. The gyros were held to spin horizontally, with the unattached rod end resting on a table. The spinning wheel was lifted to 90o up from the horizon plane and dropped. When loosed, gyros always flips over quickly into a vertical alignment, rim to rim up and down. Falling in such a ‘way, I know you are aware it can not precess. Los Angeles area?
Cheers, Glenn
PS To the best of my recollection, you can set the cradle guard barely resting on your finger tip and see if flip as it tilts.
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Glenn Hawkins - 27/02/2013 15:43:37
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| | Hello Blaze,
Yes, I have.. I used two paper clips wrapped snugly around the guard of the cradle and extending outward. Actually it was sturdy and worked well. Later for another experiment I welded a straightened clothes-hanger length to the rim guard of the cradle at the knob. Both altered gyros performed the same. The gyros were held to spin horizontally, with the unattached rod end resting on a table. The spinning wheel was lifted to 90o up from the horizon plane and dropped. When loosed, gyros always flips over quickly into a vertical alignment, rim to rim up and down. Falling in such a ‘way, I know you are aware it can not precess. Los Angeles area?
Cheers, Glenn
PS To the best of my recollection, you can set the cradle guard barely resting on your finger tip and see if flip as it tilts.
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Blaze - 27/02/2013 17:33:09
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| | Hi Glenn. That is a nice simple way of performing the experiment. Did you notice any precession as it was falling? It would be a small amount and may not be noticeable in the short time it takes the gyro to fall. It may only be seen if filmed and looking at it in slow motion. Precession should happen though.
It is interesting to note that these scenarios should work just fine in the absence of a gravitational field. By controlling the rotation or twisting (the input torque) of the arm, the system would precess at any speed you want it to. Twisting of the arm would be the same a "tilting" for a conventional gyro. More twisting (ie: more torque) means greater precession speed. In the absence of gravity, the gyro would not fall when speeding up. It would also not rise when slowing down (when input torque was removed).
cheers,
Blaze
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Glenn Hawkins - 27/02/2013 23:34:50
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| | Blaze,
That is a rather brilliant deduction. I will test it later. It should be easy if I have my old junk still findable.
Gravity causes torque, but it does not directly cause precession. The flywheel being moved through space causes precession. The force to move it may come from any source. This is why I think I can perform the outer-space like tests you speak of, but perform them as well in a gravity environment.
Consider there were a round tube with one steel ball rotating inside, and yet magically it could perform in proportionate balance without a non-concentric vibration. Set the tip of the tube on the edge of a table aliened and rotating in the horizontal plane. Now to the conditions of gyroscopic deflection. When the ball rotates from the table, the angular momentum in the ball resist changing course such as falling downward. This resistance tends to hold that side of the tube horizontally level, while the other side of the tube, having no speeding ball and momentum yet to support it, will fall. The tub is now tilted. (top view) The ball’s past place in space inside the horizontal tube began it's rotation from the table. When it rotated 90o it resided in the sideways potion of a concentric circle. It’s leveraged resistance was equal to the radius of a circle. By the time the ball rotates to the opposite side of the tube, the tube has been twisted into an oblong shape. (top view) The ball’s leverage force is reduced by what can be thought of as a sideways radius and is now is shorter leverage and less powerful. The twisting of the tub keeps changing as the ball keeps rotating, until the tube is vertical.
Gyroscopes in a normal overhung position precess, because of this of this same deflection during tilting. I think of it as ‘past’ and ‘future’ positions of speeding partial resisting at greater and lesser magnitudes of force while circling. This understanding may become clearer, when one realizes that these changes in force would be miscue, except that the particle in a flywheel, of say a Tadco toy, might be rotating at forty times a second. Miscue adds up.
Now I promise to do these tests, but at another time. It is a good question to have been brought up.
Cheers Glenn,
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Blaze - 28/02/2013 01:15:32
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| | Hi Glenn. Actually I think that I can easily test this idea with my mecanno gyro. I would have to "lock" the arm to prevent it moving up or down (this effectively removes any gravity input). I would also have to change the orientation of the flywheel as described before and modify the arm to be able to twist, but those should be fairly easy modifications. Then when I twist the arm, the gyro should precess nicely.
regards,
Blaze
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Glenn Hawkins - 28/02/2013 02:11:52
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| | Blaze,
You are correct. I have a number of odd shaped gyroscopes I just tested and in all tests at high revolutions the precession was very pronounced for about three inches, even rising skyward, before they flipped to vertical alignment.
To your number 6) post: The tests were done pretty much from my early explanation that it did not mater what twisted the gyro, torque at the rod, or the gyro moving through space, both twist the gyro. If you wish to test by twisting the rod, I think you will come to the same conclusions as I did. Let us know.
PS I am working out the best shape, size, mass and rotation speed for the kind of propulsion we have considered. Already I can tell you that the following is beginning to appear true. If you should increase the angular momentum tremendously in your new idea of horizontal spin alignment and then apply tremendous tilting force, the tilting would be minimal, while the precession distance and speed, before turning vertical, might be greatly increased. It is seeming that way.
Cheers, Glenn
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Blaze - 28/02/2013 02:43:18
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| | Hi Glenn
"torque at the rod, or the gyro moving through space, both twist the gyro"
Agreed, that is the reason a conventional overhung gyro keeps itself up, because the flywheel is moving thru space (rotating about a vertical axis thru its centre of mass) as it orbits the pivot which is what generates the counter gravity couple. The orientation of the flywheel in this thread should not generate any counter gravity couple. That is why you would have to "eliminate" gravity to use this type of system.
The idea with this thread is that by simply twisting the arm you could start, stop and vary the speed of the gyro without applying any vertical tilting force. The arm would not have to move vertically so the whole system would be very simple to build and control. If I am correct about there being no counter gravity couple generated, then there is no falling or rising to contend with when starting or stopping the gyro. However, to overcome friction, the twisting of the arm would have to be constantly applied which would be akin to drooping in a conventional overhung gyro. Total twist couldn't be more than 90 degrees before precession reversal would take place. So one would still need to have some system to make up for lost precession speed due to friction.
Interestingly, every 90 degrees that you twist the arm would cause the precession would reverse so twisting the arm 360 degrees would reverse the precession 4 times. Hmmm....
regards,
Blaze
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Blaze - 28/02/2013 02:54:12
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| | correction:
Total twist couldn't be more than 180 degrees before precession reversal would take place.
Interestingly, every 180 degrees that you twist the arm would cause the precession would reverse so twisting the arm 360 degrees would reverse the precession 2 times.
Blaze
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Blaze - 28/02/2013 03:00:36
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| | Oh wow! This just gets more and more interesting. When the flywheel axle is near horizontal you would get the most force driving precession and when the flywheel axle is near vertical you would get the most vertical force, up or down depending on which way the flywheel was spinning.
So there would be some vertical movement.
Blaze
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Glenn Hawkins - 28/02/2013 03:45:21
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| | Hi again Blaze,
Yes it gets more interesting. I agree with you all the way. As I understood the primary question, it was simple. Would a horizontally precessing flywheel precess while being twisted. Yes, if that was the question then, yes it would. The answer is, yes as I understood you. The source producing the torque dose not alter the fact that the configuration explained does produce precession.That is my jest. If the set-up carried enough angular momentum, the drop/tilt distance would be negligible in gravity per thrust and re-cocking, perhaps an little as a millimeter. Gravity changes the position and degrees of drop wherein the actions remain and take place as you would indicate, but this does not change the reactions. The reactions come about either way. Maybe I did not understand the post? but I sort of think I did understood the question.
I live on Whittling Street also on Yuka Street in Hollywood, and in La Jolla for a few years while writing. I would say you are one of the a hot tub guys out there. I shall never know? but that’s a complement. In that hot tub was invented the computer among many fantastic things.
Regards G. H.
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Blaze - 01/03/2013 02:57:40
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| | Hi Glenn
"in all tests at high revolutions the precession was very pronounced for about three inches, even rising skyward, before they flipped to vertical alignment."
This makes sense now that I have more time to think about it. I will have to build this. It has too many possibilities not to.
cheers,
Blaze
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Glenn Hawkins - 01/03/2013 15:43:12
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| | Wow! Blaze Wow!
You are on to something exciting, making the possibility of creating the perfect design conceivable. I started this far too long ago, but I did not see that twisting the rod was the answer to so much.
Another thing; I struggled a long, long time in order to determine to my satisfaction that there was no equal and opposite play at the pivot. Now with this new, call it engineering, yet to be done, it should become inarguable that there is no equal and opposite reaction. This thing might be able to move like a rowboat through space, an action I NEVER believed was possible. There is more to think out. Good luck! I may do something myself.
Smile, Glenn
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Blaze - 01/03/2013 18:23:52
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| | Hi Glenn. Here is something else for you to think about.
Twisting the rod is the input torque. This causes precession. Precession also causes a torque which is opposite in direction to the input torque and theoretically equal in magnitude. In other words the precessing gyro in this system will resist the torque being applied to the rod. This makes sense as in a conventional overhung gyro, the precessing gyro also resists the input torque (the precessing gyro generates the counter gravity couple which is opposite to the input torque, the gravity couple).
There is still some stuff to work out here but this weekend I should have some time to do so.
cheers,
Blaze
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Glenn Hawkins - 01/03/2013 19:50:23
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| | Hi Blaze,
That is an excellent analogy. Of course you are right. I too have some things not mentioned, yet to add. One is difficult to explain without drawings, but somewhat difficult even with then. This is why I’ve never mentioned them, but they relate to you findings. Later; if I can think my way through the mud.
Cheers and good fortune,
Glenn
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Glenn Hawkins - 03/03/2013 03:58:01
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| | Hi Blaze,
I foresee some problems with this design, interesting thought it is. I don't know how it could be re-cocked. I will leave in you good hands to develop and follow you. I am glad your introduced it. Keep informed. I am going back to concentrate on my ageless old design.
Regards Glenn,
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Blaze - 03/03/2013 21:26:20
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| | This is getting more interesting as I gain further understanding. I will report on this again when I have finished my thought analysis and maybe even done a few experiments to confirm.
As for resetting, that would depend on the nature of your design. I can't comment without knowing what you are doing. As for my design(s), this could work just as well as a "conventional" overhung gyro, if anything works at all.
cheers,
Blaze
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Glenn Hawkins - 03/03/2013 22:05:12
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| | The test I just now did produced nothing. I though at my methods with a stiff wire running parallel with the wheel and attached to the cages of the cage would be good enough, but is was not. I know the test set up was inadequate, because with it when the wheel was aliened vertical I still did not get any result. I drew a blank with my inadequate test. I rely on you to solve the questions. Good luck.
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Blaze - 03/03/2013 22:26:52
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| | I have just started doing some tests and so far the gyro is doing what I predicted. However, with the extra degree of freedom that this setup has, it is a little more difficult to figure out what should be happening. I have a simple tool that I use to help me keep track of things when I am predicting which way the gyro will move. My initial test setup is simply some stiff wire wrapped around the cage of the toy gyro with the wires extended to one side (which acts as the arm). This does not allow me to actually torque the arm. Instead the reaction of the gyro moving downwards due to gravity is doing the torquing. Later I will build a setup where I can "eliminate" gravity and torque the arm at will to prove out the rest of the theory.
The big issue here is that this would work FAR BETTER in a non gravity environment than it does in gravity.
cheers,
Blaze
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Glenn Hawkins - 04/03/2013 02:13:54
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| | I did the same thing with a wire. . . , see the post above. Except I managed to apply back and forth twisting motions to the rod. I put an elbow in the unconnected end of the wire about 9” back. I rested the wire on a long knife blade to support the gyro and test it at differ lengths of the wire, forward toward the gyro and backward from the gyro. There seems not to be enough friction between the surfaces of the sharp blade-to-small wire to cause a readable effect. Also taking care to manipulate the long right angle elbow should not cause much of an effect. You can see this by doing the test while the gyro is not rotating.
I predict this is going to be difficult to prove and that precession will be extremely limited. It will act as a gyro inside gimble rings acts, which is a condition that produces little, no precession. The gyro just twist around at an 180o deferential drive.
In order to precess to a substantial degree, one side of a gyroscope must be held in place, while the opposite side is tilted. Otherwise the orientation in space, with or without gravity would seem to make no difference to the 180o deferential drive event that I predict.
I wish that this were not true for you. I look forward to your findings and your report.
Glenn,
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Blaze - 05/03/2013 03:47:47
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| | Hi Glenn
"when the wheel was aliened vertical I still did not get any result"
If I understand you correctly, you had the gyro oriented with the axle of the flywheel in a horizontal position. If that is the case you will get nothing happening except the gyro falling. It will not precess.
If you have the flywheel axle vertical and let go of the gyro you will see the flywheel twist 90 degrees as it falls and you may see a very small precession movement before it hits the table.
This is the setup I used:
The flywheel is running horizontal (axle is vertical) with arm pointing directly away from me with the far end of the arm on a pivot tower. The flywheel spin is such that the left side is moving away from me (right side moving towards me).
If I have the left side of the flywheel tilted slightly down and let go of the flywheel twists and drops with barely noticeable precession to the left. This is expected.
If I have the right side of the flywheel tilted slightly down and let go of the flywheel, it precesses to the right about 90 to 120 degrees. As it precesses it also rotates about the arm and when it has rotated enough to have the left side tilted slightly down it drops to the table without much reverse precession. This is also expected. If the flywheel is tilted to the right side too much the gyro drops without much precession.
In both these cases the input torque is supplied by gravity. The next experiments I do will "eliminate" gravity. I will twist the arm manually and the gyro will precess, or at least that is the prediction and I don't see any reason at this time why that prediction would be incorrect.
regards,
Blaze
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Glenn Hawkins - 07/03/2013 00:53:59
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| | Hello Blaze. How are you?
That was not what I meant.
I propose to build descriptions of this new topic so overwhelmingly defining that there can be no mistake, or lack of certainty in what we hereafter write. When I have time and I have finished, you may redefine it, until together we arrive at the clarity of gods, in ways and methods to relate this topic to one another. Latter.
Regards Glenn,
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Glenn Hawkins - 11/03/2013 04:03:31
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| | Sorry I haven’t got back to this, busy and tired.
Glenn,
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Glenn Hawkins - 30/03/2013 15:05:04
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| | Hello Blazé,
You were correct. I am over-simplifying the following explanation well below your and the member’s common level of understanding, not because it’s needed, but because it is a good deal easier for me.
Imagine a bicycle wheel and it’s front fork, but with a two foot shaft towards the handle bars. Although it dose not matter, except for easier explanation, I am making a change. In this example the wheel is rotating vertically, not horizontally as was first put forth, while the shaft is twisted. The wheel will attempt to twist horozonally around its center of mass, that is the axes of the wheel. If however the wheel is rotating fast, it will not twisted, though under the influence the shaft’s failing attempt to twist it. You see this in gyroscopes in gamble rings. If angular momentum is strong enough, the wheel refuses yield to the force to tilt it. Instead the force is transferred to right angle circling movement.
In this example, exactly as in overhung gyroscopes, the structures do not allow the wheel to transfer right angle twist around the center of the wheel’s mass. The wheel transfer’s its torque to the shaft and consequently, both shaft and wheel must revolve around a common pivot. The trick is to build much greater angular momentum, because the displacement is to the extent that the shaft creates greater opposite leverage; gravity you know. Bingo, it works. Excellent, Blaze.
Lastly, this part is greatly against intuitive reasoning. I do not believe there would be equal and opposite force at the pivot. I base this probability on the fact that the overhung gyroscope enacts no equal and opposite reaction at the pivot.
Good fortunes to all we crew of the Enterprise. Live long and prosper (Y),
Glenn
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Glenn Hawkins - 30/03/2013 21:42:38
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| | Forget I mentioned gravity.
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Blaze - 28/04/2013 20:06:42
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| | Hi Glenn. Good idea using a bicycle wheel in the forks.
I finally got around to building a adapter for a tedco gyro and doing some more test for this idea and it does mostly what I thought (but there were a few interesting things that I hadn't thought of).
When the flywheel is spinning in the vertical plain, precession is in the horizontal plain, either clockwise or counterclockwise depending on the direction of torque applied. I did this test with the arm supported so it couldn't fall due to gravity. There really is virtually no lift generated when precessing and this was the best I could do to simulate a non gravity environment.
When the flywheel is spinning in the horizontal plain, precession is in the vertical plain but in this case it is not as easy to "remove" gravity from the experiment. One could probably use a counter balance and I may try that as well.
cheers,
Blaze
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Glenn Hawkins - 02/05/2013 17:25:51
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| | Good for you Blaze!
While the wheel is in the vertical alinement and if there is tremendous angular momentum, then when the bike fork is twisted, the wheel should attempt to revolve around its axes in the horizontal plane. This it seems should exert force on the fork to move sideways in the horizontal plane around an area of pivot. Are you sure of your test?
Cheers.
Glenn
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Blaze - 03/05/2013 01:11:14
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| | Hi Glenn. That is what I am saying happened in my experiment as well. When torque is applied to the gyro which is spinning in the vertical plain, it precesses in the horizontal plain. This makes sense of course, as the resulting motion (precession) is a 90 degree shift to the applied torque.
regards,
Blaze
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Glenn Hawkins - 03/05/2013 01:30:51
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| | Wonderful Blaze,
Keep on keeping on. This is actually significant news, in stead of untested conjectures like my own.
Regards and happiness,
Glenn
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Ted Pittman - 29/05/2014 14:17:00
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| | What would happen, in the above scenarios, if precession reversal could be avoided?
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Blaze - 29/05/2014 15:34:25
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| | Hi Ted. I don't know of anyway that precession reversal could be avoided except to stop applying the input torque.
regards,
Blaze
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Nate - 18/11/2015 12:22:30
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| | Nobody answered my question:
WHAT WOULD HAPPEN IF PRECESSION REVERSAL COULD BE AVOIDED?
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Glenn Hawkins - 18/11/2015 22:03:21
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| | Hi Nate,
Three things:
(1) I could not find that you had ask a question on this tread.
(2) Could you explain and give and example of precession reversal?
(3) If you push a precessing flywheel backwards it deflects downward. Is that it?
Glenn,
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