Does sliding the car get punished in Rfactor2

Discussion in 'General Discussion' started by David O'Reilly, Jan 15, 2021.

  1. Havner

    Havner Registered

    Joined:
    Jul 14, 2020
    Messages:
    359
    Likes Received:
    356
    Layman question. Layman testing. To all those that can analyze motec and data please have a look at this.
    Situation that is very easily reproducible.

    Before I describe I have wheel rotation set 1:1 (900 in wheel config, max rotation in rF2 config file set to 900, software limit true, range set to car). Basically my wheel and in car wheel are 1:1 with soft lock at the end of the range.

    Take Alpine GT4 car (complete default setup) and Ibarra (regular).

    My assumption is that when I'm in a high speed turn and I start to overturn the wheel there is a point when FFB start to become lighter. From what I learned this is a point where the understeer/sleep angle passes a point where there is no more traction generated. I.e. there is no point in turning the wheel more past that point. Of course I might be wrong here, please correct if I am.

    Now, get the car out of pits and hit 100% throttle. Throughout the whole test (both cases) keep the throttle flat.

    Case 1: Do the first turn flat (that is easy) and try to do the second turn flat. I turn the wheel to the point I feel it becomes lighter. This is around 80 degrees wheel turn. At 90 degrees I clearly feel I'm seriously sleeping my front wheels. Anyway, I end up in a wall.

    Case 2: Do the first turn flat, but upon entering the second turn turn the wheel to max, 270 degrees right, 19 degrees front wheels lock. You can take the turn flat. You might have to modify a line a bit, but this turn can be taken flat with such high steering angle. I'm not saying this is the fastest way to take this turn, it's not. Fastest is somewhere in between with some lift probably. But still it's pretty fast.

    My question is:
    Should the tires bite that well in such high steering angle?

    Or maybe it's not that high, only I'm fooled by the FFB? I honestly don't know. Since the situation is so easily reproducible, motec data can be generated by someone more knowledgeable than I am.

    I'm honestly curious your opinions.
     
    Last edited: Jan 23, 2021
    Nieubermesch likes this.
  2. Nieubermesch

    Nieubermesch Registered

    Joined:
    May 18, 2019
    Messages:
    792
    Likes Received:
    403
    I think you misunderstood. By understeery I didn't mean wrong, even quite the contrary, as my response was compared to some 397 Cars that have grip the more they turn when the car is already understeering.
     
    Slip_Angel and David O'Reilly like this.
  3. Nieubermesch

    Nieubermesch Registered

    Joined:
    May 18, 2019
    Messages:
    792
    Likes Received:
    403
    This, and yes, I want mostly to know for sure this is actual possible or not possible behavior, and if it is, how much or not it is under the limits of that behavior, because simulated doesn't mean correctly simulated 100%...
     
  4. Havner

    Havner Registered

    Joined:
    Jul 14, 2020
    Messages:
    359
    Likes Received:
    356
    No one?

    @mantasisg? @Yzangard? @Remco Majoor? @Bruno Gil?

    I would honestly like to hear what you think about that.
     
  5. Remco Majoor

    Remco Majoor Registered

    Joined:
    Apr 22, 2014
    Messages:
    995
    Likes Received:
    1,068
    Sorry, I didn't see that post.

    Since I genuinely do not know if it should act like that, I can give you a motec file and the video of the Alpine GT4 race of that motec file. The biting of the front end I definitely understand what you mean. I remember a video about Alonso driving like that in F1. Excessive steering to then let the front end grab at the right time which turns the car. I have this in my video in the hairpin for example. I turn in, steering goes light, then it grabs and I straighten the steering more to control the turn.

    video:


    Motec file
     
    Nieubermesch likes this.
  6. Havner

    Havner Registered

    Joined:
    Jul 14, 2020
    Messages:
    359
    Likes Received:
    356
    Thanks for the reply, unfortunately motec data is not useful for me as I'm not proficient in reading this. Hence my layman question and testing. Hopefully someone will though.

    Anyway, from what you say, you basically drive the same way in that video? And that is my question. Is that correct? You wouldn't be able to drive Alpine like that in ACC.
     
  7. Remco Majoor

    Remco Majoor Registered

    Joined:
    Apr 22, 2014
    Messages:
    995
    Likes Received:
    1,068
    upload_2021-1-24_16-39-36.png

    This is one of the moments the front end grabs. It happens after I fully lift off, which means most pressure is on the front tires have the most pressure on them, which is shown here:

    upload_2021-1-24_16-45-41.png

    To be fair, it kind of makes sense and doesnt feel like is wrong in this case
     
    Nieubermesch likes this.
  8. Nieubermesch

    Nieubermesch Registered

    Joined:
    May 18, 2019
    Messages:
    792
    Likes Received:
    403
    I've attached the video of Alonso from Driver 61(?) to my post. Think that is pertinent to show how a car regains grip during understeer, providing understeer can slow the car down and apllying throttle will help rotate when front tires are understeering.
     
    Remco Majoor likes this.
  9. Havner

    Havner Registered

    Joined:
    Jul 14, 2020
    Messages:
    359
    Likes Received:
    356
    Please try the case I described then. Because it seems there is some excessive grip generated when the wheels are on high slip angle and the steering is light. And I don't lift. I take the corner flat.
     
    Nieubermesch likes this.
  10. Remco Majoor

    Remco Majoor Registered

    Joined:
    Apr 22, 2014
    Messages:
    995
    Likes Received:
    1,068
    I'll take a look next week if I can find the time
     
    Havner likes this.
  11. Yzangard

    Yzangard Registered

    Joined:
    Dec 6, 2018
    Messages:
    351
    Likes Received:
    173
    Nope, you're wrong, this is not the case.
     
  12. Yzangard

    Yzangard Registered

    Joined:
    Dec 6, 2018
    Messages:
    351
    Likes Received:
    173
  13. Yzangard

    Yzangard Registered

    Joined:
    Dec 6, 2018
    Messages:
    351
    Likes Received:
    173
    It is a video from Driver61 explaining this strange steering technique. Point was that by doing this, you actually slow down the car, like a lot. This is surely what is happening in the test presented. Check car speed.
     
    Nieubermesch and Remco Majoor like this.
  14. Havner

    Havner Registered

    Joined:
    Jul 14, 2020
    Messages:
    359
    Likes Received:
    356
    This is a very descriptive explanation. Thank you, I learned a lot!

    That post was made yesterday, I'm not rushing anyone. I'm asking.
     
    Nieubermesch likes this.
  15. Yzangard

    Yzangard Registered

    Joined:
    Dec 6, 2018
    Messages:
    351
    Likes Received:
    173
    What explanation do you need? The moment when the steering wheel becomes lighter is not the moment when there is no more friction, it is actually the moment when the lever arm between the point of application of the lateral force generated and the center of the stressed wheel (so the front left wheel when turning right and vice versa) starts to decrease (in fact it is not the center of the wheel but more exactly the projection of the axis of rotation of the steering on the horizontal plane of contact of the wheel...yeah, not necessarily clearer said like that, let's just say "the center of the wheel" on this plane), so when the slip angle becomes important enough for this lever arm to decrease .

    Here of course I imagine that it is not clear at all, especially since the explanation is so summarized that it becomes unreadable...so here is a video in which it is explained :




    EDIT : this video is from Aristotelis Vasilakos who is the lead dev in charge of physics on ACC, this guy spent A LOT of time with GT3 teams and their engineers to understand perfectly how this works. He also spent a lot of time with experts from Pirelli for that matter. He is very interesting and very informative, his channel is a gold mine.
     
    Last edited: Jan 24, 2021
    Bruno Gil, Nieubermesch and Havner like this.
  16. Yzangard

    Yzangard Registered

    Joined:
    Dec 6, 2018
    Messages:
    351
    Likes Received:
    173
    There are so many posts dealing with the same thing...he he :)
     

Share This Page