Difference between revisions of "Talk:2973: Ferris Wheels"

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(Really rough math about how fast the wheels would turn, if they were the same size and speed as the original Ferris Wheel from 1893.)
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@[email protected] [[Special:Contributions/172.70.175.87|172.70.175.87]] 20:58, 16 August 2024 (UTC)
 
@[email protected] [[Special:Contributions/172.70.175.87|172.70.175.87]] 20:58, 16 August 2024 (UTC)
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This Amusement Ride manufacturer has a helpful diagram of rotational speed on their website: https://www.sinorides.com/everything-you-need-to-know-about-ferris-wheels/#q11
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The example wheel happens to have 18 gondolas, just like Randall's and appears to be roughly the same scale.  The sample values they provide are a linear speed of 4 m/s at the edge of the wheel and a rotational speed of just under 3 revolutions per minute.  My best guess at the gearing ratio of Randall's belt driven wheels is 10:1, so if the left wheel is being driven at normal speeds, the center wheel would be 40 m/s or 30 rpm and the left wheel would be 400 m/s or 300 rpm.  This exceeds the square root of the specific strength of standard steel, so we'll need to hope that the right most Ferris wheel is made of a particularly strong alloy. [[Special:Contributions/172.69.71.97|172.69.71.97]] 21:19, 16 August 2024 (UTC)

Revision as of 21:19, 16 August 2024

Where is the Cueball shouting "wheee!!"? Barmar (talk) 19:59, 16 August 2024 (UTC)

In the transcript I described how the cars are hanging, but I'm worried I've gone too far from transcript to explanation. Hopefully someone can improve it. Barmar (talk) 20:02, 16 August 2024 (UTC)

There's no category for "X fired me because" comics. There probably should be. Barmar (talk) 20:06, 16 August 2024 (UTC)

Just HOW fast?

I was vaguely surprised to see nobody had done the math yet. So here it goes -- someone more confident in editing the main entry can feel free to adapt this if you think it's interesting enough (I doubt anyone would want to read the math as I wrote it). But first, someone please check my work. :)

I opened the comic in a pixel-level photo editor, and took some quick measurements. The wheel on the left seems to be approximately 160 pixels wide, whiile the inner hub is about 14 pixels high.

So the gear ratio is 160:14 or about 11.04 Just for simplification, let's call it a 10x ratio.

The original Ferris Wheel took about 20 minutes to load and unload passengers, then ran for 9 uninterrupted minutes for another, full, rotation. So again, let's round up and say the wheel on the left takes about 10 minutes to go around once.

The middle wheel, then, would take a minute. And the last one, a tenth of a minute, or 6 seconds.

The original wheel (again) was about 265 feet across, or a circumference of 832 feet. So if these wheels are the same size (why not?), any car on the right-most wheel would move about 832 feet in 6 seconds, or 138 feet per second, which is about 94 miles per hour (151 kilometers per hour).

I can see why he was fired.

Taking the reverse: The rightmost wheel would take about 10 minutes for a rotation, the middle wheel, 100 minutes (1:40), and the left most, 1000 minutes (16 hours and 40 minutes).

Actually, if you move slow enough that the right wheel can load and unload (let's say 20 minutes, just like the original wheel), it'd take over a day to load the left wheel.

@[email protected] 172.70.175.87 20:58, 16 August 2024 (UTC)

This Amusement Ride manufacturer has a helpful diagram of rotational speed on their website: https://www.sinorides.com/everything-you-need-to-know-about-ferris-wheels/#q11 The example wheel happens to have 18 gondolas, just like Randall's and appears to be roughly the same scale. The sample values they provide are a linear speed of 4 m/s at the edge of the wheel and a rotational speed of just under 3 revolutions per minute. My best guess at the gearing ratio of Randall's belt driven wheels is 10:1, so if the left wheel is being driven at normal speeds, the center wheel would be 40 m/s or 30 rpm and the left wheel would be 400 m/s or 300 rpm. This exceeds the square root of the specific strength of standard steel, so we'll need to hope that the right most Ferris wheel is made of a particularly strong alloy. 172.69.71.97 21:19, 16 August 2024 (UTC)