Inertia unit of measurement

Is the engine's inertia measured in kg*m^2?

 

Yes, standard metric unit.

There is inertia calculator in my spreadsheet but it gives only flywheel inertia, which typically is used in games, but you can try to figure out how much all rest of rotational masses add to that, like alternators etc. Calculate alternator rotational mass, estimate diameter of such mass and calculate inertia for that, then add that to flywheel inertia. Calculating crank etc. one by one and adding up is method to get total inertia to somewhat accuracy, to best of my knowledge.

I updated this slide as it had error previously, but this is how it is, to best of my knowledge:

 

Okay, thanks. Also, which spreadsheet has it, the turbo one? I can't seem to find it, but I may just be blind.

 

This turbo version https://www.beamng.com/threads/turbo-torque-curve-helper-alpha-testers-needed.52512/

If you don't have Inertia sheet next to Export sheet, then you might have old version of that, I think I did some update at some point after making first ODS version.

 

I know this has nothing to do with Beam's Inertia, but it turns out the Source engine uses kg*in^2. How weird...

 

Different physics engines use different units I guess. rF2 and BeamNG uses SI units, at least most of the time, there can be few oddities that makes you pull your hair out of course

Anyway kg*in^2 and kg*m^2 only difference is that you use inch or meters in formula, it is fairly easy to jump from one to another if needed. Also it seems to be that most of the time I find data with imperial measurements, no matter the vehicle brand, so need to do conversions constantly. Then in scientific literature SI seems to be system used mostly, so it is easier to use that when making physics engine of course.

Technically speaking, I think imperial system was supposed to be replaced by SI a long time a go already? Well, they still have trouble with units even in NASA, so...

 

Well it would cost an estimated 66 billion dollars to switch the US from Imperial to metric, and even then I'd bet most people would still want to use imperial units. If it makes you feel any better there is one metric road-sign in the entirety of the USA, it's one of the roads that crosses into Canada

 

This is how I attempt to come up with inertia, if it is too small, then I just add up until revving is nice though, but for that engine frictions has to be set. This is VW air cooled flat-4, but I feel anything below 0.06 being too little, but I think there was fan too that I need to add as well as crank. I don't really know if this is correct way, but I don't know anything better. What I know is that flywheel is usually engine inertia in several sims.

 

Hmmm, that indeed must be taken account to.

Luckily there are no power steering, AC compressor, timing belt tensioners, water pumps etc. to worry about as amount of needed research would explode.


Of course it could be tuned by revving the engine and be done with that, but what fun that would be, way too easy

 

Thanks for the help