5 ms·

Solution from 1927 https://m.youtube.com/watch?v=QilY00dCof8 https://m.youtube.com/watch?v=QilY00dCof8 This was even 90 degrees

jacquesm 4y ago
Nice find, I never knew that such a thing was done in that way. You really don't want to think about what would happen if that mechanism ever triggered while driving :) Also, I wonder how they kept the alignment properly, that is a pretty small tolerance affair unless you want to go through a new set every 1000 km or so.
permo-w 4y ago
both wheels turn inwards, which means that one of them must have to change direction of rotation. that sounds like a remarkably difficult mechanical problem to solve reliably
- elihu 4y ago
  I don't think those are drive wheels in front, it looks like they just spin freely. In back you can see a regular axle with a differential, so it's apparently rear-wheel drive. I'm not sure how they get the car to rotate, though... there's probably either some mechanically interesting trick to it, or some clever camera trickery going on.
  - permo-w 4y ago
    ah yes you're right. perhaps one front wheel is powered somehow? is that mechanically feasible with the technology of the day?
    - elihu 4y ago
      I suppose an easy way to do it is to have a little drive wheel sticking out about where the license plate is, and as the front wheels turn inward, one of them makes contact with the drive wheel (like the capstan or pinch roller in a reel-to-reel tape machine). But we don't see anything like that in the video. I think if this is a real thing and not some kind of rigged demo, there's probably something weird about the rear differential or rear drive wheels. Maybe it has an alternate mode where you can't go forward, but the wheels spin in opposite directions when you apply engine torque? I'm not sure what would be the easiest way to do that. Maybe there are two drive shafts, one for forward and one for spinning in place? When the latter of the two is engaged, the "normal" drive shaft is locked in place by a brake forcing the wheels to rotate in equal and opposite directions (due to the differential) and the other drive shaft powers one of the rear wheels somehow.
elihu 4y ago
I wonder how it's propelled? Those don't look like drive wheels in front, and one wouldn't think that engaging the rear wheels would cause it to rotate, since the applied force seems like it would be exactly perpendicular to the front wheels. Maybe they have a mechanism that engages the brakes on one of the rear wheels but not the other, causing it to turn? I'm not sure if that would work, and from the last part of the video it looks like one rear wheel is turning forward and the other is turning in reverse. Alternatively, maybe they have some sort of weird mechanism that locks the drive shaft going to the rear-axle differential (forcing the wheels to turn opposite to each other) and then applies motive force to one of the wheels through an alternate mechanism, like a second drive shaft. Or maybe it's just some kind of trickery, like they're just pulling the car with a rope that you can't see, or the clips of it accelerating in a circle is a time-reversed clip of it slowing down after being given a big push.
aasasd 4y ago
Funny how there's a camera cut each time the car goes from driving to rotating the wheels, or the opposite.

jacquesm 4y ago

Nice find, I never knew that such a thing was done in that way. You really don't want to think about what would happen if that mechanism ever triggered while driving :) Also, I wonder how they kept the alignment properly, that is a pretty small tolerance affair unless you want to go through a new set every 1000 km or so.

permo-w 4y ago

both wheels turn inwards, which means that one of them must have to change direction of rotation. that sounds like a remarkably difficult mechanical problem to solve reliably

elihu 4y ago
I don't think those are drive wheels in front, it looks like they just spin freely. In back you can see a regular axle with a differential, so it's apparently rear-wheel drive. I'm not sure how they get the car to rotate, though... there's probably either some mechanically interesting trick to it, or some clever camera trickery going on.
- permo-w 4y ago
  ah yes you're right. perhaps one front wheel is powered somehow? is that mechanically feasible with the technology of the day?
  - elihu 4y ago
    I suppose an easy way to do it is to have a little drive wheel sticking out about where the license plate is, and as the front wheels turn inward, one of them makes contact with the drive wheel (like the capstan or pinch roller in a reel-to-reel tape machine). But we don't see anything like that in the video. I think if this is a real thing and not some kind of rigged demo, there's probably something weird about the rear differential or rear drive wheels. Maybe it has an alternate mode where you can't go forward, but the wheels spin in opposite directions when you apply engine torque? I'm not sure what would be the easiest way to do that. Maybe there are two drive shafts, one for forward and one for spinning in place? When the latter of the two is engaged, the "normal" drive shaft is locked in place by a brake forcing the wheels to rotate in equal and opposite directions (due to the differential) and the other drive shaft powers one of the rear wheels somehow.

elihu 4y ago

I wonder how it's propelled? Those don't look like drive wheels in front, and one wouldn't think that engaging the rear wheels would cause it to rotate, since the applied force seems like it would be exactly perpendicular to the front wheels. Maybe they have a mechanism that engages the brakes on one of the rear wheels but not the other, causing it to turn? I'm not sure if that would work, and from the last part of the video it looks like one rear wheel is turning forward and the other is turning in reverse. Alternatively, maybe they have some sort of weird mechanism that locks the drive shaft going to the rear-axle differential (forcing the wheels to turn opposite to each other) and then applies motive force to one of the wheels through an alternate mechanism, like a second drive shaft. Or maybe it's just some kind of trickery, like they're just pulling the car with a rope that you can't see, or the clips of it accelerating in a circle is a time-reversed clip of it slowing down after being given a big push.

aasasd 4y ago

Funny how there's a camera cut each time the car goes from driving to rotating the wheels, or the opposite.