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1937 film explains how a car differential works

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Re: 1937 film explains how a car differential works

#101

Post by TaylorAlexander »

tqi wrote: post #89

The lack of background music and pace is really interesting to me. Compared to a typical "how it's made" video [1] (which I feel has a similar level of detail), this video feels significantly more digestible. Those moments of silence feel totally alien and out of place in today's style, but I think contributes positively to my ability to understand and process the information. [1] https://youtu.be/8gno0_emzo8

If you’re up for it, go watch an old episode of the show Columbo [1]. Each episode from this 1970’s era TV was over an hour long with no commercials. It’s full of slow, long, quiet scenes. There’s so much time. It’s really amazing to watch. It helped inspire me while making YouTube videos to give more time when cutting things, even if it’s not optimized for algorithmic advancement.

https://en.wikipedia.org/wiki/Columbo

Re: 1937 film explains how a car differential works

#102

Post by nullc »

amelius wrote: post #10

Video says nothing about forces, however. With this explanation it seems that if one wheel gets slightly stuck, the other wheel gets all the force, causing a dangerous spinning.

> With this explanation it seems that if one wheel gets slightly stuck, the other wheel gets all the force, causing a dangerous spinning.

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.

Re: 1937 film explains how a car differential works

#104

Post by RichardCA »

ryukafalz wrote: post #92
tzs wrote: post #66

Earlier quoted context omitted.

Another great older film is "Similarities of Wave Behavior" [1] from Bell Labs. It was aimed at college students, and covers in a very clear way these topics: reflection of waves from free and clamped ends, superposition, standing waves and resonance, energy loss by impedance mismatching, and reduction of energy loss by quarter-wave and tapered-section transformers. [1] https://www.youtube.com/watch?v=DovunOxlY1k

Thank you so much for linking to this. I knew about many of the concepts in an abstract sense but this cemented them all together for me in an intuitive way.

This one's good too.

https://youtu.be/2OP0gp9v5XM

Re: 1937 film explains how a car differential works

#105

Post by Animats »

Yes, "Around the Corner", one of many Jam Handy films made for Chevrolet. They're all on the Internet Archive, where they can be seen without ads.[1]

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.

[1] https://archive.org/details/0141_Around_the_Corner_M00267_08...

Re: 1937 film explains how a car differential works

#107

Post by im3w1l »

neogodless wrote: post #27
elymar wrote: post #5

How would films like this be consumed in the 30’s? Would it be shown in theaters before a feature film?

Another comment pointed out that these were made by the Jam Handy Organization[0]. 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. [0] https://en.m.wikipedia.org/wiki/Jam_Handy

To me it looks like it's aimed at consumers, from the part at the end. It's as if the movie is intended to overcome worries "but is all this complexity really safe?" by showing how you can load the differential with running people without issue.

Re: 1937 film explains how a car differential works

#108

Post by divbzero »

tzs wrote: post #68

A good thing about that film is that after seeing it if I can't remember how a differential works I usually can remember the steps they took to get to how a differential works and then figure it out myself from there. 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.

Yes, this is the first time I’ve seen it explained starting with just two spokes. It motivates the eventual design of the differential and illustrates the mechanism far better than simply showing the full gears of the end product.

Re: 1937 film explains how a car differential works

#109

Post by baq »

leghifla wrote: post #57
amelius wrote: post #10

Video says nothing about forces, however. With this explanation it seems that if one wheel gets slightly stuck, the other wheel gets all the force, causing a dangerous spinning.

The differential (ignoring locking ones) applies the same force (approximately) to both wheels. If you remember your physics course about lever and force, see the video at 5:00, you can see that the lever is pushed by its center, hence both sides have the same length. So the same force is applied to both wheels. But the speed can be different. Hence, if one wheel is stuck, it still receives the same force as the othe…

> 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.

Re: 1937 film explains how a car differential works

#110

Post by Animats »

zackmorris wrote: post #94

Stumbled onto this explanation of how a Torsen differential works. I'm still trying to wrap my head around it, but it basically uses the one-way nature oh how a worm gear can turn a regular gear but not the other way around (due to the high gear ratio involved). 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 whe…

Oh, that's a clever design. The explanation, even with all those graphics, is poor. The idea is that one wheel can go slower than the speed it would go if the axle was rigid, but it can't go faster.

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.)

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