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Author Topic: 1 hour barrier broken!!!  (Read 717 times)

Jeremy McCreary

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Re: 1 hour barrier broken!!!
« Reply #45 on: May 02, 2021, 10:51:37 AM »

I don't want to give a top which is not good, like the Nr. 9.  But I could save and develop that design.  Adding to it a long stem, (maybe 250 mm, diameter 10 mm), this could become a top to be spun with the palms of the hands by multiple twirls.  The weight of the top could be suitable for this way of starting the top, and spinning the top could be comfortable, (but I should test it).

Another way to give Nr. 9 a new life: A detaching ribbon-pull starter with a rubber-lined stem receiver conforming to your tapered stems. The rubber would provide the friction needed for starting torque transfer while protecting your stem finishes.

Detaching ribbon-pulls are very powerful and fun in their own right -- in part because you can really feel the torque and speed in your hands. If you're careful not to pull too hard, they can also provide precise tilt control at the moment of release.

Imagine the spin times you could get -- especially with a top like Nr. 9! Examples of detachable ribbon-pulls in action at 7:08 and 7:43 below...

https://youtu.be/92OcmpkThf0
« Last Edit: May 02, 2021, 10:54:51 AM by Jeremy McCreary »
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Playing with the physical world through LEGO

Jeremy McCreary

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Re: 1 hour barrier broken!!!
« Reply #46 on: May 02, 2021, 11:01:33 AM »

I agree, and this is the reason that I am not interested in adding a motor or other similar means, as a few times I have been suggested, to my tops, because even if in this way the top could spin for hours, it would become more like a toy for children, and quite less interesting, at least to my eyes.

Oops, just saw this. If you tried a ribbon-pull, I think this opinion would change. It's still a manual start -- in my eyes, just as legit as a two-handed palm start but a lot more ergonomic.
« Last Edit: May 02, 2021, 05:58:15 PM by Jeremy McCreary »
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Iacopo

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Re: 1 hour barrier broken!!!
« Reply #47 on: May 02, 2021, 11:14:57 AM »

Can you start one of your tops with multiple twirls of two palms? Speed compared to multiple finger twirl start?

I tried but it doesn't work, I have little control with the palms. I should try with a long stem, 20 or 30 cm.
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ta0

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Re: 1 hour barrier broken!!!
« Reply #48 on: May 02, 2021, 11:31:10 AM »

Thanks Iacopo for the explanation. All seems very logical.

Can you start one of your tops with multiple twirls of two palms? Speed compared to multiple finger twirl start?

I tried but it doesn't work, I have little control with the palms. I should try with a long stem, 20 or 30 cm.
Kyokugoma players do multiple palm-twirls starts all the time. I have two kyokugomas and their stems are 4 mm in diameter and 10 cm long.
There is certainly a technique involved. It took me a while to be successful.
« Last Edit: May 02, 2021, 11:34:15 AM by ta0 »
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Iacopo

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Re: 1 hour barrier broken!!!
« Reply #49 on: May 02, 2021, 12:10:41 PM »

Hi!

Great job on breaking the hour barrier! I never had any doubts, it was just a matter of time :)

I am interested in your thoughts on the optimal weight for spinning tops. If a top is too light, say 100g, its moment of inertia is too small and the amount of starting energy we can give it is too limited. So, in an ideal world, we would make massive 100 kg spinning tops. However, when we try making heavier tops around 1kg like your Nr. 9, they don't spin as long as we expect. Is this due to the limitations of tip hardness and durability? The best weight seems to be around 300g based on your past tops. What are your thoughts?

Thank you, James ! 

I have no experience nor any data about a 100 kg top, but, at least until 847 grams, I can say that, the heavier, the better.
Generally heavier/bigger tops are more efficient and lose RPM more slowly than littler/lighter tops.
So, at parity of starting speed and toppling down speed, larger/heavier tops spin longer.

The problem is how you start the top. 
If you make finger tops, the limited strenght of the fingers is not suitable for too heavy tops, so a compromise is needed.
For example, my fingers couldn't start the heavy Nr. 9 at more than 1000 RPM, so that top can't spin for much more than 40 minutes, in spite of its excellent efficiency in losing RPM more slowly than any other top I have made.

60 mm/300 grams tops, (in the case of tops with recessed tip to be started by multiple twirls of the fingers), are much better because with the fingers I can start them at about 3000 RPM, so, even if they are a bit less efficient, they can spin for almost one hour.
I made many tops with this size/weight.

But my new top Nr. 54 is even better !  This is a new size I never tried before, 70 mm/360 grams. Finger tops with this size can spin for more than one hour ! This new size is perfect for brass tops with recessed tip to be spun by multiple twirls. Now I will have to buy a 70 mm brass rod for my next tops in this category.

Then I discovered that adding a shroud around the top makes the top to spin some minutes longer.
The littler the shroud, the most close, (no openings), the better.
If you try you will see the same.  I used paper to make this simple experiment.



So, thanks to the improved size and to the added shroud, I could reach 70 m 31 s.

As for heavier tops, I am considering to find a way to start them with more energy.  Maybe with the palms of the hands, or a ribbon, as Jeremy suggests.  Being so efficient, if I can start them at a decent speed, they certainly can spin for very long.


 
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Iacopo

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Re: 1 hour barrier broken!!!
« Reply #50 on: May 02, 2021, 12:37:24 PM »

Kyokugoma players do multiple palm-twirls starts all the time. I have two kyokugomas and their stems are 4 mm in diameter and 10 cm long.
There is certainly a technique involved. It took me a while to be successful.

I can start my tops with my palms, which is not too difficult.
But if I want longest spins, I see that with my tops I find easier to use the fingers, there is more control, especially at high speed.
I can Start the Nr. 9 at 1000 RPM with the fingers, but I find this difficult with the palms.
This maybe also depends on the fact that the scrape angle of this top is not very large if I spin the top on a mirror, and if I use a dedicated base the spinning surface is little and the top can exit from it, if I spin it with not so good control.
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Jeremy McCreary

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Re: 1 hour barrier broken!!!
« Reply #51 on: May 02, 2021, 06:04:21 PM »

... a wise person once (or twice) saying: "Spin time is not everything!"[/i]

The tachometer I suggested earlier and that Jeremy mentioned is this one:UNI-T, UT 372 with USB interface and software....
A video about the software.

I don't have it, I let Jeremy do the testing for us!

That exceptionally wise person just ordered one for $60 from Amazon US, with estimated delivery in 4-6 weeks (apparently coming by bicycle from China).
« Last Edit: May 02, 2021, 06:07:40 PM by ta0 »
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Iacopo

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Re: 1 hour barrier broken!!!
« Reply #52 on: May 03, 2021, 01:58:34 AM »

Another way to give Nr. 9 a new life: A detaching ribbon-pull starter with a rubber-lined stem receiver conforming to your tapered stems. The rubber would provide the friction needed for starting torque transfer while protecting your stem finishes.

This is a good idea, I will think to it.
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ortwin

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Re: 1 hour barrier broken!!!
« Reply #53 on: May 03, 2021, 03:01:19 AM »

Another way to give Nr. 9 a new life: A detaching ribbon-pull starter with a rubber-lined stem receiver conforming to your tapered stems. The rubber would provide the friction needed for starting torque transfer while protecting your stem finishes.

This is a good idea, I will think to it.
 

Although the idea stems from one of our wisest men, I personally don't like it half as much as your idea with the multiple twirl of two palms.
To me it would feel almost like Gasing, and there the record is at two hours already I think.  If a string should be legit, I would prefer a method where nothing but a string is needed in addition to the top. Some examples we discussed here.
@ta0: do you know of any good times reached by the Japanese with their two-palm-multiple-twirl-method?


Iacopo, I hope you can get get something extra for these new tops, maybe:
Nr. 55: +30 %  since it is the first finger top ever to beat the 1 hour barrier!
Nr. 54: +50 %  because it is the current record holder!
« Last Edit: May 03, 2021, 06:43:02 AM by ortwin »
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ta0

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Re: 1 hour barrier broken!!!
« Reply #54 on: May 03, 2021, 11:03:14 AM »

@ta0: do you know of any good times reached by the Japanese with their two-palm-multiple-twirl-method?
Kyokukoma means juggling top. They don't just stare at a sleeping top  ;)

An interesting thing is that they can also start the larger ones by just rolling the stem inside the circular opening made by the thumb and index fingers, while holding the top in the hand away from any surface.
« Last Edit: May 03, 2021, 11:05:36 AM by ta0 »
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ortwin

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Re: 1 hour barrier broken!!!
« Reply #55 on: May 03, 2021, 11:14:32 AM »

...
An interesting thing is that they can also start the larger ones by just rolling the stem inside the circular opening made by the thumb and index fingers, while holding the top in the hand away from any surface.
Sounds similar to what you once called hoola-hoop regeneration , or the levitron perpetuator. Do you have a video of that type of start?
« Last Edit: May 03, 2021, 12:16:50 PM by ortwin »
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ta0

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Re: 1 hour barrier broken!!!
« Reply #56 on: May 03, 2021, 01:29:59 PM »

...
An interesting thing is that they can also start the larger ones by just rolling the stem inside the circular opening made by the thumb and index fingers, while holding the top in the hand away from any surface.
Sounds similar to what you once called hoola-hoop regeneration , or the levitron perpetuator. Do you have a video of that type of start?
You can see it at 0:38 on the video on this post: Koma Wizard
Also at 6:15, when Otobokesan starts a smaller koma that way, what is much more difficult (but he then increases the spin with palm twirls).
« Last Edit: May 03, 2021, 04:51:14 PM by ta0 »
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