|
Main Forum Page
|
The Gyroscope Forum |
25 April 2024 21:56
|
|
Welcome to the gyroscope forum. If you have a question about gyroscopes in general,
want to know how they work, or what they can be used for then you can leave your question here for others to answer.
You may also be able to help others by answering some of the questions on the site.
|
Question |
| Asked by: |
Blaze |
| Subject: |
Could this be the reason that mass movement happens? |
| Question: |
This is a just a thought experiment and I welcome any input that may be out there. Someone may already know this or may have gone through this same thought process already.
As we know, in steady state precession on an overhung gyro, the weight of the spinning wheel is transferred to the pivot. So that means if you put a scale under the pivot when the gyro is precessing you should be able to measure the total weight of the assembly.
If a dead weight of the same mass were moving around the pivot at the same speed, there would be an easily measurable horizontal force on the pivot but that doesn’t occur with a precessing gyro. So, could it be that mass movement occurs in an overhung gyro be BECAUSE the total weight of the gyro is effectively all on the pivot? In other words, it is as if the wheel were actually sitting perfectly still and perfectly balanced on the pivot and not actually moving around the pivot. We know that the wheel has mass, and can see that it is moving around the pivot but that movement does not create a horizontal force on the pivot because the spinning wheel is in effect “just sitting on top of the pivot”?
That would then mean that IF you could somehow weigh the spinning mass while it is precessing (impossible to do of course) you would get a zero weight?
Your thoughts are welcome.
Blaze |
| Date: |
13 May 2012
|
| report abuse
|
|
Answers (Ordered by Date)
|
| Answer: |
Blaze - 13/05/2012 03:16:41
| | | Another thought.
This would also explain why the pivot does not normally precess around the wheel except for a very, very short time during the drop. During the drop (before steady state precession is achieved) the weight is not yet transferred (or fully transferred) to the pivot so the wheel attempts to precess about its center of mass (which means the pivot wants to move around the wheel), but as soon as steady state precession is achieved all of the weight of the wheel is transferred to the pivot so it is as if the all the weight were sitting on top of the pivot, so of course the pivot would not move around the wheel anymore after the drop.
Blaze
|
| Report Abuse |
| Answer: |
Luis Gonzalez - 13/05/2012 14:08:28
| | | Hi Blaze,
Some of your thought experiments above are shared by a number of individuals who have spent time pondering gyro phenomena. It's all good.
However, I particularly enjoyed your logical deduction that associates Reaction-FREE precession, to the idea that the spinning wheel's full-mass is "just sitting on top of the pivot". Excellent!!
That said, we still need a physical experiment that unequivocally proves precession is a motion without opposite reaction (as this is the FIRST link toward proving that gyro propulsion may be possible).
My Best Regards,
Luis G
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 15/05/2012 17:02:45
| | | Hello All,
The pivot dose not move during precession. The pivot dose not move at any time during the drop. The pivot dose not move when dead weight is loaded onto the wheel and shaft.
Most everyone has observed these things, but are unwilling to believe them. Some day I will explain how and why these seemingly impossible mechanics work the way they do, but not today. Until then I recommend you go forward as if you believed me.
Have a happy day,
Glenn
|
| Report Abuse |
| Answer: |
Blaze - 15/05/2012 19:30:14
| | | Hi Glenn. Nice to hear from you again.
"The pivot dose not move during precession."
Agreed, you will get no argument from me here.
"The pivot dose not move at any time during the drop."
Actually, I have done this experiment literally dozens of times and the pivot does move a very small but measureable amount during the Drop, however, it must be an abrupt drop, and the pivot must be on a smooth, low friction surface for this to happen and even then it is a very small amount. The slower the wheel speed, the greater the pivot movement during the Drop. I have done this experiment with a "precision" (the toy companies word, not mine) toy gyro and seen pivot horozontal movements of up to 1/4 inch when the wheel speeds are quite low. The whole light plastic pivot moves horozontally (probably really is moving in a circle but the distance is to short to see any curving so it looks purely horozontal). I have done this experiment with a gyro I built that has a 2 pound, 5 inch diameter wheel and mounted the whole thing on a small two axle "cart" that I built out of Mecanno (you Brits should love that I use Mecanno). The pivot moves the whole cart a small amount. In either case it is an "inch worm" movement. Those are the results of my experiments.
Best Regards
Blaze
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 15/05/2012 23:26:34
| | | Hi Blaze,
I am happy to see you working so well. What you found was baffling to me at first. I believed you, but it should not be so, because an overhung gyroscope pulls itself in a curve, and dose not rely on pushing against the pivot to accelerate.
Now, I think I know what happened. It makes me smile. My tests some years back were kind of funny. I have two crank gyros with 5” wheels weighing about a pound and a quoter, uncased in blue plastic and they have short knobs for shafts. You may have seen one. They are very powerful. I glued one into the suction cup of a commode plunger, cranked it to high speed and set the tip of the stick on a metal work bench. I tested many times and what was I looking for? That's right. I was looking for pivot movement. Because the stick was so long, the tilting force overwhelmed the high angular momentum in the wheel and everything worked, but happened very fast. I kept cutting the stick to shorten it and each time trying the experiment with less tilting force. When I finished the experiment I carried the plunger back into the house and placed it to the rear of the commode. The stick was so short you could just barely get a hand grip on it. My wife and kids had seen me leave with an entire plunger. They just looked at me. I didn't say a word about it, until a few days later I heard complaints about having to use rubber gloves to hold the plunger. I explained then and we bought a new one.
There was never any pivotal movement in those tests, nor was there in other tests. Harry K. and I were searching hard for this pivotal opposite movement.
I believe you saw only a few millimeters of movement when the gyro was spun up fast on the (long plastic shaft?) I believe the pivot movement you discovered was curved IN THE SAME DIRECTION the gyroscope was traveling, but outward as it tried to follow the curving gyroscope. Surely we know the pivot is pulled toward the gyroscope. We see this again as the overhead string is being pulled outward directly toward the gyroscope. The string curves and the pivot curves as they are pulled along by a curving gyroscope.
When I said there was no pivotal movement I should be more pacific. The pivot can't move in the opposite direction of a rotating gyro, because of reasons I have not yet explained. If you disagree that is fine. Our most wonderful gift is free thought. (The same for you too, Ram) That is all fine.
I am getting back to my time and efforts to build and do other things a man has to do. It was good to visit.
Bless you all,
Glenn
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 15/05/2012 23:26:36
| | | Hi Blaze,
I am happy to see you working so well. What you found was baffling to me at first. I believed you, but it should not be so, because an overhung gyroscope pulls itself in a curve, and dose not rely on pushing against the pivot to accelerate.
Now, I think I know what happened. It makes me smile. My tests some years back were kind of funny. I have two crank gyros with 5” wheels weighing about a pound and a quoter, uncased in blue plastic and they have short knobs for shafts. You may have seen one. They are very powerful. I glued one into the suction cup of a commode plunger, cranked it to high speed and set the tip of the stick on a metal work bench. I tested many times and what was I looking for? That's right. I was looking for pivot movement. Because the stick was so long, the tilting force overwhelmed the high angular momentum in the wheel and everything worked, but happened very fast. I kept cutting the stick to shorten it and each time trying the experiment with less tilting force. When I finished the experiment I carried the plunger back into the house and placed it to the rear of the commode. The stick was so short you could just barely get a hand grip on it. My wife and kids had seen me leave with an entire plunger. They just looked at me. I didn't say a word about it, until a few days later I heard complaints about having to use rubber gloves to hold the plunger. I explained then and we bought a new one.
There was never any pivotal movement in those tests, nor was there in other tests. Harry K. and I were searching hard for this pivotal opposite movement.
I believe you saw only a few millimeters of movement when the gyro was spun up fast on the (long plastic shaft?) I believe the pivot movement you discovered was curved IN THE SAME DIRECTION the gyroscope was traveling, but outward as it tried to follow the curving gyroscope. Surely we know the pivot is pulled toward the gyroscope. We see this again as the overhead string is being pulled outward directly toward the gyroscope. The string curves and the pivot curves as they are pulled along by a curving gyroscope.
When I said there was no pivotal movement I should be more pacific. The pivot can't move in the opposite direction of a rotating gyro, because of reasons I have not yet explained. If you disagree that is fine. Our most wonderful gift is free thought. (The same for you too, Ram) That is all fine.
I am getting back to my time and efforts to build and do other things a man has to do. It was good to visit.
Bless you all,
Glenn
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 16/05/2012 00:35:36
| | | Sorry I missed this, Blase,
You wrote: '. . . a 2 pound, 5 inch diameter wheel and mounted the whole thing on a small two axle "cart" that I built out of Mecanno (you Brits should love that I use Mecanno). The pivot moves the whole cart a small amount. In either case it is an "inch worm" movement. Those are the results of my experiments."
Profesor Liftwate had good sucess with this. By hanging a gysroscope to the outside of a toy train he could make the train follow curving tracks to complete a circle. He said the circumferance of the rack could be very large. The way he would do that of course, providing that he did it, is to attach the gyro so that it can desend, but cannot precess unless it pulls the train along. One wonders if that was somewhate the condition of your cart attatchment. Of course, I could not know.
Glenn.
|
| Report Abuse |
| Answer: |
Ram Firestone - 16/05/2012 01:16:32
| | | "The pivot dose not move during precession."
Put it on an air table and you will see that it does indeed move. The only question is how much. If mass were truly transferred to the pivot or at least acted as such in every respect then the pivot would not move.
I'm sorry but I have tried this before and there are also videos posted on youtube to prove it. Furthermore if you accept that an overhung gyroscope in a frictionless environment does not continue to drop after it begins precession, there is no energy to move the center of mass, so by conservation of energy the pivot must move in order to keep the center of mass in one place. I don't see any way around this. The only reason the pivot is stationary is because precession is typically slow and there is usually enough friction to keep the pivot stationary. The only wiggle room I see is with the initial drop and that must be proven before claims can be made.
|
| Report Abuse |
| Answer: |
Blaze - 16/05/2012 01:20:57
| | | Please keep in mind that this ONLY occurs during the Drop, NOT while precessing at steady state. I am using a Tedco Toys Precision Gyroscope. You can get these for about $10 to $15. I use the “T” handle to spin it up. It comes with a plastic cone for the pivot. One end of the axle is on the pivot. I am holding the other end of the axle. I start the gyro precession by suddenly releasing the axle from a nearly horizontal position. The pivot is on a very smooth surface (my wooden computer desk, to be precise, although it is probably “real, genuine synthetic” wood).
When the wheel speed is really high (just after spinning it up) there is almost no horizontal pivot movement during the drop (360 degrees of precession takes about 3.5 seconds). When the wheel is running more slowly the horizontal movement during the drop is very noticeable (360 degrees of precession takes about 2 seconds). When the 360 degrees of precession gets to about 1.5 seconds the whole pivot starts moving in circles due to the “slinging” effect of the dead mass.
The horizontal movement of the pivot would best be described as a quick jerk. There is no sustained movement. The jerk is in the opposite direction that the gyro is precessing, as if the pivot, for a very brief moment during the Drop, is trying move around the center of mass of the gyro wheel (or you could say the gyro is trying to precess around a vertical axis through its center of mass). The amount the pivot moves during this jerk appears to be directly related to the precession velocity, the faster the precession, the bigger the jerk, which would seem to make sense.
When I do this with the same gyro mounted on a small Mecanno cart with the pivot secured to the cart and release the gyro to start the precession, the cart jerks a bit but not nearly as much as the pivot does by itself on my computer desk, which makes sense because even though the cart is fairly light it is still considerably heavier than just the pivot. The gyro axle is parallel to the cart axles when I release the gyro. The cart axles are parallel to each other, there is no turning or curving as the cart moves. The cart can only go in a straight line.
I did the same thing with my 2 pound gyro on a larger Mecanno cart and the same thing happens, a very small jerk forward, but no sustained motion.
Blaze
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 16/05/2012 01:59:39
| | | Hi Ram,
Bless your pea pickin' heart heart. You are a smart fellow. If you didn't know. I know for you.
Hi Blaze,
I have a box of used Tedcos. You would not believe the torment they have endured over the years. LOL. You are a smart fellow and I never sell chocolate coated marshmallows. You really are. You remind me of me when I was young.
I guess I will explain precession. I hope it works for you all.
Glenn,
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 16/05/2012 02:02:23
| | | I am so very sorry. I cannot tell you yet. I haven't received permission.
|
| Report Abuse |
| Answer: |
Blaze - 17/05/2012 01:01:32
| | | The jerk or movement I am seeing is always perpendicular to the axle of the gyro. So, what am I seeing if not movement?
Just trying to figure out what is going on.
Blaze
|
| Report Abuse |
| Answer: |
Glenn Hawkins - 17/05/2012 03:30:32
| | | Hello Blaze,
You have it right. I have mislead you, or unintentionally tried to. What we see in the jerk, is I believe and you also, the result of not enough angular momentum to sustain the tilting force. The jerk is most prominent as you point out when the wheel has slowed. The jerk can also appear when you drop a gyro from a foot height or so. If it doesn’t bounce, which is weird when it dose, the jerk will be viewable again, assuming the angular momentum is not uncommonly powerful.
I have used a lot of contraptions. What I found is the same as I believe at least four other contributors here have found and you also may have have reasoned. When angular momentum is very high and the dead weight is very little, the pivot exhibits no lateral, opposite movement. . . even when dropped a foot above a platform. I did some of my experiments on polish granite.
I was wrong in this area, but I am not wrong at all when the spin is supper fast. This can be accomplished with a Dremal tool with a 1” or 2" radius rubber wheel attached to the tool and applied against the tiny axle of your Tedico. The dremel tool rotates at up to 4,000 RPM so you are looking at the possibility of tens of thousands of RPM with the big hard rubber washer/wheel. Watch-out the flywheel doesn’t break-up. It can be a little dangerous. Maybe you can find a used one.
See you later, Glenn
|
| Report Abuse |
| Answer: |
Blaze - 17/05/2012 04:34:27
| | | Thanks Glenn. Another piece of the puzzle verified.
Blaze
|
| Report Abuse |
| Add an Answer >> |
|
