2973: Ferris Wheels

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Ferris Wheels

Title text: They left the belt drive in place but switched which wheel was powered, so people could choose between a regular ride, a long ride, and a REALLY long ride.

Explanation

This comic depicts an attempted connection of three Ferris wheels using a mechanical belt drive, a system used to transfer motion between rotating shafts such as what these become. By connecting the belt to different circumferences, the relative motion is geared up or down. If the belt passes around the circumference of one wheel and is connected around the hub of another, the latter will rotate significantly faster. In this case, the second wheel's circumference is in turn connected to a third wheel's hub, resulting in even greater rotational velocity. However, this setup is mechanically unsound and possibly dangerous,^{[citation needed]} as Ferris wheels are not intended to be connected in this way. As shown, the first wheel on the left is running at a normal speed, while the other two are rotating increasingly fast, leading to a potentially hazardous situation where passengers are flung around to various extents.

Ferris wheels can vary widely in size and speed of rotation, but for illustration, let us assume a diameter of about 200 feet (60 m) and a pretty sedate speed of around 10 minutes per full rotation. The apparent ratio between the connected wheels in the comic is approximately 12.5:1, meaning the motion is significantly sped up as it’s transferred. The second Ferris wheel, driven by the first, could spin at around 1.3 rpm, with passengers moving at 9 mph (14 km/h), giving a more exciting ride, but not inherently dangerous. However, when this motion is further transferred to the third Ferris wheel, it could spin at a possible 16 rpm, with passengers traveling at over 110 mph (180 km/h), subjecting them to around 8 Gs of force. Randall has previously explored the limits of the human body's tolerance for acceleration in What If # 116 "No Rules NASCAR". Additionally, if a Ferris wheel span at 110 mph (180 km/h) it would itself be just as dangerous even without any riders. However, since the motor for the first wheel would have been selected merely to drive one wheel, it's unlikely it would be able to power the other two wheels moving at these increased speeds — if it moved at all, all three would probably start to move quite slowly, with potential damage to the motor before any friction limitations and other mechanical failures kicked in.

In the caption Randall says that he was fired for this ill-advised modification, highlighting the impracticality and dangers of the idea. A cruise line also fired the respective narrator due to an unsound engineering proposal earlier in 2935: Ocean Loop.

The title text imagines the consequences of leaving the belt drive system in place but switching which wheel is powered. If the most extreme wheel (the third one on the right) is powered, the gearing would be reversed, making for a possibly pleasant and normal ride on the right-hand wheel, but rendering the experiences of the riders on the other two wheels far too slow for an enjoyable carnival ride. One revolution of the center wheel might take two hours and five minutes, while the left wheel would take around a little more than a day per revolution. This exaggerates the impracticality and unintended effects of using a belt drive system to link up Ferris wheels, illustrating how such an idea would lead to absurdly varied ride experiences.

Transcript

[Three Ferris wheels are shown side by side, with some people stood on the ground for scale. Each of the first two wheels has a belt connecting its circumference to the axle of the wheel to its right. "Agitrons" indicate that the middle wheel is turning notably faster than the left wheel, with the gondolas seen to be rocking significantly at all points round the wheel. The spokes of the right wheel are completely replaced by "motion lines", indicating that the the right wheel is turning the fastest of all. All its gondolas are hanging outwards against centripetal force, interspersed with their own motion lines.]

[Caption below the panel:]

The county fair fired me for adding a belt drive to the Ferris wheels.

Trivia

The first (slowest) wheel can be seen to notably lack a 'spoke' at approximately the five o'clock position, supporting the point where its respective passenger seating is hung. Clearly, however, the wheel design is strong enough to withstand much greater forces in the other two versions of the wheel (which appears to be complete in the case of the second, though the thin spokes are only seen as blurs in the third wheel) suggesting that there may not be significant danger from this omission. It does not bode well, however, for general OSHA compliance in how they erect/maintain the rides, even before the belt-drive idea added its own issues.

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Discussion

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

Probably dead if he was on the 3rd wheel. 172.70.46.90 12:18, 17 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)

No direct explanation and links should be given in the transcript. I have removed it. --Kynde (talk) 19:31, 17 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)

If you can list some more than this and the one already mentioned 2935: Ocean Loop it might be relevant. --Kynde (talk) 19:31, 17 August 2024 (UTC)

I could not help my self and searched and found these:

1428: Move Fast and Break Things

1815: Flag

2219: Earthquake Early Warnings (title text)

2728: Lane Change Highway

I also remembered this one 2447: Hammer Incident, but it does not say he got fired, although I'm sure he did.

Same might happen to Steve in 1532: New Horizons but again not mention the fired word.

Here is one that got fired but not like that 649: Static.

Fired not mentioned but implied here: 1852: Election Map.

Same with this one: 1985: Meteorologist

I'm not sure if all comics someone is fired for incompetence should go in such a category, or only those where it is directly mentioned, basically as first suggested? So until someone chips in I'm not going to create the category. For what should the name be and which of these comics should be included? --Kynde (talk) 19:58, 17 August 2024 (UTC)

I once attached the motor of a Lego ferris wheel directly to its axis instead of the beginning of the gearing system. Not only did all the cabins fly across the room, the entire thing dismantled itself. Worth it! Fabian42 (talk) 01:03, 17 August 2024 (UTC)

Re. the trivia - the second wheel may have all its spokes, but the one near the six o'clock position doesn't appear to be moving, which is perhaps even more worrying than the missing one on the first wheel.141.101.98.87 13:59, 19 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​【80.77 m】 across, or a circumference of 832 feet​【253.59 m】. So if these wheels are the same size (why not?), any car on the right-most wheel would move about 832 feet​【253.59 m】 in 6 seconds, or 138 feet​【42.06 m】 per second, which is about 94 miles​【151.28 km】 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)

Ah, well, I started down my own road for calculations, based upon the assumption that they were 75 feet​【22.86 m】 diameter (from the height of the figures, assuming that the ones I actually checked definitively up to 6ft​【1.83 m】, give or take, although pixel-counts upon antialiased graphics can be quite inaccurate the fewer 'apparent' pixels there are). As a truck-portable/mounted fairground-style ride, it's probably quite a bit smaller than the 'original Ferris wheel' and many of those 'permanent' wheels (London Eye, theme park rides, etc) that are built specifically to be architectual 'statements'/tourist-magnets. I'm thinking more the kind that you'd see in Grease (though that one's 55-foot​【16.76 m】, apparently) or the one that 'Night Monkey' had to deal with in Spiderman: Far From Home. I also looked up actual specs (that's 35m, ~105ft​【32 m】 and 0.5rpm, so not too far off my initial assumptions). There also was a rather larger 60-metre (197 ft) semi-permanent transportable version with 13 minute continuous 'ride', but that'd be completely out of scale to those depicted.

If there are any actual 'carnies' out there who know what kind of thing actually gets used at County Fairs in the US, that might help. (Here in the UK there's currently a Fun Fair about a quarter of a mile from my house, at the moment - though I'm not there at the moment, but they have no 'big wheels' of that kind, only the more energetic types that do fling their riders around, like the "Terrifying Claw" and various other heavy duty hanging and/or spinning-seat rides.) ((Slightly ninjaed, now, by the above contribution.))) 162.158.33.197 21:37, 16 August 2024 (UTC)

I can't help but think of this as Randall wanting to make an upscaled version of Steve Mould's Spintronics video from a year ago... 172.68.50.126 21:54, 16 August 2024 (UTC)

Given that air resistance increases exponentially with air speed, this setup would actually act as its own speed regulator, with the main factor being the torque of the power source. Which wheel is powered would not matter much 172.71.118.167 22:05, 16 August 2024 (UTC)

Drag is quadratic, not exponential. You aren't trying to quantum tunnel through the air until you reach relativistic velocities, and then length contraction means going faster decreases drag, which doesn't help regulate speed at all. 172.71.146.49 21:06, 18 August 2024 (UTC)

Length contraction or not, if you get to relativistic velocities, the kinetic energy requirements will DEFINITELY go exponential, so it will regulate the speed. Of course, there is no material which would be able to withstand such velocities, so it's just theoretical limit. -- Hkmaly (talk) 22:49, 19 August 2024 (UTC)

If you powered the middle one, you'd end up with one moderately exciting ride, one normal ride and one really long ride, which would be highly impractical, but not overly dangerous (depending on the structural strength of the fast wheel). 172.71.142.88 23:08, 16 August 2024 (UTC)

The ratio is listed as 12.5:1, but then the calculations are done using a ration of 20:1. The 12.5 seems to be more accurate, given the drawing, but in the comments here, someone else measured the pixel ratio as 11.04. I think 10 or 12.5 would be fine, but it should be consistent. Knowing the ratio ahead of time would also make the rotation calculations easier to explain. We should probably use the pixel technique to estimate the diameter too. I don’t have access to measuring tools right now, but it’s about 20 times the height of the tallest person, so roughly 120’​【36.58 m】. --172.69.34.87 00:32, 17 August 2024 (UTC)

I am surprised that everyone seems to be doing calculations by counting how wide circes are in pixels and nobody is doing calculations based upon the angle of the (buckets? seats? cars?). What is the fastest speed for the left wheel that leaves the seats hanging down to the precision of the image? What is the slowest speed for the right wheel that leaves the seats splayed out like that? (let's ignore that one seat...) What speed for the center wheel would account for the angles of the seats? Are the answers consistant with the previous calculations based on ratios?

Also, real ferris wheels stop and start so new passengers can get on. Not only would that change the rim speed vs RPM figures but it would make it hard to unload the corpses and load fresh victims on to the right wheel. :( Source: My summer working as a carny. I was on the tilt-o-wheel but the ferris wheel was right next to it. 172.69.34.126 13:53, 17 August 2024 (UTC)

I'm not sure that the physics are depicted accurately enough for that. The net acceleration should be 1g gravity down, plus a radial component depending on the rotational velocity. The 3 o'clock and 9 o'clock positions should have the maximum deflection from hanging vertically. That's kinda the case on the 3 o'clock side, but not the case at 9 o'clock. Note, that ignores wind resistance, but even at the higher rotational speed, wind resistance should be pretty negligible for the middle wheel (9 mph if the existing discussion is to be believed). 172.71.22.99 14:44, 19 August 2024 (UTC)

Are the transcript eds going to go into the speeds depicted?

Should the transcript involve the diameter ratios when explaining the speed depiction gray lines? 172.70.211.83 23:06, 16 August 2024 (UTC)

Such analysis is going towards the speculative. Perhaps we can say that the wheels are <so many> people-heights high, but that doesn't give us any actual definitive speeds to go with the lines, with no actual given first-wheel speed (two minutes a spin? three minutes per spin? thirteen minute 'trips'?). It might be reasonable to mention the hub-to-rim ratio details, but the speed-lines just need to be subjectively described. 172.70.58.3 23:24, 16 August 2024 (UTC)

No explanation and links should be given in the transcript. I have removed it. --Kynde (talk) 19:30, 17 August 2024 (UTC)

By my measurement, wheel1 (outer) is 203 pixels from left edge (at the belt 'grip surface' radius, i.e. as far in as the outer-black-line is before it becomes 'background white' wheel rim), wheel2 hub is 16 pixels (likewise), wheel2 outer is also 203, wheel3 hub is 15 (debatable). Wheel3 (outer) is 202, but the relevence here is more that it's 238 pixels from gondola-bottom to gondola-bottom. (Wheel1 hub is 15, but doesn't even have that relevence.) Can't measure the verticals of the outers, because of the supporting structure, but the the vertical hub measurements agree exactly with the horizontal spreads (which at least means that Randall can draw circles reasonable accurately). 203/16=12.6875, 203/15=13.533... Maybe I should be looking a pixel further out, which gives 204/17=12 or 204/16=12.75. 1:12 (and, by extension 1:144 for the both) seems nicely numbered slightly better and more symbolically than 1:12.5 (or 2:25) and its square (4:625) might be, whatever choice of measurements came up with that. - The tallest figures are 10 pixels high (maybe you could stretch some to 11, depending upon where you 'zero' the ground-line), meaning 20(and-a-bit) figure-heights (some are smaller, single-pixels could be variations/stereotypically slightly smaller females, but I think there are clear child/adolescent figures as part of/all of some groupings, whether by deliberate artistic design or just a matter of how the quick squiggles turned out). 120ft (6 foot figures) is not really far off the 35m mentioned above (with the wrong feetwise equivalent!) as an actual wheel of 0.5rpm. So 6rpm and then 72rpm. 22m radius (taking a decent round figure, whilst metrifying the extended width of the) at that speed seems to be 128g (if I've not messed up), a nice 'round' figure to a nerd. But that'd be at the base of the gondalas, and decrease (bit by bit) if you move even a pixel 'inward' from the that (and a 128g centrifuge isn't going to have a paper-thin floor!)... Plenty of open questions/rooms for error in all that, so not at all worth giving as an Explanation calculation, nor Transcript detail, but it's where I personally ended up. 172.68.205.134 00:11, 17 August 2024 (UTC)

Ferb, I know how we're gonna execute war criminals today! 141.101.99.88 10:52, 17 August 2024 (UTC)

Hey, where's Perry's corpse? B for brain (talk) (youtube channel wobsite (supposed to be a blag)) 17:46, 17 August 2024 (UTC)

Assuming they're 'travelling' wheels, an 18 gondola version, somewhat like the ones depicted (with a little artistic licence), carries up to 108 people at a time and 720 passengers per hour. So 9 minutes per person-trip (not sure we can say that's one full turn, could be a multiple thereof, depending upon how it is operated, so 1/4.5 rpm or 1/3 rpm, etc). As a further datum point. 172.68.205.179 23:46, 18 August 2024 (UTC)

There has just been an unpleasant fire on a Ferris wheel in Germany (Guardian article). Was somebody trying this? 172.69.223.108 17:43, 19 August 2024 (UTC)