Differentials in land vehicles

[Ra-Ra-Rasputin]

Before i get the urge to start testing them and their possible benefits, i should probably ask: Has anyone actually tested if differential system provide any notable difference in the performance of cars (and possibly tanks, although in most cases tanks have one engine per track) ?

[CallidusVir]

wdym when you say Differentials?

[CallidusVir]

And I love your name lol!

[Chrius]

I'm not sure, but I think the same amount of power is always applied to every wheel on the vehicle regardless of traction.

[GERUNIMO]

Unfortunately I don't believe it is possible in the traditional sense other then to cheat alittle bit.
By the way, like CallidusBoy, I love the Boney M reference!

[Goobs]

You could theoretically assign a gearbox or a clutch to activate a different ratio based on steering angle?
But it would be very bulky and janky

[Ra-Ra-Rasputin]

You can make a (rather crude) differential using a clutch for each side of the driving wheels, you just need electronics linked to turning to handle all that. I already made an anti-slip system for one of my cars, so this shouldn't be too difficult!

I was just wondering about it since there is a significant power loss in land vehicles on turn whether or not a differential would mitigate it.


Also for those that don't know, a differential is a set of gears that allows the driving wheels in a car to rotate at different speeds on the left and right side. Without a differential the left and right wheel would rotate at the same speed and on a curve either the inside wheel would have to turn too much, or the outside wheel would have to skid.

[ElfBossHogg]

From the perspective of a differential how did you intend to determine the required speed difference for the turn? I'm wondering if this may be something where the angular speed sensor may be effective. Since we can't effectively measure wheel slip you could use the angular speed sensor to determine the turn rate and apply a small dampener proportional to that value to the inside turning wheels.

[Ra-Ra-Rasputin]

Originally posted by ElfBossHogg:

From the perspective of a differential how did you intend to determine the required speed difference for the turn? I'm wondering if this may be something where the angular speed sensor may be effective. Since we can't effectively measure wheel slip you could use the angular speed sensor to determine the turn rate and apply a small dampener proportional to that value to the inside turning wheels.

I'd start off with a system that simply shifts clutch pressure based on steering input on a curve that simulates the actual turning radius on a car, using nothing but magic numbers and no sensor feedback. The clutch pressure would be much lower on the inside wheel driving more power to the outer side.

Second draft would feature sensor input, i'd probably locate the sensor mostly toward the front side of the car (to allow a bit of processing time) and then tone down the input as needed.

Third i'd probably sneak in my anti-slip system and try to work it in and see how it performs. This might be relatively easy as it works by adjusting the engine throttle (which could just be done by adjusting clutch pressure instead)

Instead of clutch pressure, i could actually just use the variable brakes. That's an idea worth exploring probably, as per-wheel brakes would allow tighter turning too!


I measure wheel slip the same way some ESR systems do, by watching the positive delta of the engine RPS. If it's determined to be too high (magic numbers) it throttles down aggressively by enforcing a low-throttle setting instead of reading an input until the delta is acceptable.

I also have a prototype of it that is more aggressive and responsive by firing an electric motor in reverse to force the RPS down in short stuttering bursts. The downside of this is the power drain of a larger alternator, but it works reasonably well

[Soldner42]

Actually i have some sort of Differential applied to my SDKFZ251 Halftrack alike Vehicle. As in the Original the Engine actually Powers the Tracks, and if i take turns i use wheels but also take the Power of the Clutch away in which Direction i want. for example.. If i take a turn to the right my right track isnt powered anymore resulting in more Power in the Left Power and resulting in the Turn Radius to be way smaller as if i would power both Tracks,but also giving the left Track more Power to actually do the Turn without Problems with the Engines torgue or low RPM, same goes for Tracked only Vehicles. But doing this on a Wheeled Vehicle? Its Possible.. but im not sure if it makes any sense at all since the result would probably just be a minor change from a normal Vehicle.

[Ra-Ra-Rasputin]

Originally posted by Soldner42:

Actually i have some sort of Differential applied to my SDKFZ251 Halftrack alike Vehicle. As in the Original the Engine actually Powers the Tracks, and if i take turns i use wheels but also take the Power of the Clutch away in which Direction i want. for example.. If i take a turn to the right my right track isnt powered anymore resulting in more Power in the Left Power and resulting in the Turn Radius to be way smaller as if i would power both Tracks,but also giving the left Track more Power to actually do the Turn without Problems with the Engines torgue or low RPM, same goes for Tracked only Vehicles. But doing this on a Wheeled Vehicle? Its Possible.. but im not sure if it makes any sense at all since the result would probably just be a minor change from a normal Vehicle.

I absolutely love half-tracks because they're absolutely insane, and ever since i found out they exist i hardly can still believe they're real!

It'd be really easy to do in an electric motor driven vehicle because then like in a tracked vehicle you could drive those wheels individually, but a differential is a little bit more passive than that. It's the weird arrangement of cogs found in all cars' driving wheels.

The rather silly part is that the absolute best video to describe what the hell the thing does and why it exists is in a video from the 30's. I recommend skipping the first 2 minutes of the video, it's just fancy driving. https://www.youtube.com/watch?v=yYAw79386WI

[Soldner42]

Originally posted by Ra-Ra-Rasputin:

Originally posted by Soldner42:

Actually i have some sort of Differential applied to my SDKFZ251 Halftrack alike Vehicle. As in the Original the Engine actually Powers the Tracks, and if i take turns i use wheels but also take the Power of the Clutch away in which Direction i want. for example.. If i take a turn to the right my right track isnt powered anymore resulting in more Power in the Left Power and resulting in the Turn Radius to be way smaller as if i would power both Tracks,but also giving the left Track more Power to actually do the Turn without Problems with the Engines torgue or low RPM, same goes for Tracked only Vehicles. But doing this on a Wheeled Vehicle? Its Possible.. but im not sure if it makes any sense at all since the result would probably just be a minor change from a normal Vehicle.

I absolutely love half-tracks because they're absolutely insane, and ever since i found out they exist i hardly can still believe they're real!

It'd be really easy to do in an electric motor driven vehicle because then like in a tracked vehicle you could drive those wheels individually, but a differential is a little bit more passive than that. It's the weird arrangement of cogs found in all cars' driving wheels.

The rather silly part is that the absolute best video to describe what the hell the thing does and why it exists is in a video from the 30's. I recommend skipping the first 2 minutes of the video, it's just fancy driving. https://www.youtube.com/watch?v=yYAw79386WI

Why skip the first 2 Minutes? Thats a badass Performance these buds do there. But i do get what a Differential is. And i just wanted to say that it is Possible, but like others said, you either need to cheat a bit with LUA Microcontrollers or by creating huge Mechanical machines that probably just fit in Ships. So at the moment its probably the best way to use multiple clutches and disengage some of them when Turning creating a similar effect to a Differential. But just a similar one and just when Turning. hmpf.

[Ra-Ra-Rasputin]

Originally posted by Soldner42:

Why skip the first 2 Minutes? Thats a badass Performance these buds do there. But i do get what a Differential is. And i just wanted to say that it is Possible, but like others said, you either need to cheat a bit with LUA Microcontrollers or by creating huge Mechanical machines that probably just fit in Ships. So at the moment its probably the best way to use multiple clutches and disengage some of them when Turning creating a similar effect to a Differential. But just a similar one and just when Turning. hmpf.

Why skip it? Well good sir, today is the age of instant gratification, and fancy driving and marketing speech has no place in it, none at all!

I will probably start properly tinkering with this nonsense tomorrow. I have a rather extreme performance car that can take turns at ridiculous speeds by more or less being squeezed against the ground with an absurd amount of force (in one example, about 7 times the mass of the car), but a lot of simply designed cars do have trouble in the game, so i was wondering if differentials might be a trick to give people the edge.

It'd definitely be a hell of a lot simpler than trying to talk them through making an ESR system or an active flap and per-wheel brake operated rollcage and gradual downforce system, or modifying the spiderweb of my rather insanely extensive microcontrollers! My cars are basically extremely unstable wheeled missiles only kept in check by electronics, and about as likely to explode in a real situation.

But yes, you're definitely correct in that it's not really technically a differential, just a weird analog

[Soldner42]

Originally posted by Ra-Ra-Rasputin:

Originally posted by Soldner42:

Why skip the first 2 Minutes? Thats a badass Performance these buds do there. But i do get what a Differential is. And i just wanted to say that it is Possible, but like others said, you either need to cheat a bit with LUA Microcontrollers or by creating huge Mechanical machines that probably just fit in Ships. So at the moment its probably the best way to use multiple clutches and disengage some of them when Turning creating a similar effect to a Differential. But just a similar one and just when Turning. hmpf.

Why skip it? Well good sir, today is the age of instant gratification, and fancy driving and marketing speech has no place in it, none at all!

I will probably start properly tinkering with this nonsense tomorrow. I have a rather extreme performance car that can take turns at ridiculous speeds by more or less being squeezed against the ground with an absurd amount of force, but a lot of simply designed cars do have trouble in the game, so i was wondering if differentials might be a trick to give people the edge.

It'd definitely be a hell of a lot simpler than trying to talk them through making an ESR system or an active flap-operated rollcage and gradual downforce system, or modifying the spiderweb of my rather insanely extensive microcontrollers!

Well, i wish you Fun doing so.

Here is my SDKFZ251 Prototype..

https://steamcommunity.com/sharedfiles/filedetails/?id=1955021577

im neither Finished with its Design nor its Technical aspects. Its just very Basic to test if its even able to drive at all or be usefull. And well, its not usefull at all in Stormworks.. so i stopped working at this thing very long ago.

But if you want you can Download it to watch how i solved the "Differential". To make things fast i downloaded a Microcontroller for Tanks from the Workshop and just adjusted it a bit. Turning works quite well, just dont change Gears at all, because i didnt adjusted the Gearboxes so far and the Engine isnt adjusted as well, this Vehicle behaves really bad, but yeah, just an Prototype.
Also, most Dials and signs are German.. for obvious reasons.. but that shouldnt be that much of a Problem.

[Ra-Ra-Rasputin]

So i got around to testing it finally. Procrastination really is one female dog.

Results are mixed, if partially promising. A differential that solely works on adjusting the clutch via magic numbers to have a maximum of 50% difference ( 0.75 clutch pressure vs. 1 ) at full wheel tilt does allow taking tighter turns at higher speed and seems to work even better than actual sensors. Higher differences can cause very sharp turns but they're not easily controlled, and often cause you to lose control. I'm sure there's electronics and/or aerodynamics that can work against it.

The downside is that unless you have some sort of traction slip control, it has the potential to making the outside wheels skid. That being said, unless you're taking the turn at full throttle anyway, this shouldn't really be an issue in most cases.

Also, instead of using brakes, i tested a system where the wheels are hooked up to generators via a pair of gearboxes and the brakes disengage the engine while enabling the generator clutch. I'm getting rather impressive amounts of electricity generation thanks to the wheel and car torque, and this means an alternator isn't sucking up power from the engine.