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Author Topic: Spinning giant top  (Read 237 times)

ta0

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Spinning giant top
« on: September 01, 2019, 02:58:17 PM »

Here is Guillermo Vizcaino from the island of Palma de Mallorca, Spain, spinning the giant top he made.

https://www.youtube.com/watch?v=CS7pmAqQAIY

I'm sure he was inspired by the Taiwanese giant tops of Daxi.

Photos detailing the construction in the Spanish section of the forum.
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ta0

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Re: Spinning giant top
« Reply #1 on: September 01, 2019, 03:08:03 PM »

We'll see him competing at worlds I'm sure.
Here is a video doing Jose's snapstar to ghost catch:

https://www.youtube.com/watch?v=jU3ToSDRCoM

I think he is trying Neff's WWW here:

https://www.youtube.com/watch?v=RJZFje0xAOo

Do we have a lurker around?  ;D
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cecil

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Re: Spinning giant top
« Reply #2 on: September 01, 2019, 03:52:15 PM »

I love this people all over the world playing with tops. This guy is fantastic - and the tops have good tips. This is America it’s time to catch up with the rest of the WORLD. I say we out trick them and when fighting we split there tops in half. U.S land of the top TERMINATORS. Thanks for sharing.
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jim in paris

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Re: Spinning giant top
« Reply #3 on: September 02, 2019, 01:14:19 PM »

fantastic giant top !

dragging the top doesn't seem to work : may be Guillermo should try the Joe Mauk 's set up

does he read the forum ?

jim
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Jeremy McCreary

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Re: Spinning giant top
« Reply #4 on: September 02, 2019, 02:04:49 PM »

dragging the top doesn't seem to work : may be Guillermo should try the Joe Mauk 's set up

He can clearly get the big top above its critical speed -- though not by much. Keeping the top upright during spin-up would help him get the most out of the launch speed available.

One approach: A helper could hold the top upright during spin-up with a freely-spinning stem sticking up from the crown.

The large size is advantageous WRT critical speed. Suppose you have a normal-sized peg top with max diameter D1 and known critical speed wC1. Now suppose you make a copy with the same shape and internal mass distribution, including relative CM height, but with max diameter D2.

Then the copy's critical speed would be

wC2 = wC1 sqrt(D1 / D2)

The weight ratio would have no effect on critical speed. But it would definitely affect attainable launch speed -- mainly via axial moment of inertia and tip resistance.

« Last Edit: September 02, 2019, 02:30:33 PM by Jeremy McCreary »
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Playing with the physical world through LEGO

ta0

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Re: Spinning giant top
« Reply #5 on: September 02, 2019, 06:10:44 PM »

I'm not sure if the tip is big enough to be a "sleeper' tip for that top.
He should spin it once using a motorcycle or car to pull . . .  >:D
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Jeremy McCreary

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Re: Spinning giant top
« Reply #6 on: September 02, 2019, 07:31:22 PM »

I'm not sure if the tip is big enough to be a "sleeper' tip for that top.... He should spin it once using a motorcycle or car to pull . . .

Interesting. In LEGO non-throwing tops, I consistently find that the finer the tip -- i.e., the smaller its radius of curvature at the contact -- the better your odds of twirling a sleeper from the start. On some surfaces, a finer tip would also be harder to pull out from under the top.

So, good things to try -- separately or in combination...
1. Boost spin-up torque by upping the force pulling the rope -- without  pulling the tip out from under the top in the process. Seating the tip in a divot might help. Suzuki 1000, team of horses, Vespa, or just another human?
2. Make the top's angular momentum at the time of release as vertical as possible.
« Last Edit: September 02, 2019, 08:08:47 PM by Jeremy McCreary »
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Jeremy McCreary

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Re: Spinning giant top
« Reply #7 on: September 02, 2019, 11:17:17 PM »

Typical example of the spin time to be gained by starting a peg top off asleep...

At 1:30 below, I started my 3" Relampago peg top vertically with a wind-up starter. It stayed asleep from 0-125 s and fell at 150 s. After sleeping, it quickly transitioned to a surprisingly long-lived "terminal mode" characterized by rapid, high-angle precession (not shown). It was still in terminal mode when it finally fell.

https://www.youtube.com/watch?v=1AXNwJ9tr6s

At 2:41, I started the same top at about the same release speed. But the release wasn't exactly vertical. Since the sharp tip on glass keeps the top from self-righting, it just skipped sleep and quickly transitioned to terminal mode (2:50). And this time, it stayed up only 90 s -- a 40% drop in spin time.

Every peg top I've started in this way ended its spin in terminal mode and stayed up longer when it started out sleeping. Guillermo's big top ended in terminal mode, too.
« Last Edit: September 02, 2019, 11:35:15 PM by Jeremy McCreary »
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Ketzaltlipoka

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Re: Spinning giant top
« Reply #8 on: September 10, 2019, 05:58:29 PM »

 what a Really MEGA BIG TOP!!!
it must be a little heavy...surely..just a little....
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