h a l f b a k e r yNot so much a thought experiment as a single neuron misfire.
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There are many systems basically based on two gyroscopes which are axially in line and counter-rotating.
Laithwaite, an electrical engineer, formost authority on electromagnetic linear propulsion (MagLev etc.) became very interested in this. He even made a demonstration to the Royal Institute using
a 25Kg gyro which he span up using an electric drill and raised above his head with one hand (he was about 60yrs old at the time). He made a crack about antigravity or something similar, and was ridiculed from that moment on.
Of course it is all simple mechanics, but it got me thinking about why the gyro went up above his head, and where did the energy come from? The only thing I could think of was that the gyro slowed down a little during the demonstration, and the energy was transfered from Kinetic to Potential energy.
So, many people have tried the two gyroscopes idea above. I cannot find any definite results anywhere. Of course, with two gyros in counter rotation, the center point of the shaft is rotated so that Laithwaites demonstration is performed by two gyros together. But this requires a steady place to turn from (Laithwaite had his feet on the ground, and used his body to twist the gyro around w.r.t. the ground.). Laithwaite claimed a few percent decrease in the apparent weight of his two gyroscope system (not antigravity! - just force in the upwards direction). He also had big problems with the shafts breaking.
In space, this system could never work, since as the gyros were twisted one way, the spaceship would twist the other. So why not build yet another set in opposition to the first, and use one set to push against when twisting the other set? So now there would be four gyros at work. Further stabilisation (steering) would be achieved by varying the rotational speed of each gyro.
I hope you can see what I am getting at? Without a simple drawing it's hard to describe.
How Gyroscopes Work:
http://plus.maths.o...eatures/gyroscopes/
[Amos Kito, Oct 05 2004, last modified Oct 21 2004]
Laithwaite background
http://www.alternat...eric-laithwaite.htm
[Ling, Oct 05 2004, last modified Oct 21 2004]
BBC historical review
http://www.bbc.co.u...ithwaite_eric.shtml
Note comment about 50lb gyro lifted above his head. [Ling, Oct 05 2004, last modified Oct 21 2004]
Gyroscopic Propulsion
http://www.gyroscopes.org/propulsion.asp
"Warning - Gyroscope propulsion is currently just speculative research..." [half, Oct 05 2004, last modified Oct 21 2004]
More details about the 50lb gyro experiment
http://www.keelynet...rchive/00001563.htm
But ignore the aether etc. comments [Ling, Mar 17 2005]
Gyroscopic antigravity invention
Gyroscopic_20antigravity
[bungston, Mar 18 2005]
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I've thought about this as well. What's important to note, is that the gyroscope is producing torque, not just a directional force. |
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two gyroscopes would produce opposing torques (which is why the shafts would break), yielding a slight directional force, but a lot of force consumed in the conflicting twisting. |
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If a bar through the axis of the gyroscope doesn't have a stationary point of it's own, no angular force is visible. |
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Try it with a bicycle wheel some time. Feel the force when you try to hold one side of the axis against it's natural rotation. |
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K955301,
Yes, I agree that is why Laithwaite broke the shafts, and I understand that a precessional torque is created. But does that explain, or can anyone explain, why an old man could lift 50lb above his head using just one hand? |
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I've studied the first link, and the 10Kg rotating mass can be lifted at the end of the shaft, but it is still 10Kg. Is it that Laithwaite forced the precession to go around faster so that more force was created than required to cancel out the force due to gravity? |
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Ling: The idea is baked as are many other anti-gravity patents, albeit not well known. Go to www.uspto.gov and do a patent number search for 3,555,915. There are simpler and more effective means for generating inertial propulsion, very practical for keeping satellites in orbit. See: 3,968,700 and 4,631,971. You might also check the book: Antigravity Propulsion Devices by B.C. Ebershaw, copyright 1980. Most of the best ideas you'll never see (have military gag orders) but you can learn a lot by sleuthing out various antigravity/levitation/free energy sites online. Just do a google search using any of the above as a search term. |
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When a force is applied to a gyro, that force tends to come out of a point 90 degrees in the direction of the turn. |
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<rambling digression> I was doing my Electrical Engineering degree at Imperial in the 70s, and well remember Eric Laithwaite's hugely enthusiastic lectures and demonstrations of linear motors and gyroscopes. A particularly fine demo of the structure of the then brand-new idea of a linear motor was when he hoisted a large conventional motor onto the lecture bench, then pulled open a giant zipper across one side of the stator, which would then unroll onto the timber with its armature perched on top. Off with the armature, apply power to the now flat stator windings, and he'd drop a piece of steel onto the windings. This would promptly be shot through the wall. |
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We also enjoyed the staggering crashes that would emanate from his basement lab in the Electrical Engineering building, generally accompanied by a widespread power failure. |
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I saw some startling gyroscope demos as well, but probably due to the undergrad beer intake didn't question things as much as I should have. A very smart man. |
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Personally I would honour Eric with the Order of the Gilded Croissant were he still with us. </rambling digression> |
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A simpler and safer gyroscopic steering system can be done with a 4 output differental oscillator. A small wieght at the end of vibrating wire or reed at about 20K cps in each of the four axies will do the job. The reeds need to located at furthest equidistant points from the center of mass. All reeds vibrating at the same speed ship flies strieght. Vary speed of one or a combination of reeds ship turns. SIMPLE. This is how bees and flies do it. |
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I do not understand the physics of the vibrating reed bit. A vibrating reed in one plane does not seem like a gyroscope to me and I am unclear where the force on the vessel (or bee) comes from if one reed is made to vibrate faster. |
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I don't know what reality you're living in, but conventional space only has three mutually orthogonal axes (plus time makes four dimensions). |
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Two parallel counter-rotating gyroscopes will produce opposite precessional torque, but if the axes are fixed to common structure, these opposing torques will cancel each other via torque or bending moment on the joining structure. The structure as a whole will behave as if there were no rotating components. A structure containing three orthogonal gyroscopes, however, will exhibit three-axis rigidity. |
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I'm lost, Ling - are you proposing the
gyroscope system as a means for
generating a net force, as in antigravity
etc, or as a stabilising system? If the
latter, then fine. Sorry if I'm missing
the point.... |
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Basepair, unfortunately more like the former (but I do not agree with the term "antigravity"). It is not "anti" anything.
Freefall, I'm in the HB zone, and I am aware of the problems with the shaft:
//Laithwaite claimed a few percent decrease in the apparent weight of his two gyroscope system (not antigravity! - just force in the upwards direction). He also had big problems with the shafts breaking.// |
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I wonder if you can you answer this? (copied from above): |
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//But does that explain, or can anyone explain, why an old man could lift 50lb above his head using just one hand?// |
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Of course, when he lifted it, the axis of the shaft changed from downwards pointing, to upwards pointing. Never-the-less, the whole thing was raised. How? |
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Well, for one thing a reasonably fit 60-
year-old person ought to be able to lift
50lb. And for another, lifting becomes
surprisingly easier when you don't have
to provide torque to stabilise it - it's
surprising how much of the effort of
lifting (especially above the head) is
actually more about lateral
stabilisation. |
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I reckon that if I had a system which
could give me a "few percent decrease"
in apparent weight then:
(a) I would call it antigravity (what else
could it be called)? and
(b) I would not find it too difficult to
repeat the test to anyone's satisfaction,
thereby more or less guaranteeing
myself fame/fortune. I don't think I'd
just claim it and then leave it at that if it
were as large an effect as "a few
percent". What I mean is, a few percent
decrease in apparent weight ought to
be easy enough to prove, rather than
just to claim. |
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What basepair said. 50 lb is not really all that much. When lifting a 50 lb weight, you also have to provide the effort to hold it out laterally from your body, as well as lots of stabilization effort. (this is why free weights are more effective than a rigid machine when equivalent weight is used, and why dumbbells are more effective still.) |
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When the object is already rigidly oriented due to gyroscopic effects, providing a 50 lb vertical force is almost trivial for anyone of reasonable fitness. |
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As for the "few percent decrease in weight", that all comes down to his personal claim. Carefully controlled laboratory tests have never been able to find any measurable decrease in weight due to gyroscopic effects. |
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Also gyroscopes store energy. Once he uses his legs to
get it moving it doesn't want to stop until it gets above his
head. Wait, does that make any sense? |
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My understanding is that any system of
gyroscopes, however coupled and
oriented, has no special properties with
respect to translational movement. So,
a 50lb box of gyroscopes, however
arranged, will act no different from a
50lb box of bricks if you're only trying
to lift it vertically. |
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There is no magic about gyroscopes -
they are just lots of small masses
moving very fast, which happen to be
arranged in a disc-shape and happen to
be going in circles, and have the normal
reluctance to having their momentum
altered. |
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But gyros resist change -- so gyros don't want to let the
plane slow down or turn, but they will let it drop, but
only because they weren't moving up to begin with -- so if
the guy got the gyros moving upwards to begin with, with
his legs, then the gyros would store all the energy he put
in with his legs and would not want to stop moving
upward or turn to any side before they ran out of the
momentum that the guy put into them, right? |
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JHC - perfectly true about not letting
the plane turn. Also, they will of course
tend to keep moving up once they are
got moving, BUT no more so than a box
of bricks (ie, the linear momentum of a
box of gyros is no different from
anything else). |
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The fact that they are spinning gyros
doesn't make any difference to the
vertical lifting. |
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It seems to me that gyroscopes could be used to simulate antigravity, and I posted an idea to this end a while back. Imagine a massive gyroscope spiining fast. It is lifted off the ground and attached to a wall with a horizontal cord. On letting go of the gyroscope, it must fall in an arc because of the cord, landing not directly below its original position but rather against the wall to which it is tethered. |
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This is good stuff. I still would like more about the vibrating reed. Vibration is not rotation, and I do not think a vibrating thing has inertia. A vibrating thing in a vacuum will eventually covert the vibration to heat and stop, right? A frictionless gyroscope in a vacuum will never stop. |
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A falling gyroscope which did not need to change its plane of rotation would fall as fast as anything else. But this one is tethered, and to follow the arc, the gyroscope must change its plane of rotation. It would resist this. A gyroscope with sufficient speed and stored energy would move more slowly along this arc than a still mass would. |
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I am not sure if there is an amount of stored energy which would allow the gyroscope to hover at the end of its tether. The assumption that there might be underlies my antigravity invention. |
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Your tethered gyro would fall down
immediately - it's axle would remain
horizontal, but it would fall downward
and inward (no torque problems).
You'd wind up with the string vertical
but the gyro axle horizontal. What I
mean is, you would go from this: |
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(where 0 is the gyro seen edge-on, = =
is its axle, --- is the string and X is
whatever it is tethered tol) to this: |
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You can do this yourself with a kid's
gyro. |
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The gyro would, I guess, "float" if it's
axle were extended as a continuous rod
which was hinged to (or rested on) the
wall). Again, you can do this with a toy
gyro (the cage it spins in has extensions
colinear with the axle, and you can
balance the end one of these on your
fingertip while the gyro spins with its
axle horizontal and precessing in a
horizontal circle). |
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Having just dug out my toy gyroscope
("Not just a toy...a scientific discovery!"),
I have experimental confirmation of the
above. |
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When a gyroscope precesses - let's say its axle is horizontal and one end of the axle is on the top of a post - then the other end of the axle rotates around the post.
The rotation is a spiral, with a very slight downward slope. So as the gyroscope precesses it gets slightly lower and lower each time. The slope depends mostly on the rotational speed of the gyroscope, and is much more noticable when the rpm of the gyroscope slows down, and the precession speeds up.
Now consider if someone were to force the gyroscope to precess in the other direction. Would it follow a spiral which is in the upwards direction? If the forced precession was quicker, would the slope be greater?
I believe that this is the principle that was used by Laithwaite. Although Basepair is probably right when he says that the vertically acting weight at the supported end is unchanged, the gyroscope's rotating mass is lifted above the horizontal position by the forced precession in the "wrong" direction. |
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[Ling] you're right about the precession
and the downward spiral, I think. |
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"the gyroscope's rotating mass is lifted
above the horizontal position by the
forced precession in the "wrong"
direction" - I would guess you may be
right, but then you're just effectively
using the gyroscope as a lever system
to convert the applied force in one
direction into a force at 90 degrees. |
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It's not that I have anything about
gyroscopes, it's just that they don't do
magic. They're just a way of packing a
lot of momentum into a small space,
which is neat and useful but obeys the
same laws of physics as anything else. |
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Yes, a bit like rolling it up a slope instead of lifting it. |
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In that case, we are as one :-) |
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>>gyroscopes don't do magic. They're just a way of packing
a lot of momentum into a small space... |
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Human beings also don't do magic and are a way of packing
(and organizing) a lot of energy into small spaces, but we
come up with some pretty amazing stuff. Which makes
me wonder if maybe everything is just momentum storage
-- everything from strings on up to gravity -- just
gyroscopic energy storage? |
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