Precision Regulators and Precession??

Discussion in 'Clock Construction' started by ItsAllRelative, Feb 4, 2018.

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  1. ItsAllRelative

    ItsAllRelative Registered User

    Jan 28, 2018
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    I have some questions involving precision clocks and the information that can be gained from "reading" them. I hope this is the correct place on this site for the question but if not a redirect would be greatly appreciated.

    This post may be a bit long winded, but I want to explain my position before simply introducing the questions so you can see why my train of thought is where it is at now.

    I have been reading up on the achievable accuracy of pendulum clocks specifically the Shortt-Synchronome and "Clock B" in the Royal Observatory and it really is impressive the level of accuracy these clocks have achieved for being subject to the laundry list of environmental variables, especially considering how long ago they were created (at least theoretically with Harrisons design).

    I have read through many articles stating that the Shortt clock was the first pendulum clock operating more accurately than the earth itself as a regulator, allowing us to observe variations in the Earths rotation (1924-1927 Admiral Fountaine personal observatory) which was confirmed shortly afterwards by the Greenwich Observatory in 1927.
    Although the International Journal of Science "Nature" published a paper by J. Jackson and W. Bowyer in June 1928 that closes with the statement below countering that claim?
    "It appears that the principle of their constructions is such that they could be used to check the uniformity of the earth’s rotation if only material stable for several years to 1 part in 100 millions could be obtained for the manufacture of the pendulums…..a run of a few years would possibly suffice for errors of 1 second to accumulate in the earth’s rotation, but a variation of 1 percent in the growth of the pendulums would introduce greater irregularity in the clock error. It appears impossible to be certain that any piece of material has the required degree of stability, and until pendulums of different materials in different parts of the earth agree in supporting the motion of the moon and planets against the earth’s rotation, clocks will not play an important part in checking the uniformity of the earth’s rotation."

    In the book "My Own Right Time", Mr Woodward explains his application process' for obtaining specific information(data) from "noisy" samples from clocks. He is very mathematical and precise with his explanations and lists the supportive information, giving insightful examples to what was learned along the way and how it is applied in the field. Similar Articles can be found online regarding the two clocks I listed above with detailed charts showing changes in temperature, barometric pressure, humidity, ect.
    I have even found documents showing the ability of these and other precision regulators to show the differences in local gravity at different locations on the earth! BUT their is one subject I can't seem to find covered in any of these, PRECESSION!


    The physics and mathematics supporting the operating principles of a Foucault Pendulum are well documented, as are examples of its mechanical inception and operation backing up the Data. In short, we know that the rotation of the earth can be expressed through a pendulum who's design has been optimized to allow this behavior however I can't seem to find any scientific publications that elaborate on the Q of a system like this. This leads to my Questions.

    Has anyone observed the effects of Earth's rotation on a precision Regulator incorporating the clocks latitudinal location on Earth?

    Has anyone analysed detailed charts of a clocks performance with comparisons to the above sources of noise supporting a new, previously undocumented form of noise?

    If I understand these subjects correctly....
    A precision regulator should experience measurable increased friction through rotational torque applied to the suspension of the pendulum. The pendulum is operating in a linear plane in space while the earth and clock holding the pendulum are moving underneath its nose.
    I understand the force may be quite small and express itself over a long period of time, But if a Foucault Pendulum can be designed and optimized to express this force, we know its role on physical pendulums is present and measurable.

    Is it really possible we can detect local gravitational differences as well as the nutation of the Earths rotation with a simple pendulum, but the rotation of Earth in space has no measurable effect on the clock??

    When I consider the way this effect would apply itself, it becomes more frustrating to think it has not been observed before especially in a knife-edge suspension. I feel that the elasticity of a spring suspension may "absorb" these forces, but a knife edge must surely feel a change in its operating friction?

    Is the force so small that the general "damping forces" present in a precision regulator completely overshadow it? Or is the Q of a Foucault pendulum high enough that only then this behavior is observable?

    I would love to hear any thoughts or opinions on the subject!
     
  2. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Is the precession not resisted by the mechanical properties of a conventional pendulum to the point where a constant, equilibrium is achieved and which then plays no further part as a variable in the pendulum performance. I think you may be concentrating on all the wrong areas. Until you are confident that you can design and build a suspension and escapement arrangement for driving a spherical pendulum that has the precision necessary to expose such influences they are of little concern. It has taken 300+ years of the best minds in Horology to achieve this with a conventional pendulum so I can only but wish you the best of luck with your precision spherical pendulum.

    Working on a design for the overall appearance of the clock before you have any idea what the suspension and escapement assemblies are going to look like is most probably wasted time and effort. In addition when designing components it is good practice to take account of their easy of manufacture. A free standing clock is not the best arrangement for a precision clock. The suspension/pendulum should be connected to the rest of the planet by the shortest most rigid path possible. At least during the development phase you will need easy access to your pendulum bob for adjustment purposes.

    Phil
     
  3. ItsAllRelative

    ItsAllRelative Registered User

    Jan 28, 2018
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    Phil,

    Firstly, thank you for being an active member and following along with my concept and let me also state that exactly as you have described, I believe the clock MIGHT simply be absorbing these influences and averaging them out over an extended period of time.

    You claim that I may be looking in all the wrong areas and that until I’m confident I can design and build an escapement and suspension method for driving my spherical pendulum clock with the necessary precision to expose the influences they should be of little concern. This is where I have to disagree, it doesn’t make sense to NOT investigate these things!

    Of course its possible! As a matter of fact it would be hard for me to believe it isn’t possible. If you want a clock with a pendulum that makes a circle, an ellipse or even a square, its possible. Their isn’t only one way to do it either, there are MANY. Their are COUNTLESS variations of escapement used today, and I’d imagine the list of unused/forgotten escapements is monumental. Each of these represents ONE way of impulsing a simple pendulum. Each has its own advantages and shortcomings, and each has an environment where it is designed to work. Just as their are variations in impulsing the pendulum, so too are their variations in maintaining power, clicks, calendar mechanisms, winding systems, etc, etc. Every piece of the system must be considered with the next.

    The suspension and impulsing methods for a precision regulator and a Foucault pendulum are massively different, I understand this. The clock that I am designing now will be a type of hybrid, allowing similar behaviors of the Foucault combined with traits of a simple pendulum clock. I do NOT intend on this being a precision regulator by any means and I am not interested in creating the most accurate pendulum clock, nor following exactly in the footsteps of those in front of me.

    If a Foucault pendulums design (which closely resembles the “ideal” suspension I’m after) so clearly demonstrates this behavior, even though the best precision regulators don’t show any sign of it, it MUST be taken into consideration for the selection out of the MANY ways to achieve a spherical pendulum design(escapement, suspension, etc).
    What if the precession effect is VERY measurable in the operation of a spherical pendulum clock. How could this negatively impact the clocks behavior? OR, what if the clocks operational precession and earthly precesion rates could be “synched”? Would the clock have to be designed to operate specifically to its latitudinal location? Which part of the Foucault design makes this effect so exaggerated? Is it the Q of the system itself? How can this impact the escapement?
    Should the impulses be linear?
    Breakdown to chaotic motion of a forced, damped, spherical pendulum - ScienceDirect
    Rotary?
    A spherical pendulum system to teach key concepts in kinematics, dynamics, control, and simulation - IEEE Journals & Magazine

    My point is this. You mention the 300+ years of experienced leaders in the inventions contributing to Horology and where it is now. Don’t you think that if the maker of each of those failed/inefficient escapements looked far enough into their design they could have modified it or changed it entirely to be optimized from the beginning? We have a long list of failures because not enough variables were considered. I want to make it clear that I am not blindly posting questions to this website hoping for others to tell me what to do and how, but instead to gain the insight of the experienced builders and tinkerers here. For example with the initial post to this thread, I am looking into the physics of the system and how they could apply to a pendulum clock, Simple or spherical.
    http://newt.phys.unsw.edu.au/~jw/pendulumdetails.html

    This thought process is for the sake of success of my project. I am following this path to explore new possibilities with a pendulum that haven’t been explored yet. I want to challenge myself in all aspects and create something noteworthy in the long run. Just as my username implies, I know its all relative. Mechanical clocks/watches today are unnecessary. They are easily eclipsed by atomic and satellite clocks but the users of this site continue conserving and constructing them. Each is special for its own reason and everyone is here with a passion.
     
  4. Allan Wolff

    Allan Wolff Moderator
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    Mar 17, 2005
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    Nick,
    I am impressed with your determination and confidence on this clock project and I am looking forward to seeing how your design develops. It is obvious that you are doing a great deal of research and are willing to try new concepts. No doubt some will fail while others will be a great success. Innovation comes when people push the envelope and try new things, like Tokkie's 30-legged gravity escapement.
    Much of the physics you are dealing with is over my head as it has been a long time since I have exercised that part of my brain, so I am looking forward to following your progress. Keep up the good work and keep us posted,
    Allan
     
  5. jhe.1973

    jhe.1973 Registered User
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    Feb 12, 2011
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    Hello Nick,

    Welcome to this forum as I see that you are fairly new with your postings here! It looks to me that you are sincere/passionate in your desire to explore all that you can with your project. Because of this I believe that you have much to add for all of us here looking to expand our understanding.

    My own personal experience with gravity affecting precision regulators happens every year that I take my own clock to display at our Regional.

    The community center where the event is held is at a (roughly) 2000 foot elevation and we live north, 3 hours away, at 5000 feet. Just like clockwork (pun intended) I have to change the regulation the same amount and back again when we return.

    One year I purchased 3 clocks from one of our members down in this area. A Synchronome, Hipp Toggle and Pulsynetic all with seconds pendulums. When I got them installed back home each one needed similar re-adjusting.

    For just over 3 years I worked for the Physics and Astronomy Department of one of our universities. Each day I walked past the Foucault Pendulum in our lobby without giving it any thought. Your post here gave me reason to consider its operation and I thank you for that.

    However, I had to read your post quite a few times to arrive at what I believe is the focus of your concern.

    The initial area I had difficulty was your first mention of precession. I first thought that you were referring to the axial precession of the Earth. Looking into that I discarded that possibility seeing as how that is roughly a 26,000 year cycle.

    The other area I had trouble with was your mention of "rotational torque applied to the suspension". A pendulum oscillating in a linear plane is actually rotating in a segment of an arc as if it is mounted on an axle. It did not seem that this was the direction of the torque you are referring to.

    I eventually realized that the torque you have in mind is likely what exists when looking down on a swinging pendulum from above and comparing its motion to the complete clock.

    With a typical Foucault design the very long pendulum is suspended over a large surface. Even with these factors the variation of each swing of the pendulum is hardly noticeable. It is the accumulation of many swings that eventually show the rotation of the Earth under it.

    At the instant of the precise end of each swing, the pendulum is stationary as is the Earth (in relation to the stopped pendulum) at this specific instant. My guess is that with a conventional suspension spring the tiny twist/torque that you have pointed out is released at each end point of the arc. If it was not, it would have to build up and lead to a visible twist.

    It is my understanding that a pendulum supported by a knife edge does not rest on a flat anvil because the pendulum will eventually walk off of it. The anvil is slightly concave or even slightly grooved. I used to think the walking action is due to the difficulty of maintaining a surface that is perfectly perpendicular to gravity. Your mention of this torque has me questioning my assumption and leads me to suspect that this torque HAS been observed, but not necessarily properly recognized.

    Measuring the displacement caused by this tiny torque might be possible using a laser mounted on the pendulum and having its beam landing on a distant target.

    Measuring the force of this tiny twist seems to me to be considerably more difficult.

    Hope this is of some help!
     
  6. ItsAllRelative

    ItsAllRelative Registered User

    Jan 28, 2018
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    Allan-

    If I’m being completely realistic with myself and honest with you, I’m sure that some of that confidence you see is actually me being a bit zealous. Right now I’m only conceptualizing the clocks operation, putting together a type of “roadmap” of potential solutions to its creation. Anything that seems even remotely applicable to the subject I find myself wanting to explore deeper and deeper. Learning new things gives me great pleasure, and the availability of knowledge in the electrically connected world we live in is all but neglected by too many people. Educational and explorational opportunities are abundant and I’m certainly taking advantage of that.

    This will be my first clock which is a massive undertaking in and of itself, but the path I chose to challenge myself with the most was creating something new(theoretically and physically). I’m a very inventive person and the mechanical “complexity” of things I see more as mechanical simplicity so I want to challenge myself in all aspects of the project, if not for any other reason than to explore for the sake of exploration.


    Nothing has ever drawn my interest even remotely close to the way Horology has for the last 6 years or so. From the history of tools, materials and constructions, through to their modern day iterations, combined with the steadily expanding accomplishments of mathematics and mechanical designs, I can hardly conceive of a greater, more tangible, and relevant field of interest. I may not make a single practical scientific, mechanical, or theological contribution to horology, machining, math, astronomy, or any other fields related to the subject. BUT, most importantly to me is discovering the path I’m taking myself, and sharing the information I gain along the way. That has been my biggest inspiration this far and is the reason for me joining this site, to continue discovering and exploring Horology while connecting with others who share a similar passion for the subject. OH, and the physics….they’re way over my head too hahaha…this is a learning experience for me too….a BIG one.
     
  7. ItsAllRelative

    ItsAllRelative Registered User

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    Jim-

    Its awesome to hear from someone with your extensive background and hands on experience with these subjects. I have read through some of your content here before on your regulator project, but I still have much to digest in terms of your content both here and on your website. The story on the experiences you’ve had with the timing rates and regulation of your clocks is very interesting and something I hope to be able to see one day “in the metal”.

    You’re right with the precession….I should have clarified the difference of axial precession (the 26,000 year cycle), from that of the precession that the pendulums plane of oscillation experiences due to the movements of the Earth. If I understand correctly, it was the Nutation of the earth(wobble) that is experienced during the 26,000 year cycle that was Detected by the Admiral and Confirmed by the Observatory.

    Nutation.jpg

    *This website has a brief and detailed explanation of Axial Precession and Nutation, as well as some VERY in depth info about its causes. Includes links to research papers and other supporting sites.
    https://sites.ualberta.ca/~dumberry/nutation.html


    You also correct with regard to the direction of the torque that is being applied to the pendulum.

    The physics of the forces even a standard simple pendulum would be subject to are complex and not easy to visualize. Being based off a stationary plane of oscillation, they are easy to understand, but once earths rotation is considered I have to slow down to digest it all. I can barely begin to scratch the surface.
    http://newt.phys.unsw.edu.au/~jw/pendulumdetails.html

    Allan-Thats what I’m talking about….over me head!! ^^


    This is the type of information I’m seeking to understand. I didn’t go to school for Mechanical Engineering or physics and the highest level of math I reached in High-school was AP Calc (I attended Berklee as a drummer not physics major hahaha). I am diving into the physics at my own pace, focusing on the pieces most applicable to my inquiries.

    This channel on You-tube has a HUGE amount of detailed and to the point information on categorized subjects.
    https://www.youtube.com/user/ilectureonline

    This is my go-to for education on the subject, but I’ve also joined Physics Forums so I can ask questions as I go. Already I’ve found that by viewing one video on the subject of spherical pendulums from the YouTube channel above, I have to watch 5-6 more videos on the subject to understand certain things, and again with each of those videos a few more.


    I don’t have anything up yet on the physics forums, but this link will take you to my page, which will automatically update as I become active on that site.
    https://www.physicsforums.com/members/nick-amos.639649/


    Once I have a basic understanding of the maths involved with the physics of a Foucault pendulum, I will begin chiseling away at applying it to known installations around the world. I will find the information I can on pendulum length, arc length, weight of the bob, latitudinal location etc. I will then complete the same math applying data typical of regulator clocks at regular latitudinal locations. My goal would be to understand the damping coefficient induced by frictional drag or other resistance to these forces and compare that with other frictional loses a clock experiences....Seems like a unanimous vote so far that the effect is small and most likely insignificant. Then, its off to the races to apply the same math to my system and see what type of role it may play. HOW am I going to do this, what pieces of data will I need, how much is theoretical, where do I draw the line:???:....I'm not sure yet. Stay tuned!
     

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