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3 May 2024 15:32
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Question |
| Asked by: |
Eric James ----- |
| Subject: |
A Convoluted Concept |
| Question: |
"A Convoluted Concept"
Some of my thought experiments involve gyroscopic behavior. In one, I envision a pair of gyroscopes mounted on powered gimbals. Basically, the gyroscope's axis and motors would connect to the inside of a ring. That ring's axis would subsequently be powered and attached to a larger ring. Then, that ring would also be powered and attached to an "axle" linking both gyroscopes and gimbal assemblies. All axis of rotation would also include braking mechanisms.
What I thought, was that if two gyroscopes mounted on an axle (envision a set of dumbbells, or car axle) were thusly attached and controlled (by computer), you could cause each gyroscope to precess against the other and/or the main assembly by using opposite rotation and creating a "twisting" motion in the gimballs and braking them at desired angles.
You could spin-up the whole assembly longitudally, by using the gyros in a harmonious angle, or with a center flywheel while keeping the gyroscopes inline to prevent precession. Then, when your axle is acting as its own gyroscope, you twist and brake the gimbals. One to act as a brake, and one to "encourage" continued rotation.
I suspected that by doing this, you may be able to get the assemblage to "throw" itself forward from a standing point in space.
My basic principal is that by suddenly causing an interaction between the gyros and the main assembly, you might change its point of rotation without changing its center of mass. It'd be kind of like spinning a baton at its center and then lightly hitting one end in a harmonious way, causing its center of rotation to move to the interaction with your hand. You'd get a lot of flight for a relatively light hit. The neat part is the "hit" is self-contained and repeatable.
By the laws of motion, a spinning center of mass, that is not synchronized with the center of rotation, must move linearly away from the center of rotation (due to "centrifugal" force).
I originally got the idea by thinking that the resistance a gyro exhibits when being turned over could be used as a sort of "space brake." The gyro basically creates a drag on one end of the assembly thereby causing a shift in the center of rotation. The axle would need to have a controlled flexibility between the center of mass and the gyro. That flexible point is where the new center of rotation should occur.
Anyway, I'm pretty sure that it will wobble all about, but I have doubts that you could get a directional force from it. I do think it might be worthy of investigation.
I also thought that it might be a good concept for slowing a spinning body without expending fuel.
It's too compex for me to properly analyze, what do you think?
Eric
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| Date: |
1 May 2005
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Answers (Ordered by Date)
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| Answer: |
Victor Geere - 06/05/2005 09:59:04
| | | Can you publish a picture somewhere?
One thing that I would like to warn you about is that multi-dimentional gyroscopes can be dangerously confusing, if a one dimentional gyroscope is not confusing enough. It is virtually impossible to imagine the nett force on a gyroscope when it is spinning inside another gyroscope, or if you can imagine it, to explain it in words in terms of an xyz area. See Nitro's first law.
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| Answer: |
Eric James ----- - 06/05/2005 15:23:11
| | | Victor,
Hence the name "A Convoluted Concept."
I am fully aware of the complexities of my concept. I also predict that it won't work. But it is an intriguing puzzle, wouldn't you say?
It's an attempt to use gyroscopes as temporary fulcrums in a method similar to the Alex Jones invention.
Consider that a typical mass spinning in space will naturally always and automaticaly center that spin around its center of gravity.
If it is initially spun (more accurately, slung) outside that center of gravity, the angular momentum of the mass outside that center is immediately realized as linear momentum upon release (much like in a hammer throw).
The difference of course is that I'm attempting to change the center of rotation without an additional mass being attached (like the person attached to the hammer in a hammer throw) that extends the center of mass from the considered mass and into the entire system.
Instead, I propose using the drag of a gyro (turned on its axis) as a sort of psuedo mass (so to speak).
Will it work? I doubt it. Even if it did, it'd be quite the engineering challenge.
Personally, I predict that all that will happen is that the plane of rotation will begin shifting to new angles (as a function of precession). Basically merely spinning in two axis (tumbling).
I've also considered using twin (counter-rotating) gyros on either end (four in total) to prevent (cancel) the tumble. However, in this case the gyros would simply cancel themselves out and have no net effect.
After imagining many such variations (wider gyros, gyro spacing and whatnot) I've concluded that the only thing that makes this even remotely possible is the flexible joint in the axle (kind of a third but limited axis).
Even so, I don't think it will work. I think the flexible point will reduce the precession effect and therefore just be canceled out once again. But, there is that instant of momentum propagation where things can be a bit uncertain...
I mostly just use this concept as a mental exercise in motion dymnamics. I figure that if someone gets it to work (like that's ever going to happen), I'll make some money on the talk shows and such. ;)
As for a picture? Maybe I'll draw something up...
Eric
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Victor Geere - 09/05/2005 16:19:08
| | | I kind of catch your drift, but I don't think it will work either. As a tip, I find it a bit easier to think in terms of an airbed than in terms of space, because an airbed gives a point of reference, but it intruduces gravity. Whatever. It is sometimes usefull.
Here's a thought. Imagine an eifel tower model with a precessing gyro going around it. Now think of yourself standing on the precessing gyro while holding a string attached to the eifel tower. If you were to jump, the oposite force will not cause the gyro to fall, but to precess and your weight is distributed horisontally. As you jump, the string pulls the eifel tower up, and the gyro with it as it attempts to continue along the horisontal path. When you land on the gyro again, the force from your weight causes the gyro to precess and your weight is again distributed horisontally, while you are holding the eifel tower by the string. So you jump again... each time lifting the eifel tower a bit more. The nett weight of the system including you stay the same, so the whole thing will fall. Now imagine it in space. Interesting hey?
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| Answer: |
Eric James ----- - 10/05/2005 04:07:33
| | | Victor,
Okay, I'm imagining it in space.
First, you flex your legs to jump and your legs leave the gyro and you are floating free. Oops, that didn't work.
Okay, so you straighten your legs to resume contact with the gyro.
You "jump" using only your feet. You also pull the line tight to prevent the tower from drifting away.
Oh no! You keep moving away from the gyro (rising) and eventually move past the pivot point and the tower separates from the system! The gyro is moving away in one direction and you, the line and the tower are drifting away in the other!
Or, since you don't need the tower(just attach the line to the end of the axis), you jump out and away (to put tension on the line).
The gyro does indeed begin to precess (actually it'll twist around a bit from the standpoint of the center of mass), but oh no! You don't fall back to the gyro! You just keep going around until you strike the partially twisted gyro on the other side and you and the gyro are kicked off of each other at an odd angle and then you bounce back and the line gets tangled and you head into the spokes of the gyro and come out as space mush!
Or, the gyro precesses (twists) to a point where it is parallel enough with you that through friction with the axis bearings it begins to impart angular momentum into you and your line and you begin to rotate about the axis faster and faster (causing a tumble in the process) until you can't hold on any longer! You lose your grip and float away!
How's that? Not what you envisioned, I suppose.
Eric
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| Answer: |
Victor Geere - 10/05/2005 14:51:25
| | | Are you having fun yet?
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Victor Geere - 10/05/2005 16:05:36
| | | The point of this exercise is to allow the active force to succeed and to use precession to divert the reacitve force sideways.
If you have a picture of your "Convoluted Concept" yet Eric you can mail it to me and I will publish it on the internet for you.
Victor
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Eric James ----- - 11/05/2005 02:03:40
| | | Victor,
I am a lazy, lazy man. I wouldn't hold my breath waiting for that drawing.
I do intend to do it, it's just that I've got lots of things going on. Maybe in a week or two.
You are welcome to draw something up and show it to me and I'll tell you if your close...
Eric
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Glenn Hawkins - 12/05/2005 06:19:56
| | | Eric: “It's too complex for me to properly analyze,”
Victor: “…multi-dimensional gyroscopes can be dangerously confusing,”
Vector: “It is virtually impossible to imagine…”
Eric: “…is an intriguing puzzle,”
Eric: “…doubt, doubt, doubt.”
Eric: “I don't think it will… I don't think it will…”
Victor: “I kind of catch your drift…”
Victor: “Interesting hey?”
If ever I have seen a befitting conversation about gyroscopes, this is it.
Eric, I do not know that this would not work. “…you twist and brake the gimbals. One to act as a brake, and one to "encourage" continued rotation.” It is a nightmare, a nightmare on your hands. You could spend years bouncing back and forth and amazingly continuing to learn more than you thought was there to learn and still never know if it would work. You must build it if you want to know badly enough. You do not know if it will work. You do not know why it would not work. No one does. I sure don’t.
Glenn Hawkins,
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