Talk:Gyroscope

message: This article claims that momentum wheels and flywheels are gyroscopes.  Is this true?  The definitions I have read state that gyroscopes are devices designed to resist rotation of the spin axis, which is not the purpose of the devices I just mentioned.  Obviously, they have this property as a side-effect, but this is not enough to make them gyroscopes. -- Heron 21:29, 25 Jul 2004 (UTC)
thread_title:  Are flywheels gyroscopes? 

message: Wikipedia is not a science journal it is a public use encyclopedia. Therefore all science terms should include reasonably easy to understand lay descriptions. 
75.252.224.147 (talk) 08:15, 18 May 2009 (UTC)
thread_title: Writing Too Technical: Need For Lay Explanations, Also Description of Gyroscopic Inertia Should be More Prominent

message: I don't understand much of this entry.  Can someone write an easy to understand version?  Gyroscopes explained so a kid can understand?
:How about the following introductory paragraph?
::A gyroscope is a wheel spinning on an axle, mounted in a frame which allows the axle to be pointed in different directions.  When the wheel spins, its rotating mass causes the axle to point in a fixed direction, and to resist any attempts to change its direction.  This makes it useful for navigation, balancing of machinery, and demonstrations in physics classes. 
:Please tell me if this is detailed enough, or too simple. --Heron 08:23, 7 Sep 2004 (UTC)
replies: text: I like it.  That will make a good intro. StuRat 02:19, 28 October 2005 (UTC)
thread_title:  Confused 

message: With respect to what reference frame does a gyroscope have a tendency to remain rigid in space?  I.e. In what reference frame does the plane of the gyroscope remain constant?  The surface of the earth?  A celestial reference frame?
Gyroscopic rigidity and precession affect the attitude indicator and heading indicator of an aircraft, but there are 2 different gyroscopes for these 2 instruments.  It may be necessary periodically to reset these gyroscopes because they can drift, usually due to to friction in the mechanism or other physics in the construction of the gyroscope that makes it deviate from it's theoretical ideal performance.
But one flight instructor told me that the heading indicator in particular drifts at a certain pace in a certain direction (and generally needs to be reset every 15-30 minutes or so) because the earth is rotating and the gyroscope, being rigid in space, is then not rigid w.r.t. the earth's surface.  This theory is consistent with my experience as a pilot, but I can't say with certainty that this is what's happening.
Thus far, I have not found a satisfactory answer to this question.
142.103.14.11 22:56, 7 March 2006 (UTC)
thread_title:  what reference frame for rigidity? 

message: In the intro it says "this is also known as gyroscopic inertia or rigidity in space."
Thats very ambiguous, it sounds as if its saying gyroscipic inertia is another name for gyroscope. More reasonably it would mean that its a synonym to angular momentum. If thats the case, it should NOT link to this page, it should NOT be bolded on this page, and it should be much less ambiguous. Please someone either change it, or answer me so *I* can change it. Thanks. Fresheneesz 22:21, 15 March 2006 (UTC)
thread_title: Gyroscopic inertia

message: a gyroscope spins faster when force is applied. I think it's due to the conservation of energy law, i.e. that the energy i apply to overcome the resistance to spin must show itself somewhere, but I have tried and tried to think how, using Newtonian laws of motion, the result is an increase in the spin speed. How is the force transferred in this direction, when the only direct physical connection between me and the gyro is my hand on the housing which hold the gyro's axle? I wonder if there is something non-Newtonian going on, but that seems a bit far fetched to me. I'd be very grateful for an answer. -142.103.14.11  14:52, 28 April 2006
:I'm not sure I know exactly what applied force you mean, but in case you are refering to something like the Dynabee, the answer, as posted there, is a lot less mysterious than you theorize above:
::"The axis of the gyroscope in the gyro powerball is fixed to the spinning mass and it rests in a little groove inside the wrist exerciser device, which almost completely covers the gyroscope inside it, except for a small round opening on top of it, which is where you can manually start the gyroscope. Once the gyro is spinning, tipping the device will cause the gyroscope to start precessing, with its axis slipping around in the groove in a circular fashion. The groove inside the device, is a little wider than the axis, and the gyroscope's evasive action towards the externally applied force will cause one end of the axis to push against the upper rim of the groove, while the other end of the axis pushes against the lower rim of the groove. While the axis is slipping around inside the groove, the friction between the axis and the groove rims will accelerate or brake the spinning gyroscope, with a maximum effect when the axis starts "rolling" inside the groove. Since this friction force is essential for the device's operation, the groove must not be lubricated. The acceleration of the gyroscope is best when the precession of the gyroscope is supported and amplified by wrist motion."
:-AndrewDressel 19:12, 12 October 2006 (UTC)
thread_title:  I still don't understand why...... 

message: Added reference to right-hand rule and brief description of how it applies. AndrewDressel 12:13, 16 May 2006 (UTC)
thread_title:  Right-hand rule 

message: "Examples of some free-output-gimbal devices ... the front wheel of a motorcycle. Countersteering is how motorcycles turn corners using the gyroscopic roll reaction of the spinning front wheel."
Any references for this claim that have actually done the experiement or the math? My understanding from reading the liturature ( and
, etc.) is that countersteering is simply a technique for causing a motorcycle to lean and that gyroscopic effects are not necessary. -AndrewDressel 02:27, 15 August 2006 (UTC)
replies: text: None found, so I've taken it out. -AndrewDressel 14:32, 15 August 2006 (UTC)
thread_title:  Motorcycles 

message: Well, I made a few new images for the article, including an animation showing how the gyroscope wheel works. They were originally made with a left-handed spin, so I flipped them horizontally to fix it. ☢ Ҡi∊ff⌇↯ 20:00, 4 October 2006 (UTC)
thread_title:  New images and diagrams 

message: I'm really confused about how a hard disk can be a gyroscope and still work when it's being moved around. See my entry on the hard disk talk page here. Twilight Realm 19:19, 29 October 2006 (UTC)
thread_title:  Is my hard drive defying physics? 

message: I guess I'm just an idiot, but I'm having a hard time understanding the whole bicycle wheel/rotating stool thing. Could someone explain it for me please? --SuperCow 05:37, 21 February 2007 (UTC)
thread_title:  Still Not Quite Understanding... 

message: I just added John Serson to the History section, then deleted him again, then added Laplace.  I ought to explain.
At first, I saw Serson on gyroscopes.org and thought that he had a prior claim to Bohnenberger, so I added Serson to this article.  I also created an article on Serson.  I then found that Serson's design was merely a spinning top and didn't really deserve to be called a gyroscope, so I removed him again.  I then found the article at the Institute of Navigation that explained the link from Bohnenberger via Laplace to Foucault, which I thought was much more interesting, so I added that the the article.  Now we have an accurate history, and a new article on John Serson, so everybody wins, I hope. --Heron 14:53, 2 June 2007 (UTC)
thread_title:  Serson 0 - Laplace 1 

message: Needs expanding so as to provide a brief description of where gyroscopes appear in these fictional texts 124.182.230.53 11:50, 29 July 2007 (UTC)
replies: text: Agreed, this section is completely useless as it is now. Either this section should be expanded to include the way in which gyroscopes are used in those fictional texts or it should be removed. However even an extended section would IMO not make much sense here. A gyroscope is not by itself something fictionary nor does it play a major part in any of these fictional texts. So I don't really see why it is relevant to have this section in this article. Hadoriel 11:06, 13 August 2007 (UTC)
thread_title:  Gyroscopes in Fiction 

message: Today gyroscopes are used in dozens of different technological machines from the International Space Station to modern aircrafts and even in underwater torpedos. However there is virtually no mention of this in the article. I think a paragraph about this should be added as this is the main use of gyroscopes today. Hadoriel 11:11, 13 August 2007 (UTC)
thread_title:  Gyroscopes in modern technology 

message: I'm new to wikipedia, so forgive me if I'm speaking out of turn.
I work with, and lecture on, all sorts of things to do with gyroscopes and I am pretty comfortable with them.  I've created lots of videos on things to do with spin (see http://www2.eng.cam.ac.uk/~hemh/movies.htm ) and I've got a page devoted to gyroscopes and boomerangs ( http://www2.eng.cam.ac.uk/~hemh/gyroscopes.htm ).  We've also set out to reproduce all of Laithwaites experiments - see http://www2.eng.cam.ac.uk/~hemh/gyroscopes/htmlgyroscopes.html .  I'd be happy to help out with the gyro page and if appropriate it may be thought appropriate to include links to our work.
But my main reason for writing gere is to say that the opening sentence of the Wiki Gyroscope page is not correct.  It reads: 
"A gyroscope is a device for measuring or maintaining orientation, based on the principle of conservation of angular momentum."
But a gyroscope would be useless if angular momentum were to be conserved.  The whole point is that a gyro exhibits precession and this requires the imposition of an external couple, thereby changing the direction of its angular momentum - being a vector quantity.  Is there any chance of changing this sentence to read:
"A gyroscope is a device for measuring or maintaining orientation, based on the principles angular momentum." 
Hughhunt 19:52, 23 September 2007 (UTC)
replies: text: I agree. The phrase "tends to resist changes to its orientation" should also be changed. Perhaps something like "moves in a direction perpendicular to the applied torques and at a rate inversely proportional to its rate of spin" would work. -AndrewDressel 13:39, 25 September 2007 (UTC)
replies: text: I'm not sure I see the problem.  Angular momentum IS conserved--if the external torque is zero, the angular momentum doesn't change.  The usefulness of a gyroscope for measuring orientation derives from the fact that in practice, even with gimbals it is impossible to eliminate torque entirely--if it weren't, you could put a stationary carton of milk (or whatever) in gimbals, and it would maintain its orientation.  The orientation of the axis of a gyroscope changes less in response to a given torque than does the "axis" of a stationary carton of milk with the same moment of inertia.  The gimbals minimize the torque, and the spin of the gyroscope minimizes the change in orientation produced by whatever torque manages to get through.  So I certainly wouldn't go so far as to say the opening sentence is incorrect.  On the other hand, it would probably be good to point out that, aside from precession, there is no such thing as "gyroscopic stability" a misconception many people seem to hold. Rracecarr 13:59, 25 September 2007 (UTC)
replies: text: Surely if the external torque is zero (and hence angular momentum is conserved) then a gyroscope can no longer be used for "measuring or maintaining orientation"? To actually make a measurement you need that torque. --The Great Apple 15:18, 16 November 2007 (UTC)
thread_title:  opening sentence is inaccurate 

message: In this section, the line:
" perpendicular to both the gravitational torque (downwards)"
implies that there is downwards (wrt the model system described) torque.
This is, in fact, an error: there gravitational force is downwards, but the
torque is not.  Consider that t = r x f, where t = torque, and r is the
distance from the centre of rotation that the force, f, is applied.  In the
described system, if we take the attached end of the gyroscope as the
origin, and the free end of the gyroscope as (l,0,0), where l is the length
of the thing, we end up with t = r x f = (l,0,0) x (0,0,g), where g is the
force of gravity, which is downward in the z direction).  Therefore,
the torque is in the y direction. 129.128.128.32 (talk) 01:05, 26 August 2008 (UTC)
replies: text: Good catch on this one. Yes, the torque due to gravity is not "downwards". I believe I have corrected the text. -AndrewDressel (talk) 14:21, 26 August 2008 (UTC)

text: Not sure about this one, perhaps because "motion" is ambiguous to me. I've replaced it with "rotation about an axis". The axis of precession \boldsymbol\Omega_P is perpendicular to both the axis of applied torque \boldsymbol\tau and the axis of rotation \boldsymbol\omega. -AndrewDressel (talk) 14:21, 26 August 2008 (UTC)
thread_title:  Error in Section:properties 

message: I am not certain why a gyroscope would flip around if the earth rotates in 12 hours. I mean the person who mounted the gyroscope already had that movement, right? so the original wheel too already has inherited that rotational movement.
Can someone help clarify?
As far as I can see, the math simply says angular momentum is conserved, hence mass and MOI remaining constant, angular velocity w is conserved. i.e w=(r x v)/|r^2| , let r=xi + yj be the coordinates of a point on such a wheel (point mass)
So x.dy/dt - y.dx/dt= constant for a 2 d plane rotation in the xy plane if w has to be constant. (given r is constant w.r.t time)
assume an origin O as the pivot, x=r.cos(wt) , y=r.sin(wt)
so the gyro will maintain its angular momentum w.r.t the original origin O and the above equation holds.
consider this object itself is rotating about another origin O` , the equation cannot be hence written can it?
i mean typically such a rotation would be
x= r1.cos(w1t)+r2.cos(kw1.t), y= r1.sin(w1t)+r2.sin(kw1.t)
dx/dt = -(r1.w1.sin(w1t)+r2.k.w1.sin(k1w1.t))
dy/dt = r1.w1.cos(w1.t)+r2.k.w1.cos(kw1.t)
....
obviously such a motion does not conserve angular momentum
However, considering that the original person who placed the wheel and the point mass already possessed that motion w.r.t O`, how does one eliminate that consideration in a gyroscope?  —Preceding unsigned comment added by Alokdube (talk • contribs) 08:43, 9 March 2009 (UTC)
thread_title:  not clear 

message: A mathematical error.  The math description of the mechanics is totally incorrect.  Author claims I is the moment of inertia!  Which one?  There are three principal values.  The angular momentume vector is given by the dyadic prodcut of the principal moments of inertia and the principal angular velocites.  From there on it's Newton, but using a rotating axis system, as is conventional, is complicated and tricky.  Still an all there's no point in using equations that are blatantly incorrect.    I recommend that they be removed. Also that this section be written by someone who has a professional knowledge of the dynamics of rotating bodies.  —Preceding unsigned comment added by Polypuss (talk • contribs) 17:01, 18 April 2009 (UTC)
thread_title:  gyroscopes  

message: Can the bionic gyroscope developed by Dedy Wicaksono (TU Delft) be mentioned ? http://dedywicaksono.wordpress.com/2008/10/21/my-phd-research/  —Preceding unsigned comment added by 81.245.64.190 (talk) 11:12, 8 July 2009 (UTC)
thread_title:  Bionic gyroscope

message: I uploaded a section on the directional gyro.
Arydberg (talk) 12:36, 21 July 2009 (UTC)
thread_title:  Directional gyro 

message: Gyroscopes naturally slow down because of friction.  Would someone please explain how you speed them up again without throwing them 'off'.  Simply using an electric motor would probably change the weight distribution or the rotational axis whenever it is active.  The article explains the function, but not the mechanism.--128.240.229.68 (talk) 17:28, 11 December 2009 (UTC)
thread_title:  Please clarify something 

message: The gyroscope articles could use some reorganization.  
I would argue that the term "gyroscope" refers to any device for measuring or maintaining orientation, so the article named "Gyroscope" ought to give an overview of the various types of devices that the term may apply to.  This article is trying to do two things at once: speak of gyroscopes in the general sense, but also mainly describe the older mechanical, rotary gyroscope.   I think the main article for the term "gyroscope" ought to have the overview (and maybe history) of gyroscopes and a big section of this article could be separated out into an article titled "Mechanical gyroscope" (maybe some parts of it could be in an overview section the main article).
There are several articles on types of gyroscopes that aren't easily found without digging:
* Vibrating structure gyroscope
* Quantum gyroscope
* Fibre optic gyroscope
* Control moment gyroscope
* Rate integrating gyroscope
* Ring laser gyroscope
* Anti-rolling gyro (?)
Currently a few of these other types of gyroscopes are on the disambiguation page along with bands and record labels, which I think isn't the best place, given that they all refer to devices based on similar principles.
Also, does the patent list add much to the article?  I'd propose removing it, or at least scaling it down to something relevant.
Pvercello (talk) 06:51, 8 June 2010 (UTC)
replies: text: I've removed it once again. I see absolutely no reason to have it, let alone a compelling argument in favor of keeping it. --Ronz (talk) 00:42, 13 September 2010 (UTC)
thread_title:  Gyroscope articles need organization 

message: A few sources cited here at Wikipedia gives Foucault's naming of the gyroscope as 1852, but according to The Gyroscope Applied, K.I.T. Richardson (1954) page 37 says it was in 1851. Can someone check and clarify. Richard n 19:01, 28 June 2010 (UTC)
thread_title:  Foucault - 1851 or 1852 

message: "U.S. Patent 20,100,132,463, "MULTI-AXIS MEMS GYROSCOPE"."-I'm not sure what's being cited here, but there aren't that many patents in the US. Also, the link doesn't work.  —Preceding unsigned comment added by 205.254.147.8 (talk) 20:37, 6 July 2010 (UTC)
replies: text: This is actually an application number, not a patent.  Should really read as 2010/0132463.  I'm not sure if Google can link to patent applications, so I won't update the article until I can see if the link can be corrected also. DdDave (talk) 17:16, 8 September 2010 (UTC)

text: The list of patents has been removed anyway, so this issue is dead. DdDave (talk) 16:30, 9 September 2010 (UTC)
thread_title:  Bad source 

message: Somehow the gyros used in the GP-B experiment weren't in this article. The summery in the GP-B article was not gyro-centric so I wrote a new summery with appropriate citations. I also couldn't find a name for the general class of gyroscope under which this specific example resides, so I called it "London moment gyroscope." I didn't change the GP-P article to match since the rest of the "experiment" section there is non-technical. I Don't think it needs a new article until more information on other applications (other than the GP-B) turns up. Theshadow27 (talk) 19:21, 18 January 2011 (UTC)
thread_title:  Gravity Probe B London moment gyros 

message: I have an idea for an animation that actually shows how precessional torques arise from linear momentum.  Of course, since it is my idea I think it is better than any other animation.  But I do not have the tools needed to make the animation.  So, is there anyone, with the tools who would like to collaborate on making a better (or at least different) animation?
The image depicts a story board for this animation.
thumb|800px|right|Story board for a gyro animation.
Constant314 (talk) 04:35, 1 February 2011 (UTC)
thread_title:  Another animation 

message: Does the measurement have any dependency on the position of the gyro relative to the center of mass
of the system?  For example, if the gyro is near the front of an airplane, does it result in different
cumulative error than if it is near the center of mass?  — Preceding unsigned comment added by 192.55.55.39 (talk) 19:48, 30 June 2011 (UTC)
thread_title:  Neeed discussion on placement of the gyroscope relative to the center of mass of the vehicle 

message: "Within mechanical systems or devices, a conventional gyroscope is a mechanism comprising a rotor journaled to spin about one axis, the journals of the rotor being mounted in an inner gimbal or ring; the inner gimbal is journaled for oscillation in an outer gimbal for a total of two gimbals.
The outer gimbal or ring, which is the gyroscope frame, is mounted so as to pivot about an axis in its own plane determined by the support. This outer gimbal possesses one degree of rotational freedom and its axis possesses none. The next inner gimbal is mounted in the gyroscope frame (outer gimbal) so as to pivot about an axis in its own plane that is always perpendicular to the pivotal axis of the gyroscope frame (outer gimbal). This inner gimbal has two degrees of rotational freedom."
Well the diagram  and the explanation  clearly show three "rings",   so why does it say "for a total of two gimbals"?  I suspect the reason for this is that the gimbal is actually the pivoting joint between the rings,  but I am not really an expert.   This section needs to be checked so that it makes sense.Eregli bob (talk) 21:56, 14 January 2012 (UTC)
thread_title:  Bogus description 

message: It is possible to quickly find whether or not an egg has been boiled, by spinning it on a plate. Start spin with egg on its side ( use two hands to get fast enough rate), boiled egg will spin up on one end as a top. Someone might make a video of this and add notes. I wonder if spinning one direction or another makes any appreciable difference due to Coriolis effect? SignedJohnsonL623 (talk) 05:44, 21 October 2012 (UTC)
thread_title:  Demonstration 

message: a. Does the gyroscope change orientation in time with earth? 
In other words, if I leave a 3 gimbal gyro spinning horizontally from the morning will I find it oriented vertically in the afternoon? - פשוט pashute ♫ (talk) 20:48, 15 November 2012 (UTC)
replies: text: Yes, but a mechanical gyroscope will not be an accurate indicator of the earth's rotation because of "remnant unbalance of the rotor and friction in its bearing", according to http://www.sciencedirect.com/science/article/pii/S0921452600007535. For example "The drift of radio-control type gyroscopes is on the order of tens of degrees per minute." and "The GyroEngine model GE9300-C has a typical drift rate of about 9 degrees/min." according to http://www.eng.yale.edu/ee-labs/morse/other/pos96ch2.pdf -AndrewDressel (talk) 21:30, 15 November 2012 (UTC)

text: That appears to be explained here: http://www2.eng.cam.ac.uk/~hemh/gyroscopes/laithwaite.html -AndrewDressel (talk) 21:30, 15 November 2012 (UTC)
thread_title:  Gravity effects? 

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