6 ms·

How Differential Steering Works (1937) [video]

145 points by Phithagoras 9y ago

csours 9y ago
Jam Handy is under-appreciated in my opinion [0]. I wonder how videos like this would be received today. 0. https://en.wikipedia.org/wiki/Jam_Handy https://en.wikipedia.org/wiki/Jam_Handy
- fhood 9y ago
  Pretty well given the attention they get whenever they do the rounds.
- jerf 9y ago
  Ten years ago I also would have wondered. Now I know; there are a lot of fine YouTube channels of a similar nature. It is certainly true that one must filter through a lot of garbage to find them, but they are there. Different topic, but here's just an example to get you started: https://www.youtube.com/watch?v=KfuARMCyTvg https://www.youtube.com/watch?v=KfuARMCyTvg
polote 9y ago
Same video over and over again https://hn.algolia.com/?query=differential%20gear&sort=byPopularity&prefix=false&page=0&dateRange=all&type=story https://hn.algolia.com/?query=differential%20gear&sort=byPop...
- csours 9y ago
  It's still interesting, and it's still a very good demonstration on how to explain a concept new to people. https://xkcd.com/1053/ https://xkcd.com/1053/ - Ten Thousand
- dsfyu404ed 9y ago
  It's like a rubber ball fired out of a cannon into a concrete box. It hits reddit, it hits HN, it hits FB it hits forums, wash, rinse, repeat.
- crispyambulance 9y ago
  Hey, its the first time I saw it. Nice stuff. Should be recycled.
  - thatswrong0 9y ago
    Wait you didn't see this when it was posted the first time 8 years ago? Then you clearly shouldn't get the chance to see it again.
eosrei 9y ago
The differential stops sliding of the rear wheels, Ackermann Steering Geometry stops sliding of the front turn wheels: https://en.wikipedia.org/wiki/Ackermann_steering_geometry https://en.wikipedia.org/wiki/Ackermann_steering_geometry Tires slide during sharp low speed turns on some vehicles due to lowering, lifts, tire changes and even production defects.
Animats 9y ago
It's part of a series for Chevrolet by Jam Handy. The Internet Archive has many more of them. A few: "Streamlines": https://archive.org/details/0142_Streamlines_M7960_09_08_44_00 https://archive.org/details/0142_Streamlines_M7960_09_08_44_... "Down the Gasoline Trail": https://archive.org/details/0542_Down_the_Gasoline_Trail_06_12_55_14 https://archive.org/details/0542_Down_the_Gasoline_Trail_06_... "What Stops Them": https://archive.org/details/0797_What_Stops_Them_M6850_06_27_31_00 https://archive.org/details/0797_What_Stops_Them_M6850_06_27... "No Ghosts": https://archive.org/details/0797_No_Ghosts_M7860_06_16_49_00 https://archive.org/details/0797_No_Ghosts_M7860_06_16_49_00 They were really trying to get across how a car works.
- dsfyu404ed 9y ago
  >how a car works Spinning levers, obviously...
- Stratoscope 9y ago
  Jam Handy was a national treasure. Another of my favorites from them is "Back of the Mike", a look at how radio dramas and their sound effects were produced: https://archive.org/details/Backofth1938 https://archive.org/details/Backofth1938
- jdnier 9y ago
  Wikipedia on Jam Handy (olympic swimmer as well as educational film maker): https://en.wikipedia.org/wiki/Jam_Handy https://en.wikipedia.org/wiki/Jam_Handy
dsfyu404ed 9y ago
Hopefully coming soon "Show HN: I wrote a bot to re-post highly up-voted videos if they haven't been re-posted for a certain time period."
dclowd9901 9y ago
I wish, in school, teachers would have taught us things like this, how gears are just concurrent levers, how cams introduce asynchronicity to an operation. This is stuff I only started learning from working on and learning about cars. I remember even when I was in school (a good time ago now), they were already killing off shop classes and the like. How sad that schools couldn't see what values classes like that have in critical problem solving.
- rjbwork 9y ago
  They could. The bureaucrats didn't, and moreover didn't care. I took a hands on physics class in high school (elective at a magnet school) called power and energy, in which we took apart, cleaned, and put back together an engine as our semester project, as well as learning all the math and physics behind the way in which they operated, how to calculate pretty much everything they did, etc. It was an enormously valuable class in learning, fairly early on in my proper STEM education, how a system could be made up of many moving parts and subsystems - an obvious boon to my work today in software.
- Pulcinella 9y ago
  Contact your local school board and state education agency. The schools I have taught at still have these classes (automobile mechanics, applied physics, etc) because parents fight for them. They are probably still able to legally be offered as courses (states usually don't remove entire course from state standards. The just go unupdated). School boards like to remove these courses because they are expensive (among other reasons) and on paper they look unpopular (hard safety caps mean a 15 person shop class looks unpopular compared to a 45 student overfilled history class). Schools and school boards are parts of the government most susceptible to public pressure. As a teacher, I want parents and community members to lobby their local schools. They don't listen to teachers but they buckle to parent complaints[1]. Please use your "complaining" powers for good. [1]Unfortunately, schools can have a bad habit of viewing all parent contact as "complaints" or "whining."
- rdtsc 9y ago
  I was in a Soviet school system (it was towards the end). And somehow we had a really fun shop class. We did stuff with electricity. Had a lathe, wood and metal. Remember making our own hammers. Learned to use a coping saw, a wood plane. School was remodeling so they let do demo work. Totally unsafe but loads of fun. Didn't learn about cars much though. We had so many things there that would be considered unsafe and dangerous these days for US kids here I'd imagine. Same thing with chemistry experiments. Though interestingly there more encouragement here to play contact sports like football which leads to concussions and injuries.
epx 9y ago
The nice thing is, a planetary gearset can do basically the same, and is the building block of automatic gearboxes and Prius power distribution between ICE, electric motogenerator and wheels.
- THE_PUN_STOPS 9y ago
  Relevant and amazing link: http://eahart.com/prius/psd/ http://eahart.com/prius/psd/ Did a project based around the Prius PSD in my Mechanical Dynamics and Vibrations class. Very cool, really opened my mind to the power of gears.
  - derekp7 9y ago
    Also, a youtube demonstration: https://www.youtube.com/watch?v=dLNDGUISTYM https://www.youtube.com/watch?v=dLNDGUISTYM (this is the Toyota eCVT), and a teardown of the Ford version: https://www.youtube.com/watch?v=hHU5xFOBcsU https://www.youtube.com/watch?v=hHU5xFOBcsU
amenghra 9y ago
You can buy a Lego differential gear to keep as a desk toy: https://www.amazon.com/LEGO-Technic-Differential-connectors-pieces/dp/B01DC74EA4 https://www.amazon.com/LEGO-Technic-Differential-connectors-...
- llsf 9y ago
  Omg, great! I did it with lego technic back in early 90's (without those new fancy gears) when the simplicity and power of the differential struck me :) The simplicity of the differential is just beautiful !
  - glandium 9y ago
    FWIW, there was a differential in the lego technic 8865 Test Car from 1988: http://www.technicopedia.com/8865.html http://www.technicopedia.com/8865.html I think this was the first model with a differential. At least, that's what introduced me to it.
    - amenghra 9y ago
      The 8865 was the first model with a differential. I wrote about being an adult fan of lego[1]. Over time, I purchased all 7 "super cars" that Lego manufactured. One of each car was sold every ~5 years and each one improved the previous generation's already amazing gears, steering, etc. Fun fact: who is the largest manufacturer of tires in the world? [1] https://www.facebook.com/notes/alok-menghrajani/afol-adult-fan-of-lego/10153486258678947 https://www.facebook.com/notes/alok-menghrajani/afol-adult-f...
      - glandium 9y ago
        You typoed, you meant the 8860 :) I actually saw it in a catalogue back in the day, but I hadn't realized it had a differential. It was also already old when I was into Lego technic in my teens, at which time the 8865 was new and shiny. Edit: It also seems both the 8860 and the 8865 were using the same parts for the differential.
Analemma_ 9y ago
The training video for old Navy mechanical fire control computers is a similar classic: https://www.youtube.com/watch?v=lr1uK24SND8 https://www.youtube.com/watch?v=lr1uK24SND8
- deleted 9y ago
  [deleted]
deleted 9y ago
[deleted]
gkya 9y ago
I like how informative these videos are. Some more of these and I'd feel I could make working toyish automobile. I wonder why we dont get this kind of videos for our time's tech. Maybe computers and especially software are too complex to represent like this?
leoc 9y ago
There's a flood of these mid-century instructional videos appearing the Web just over the past couple of years, right up to the present week. (I quite like the Jeff Quitney account on YT https://www.youtube.com/channel/UCM-kjdrQge9AACfB3MSRyrg https://www.youtube.com/channel/UCM-kjdrQge9AACfB3MSRyrg , a fairly nice firehose of videos in good quality, which even seems to have some that aren't on the IA.) One thing I've taken from watching them is that US accents seem to have changed a lot in the past few decades: you hear presenters with accents that afaict don't seem to exist anymore. Jam Handy's is one, but there are more dramatic examples.
- michaelbuckbee 9y ago
  The TransAtlantic Accent! -> https://www.youtube.com/watch?v=Gpv_IkO_ZBU https://www.youtube.com/watch?v=Gpv_IkO_ZBU
  - leoc 9y ago
    But listen to how he pronounces the 'o's (in particular) in "and it couldn't get a good enough grip on the road" and "both rear wheels to the engine" https://youtu.be/yYAw79386WI?t=164 https://youtu.be/yYAw79386WI?t=164 : Handy surely didn't learn that from an elocution class teaching RP-lite. Is it a trace of an Irish accent? a Scandinavian-American "Lutheran" accent?
    - janzer 9y ago
      To be clear, I'm pretty sure the narrator in these films is not Jam Handy. There is an interview with Mr. Handy himself here https://www.youtube.com/watch?v=AlDdE3Q5BWM https://www.youtube.com/watch?v=AlDdE3Q5BWM Possibly interesting sidenote, to this day a large number of the audio/visual and staging companies in the Detroit area can trace their lineage back to the Jam Handy Organization. Although I have a feeling we may now be a generation far enough removed that many of them may no longer know it.
- pavement 9y ago
  You're referring to the Transatlantic accent, which was a contrived manner of speaking: https://en.wikipedia.org/wiki/Mid-Atlantic_accent https://en.wikipedia.org/wiki/Mid-Atlantic_accent Another odd, acquired accent is the manner of speaking employed during air traffic communications, with elongated R sounds, as when pronouncing words like "roger" over poor signal quality. You can almost hear the air traffic control in mission control's transmission in 2001: A Space Odyssey, but only slightly: https://www.youtube.com/watch?v=QFSE4dUJYM8 https://www.youtube.com/watch?v=QFSE4dUJYM8
chb 9y ago
I like how they ghost ride the whip at the end of the video.

145 points by Phithagoras 9y ago

Jam Handy is under-appreciated in my opinion [0]. I wonder how videos like this would be received today. 0. https://en.wikipedia.org/wiki/Jam_Handy https://en.wikipedia.org/wiki/Jam_Handy

fhood 9y ago
Pretty well given the attention they get whenever they do the rounds.
jerf 9y ago
Ten years ago I also would have wondered. Now I know; there are a lot of fine YouTube channels of a similar nature. It is certainly true that one must filter through a lot of garbage to find them, but they are there. Different topic, but here's just an example to get you started: https://www.youtube.com/watch?v=KfuARMCyTvg https://www.youtube.com/watch?v=KfuARMCyTvg

polote 9y ago

Same video over and over again https://hn.algolia.com/?query=differential%20gear&sort=byPopularity&prefix=false&page=0&dateRange=all&type=story https://hn.algolia.com/?query=differential%20gear&sort=byPop...

csours 9y ago
It's still interesting, and it's still a very good demonstration on how to explain a concept new to people. https://xkcd.com/1053/ https://xkcd.com/1053/ - Ten Thousand
dsfyu404ed 9y ago
It's like a rubber ball fired out of a cannon into a concrete box. It hits reddit, it hits HN, it hits FB it hits forums, wash, rinse, repeat.
crispyambulance 9y ago
Hey, its the first time I saw it. Nice stuff. Should be recycled.
- thatswrong0 9y ago
  Wait you didn't see this when it was posted the first time 8 years ago? Then you clearly shouldn't get the chance to see it again.

eosrei 9y ago

The differential stops sliding of the rear wheels, Ackermann Steering Geometry stops sliding of the front turn wheels: https://en.wikipedia.org/wiki/Ackermann_steering_geometry https://en.wikipedia.org/wiki/Ackermann_steering_geometry Tires slide during sharp low speed turns on some vehicles due to lowering, lifts, tire changes and even production defects.

Animats 9y ago

It's part of a series for Chevrolet by Jam Handy. The Internet Archive has many more of them. A few: "Streamlines": https://archive.org/details/0142_Streamlines_M7960_09_08_44_00 https://archive.org/details/0142_Streamlines_M7960_09_08_44_... "Down the Gasoline Trail": https://archive.org/details/0542_Down_the_Gasoline_Trail_06_12_55_14 https://archive.org/details/0542_Down_the_Gasoline_Trail_06_... "What Stops Them": https://archive.org/details/0797_What_Stops_Them_M6850_06_27_31_00 https://archive.org/details/0797_What_Stops_Them_M6850_06_27... "No Ghosts": https://archive.org/details/0797_No_Ghosts_M7860_06_16_49_00 https://archive.org/details/0797_No_Ghosts_M7860_06_16_49_00 They were really trying to get across how a car works.

dsfyu404ed 9y ago
>how a car works Spinning levers, obviously...
Stratoscope 9y ago
Jam Handy was a national treasure. Another of my favorites from them is "Back of the Mike", a look at how radio dramas and their sound effects were produced: https://archive.org/details/Backofth1938 https://archive.org/details/Backofth1938
jdnier 9y ago
Wikipedia on Jam Handy (olympic swimmer as well as educational film maker): https://en.wikipedia.org/wiki/Jam_Handy https://en.wikipedia.org/wiki/Jam_Handy

dsfyu404ed 9y ago

Hopefully coming soon "Show HN: I wrote a bot to re-post highly up-voted videos if they haven't been re-posted for a certain time period."

dclowd9901 9y ago

I wish, in school, teachers would have taught us things like this, how gears are just concurrent levers, how cams introduce asynchronicity to an operation. This is stuff I only started learning from working on and learning about cars. I remember even when I was in school (a good time ago now), they were already killing off shop classes and the like. How sad that schools couldn't see what values classes like that have in critical problem solving.

rjbwork 9y ago
They could. The bureaucrats didn't, and moreover didn't care. I took a hands on physics class in high school (elective at a magnet school) called power and energy, in which we took apart, cleaned, and put back together an engine as our semester project, as well as learning all the math and physics behind the way in which they operated, how to calculate pretty much everything they did, etc. It was an enormously valuable class in learning, fairly early on in my proper STEM education, how a system could be made up of many moving parts and subsystems - an obvious boon to my work today in software.
Pulcinella 9y ago
Contact your local school board and state education agency. The schools I have taught at still have these classes (automobile mechanics, applied physics, etc) because parents fight for them. They are probably still able to legally be offered as courses (states usually don't remove entire course from state standards. The just go unupdated). School boards like to remove these courses because they are expensive (among other reasons) and on paper they look unpopular (hard safety caps mean a 15 person shop class looks unpopular compared to a 45 student overfilled history class). Schools and school boards are parts of the government most susceptible to public pressure. As a teacher, I want parents and community members to lobby their local schools. They don't listen to teachers but they buckle to parent complaints[1]. Please use your "complaining" powers for good. [1]Unfortunately, schools can have a bad habit of viewing all parent contact as "complaints" or "whining."
rdtsc 9y ago
I was in a Soviet school system (it was towards the end). And somehow we had a really fun shop class. We did stuff with electricity. Had a lathe, wood and metal. Remember making our own hammers. Learned to use a coping saw, a wood plane. School was remodeling so they let do demo work. Totally unsafe but loads of fun. Didn't learn about cars much though. We had so many things there that would be considered unsafe and dangerous these days for US kids here I'd imagine. Same thing with chemistry experiments. Though interestingly there more encouragement here to play contact sports like football which leads to concussions and injuries.

epx 9y ago

The nice thing is, a planetary gearset can do basically the same, and is the building block of automatic gearboxes and Prius power distribution between ICE, electric motogenerator and wheels.

THE_PUN_STOPS 9y ago
Relevant and amazing link: http://eahart.com/prius/psd/ http://eahart.com/prius/psd/ Did a project based around the Prius PSD in my Mechanical Dynamics and Vibrations class. Very cool, really opened my mind to the power of gears.
- derekp7 9y ago
  Also, a youtube demonstration: https://www.youtube.com/watch?v=dLNDGUISTYM https://www.youtube.com/watch?v=dLNDGUISTYM (this is the Toyota eCVT), and a teardown of the Ford version: https://www.youtube.com/watch?v=hHU5xFOBcsU https://www.youtube.com/watch?v=hHU5xFOBcsU

amenghra 9y ago

You can buy a Lego differential gear to keep as a desk toy: https://www.amazon.com/LEGO-Technic-Differential-connectors-pieces/dp/B01DC74EA4 https://www.amazon.com/LEGO-Technic-Differential-connectors-...

llsf 9y ago
Omg, great! I did it with lego technic back in early 90's (without those new fancy gears) when the simplicity and power of the differential struck me :) The simplicity of the differential is just beautiful !
- glandium 9y ago
  FWIW, there was a differential in the lego technic 8865 Test Car from 1988: http://www.technicopedia.com/8865.html http://www.technicopedia.com/8865.html I think this was the first model with a differential. At least, that's what introduced me to it.
  - amenghra 9y ago
    The 8865 was the first model with a differential. I wrote about being an adult fan of lego[1]. Over time, I purchased all 7 "super cars" that Lego manufactured. One of each car was sold every ~5 years and each one improved the previous generation's already amazing gears, steering, etc. Fun fact: who is the largest manufacturer of tires in the world? [1] https://www.facebook.com/notes/alok-menghrajani/afol-adult-fan-of-lego/10153486258678947 https://www.facebook.com/notes/alok-menghrajani/afol-adult-f...
    - glandium 9y ago
      You typoed, you meant the 8860 :) I actually saw it in a catalogue back in the day, but I hadn't realized it had a differential. It was also already old when I was into Lego technic in my teens, at which time the 8865 was new and shiny. Edit: It also seems both the 8860 and the 8865 were using the same parts for the differential.

Analemma_ 9y ago

The training video for old Navy mechanical fire control computers is a similar classic: https://www.youtube.com/watch?v=lr1uK24SND8 https://www.youtube.com/watch?v=lr1uK24SND8

deleted 9y ago
[deleted]

deleted 9y ago

[deleted]

gkya 9y ago

I like how informative these videos are. Some more of these and I'd feel I could make working toyish automobile. I wonder why we dont get this kind of videos for our time's tech. Maybe computers and especially software are too complex to represent like this?

leoc 9y ago

There's a flood of these mid-century instructional videos appearing the Web just over the past couple of years, right up to the present week. (I quite like the Jeff Quitney account on YT https://www.youtube.com/channel/UCM-kjdrQge9AACfB3MSRyrg https://www.youtube.com/channel/UCM-kjdrQge9AACfB3MSRyrg , a fairly nice firehose of videos in good quality, which even seems to have some that aren't on the IA.) One thing I've taken from watching them is that US accents seem to have changed a lot in the past few decades: you hear presenters with accents that afaict don't seem to exist anymore. Jam Handy's is one, but there are more dramatic examples.

michaelbuckbee 9y ago
The TransAtlantic Accent! -> https://www.youtube.com/watch?v=Gpv_IkO_ZBU https://www.youtube.com/watch?v=Gpv_IkO_ZBU
- leoc 9y ago
  But listen to how he pronounces the 'o's (in particular) in "and it couldn't get a good enough grip on the road" and "both rear wheels to the engine" https://youtu.be/yYAw79386WI?t=164 https://youtu.be/yYAw79386WI?t=164 : Handy surely didn't learn that from an elocution class teaching RP-lite. Is it a trace of an Irish accent? a Scandinavian-American "Lutheran" accent?
  - janzer 9y ago
    To be clear, I'm pretty sure the narrator in these films is not Jam Handy. There is an interview with Mr. Handy himself here https://www.youtube.com/watch?v=AlDdE3Q5BWM https://www.youtube.com/watch?v=AlDdE3Q5BWM Possibly interesting sidenote, to this day a large number of the audio/visual and staging companies in the Detroit area can trace their lineage back to the Jam Handy Organization. Although I have a feeling we may now be a generation far enough removed that many of them may no longer know it.
pavement 9y ago
You're referring to the Transatlantic accent, which was a contrived manner of speaking: https://en.wikipedia.org/wiki/Mid-Atlantic_accent https://en.wikipedia.org/wiki/Mid-Atlantic_accent Another odd, acquired accent is the manner of speaking employed during air traffic communications, with elongated R sounds, as when pronouncing words like "roger" over poor signal quality. You can almost hear the air traffic control in mission control's transmission in 2001: A Space Odyssey, but only slightly: https://www.youtube.com/watch?v=QFSE4dUJYM8 https://www.youtube.com/watch?v=QFSE4dUJYM8

chb 9y ago

I like how they ghost ride the whip at the end of the video.