Physics Philosophy 101

You like it, but something is wrong ? Maybe stop for some time. If you don't get what you want, then try other titles Dirt rally for rally, rF2 for awesome physics and dynamic track and night, AC is a bit dry - literally. Using ripped mods and lying to yourself that they are fine doesn't help to enjoy game either.

Driving online or/and modding livens things a lot

Maybe you should sleep at night, drive in the evenings

Your friends find it annoying ? You don't need those friends lol

 

MrDeap were you formally known as Arch around here ?

 

I don't really notice a weird oversteer behavior in AC.

It's not drifting because it is not losing 100% traction from the back tires, but the car definitely rotate due to the nature of the slip angle.

If you do proper research, you'll get an obvious answer... which is a definitive no.

Who is Arch?

 

@MrDeap You seem to think "traction" is some sort of an off/on switch....it's not. Even at ridiculously high slip angles tyres generate a lot of lateral forces....you post these "advanced" pictures but in the end are you sure you get it? At all?

Understeer only means the fronts tend to operate at a higher slip angle than the rears...it doesn't mean you lost "all traction"(lol what does that even mean?), it doesn't mean you're going straight either. Like others I have no idea what you were trying to say here but it's not making a lot of sense.

 

It's my fault. I asked and guys are trying to answer.

When ever I doubt AC I just try something else.

There are holes. No disrespect to Kunos. We are all going to experience, expect and come away with something different.

There has been a few times one of you guys have said something as a joke, serious, yell, and I go, ok, I hadn't thought of that? And driving makes more sense.

This is all really cool stuff but we still have to use our imagination to get submerged enough to have a good drive.

That's why everyone how tries the sim goes too fast and breaks too late they are not submerged enough. Just not taking it serious.

Is a sim even 50% of the real thing?

What ever that number is AC has the highest %. I think.

 

Arch was a guy who was working on Skyline physics, and maybe some other projects, I think he was qualified. Well at least for me, I haven't followed most of the discussions.

Pardon if my philosophy is wrong there. I think rear end in some particular understeer cases rotates a bit not due to nature of slip angle, but because of inertia of mass which is held by rear wheels. I think thats how you go fast around Monaco You use rear end inertia to bend car around those tight slow corners with barriers. I don't know what slip angle does VERY well, but I think it defines how much slide is too much, or still manageable.

@vegaguy 5555 HAHA, well nobody will ever know precisely the percentage, I think equation would be super complex lol

But AC has 0 simulation value in assetto_corsa.ini, and reality has no simulation value (saw that in PRC lol). So I guess AC is pretty much 100percent real thing.

 

I think I just had an 'ok' moment. Good answer.

 

If you lose all traction on all 4 tires you're aquaplaning. When you go to the limit of the slip angle it will enventally lose traction. The traction lost, this I don't know... I'm sure it's enough in a point it is very bad for the lap.

What I'm pointing out is mostly when the back end get not slip angle & you understeer. You kind of get than example below.

 

I think there were a lot of oil on the track. In Nordschleife video.

Lol just used "car bending" advice myself and eventually did 2seconds faster around 88Monaco circuit with new MP4/4 mod. It is a shame that there are no lap times registered in RSR app, makes you wonder if people doesn't use RSR app, or the car.

 

I still don't get it i'm afraid.

 

@chakko Me too :/

He is talking something about rear end behavior while understeering. He thinks car should just go straight out of the corner when understeering, and then shows us video where multiple cars goes off because of massive oil patch, plus calls it aquaplaning ? Hard to understand.

 

Even in the pretty gross understeer in the Nordschleife video the rears are still at 3-4 degrees slip and generating lateral forces. There is rotation all the time...all the cars heading into the wall were still rotating all the way into it.

These :


- The apex point change a bit because of the rotation. I suppose the target point is near the back tire on the wheelbase. It's a pivot point that slip.

- Well I do notice that often the slip angle have been dialed down greatly(less twitchy). The back wheel doesn't steer, but change direction while cornering, which make the car rotate. Again, because the back end rotate, the slip angle on the front tires is reduced, because it rotate, thus you feel the car rotate even when understeering. Obviously, no rotation while understeer... the car won't turn & go straight.

- When you understeer you lose all front traction & I suppose the rear lose the slip angle due to no more force lateral force available, thus end up going straight. When cornering efficiently, you kind of take a sort of small drift angle, meaning that the back end actually change direction due to lateral force while gripping.

Obviously while drifting the front tire also get lateral force & the contact patch change from it.


do not make ANY sense whatsoever.

 

This thread right now:

I kind-of start to understand what MrDeap is trying to say and it's not "wrong" just confusingly presented and without clear reference to this thread...

So just leaving it alone and moving on with life would be the most philosophical thing to do now

 

A lot of people seem to confuse "going too fast for the corner and thus unable to turn into it" with "understeer"... if you're going too fast and you steer sharper than your traction allows, the options are (1) front tires lose grip first and you slide off the track still pointing forward (2) rear tires lose grip first and you slide off the track in a fast spin, the only middle ground is (3) all 4 tires lose grip and you slide off in a slow spin.

 

This touches on something that i think confuses some people... As i see it: there is kinematic "understeer" - like Phil mentions, need of a higher slip angles to perform a turn, that does not include concept of maximum grip at all. And "racing" understeer (idk proper term) - something that driver complains about to his engineer when there is not enough grip on the front tyres. The issue is that both concepts, while using the same terms, operate on different parts of the slip angle - grip curve.

To visualize the difference:

Left side - kinematic, often found in educational materials (like the fist image posted by MrDeap on page1 here) - where the linear relation of grip and slip angle is used to determine slip angles of front wheels (never reaching any limit of grip). and
Right side - what racers actually mean when mentioning understeer - where steering angles does not matter really, only the difference between maximum lateral force on each axle.

I feel like this "duality"of the term "understeer" causes another layer of confusion when both slip angle graphs or diagrams and grip limits are used together (like MrDeap used earlier). To give an example of what i mean: it would be possible to have a car that is by kinematic/slip angle definition "oversteery" and still "understeer" on track.

 

I suppose it can be done on a oversteer setup, but can only happen during the entry phase. During exit(acceleration) the front have less contact patch, thus need to rely more on the back slip angle.

Kind of relate to the kind of understeer I suggest.


-------------------
An easier way that respond to the back tire slip angle


Rotation


Friction circle


I'm surprised for the low amount of view on those videos.

 

Unfortunately no. It can happen in steady conditions too.

For example of kinematic approach look at this video:

In this case a car with CoG moved forward is "understeery" because of how equations go.
Or similarly but in direct relation to slip angles it is discussed here: http://racingcardynamics.com/understeer-and-oversteer/

Nowhere in this two sources a limit of grip is used, nor is any influence of roll bars and spring stiffness that would dictate how is the balance at the limit during cornering and thus how would the car respond to extreme inputs. So we could very well end up with a car that can be classified as "understeery" by theoretical approach like in the links above, but oversteers on track (let's say we weld rear ARB or something like that).

My point is that earlier on page one you used slip angles and kinematic diagrams (maybe unknowingly) to explain the "on the limit of adhesion" behavior which don't really work well together as i'm trying to show in last two posts - and that's why i could not get my head around what you were writing.

 

I had much trouble understanding tyres and weight distribution and load.
Watching this video made me totally understand.



Στάλθηκε από το m2 note μου χρησιμοποιώντας Tapatalk

 

Whilst my technical knowledge of this kind of stuff is very limited, I sometimes think that excessive understeer is quite good for training someone to drive through corners correctly, rather than try and "haul" the car around it by brute force and ignorance (ie. turning the steering wheel much further than is required). It has helped me learn to trust that the (apparently) slower speed at which I am taking corners is actually the correct speed for that particular car (and settings). Does that make sense?

 

Yeah thats awesome lecture ! But are you sure that you totally understand things now ? Many times I thought that I understand things "totally" till realizing that I barely scratch the tip of the iceberg a lot of times

Could watch engineering explained channel whole day too.

Might even go back in past forum posts and read a thread about dampers, to strain my brain completely

@Cristopher Low It doesn't make much sense to me, because you said that excessive understeer is better than brute force and ignorance (ie. turning the steering wheel much further than is required)". Isn't it the same ? I thought that you are going to to say that for rookies understeer is better than oversteer. Part about speed is strange too.