Physic discussion thread

I'm willing to bet the F309 also has a locked diff 95% of the time. It just makes a car like that feel so much more unresponsive when compared to the Formula Trainer for example. I love the Trainer.

However I think that there will forever be a different feel in the FFB between AMS1 and AMS2. And I actually prefer the latter.

 

Yeah I agree on your point that it's a bit tricky to hone other aspects of the physics before the LSD is sorted out as it's such a commanding thing in the end.

 

I wasn't able to add a picture when editing so sorry for the double post.

F309 diff is definitely looking quite locked based on rear tire speeds around Goiania Short. I put the playhead on the only point where it was a bit open, quite late into T1 (hairpin in the short layout). Tire speeds at that point are visible in the top right corner. Otherwise they are practically identical, .1 difference max.

There is that one point where the inside tire spun faster under acceleration, but it's irrelevant as behavior off throttle is the issue here.

 

Testing on slower tracks the F390 has relevant inner wheel spin on standard setup in acceleration.

Coasting on the other side seems to be too tight even trying to fully open (0 preload, 89 ramp and 2 clutches).

 

I will drive any car that's consistent and not boring to drive. F309 is not boring even though it has this flaw. Far from it. Still, I would love to lift and trail brake into the apex with that mind bending rotation you expect from an open wheeler. But it is what it is for now and fun anyway. Just not as fun .

Formula Trainer does give me the experience that I like most. Just drove it for an hour today and it's just .

Was this to or from Renato? And is it confirming or invalidating the data, cause I'm not sure

I'm using Second Monitor by the way. Tire speed data can be found inside the Braking tab. I am a bit concerned that it's just faulty data / recording, but it's at least a reason for someone to double check with other software.

I used another app earlier that I found from Race Department which had similar looking data, but the update rate was so low that I couldn't trust it.

 

Yes, I did the same test.
F309 at Ortona in both AMS1 and 2.
Massive difference in turn-in and rotation on throttle in general.

Never spun out in AMS2, swapping ends often in AMS1.

 

Game difference.

 

Yeah that one. And oops, there's my problem. I have it at 9 I think. Second Monitor doesn't seem to care (I get data each 0.03s or so) though.

It needs to be said that I also tried with 0Nm preload, 2 clutches and 89/89 ramps in AMS2. The graph I posted used the default setup though. The rear just will not open before you're turning a lot and at slow speed. Another sim's telemetry showed difference between rear tire speeds all the time in a limited slip differential car. It just limits how far apart and how easily they are allowed to separate based on the setup.

Also as far as anecdotal evidence goes. If you drive the McLaren F1 GT1 at say 50km/h and carefully start turning the wheel more and more, you can notice when the differential snaps open and it starts turning a lot faster. Another way to describe the sensation is that there's a step in the otherwise linear steering response at slow speeds. I usually feel this at Spa T1 and can see it in telemetry as the rear tire speed difference going from 0 to ~3 rad/s in an instant.

 

Yep and you don't have any difference in T1 . Stiff...

Btw. I meant to say that I tried with the default and also with those numbers I mentioned that should provide a very loose feel if the differential responded correctly.

 

Crimson mentioned this kind of thing above - lift off oversteer - most road cars we drive on a daily basis are designed to UNDERsteer, especially when there is torque added in a kinda 'no surprises' kind of way.

So the f-reiza's are the most neutral 'well behaved' cars in terms of avoiding this problem - is this what people are saying? Because thats my impressions that they get close to the actual design intention, they maintain more of what one would expect. Maybe the Ultima track car too which has improved out of sight but I was not paying attention.

This reiza-made cars and some others yes is what I base my generally great impressions about the title upon - as they feel free and easy/slick in turns. I have been driving them mostly recently and the new cars, gt1s which are steady anyway.

There's turn in, corner, and exit, and the f-reiza's (and others of course) feel the most unshackled from this problem. So too gt3's.

This can be such a problem for adjusting driving (corner correction or corner-'hacking it') that if you go to ACC you need to acclimatize again.

While I drive with all aids off, it could be the system under the hood relies on some of these things to get it by.

Its no secret that Rfactor2 'flubs' a few things here and there and its drivetrain model was not particularly sophisticated.

Is this a case of having a sophisticated drivetrain model, etc?

I,e I am saying most people would probably never pick up on that. I always wondered why 1 cars would not turn on a dime and 2 were not stable at high speed as much, like they were lumps, in some cases and if you had someone pushing the car from the side, like the car needed an extra force on it. Last patch smoothed some things over and some cars genuinely gave a brilliant feel, but yeah this kind of thing you see it on youtube as well - a lot of those people probably can't put their finger on the trouble, even if they vaguely know something is there thats up.