if you really want to see something cool, check out interaxle differentials and detroit dfifferentials. https://www.youtube.com/watch?v=e-d-uOYCrRE
torsen differentials are incredible as they can in many cases overcome the traction difference problem https://www.youtube.com/watch?v=JEiSTzK-A2A
Most off road vehicles have locking differentials.
"Aaaahhhh... so that's why he told me that..." Thanks Uncle Bill!
At least this is how it was explained to me by my mechanic friend
It is amazingly effective indeed. One time I was driving through ice and snow, and at the traffic light I turned of the ESP by mistake (was trying to plug in my phone charger in the lighter socket beside the button). When I took off I nearly crashed myself off the road, I never realised how slippery it was, and how much the car was covering for my ignorance.
So this is useful when you’d prefer a conventional axle: when one one side has a grip and the other side none.
European documentaries usually simply follow the process and neutrally explain what is happening.
There are still a lot of great YouTube channels - Applied Science, Tech Ingredients and such. Nationality has nothing to do with this. 1970’s American television was amazing. Watch some Bell Labs videos or how Saul Bass did branding.
Technology Connections, Numberphile, 3blue1brown, NativLang, Ben Eater, VSauce, Tom Scott etc.
As a teenager I could watch NatGeo and perhaps another similar channel with 2 hour dragged out documentaries with talking heads edited and narrated by people who don't love the topic the way these YouTubers do.
I think the Internet is still great if you curate what you watch and read, it's better than ever. But perhaps it's worse on the average. The junk is more potent and the intellectual poison is dosed higher than even the worst reality shows used to be on TV.
Both of these can be true at the same time.
Also, you're watching this 1937 docu on YouTube, not on Discovery Channel on TV.
Not sure if there is any disagreement, you're resonating with what I said. Both are true - there is some shitty stuff and there are some great channels. Cherry picking examples doesn't actually drive my point so let me try again - It's not so much about specific channels/documentaries, but whether nationality has anything to do with it. I just don't think Americans produce content that's any different than Europeans. That was the point I was trying to convey.
Those productions are often actually really boring though. For all the bad stuff we say about History Channel and alien documentaries, it was torture to watch some boring history docus in school history class about some medieval battles with a dry voice detailing the dates and the names etc.
Sure there's a space in between, I just mean that the very commercial-focused documentaries are more an American thing and arrived along with American style cable TV to Europe.
It's just like in sports now where someone has to be rambling about something the entire game, even though you're watching it. It's still useful, often to find out which player shot or for the added excitement with the crowd. But they ALL feel the need to fill dead space the entire show which I personally would experiment with if I ran the show. There's plenty going on always already. Humans are weird like that.
I'm sure this has applications in Youtube and other educational videos or whatever.
I think that's because the older movie is an actual educational movie, while the video you linked is really pseudo-educational entertainment. An educational video has the goal of leaving the viewer with actual understanding of something, while the pseudo-educational video only cares to vaguely tickle the viewer's curiosity, and is fine to leave them nearly as ignorant as when they started. While the two movies may have a "similar level of detail," the educational video focuses on fully explaining a specific problem and solution, while the pseudo-educational video only vaguely skims through the high-level steps of some manufacturing process and barely even explains what the product is for.
http://www.engineerguy.com/ makes educational videos similar to this 1937 movie on a lot of similar topics.
Instead of running through all the parameters in ten minutes and one second, the dude keeps twiddling the knobs and lets you hear what they do. He spends ten minutes on dialing just one sound.
As a bonus, since the vid is from the early eighties, you can occupy yourself by guessing exactly how high the man is.
That suggests that it didn't just tell me how a differential works. It taught me how someone who needs to invent a differential should think about the problem.
There's a whole series. "Spinning Levers" (transmissions), "Down the Gasoline Trail" (fuel), "Just a Spark" (ignition), "Tough Friends" (steel), "No Ghosts" (frames), and more.
Original discussion here: https://news.ycombinator.com/item?id=15122031
It's worth going through the previous discussions for the recommendations of similar films
As for this video itself, I've seem it a few times, and it still really does amaze me how much care was put into this. I assume the video is government funded, and it kind of makes me sad to realize that they had the capability to create educational videos of this quality 90 years ago, but it wasn't high enough priority to broadly apply to the general masses.
The video was made by the Jam Handy organization. They did videos for several car companies, and sometimes a consortium of them, is my understanding https://en.m.wikipedia.org/wiki/Jam_Handy
That does take the wind out of the sails of the argument that it could've had a broader focus than just the differential engine. In that case I'll shift my dismay to "90 years ago, videos of this caliber were possible, and yet educating people on a broader scale didn't enter the minds of any entity which could've afforded it."
Just hypothesizing, but either GM might distribute these and have showings for staff as part of training. Almost certainly not for the engineers that already learned this but perhaps sales staff so they could better explain the mechanism and benefits to buyers.
The OP was asking how people might watch a video like this, not who is watching it. In 1937 broadcast television was relatively new and few people owned a tv. For example, the wikipedia page for TV in 1937 notes that by the end of that year 2,121 TVs had been sold in England:
My understanding is US conscription only restarted for WW2 in 1940.
I wonder if such vehicles even had a transmission, or if that was a technological advance that came later? And if, before differential car axles were invented, anyone tried solving the same problem by driving two wheels with separate engines?
With modern electric vehicles that lack a transmission, having a separate motor for each drive wheel seems like a reasonable thing to do now. I assume someone's already built such a thing; the Cybertruck is planned to have a 3-motor variant, though I don't know if two of the motors will share a differential or if they'll just each go to a separate drive wheel. Also the Rivian might have separate motors per wheel, I'm not sure.
AFAIK there isn't currently open-source CAD tooling for designing hypoids.
Edit: nice (short) discussion on this on reddit from 2 years ago https://amp.reddit.com/r/cars/comments/9d33os/why_did_the_ch...
So in this differential, the housing can turn both wheels simultaneously, but if one wheel slips and becomes free, it can't direct the torque to the free wheel:
Maybe someone has a better explanation?
With that design (which seems to be a Torsen Type A), the faster wheel does all the work of propelling the vehicle on turns, but the wheels lock together if one starts to slip. So it's for off-road vehicles, like the military HUMMV. (But not the civilian Hummer H1. That used a Dana differential more suited to on-road driving at higher speeds.)
It worked very nicely on highways.
With this explanation it seems that if one wheel gets slightly stuck, the other wheel gets all the force, causing a dangerous spinning.
This is how a (open) differential behaves, though a spinning wheel isn't so much dangerous as ineffective. This limitation can be overcome using a locking differential or a limited-slip differential, or a traction-control system that selectively applies brakes to a spinning wheel to simulate a limited-slip differential.
So, while such simple differentials can get stuck fairly easily, they also work surprisingly well. The obvious trick is to apply some breaking power to the spinning wheel to then apply force to the stuck one, thus traction control. Or to just lock a differential when bouldering etc. More complicated mechanical systems can always provide some power to both wheels, but they aren’t actually necessary.
Your comment really shows how great the video is... That is exactly how an unlocked non-limited slip differential works, much to the irritation of anyone who has found themselves stuck in sand or a patch of ice.
Hence, if one wheel is stuck, it still receives the same force as the other, only speed is lower.
What is more annoying is when one wheel is freely slipping (like on ice), the other will have nearly no force applied to it and the car is stuck.
i've learned about this the hard way about ten years ago: started my car, put it in first gear (manual), stepped outside and marveled at the freely spinning wheel on a patch of ice.
fortunately got a push from a stranger who happened to pass by.
This is not necessarily true. Imagine a similar symmetric lever with a weight on one side, and a force on the axis that accelerates rotation. The acceleration of both ends of the lever are equal, but the force is not equal (since the weight is 0 on the other end).
Anyway, the point of my comment was that a thorough analysis of this configuration is more involved than this video of which it was claimed that it "perfectly" explains how this works.
Anyway, I did write "approximately" to avoid discussing acceleration/inertia of the differential itself. I should have written "in steady state" or something like that. It is true that a complete discussion can be more involved
Did you say youts?
This video has been posted 20+ times, over the years!
The idea was around, it just wasn't very practical at the time due to various constraints on engine size and component layout. It was simpler to keep the driving and steering wheels separate. The stereotypical American car with a huge V8 filling the engine compartment and an equally massive transmission wouldn't leave much space to route the driveshafts.
Also, FWD requires a differential too.
 They later tried to make a big engine and FWD fit, and ended up with this design: https://en.wikipedia.org/wiki/Oldsmobile_Toronado
In 2008 the original general motors was effectively dissolved, the current GM simply purchased some of their assets, which happened to include their names and trademarks.
I'm aware of government (financial) aid, as well as appointing government officials to "consult" and direct restructuring, but it's much less clear that it was "effectively dissolved" or that a "new" General Motors purchased assets from the old one.
A new company, General Motors Company, was created, and it bought the more useful assets of Motors Liquidation. Not all of them. Motors Liquidation was left to sell off unwanted plants, and such assets as GM's car collection. (GM used to have a collection of one of everything they'd made.) Today's GM is General Motors Company, much smaller than "Old GM".
Some upcoming models, such as the Rivian R1T pick-up, put a discrete motor at each wheel, allowing each to be driven independently without need for a diff.
Has anyone else noticed that today's educational content intended for adults increasingly uses a format that was regionally only used for very young children? There is almost always personality emoting and doing accidentally on purpose funny things and laughing, exaggerating everything to keep people engaged.
Some excerpts from the book:
> “Dr. Ruth Westheimer is a psychologist who has a popular radio program and a nightclub act in which she informs her audiences about sex in all of its infinite variety and in language once reserved for the bedroom and street corners. She is almost as entertaining as the Reverend Billy Graham, and has been quoted as saying, “I don’t start out to be funny. But if it comes out that way, I use it. If they call me an entertainer, I say that’s great. When a professor teaches with a sense of humor, people walk away remembering.” She did not say what they remember or of what use their remembering is. But she has a point: It’s great to be an entertainer. Indeed, in America God favors all those who possess both a talent and a format to amuse, whether they be preachers, athletes, entrepreneurs, politicians, teachers or journalists. In America, the least amusing people are its professional entertainers.”
> “We may surmise that the ninety million Americans who watch television every night also think so. But what I am claiming here is not that television is entertaining but that it has made entertainment itself the natural format for the representation of all experience. ... The problem is not that television presents us with entertaining subject matter but that all subject matter is presented as entertaining...”
> “Books, it would appear, have now become an audio-visual aid; the principal carrier of the content of education is the television show, and its principal claim for a preeminent place in the curriculum is that it is entertaining.”
Can someone explain this to me? Billy Graham is... the last person I’d think of as an amusing figure.
In the chapter "Shuffle Off to Bethlehem," Postman compares the 20th century televangelist with 17th-19th century spiritual leaders:
> “Television’s strongest point is that it brings personalities into our hearts, not abstractions into our heads. That is why CBS’ programs about the universe were called “Walter Cronkite’s Universe.” One would think that the grandeur of the universe needs no assistance from Walter Cronkite. One would think wrong. CBS knows that Walter Cronkite plays better on television than the Milky Way. And Jimmy Swaggart plays better than God. For God exists only in our minds, whereas Swaggart is there, to be seen, admired, adored. Which is why he is the star of the show. And why Billy Graham is a celebrity, and why Oral Roberts has his own university, and why Robert Schuller has a crystal cathedral all to himself. ”
> “It would be a serious mistake to think of Billy Graham or any other television revivalist as a latter-day Jonathan Edwards or Charles Finney. Edwards was one of the most brilliant and creative minds ever produced by America. His contribution to aesthetic theory was almost as important as his contribution to theology. His interests were mostly academic; he spent long hours each day in his study. He did not speak to his audiences extemporaneously. He read his sermons, which were tightly knit and closely reasoned expositions of theological doctrine Audiences may have been moved emotionally by Edwards’ language, but they were, first and foremost, required to understand it. Indeed Edwards’ fame was largely a result of a book, Faithful Narrative of the Surprising Work of God in the Conversion of Many Hundred Souls in Northampton, published in 1737. A later book, A Treatise Concerning Religious Affections, published in 1746, is considered to be among the most remarkable psychological studies ever produced in America.”
He was so popular he even got to meet the queen of england when he was in the UK:
(This is dramatized in Netflix’s Crown Season 2 Episode 6)
All his videos are absolutely phenomenal - the best educational content I've seen on YouTube. I cannot recommend them highly enough. In my experience it is more akin to reading a (very engaging) textbook than watching a video. I often find myself pausing to think things through and can _feel_ myself grasping at new ideas and learning while watching.
The down votes are likely due to that as the comment does not contribute to much. If folks don’t want to hear more about 3b1b, it will just not gather upvotes.
Earlier today I was trying to find a list of all Alfa Romeo models to identify a car, and all the top results were ten paragraphs of SEO infused filler bullshit, with some smattering of half or less of the cars. Genuine enthusiasts get crushed under the weight of mighty marketing budgets seeking a pittance of adsense dollars.
It's an op-ed designed to get clicks and turn ad dollars, in a format that extracts even more clicks once you arrive. That's what's frustrating, all the genuine information is being replaced with content marketing apparatuses. That's not really Google's fault intentionally, it's just how the ecosystem has evolved.
Even the ones that are not hit-you-on-the-head scatological are still, as you say, trying to be funny and engaging but in a patronizing way.
Perhaps I am not the target audience but I preferred young science books that made you feel like you were learning real science — learning about the chemistry of plastics for example. The science wasn't a footnote to the experiment, it was the reason for the experiment.
Mae and Ira Freeman's science books for kids were great for younger readers. Kenneth Swezey's books. The classic "Golden Book of Chemistry" is a little slick, but still good (https://www.academia.edu/37919681/The_Golden_Book_Of_Chemist...).
Or maybe I just preferred the presentation of the older books...
I often mock some of my American friends by mimicking them when they say that some rather mundane thing is "AMAZING" or "OH MY GOD I CAN'T BELIEVE IT" or "THIS IS INSANE" and no, Mark, it's not insane, it's just a decent piece of a cake.
Of course my default French blasé attitude towards everything errs the other way, there's probably a compromise to be found. But at least when I say that I found something to be "amazing" my friends generally take note, because it's not something I say lightly.
That's sort of the main issue for me, it's like the loudness wars for music mixing, when people tell you how to unclog your drain as if it was the most amazing thing that ever happened to them the baseline is completely skewed.
BUT WAIT, THERE'S MORE!
And to keep videos above a certain length so that the algorithm prefers them over short, concise videos, and that the chance is higher for multiple ad rolls (= more monetization).
- fluid based car transmission
- navy canon driver based on analog computers
- wave principles (using super cute appartus to show impedance)
Perhaps the patience level of audiences of that era was much higher than today? But that's OK, now, thanks to modern media technology, you can randomly access any part of the presentation or speed it up at will.
Remember, the idea is to handle the situation when torque on one wheel is not the same as the opposite wheel. Now it can be done with an electronic LSD which applies braking force
"Line, Grey, Black-and-white, Exercise equipment, Monochrome, Machine, Monochrome photography, Barbell, Circle, Gas, "
Other non-car images on the site have text that's really disconnected from the context, such as an Apple logo on a story about the Apple car called "Christmas shopping in the city of Hamburg" which I guess came from the context of the stock photo being a Hamburg Apple store photographed at Christmas time. Pictures of people seem to be labeled with the events they're photographed at, even when it's nothing to do with the article.
Poor blind people having to figure out that "f1 eifel grand prix" means "George Russell".