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Physics improvements to BF1
(89 posts, started )
It was just a suggestion, i don't know how difficult it would be to make advances to the aero.

Also the rear wing of an F1 car gives a lot more downforce than the front wing normally, so in a slide there would tend to be less rear than front grip. (going by the loss of downforce when yaw occurs)

"petrichor" I not really sure that the large side surface area at the rear of the car would siginificantly straighten out the car in a real slide, otherwise F1 drivers would be able to drift F1 cars or correct slides with ease. It may help a little though.
Quote from axus :. And AFAIK X-Plane already has a CFD model so it can't be that heavy...

Uh, hell no.

X-Plane uses blade element theory. That might be appropriate for car wings, but car wings are in a realm of aerodynamics simply not seen in airplanes, so the model would probably have to be rather impure to be "realistic". At low angles of attack with single element wings theory is very accurate. Modern multi-element car wings operating at the verge of stall are not going to be accurately aerodynamically modeled by any reasonable theory AFAIK.

CFD=not going to happen. Calculation for a single moment with a single set of conditions would take a typical PC minutes to hours, depending on the complexity and amount of iteration. Not only that, CFD over a "low poly model" is far more worthless than table lookups or things like blade element theory.

As to suggestions that the advertising endplates are going to give the car longitudinal stability, consider that any vertical surface forward of the CG does the opposite. The moments are small and the areas fairly small. On the other hand, taking a wing that is on the verge of stalling and yawing it even a couple degrees (like, less than five) away from the flow will dramatically effect its performance. Anyone that has ever kicked a rudder pedal in a Cessna thats about to stall knows this.
Reading this thread and thinking over somoe of the comments again I can't help but think that some people want the cake and too eat it too.

I mean, maybe LFS is ALOT more like real life than anyone suspects. You can't expect any car, even a F1 car to corner like it's attached to rails at greater and greater speeds. There will be a limit at some point. But it's the nature of cars and tracks that nothing will ever be perfect. They may be trying with the new F1 tracks to give them Snooker table surfaces and huge run off areas but even those tracks still have imperfections. Ripples, bumps, huge **** off holes, barriers, change in tarmac, off cambers, blind corners, bad setups, bad driving; The list is endless. All these things conspire to make driving, let alone racing driving, difficulty at the best of times. Driving a car is an insanly complicated thing, that even the most experianced get wrong sometimes.

So when people critizise the handling of the BF1, or any car in LFS for that matter, they need to take into account so many factors before berating the cars physics and aero. Take that double apex hairpin in Kyoto GP. Maybe it's difficult to control a car through there because it's difficult to control a car throught there. The problem is as simple as that, it's up to you to come up with a fix. Test and test some more. Prehaps lay off the critism untill you can drive and setup the car properly.

In regards to the comparision of Flight sim (Xplane was it?) aero and the aero needed for something like LFS, they are very different things. A car has so many things to deal with than just 'air'. Air behaves differently at ground level than it does 'up there' espeacially when you add in some serious F1 speed. You also have ground effect, lateral movements, rapid changes in direction, vertical movements, rapid decceleration and raped acceleration and basic mechanical grip.

Anyway with this new patch, although not perfect, it's still such an improvement and the theory behind everything so evident that how anyone can seriously critisize at this moment in time is beyond me.
That one came across pretty fan-boy ish mate. Finding ways to convince yourself / others that lfs is real, instead of looking at it objectively. LFS is a partially completed simulation - every physics update is a great leap forward. To assume that anyone commenting at all negatively / constructively lacks all feeling for vehicle dynamics, but then when the next patch comes out somehow the hordes saying how much better it feels is valid, seems pretty backwards to me
Sorry to bring this up again. Earlier in this thread i heard that real F1 cars lose considerable downforce at high speeds with tiny amounts of yaw (when the car starts to slide), and that LFS did not yet simulate this, and you actually had uniform downforce based on speed, but not which direction that you were facing.
Someone else, claimed that LFS DOES actually model this loss of downforce. Can anyone clear this up? And if it does, how large is the downforce drop off ..... etc
iirc the downforce is full at zero yaw and zero at 90 degrees yaw, and the change is approximately linear, and applies the same to all cars with downforce.
I am just gessing here, but surely the change must be almost almost exponential? i.e half downforce levels at say 5 - 10 degrees?
Possibly even more agressive than that, but yes, it should be in that region.
Also I don't know if the 8° optimal slip that we have on all LFS tyres are that realistic.
Ive just watched a replay of a lap where i was purposely flicking the car into slides, with the forces view on, an didn't really notice any loss of downforce until i span the car fully.

How many other people out there think that this is a realism problem which should be fixed? ... Devs..?
at what speed?
140-150 mph (220 - 240 km/h) or so
Quote from DaveWS :Ive just watched a replay of a lap where i was purposely flicking the car into slides, with the forces view on, an didn't really notice any loss of downforce until i span the car fully.

How many other people out there think that this is a realism problem which should be fixed? ... Devs..?

Interesting experiment, I'll have to try that. I won't say I will, because I did that with Shotglass regarding flatspots or something and STILL haven't got round to it.
No idea if that can be of any use, but I think the main differences between a real F1 and the BF1 are that in LFS some things about the differentials are not implemented (I'm sure Scawen want to do them) and the suspension doesn't have a 3rd spring, which I'm sure Scawen wants to have too.
I was watching the Turkish Grand Prix today, and one thing that i noticed while the cars were on the parade lap was the way they were warming up the front tyres. They would be driving at slow speeds and then turn the wheel to full lock, causing the car to understeer ahead and heat up the fronts.

I thought that i would try out this technique on LFS in the BF1. However when i tried it out the car didn't understeer at all, in fact the car was turning far too much, and even sometimes oversteering, not what i had observed on the TV.

I guess that this is a tyre physics issue, so i carried out some more "tests":

This first test is on the skidpad, where i have driven to the outer ring, and at the limits of the cars lateral grip, proven by the green arrows on forces view (f key). I have then turned into the turn with FULL steering lock, expecting the car to understeer wide and take a wider path (as on the TV). Instead the car began to oversteer and take an ever tightening line!

The second test is on the dragstrip. I have driven to the limiter in 4th for a constant speed, and given my best attempt at "threshold" braking. I have then repeated the test with fully locked wheels, which gave a shorter braking distance! (marginally). This test was with the RACE_S setup but no downforce.

The third test is on the dragstrip but accelerating with NO tc. I set a time of 9.5 seconds. I then tried again with tc set to 5%, and set a time of 9.24 seconds. I am certain that if this test was carried out in real life the results would be several seconds out, not 0.26 seconds out.

The forth test is my attempt at a parade lap in the BF1. A total disaster.

Unless otherwise stated the tests have all been with the standard RACE_S setup.

Some tests may have been crude and inaccurate, but still give a conclusion.

I recommend you view the tests in the forces view.

Here is a link to a typical parade lap, where you can see the technique that the drivers are using to warm the tyres: http://www.youtube.com/watch?v=1XFWJIDzQJo
Attached files
Skid pad corning test.spr - 6.6 KB - 242 views
Drag run NO tc.spr - 3.8 KB - 238 views
Drag run tc at 5%.spr - 2.7 KB - 217 views
F1 style parade lap attempt.spr - 6.4 KB - 239 views
They have the advantage of a) being better drivers than us b) being in the car and c) not having to make do with crappy force feedback and tyre sounds for feedback.

If your car was oversteering doing it then maybe you weren't doing it right? Maybe the F1 drivers aren't just 'weaving the wheel about', but are doing so in direct relation to what the car needs to promote understeer. Of course, LFS's physics aren't going to be 100% (that is impossible).

As for the braking, who is to say your threshold braking is any good. They say the last thing a driver learns how to do well is braking. Try (using Shift-U) braking from 100mph in any car, using the gears and brakes, using the brakes only, and locking the wheels (don't do this bit in real life). When you stop put a marker by your front wheel, then repeat. Do it about 30 times and see how consistent you are.

Tip: Use a different colour cone for each type of test so you can see at a glance how well you did in each. I'd suspect that all these braking tests are let down by poor threshold braking.
Quote from tristancliffe :If your car was oversteering doing it then maybe you weren't doing it right? Maybe the F1 drivers aren't just 'weaving the wheel about', but are doing so in direct relation to what the car needs to promote understeer. Of course, LFS's physics aren't going to be 100% (that is impossible).

As for the braking, who is to say your threshold braking is any good. They say the last thing a driver learns how to do well is braking. Try (using Shift-U) braking from 100mph in any car, using the gears and brakes, using the brakes only, and locking the wheels (don't do this bit in real life). When you stop put a marker by your front wheel, then repeat. Do it about 30 times and see how consistent you are.

Tip: Use a different colour cone for each type of test so you can see at a glance how well you did in each. I'd suspect that all these braking tests are let down by poor threshold braking.

I have thought about all of these things, but i did have 30 odd attempts at getting the braking right (no i was not consistant, but never managed to beat locked wheels), and all wheels were green in forces view on my best attempt...

I have some experience in Karting, and if you lock the wheels, you will not stop until you see a barrier. Why have ABS? because locked wheels do not stop quickly.

Any real car understeers in real life with full lock compared to the correct amount of lock required for the turn.

Just look at the replay of the skidpad test, then please make another comment.
I haven't watched the replays.

Why have ABS? Because it enables you to turn. In fact I'd go so far to say that with road ABS the stopping distance would be shorter with locked tyres than the ABS stopping distance. But you'd just drive into the accident rather than drive around it safely. That is the major benefit of ABS.

In LFS I can routinely get understeer from steering to much. I do it a lot on outlaps in qually. But I don't drive the BF1 much, as I'm not either talented enough, or just because only about 10 people are in LFS, so the racing tends to be awful. And when I do drive it I'm more concerned about everything else than warming up the tyres like real life drivers.

Don't get me wrong - I'm not saying you are wrong in your analysis, just that any old person can't necessarily do in a sim what talented racing drivers can do in a car, no matter how realistic the sim.
Sometimes when I turn very fast the wheel to the left and right, the BF1 does lose a bit the control but very often I manage to get it back in to control.
I never drove a F1 car but what I see on TV it does not look like that when somebody is losing the control of the car at 300 km/h that he will get it back on track

I think there is some improvement to make
Acyually Tristan, a well caliberated ABS will definitely stop FASTER than non-ABS if the driven surface was suited to the ABS settings. A great example is the Lotus Exige's ABS. It's designed for thereshold braking and only really activates on panic applications. It's also well known that Kinetic firction of a tire can be about 30% less than rolling friction.

The ultimate stop is generated only when the tires are slipping a finite amount. That's why an over-active ABS would easily increase braking distances, especially for someone who has no idea how to threshold brake. An extremly skilled trail-braker would or well tuned ABS would generate the best stops.

However, I do agree that the BF1 could use better physics. In fact, I don't drive the downforce cars much because of their incomplete aero physics. Can't believe the aero has NO ptch sensitivity. Maybe Scawen somehow programmed the ULTIMATE active suspension system for all the downforce cars....

The biggest aero issues are definitely in the GTR class. Can't believe 3 massively different body styles have identical Aero! No wonder the XR GTR and FXR are suffering unfairly, since their aero packages are horribly mismateched to their mass distributions.

Another point is the fact that F-1 cars have a 3rd spring/damper setup that connects the spring/damper stes of both sides at the rear suspension. This gives 2 ENORMOUS advantages:

1. Stiff on vertical compression. Reduces pitch sensitivity and squat under aero load. Additional damper also better controls heave motion

2. Forces the inside wheel more to the ground whilst cornering, improving traction.

My point is, unless both aero AND F-1 suspension simulations are completely worked out, don't expect near perfect physics. For best realism, I recommend the non-downforce cars for now.
Read my post again, and you'll see I said road car ABS. Whilst the Exige is a road car, it's primarily track orientated - not a comparison. Besides, who wants a track day car with ABS???

Sometimes you speak sense James, and other times you read what you want to read and make up the bits in between

Can't believe the aero has no pitch sensitivity? No ther sim has yet either, but LFS is a work in progress. You always seem to forget that. Maybe Scawen just hasn't got around to improving the aero model completely yet?

And now we come back to the balancing issues, which you seem incapable of writing a post without blathering on about... You've made the point in more appropriate threads, why not let it lie until Scawen has time/inclination to do something about it.
Look there's no point in argueing. I made this thread, so we could find out areas of LFS physics which could be improved in the future. tristancliffe, it seems to me that all you do is defend LFS. Look i believe that LFS is one of, if not the best sim out there at present. But it still needs work. Why was this sub-forum made? So people could pick out areas for improvement. Thats why i started this thread. You can't expect LFS to be improved unless people post (constructive) criticism.
That's what I've been trying to do since I've got here (useful critism). And some still think I'm uttering crap... Hah.

Oh, well calibrated ABS is a boon for track racing, especially when racing gets long and consistancy under driver fatigue REALLY counts. Last time I checked though, the ABS stopping distances tend to consistantly BETTER than non-ABS on TARMAC. However, ABS DOES increase braking distnces if you're on a low traction off-road surface. That's why Mitsubishi Pajeros come with Multi-Mode ABS.

And yes, my chief reasons for getting the S2 license are:

1. Fundamentally good physics.
2. Constant improvements.

Which again explains why I tend to point out flaws that I find too obvious.
we had a fairly extended discussion of abs pretty recently in this thread here if interested
http://www.lfsforum.net/showthread.php?t=9929&page=2

continually pointing out the same flaws, that have been pointed out over and over before you arrived, does get a little repetitive

Physics improvements to BF1
(89 posts, started )
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