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Author Topic: Kinetic sculpture designed by Clayton Boyer  (Read 20761 times)
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ArtF
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« Reply #30 on: December 06, 2016, 11:10:35 PM »

Wow, thats quite a spring. I have a couple similar.. but mine of that size are way more than 4 lbs..

 I did back roll it, it worked fine in the original bat. But the springs Im using are much smaller. The spring
Im using sits on a 3/4" thick spool. Yours looks to be 2" thick or so.. How hard is it to roll off the spool?
Does it feel like 4lbs or much more? I have a couple that size and I can barely unroll the things..

Art
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Kineticrazy
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« Reply #31 on: December 07, 2016, 06:20:17 AM »

If the seller can be trusted Huh it's 4.3 pounds, and an inch and a quarter wide. I can retract it, but it's my first 4 lb. spring so I have nothing to compare it to. I will test it with a known weight when I get a chance. It seems like it wont like being back wound.

heres the link on e-bay. He's got one more for sale...th e price was right anyway...

http://www.ebay.com/itm/Stainless-Steel-Constant-Force-Spring-48-L-X-1-25-W-25000-Cycle-Life-4-37lbs/291898742447?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D38530%26meid%3Dedb1d654c1b14e6e8d7d8ca2a0b06e23%26pid%3D100033%26rk%3D8%26rkt%3D8%26sd%3D311745280230
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ArtF
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« Reply #32 on: December 07, 2016, 07:16:16 AM »

It could very well be, Im no expert on springs. The one I used was only 3/4" wide or so in the original,
the spring Im using now is quite easy to roll, and does seem to have about 4lbs of torque, though I
have never measured it.

  I'll make sure to do a section on these springs when I finally get to a video on the bat mechanism
...when it works. Smiley

Art
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Kineticrazy
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« Reply #33 on: December 07, 2016, 08:32:18 AM »

Some spring info Mark had posted earlier, suggested by Clayton Boyer to power "Zinnia". A 1 lb. pull.

http://shop.sdp-si.com/catalog/product/?id=A%203x51-20006
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Dan Mauch
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« Reply #34 on: December 07, 2016, 02:18:36 PM »

  One thing that I found was that 5mm acrylic dogs and parts seem to have less drag than wood. My version of zinna runs for  14:57 minutes. I was surprised by how much better the plastic parts performed over the wood.
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ArtF
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« Reply #35 on: December 07, 2016, 05:22:55 PM »

Hi Guys:

 Just posted a video of the new module simulatin g a proposed vane shape.. This shows how you can manipulat e the speeds between them and kinda looks like what Ive been aiming for. The shapes were dxf's..

Art

https://www.youtube.com/watch?v=FbXJ3ZwNUrE&feature=youtu.be

and another

https://www.youtube.com/watch?v=zkT3JidkmLM
« Last Edit: December 07, 2016, 05:27:30 PM by ArtF » Logged
Kineticrazy
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« Reply #36 on: December 08, 2016, 08:32:57 AM »

Dan,
   The friction reduction you've found, I'm trying to picture exactly where the friction occurs. Is it the pin passing over your plastic pawls that flows more smoothly?

Art,
   You've got a handle on the science behind these things, I wanted to ask you about something I've noticed. I was experimen ting with trying to increase the number of rotations in my engine. I added magnets to increase the time power is supplied to my outer wheel. To my surprise I had no improveme nt. It seems that one pound of force produces the same number of turns, no matter how long that force is applied. Do you agree with my finding? This would suggest adding weight is possibly my solution, sadly my ratchet and pawl design doesn't like additiona l weight, and wont release on the back swing.
  I read an earlier post you made concernin g flywheel radius (larger radius, slower rotation), and am going to experimen t in that direction .

I plan on using David Roy's pawl and pins design in the future, but am trying to get the most out of my current project. If anyone has any suggestio ns, feel free to chime in !

Eric
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ArtF
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« Reply #37 on: December 08, 2016, 09:31:12 AM »

Hi Eric:

  Magnets will add nothing typically to rotation. As you approach a magnet, it does pull, but as you leave it
an exactly equal amount of energy is subtracte d. Magnets will never give you energy, BUT they can influence the
non-intuitive motions of connected vanes etc.. which we'll discuss soon on release of kinetics.

  Your rotation speed typically in a vane system is a result of angular inertia and thrust of the spring. This inertia is a combinati on of the weight of the wheel and the centering placement of that weight.

  Gravity cares not a whit if you weight a ton, or an ounce. It will affect you the same. BUT, it matters if that ton or ounce is off center, as it does in all pendulums and most vanes. You will find that no matter what you do in terms of weight and balance, your time will be mostly the same, but your speed will vary. As a mass becomes more off center from its pivot the inertia increases by the square of the distance. Inertia is the reluctanc e to turn, but also the reluctanc e to slow.  In other words its a measure of how much energy it will take to change the rotation speed. So lets say your vanes do 4 rotations in 15 seconds, then slows to a stop. In an effort to increase that time, you increase the mass so it slows down due to increased inertia. What you'll find if you slow it down by half, if that you'll do 2 rotations, but it will still take 15 seconds. Worse yet, if you off center the mass in that effort to get it slower, the gravitic losses will increase. It will begin to act like a pendulum and youll get no full rotations, but the time will exasperat ingly remain about the same.  A pendulum 36" long will take a second to swing a cycle,
and it doesn't matter if you use a car as a bob, or a car battery, or a feather.

  Now we all want the vanes to be off center masses, we typically need that swing at the end, we know it will start from near the top, and swing down to the bottom with kinetic power equal to its mass propertie s, but its a balance. Too much and the vane losses any real speed.. so finding that balance is an important part of the vanes you choose, the speed due to inertia, and the time due to the laws of gravity are intrinsic in how you design the arms, as it impacts heavily on the visual interfera nce
component s of the design. As you can imagine, two cool looking vanes turning too fast no longer look cool. Too slow and the same thing happens. Its a range of end speeds one wants to complimen t the visual elements.

    Now Im one that finds it very hard to imagine effects such as these. How arms will look as they pass each other can
actually be considere d as a frequency equation and based on human perceptio n times, something Ill be investiga ting in the future, but I digest ( breakfast ). :-)

    To increase the number of rotations, assuming you don't have too much friction in bearings and such, requires
either lowering the weight of the vanes ( though total time of rotations will stay near identical) or adding power by
increasin g spring or weight, which will also increase end run time of the cycle ( and lower total run time of the device. )

 So its all a balance. Not a very intuitive one, but a balance none the less. The more you understan d about angular
momentum, inertia and mass, the more intuitive it becomes.

   In the new module, ( weeks away or less I hope), you can specify a material ( like 1/4 plywood, or 1/2" steel..et c...)
to get an idea as to how they differ. You can drag center of mass to a new location to observe the effects that creates
in terms of total time and speed. I did this that way to try to create not only a sense of realism, but to try to educate
on how all these things combine to control your sculpture .  I will be adding magnets and such so you can observe
how no matter how clever you consider yourself you just cannot get energy from them. Ill be allowing dxf's of various
shapes, sizes, materials and propertie s to be used with as realistic a gravity simulatio n as my talents allow me to make.

    I'm doing all this because I too find it hard to think in 4th dimension space. Consideri ng time isn't something humans
do well except those very lucky artistic types I admire so much. So soon you can play with all these factors to try to
imagine how to get more run-time and how to make that run-time not go too fast, or too slow for your design.

  I cant promise reality, its the nature of simulatio ns that you get only so close, but I think such a tool is probably
very valuable to others who want to be as artistic as possible but just cant imagine what monarch will look like
till it spins.

 Long answer I know, but in summary, you can slow your vanes, or speed them up with mass manipulat ion, but total run-time will be much the same unless you increase power. Or so the numbers tell me, they never lie, but I often misunders tand what they say. Smiley

Art

 

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Kineticrazy
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« Reply #38 on: December 08, 2016, 08:31:42 PM »

Art,
  Excellent response! Very informati ve. I do want to explain that I did not add magnets thinking they would pull my vanes or wheel, but the added magnets were there to keep the pawl in the up position for a longer duration, allowing for a longer push.

Man, it is difficult describin g these things  Grin

I am very happy with your teachings, Obi-Wan. I shall seek a balance within the force !!!

Not yet a Jedi,

Eric
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ArtF
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« Reply #39 on: December 08, 2016, 08:40:42 PM »

Eric:

 Sorry I misunders tood. Its a common discussio n in many places on using magnets to add speeds and such. Smiley
And yes, these are all really hard to describe things.

Art
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Kineticrazy
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« Reply #40 on: December 08, 2016, 08:52:45 PM »

Art,
  I did not want you thinking I was a "free energy" nut  Tongue

In the words of a movie astronaut recently stranded on Mars...."You scienced the shit out of it!"
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ArtF
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« Reply #41 on: December 08, 2016, 11:04:37 PM »

lol.. there's worse types of nuts about..


Art
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Dan Mauch
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« Reply #42 on: December 09, 2016, 12:07:41 PM »

Dan,
   The friction reduction you've found, I'm trying to picture exactly where the friction occurs. Is it the pin passing over your plastic pawls that flows more smoothly?

I found that even the slightest drag of the spring rubbing against the flanges of the spools was one place.  The dogs slide better than the wooden ones and they are a bit heavier so the actuate better. It's been at least a year since I built it but at age 74 I am sure there were other reasons why the acrylic run better than the wood.
Dan Mauch

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Kineticrazy
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« Reply #43 on: December 09, 2016, 10:13:55 PM »

Thanks Dan,
    I'm questioni ng the use of bearings in my machine. I use skateboar d bearings, shields removed, cleaned and lubricate d...but they don't spin like the bearings I remember as a kid.The caged balls in skateboar d bearings seem to slow them down. They don't "free wheel" but seem to have more friction than a sleeved hole and shaft would have. What sort of bearings have you been using? Your sculpture s are beautiful and run well, I would love to know some of your methods.. .counter rotating wheels has got me a pulling out what little remaining hair I have left, and you seem to have them mastered. I would be overjoyed if you shed some light on their design.

74 is the new 50 !!

Thanks for your time,

Eric
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Dan Mauch
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« Reply #44 on: December 10, 2016, 10:47:51 AM »

 Yesterday after looking at the side of my version of Zinna I then remembere d that the pin that the storage spring spool  also had a slight drag which was another reason to make that spool also out of acrylic. I also installed bearing on the other spool. BTW I only wind my Zinna 18 turns and get about 15 minutes of run time with  stock spring Boyer recommend s. I am using shielded bearings but I run them for a time before installin g them. When I use to work on Submarine s one of the jobs was to assemble the SV radar gearbox. After it was assembled I place thermomet ers on the cases where the bearing were and it was surprisin g. When I ran the gearbox in the shop the temperatu res rose on the bearing housings but after about a 1/2 hour of running the bearing temps would drop to ambient. I never forgot that and thus always run my bearings either by a electric drill or some bearings I take out to the shop and use a compresse d air nozzle with the bearing on an arbor and spin it up. You be surprised at how fast they run that way. Possibly 100000 RPM !!!!
Dan Mauch
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