NKP and RF2 - why is NKP superior in terms of raw car handling ?

For me, F3/2, F3.5, and Megane are all very good sim cars, and all provide plenty of info/FFB regarding what the cars doing....now, I certainly didn't have that opinion with some of the early builds, and atm, I think the FISI needs some lower speed attention, and at least for me, I find the Nissan GTR a PITA to control the rear.

I think people need to refer to which car and at what corner perhaps, as I can't relate to what James is saying wrt some cars, but can on others.

 

I'm not being arrogant and I don't think I'm an expert, that is the reason why I don't go mentioning ut all the time and giving out my name and all that stuff, but once in a while I have to mention it because too many people think they know how these things truly work because of onboards. Ill say it again in our games we feel 75% less feedback and the little feedback we do feel happens wayyyyyy later than in real life. Going by onvoards all your watching is steering movements correcting once you go past a certain grip threshold, most of the corrections you make in real life don't even get to the point where you can visually see it from an onboard cam that's how much more and how much earlier you feel everything in real life. Its possible to drive a very loose or tight car and make it look decently balanced by an onboard cam because you can't tell with an onboard cam what the driver is feeling and what the car is doing unless he really crosses the grip threshold to the point where he has to do some decent corrections, onboard cams only give the masses a general idea of what the drivers are doing.

*alright hiohaa now pick apart every line of my post and analyse every word I wrote, geez your like a lawyer

 

I am thinking I need to get NKP to see how the cars feel there hehe. I am no professional by any means, and I do find the cars with the basic setup in rF2 difficult to drive to near impossible at times. One example I can give is losing the backend coming out of a corner. In that situation, in the Nissan Z car I attempt a correction and end up spinning the car in the opposite direction with a snap spin. This to me doesn't seem realistic, but I put most of the blame on my lack of putting together a setup that is correct for the car and track. The rest goes to my lack of expertise in driving race cars in general.

I will say however that with a proper setup, the cars feel pretty much like I would expect them to be with my limited knowledge of real racing, it is all a matter of getting used to driving the specific car on the specific track and learning both properly.

BTW, for those that consider military simulators as tank sims, consider that all fighter pilots use flight simulators, and doing a proper flight simulator is a lot more difficult that doing a car simulation as the aircraft require 3 dimensions of travel and not just 2.

 

Exactly, +10.

I dont know how hihoaa (sorry if I misspelled) drives but honestly I dont believe he truly drives "on the limit as he says".

Everybody who ever read a serious article about physics of racing knows that to do a lap on the absolute limit means to use all of car grip under every braking, in every corner, in every acceleration on every straight, while maintaining absolutely perfect racing line, which isn't even the same for every car on the one circuit, and to have the shortest braking distance. Think about it and I think you will realize most of us were NEVER even close to true limit, not even in a sim let alone in real life. Even F1 drivers are rarely on this limit, more like 95-98% of it.

Saving huge slides is not the goal of racing driver, thats more like basics of every good driver. To be the fastest in a corner you need to be using 105-110% of tyre grip, depending on tyre (generally street cars have this number, and racing slicks more those 105%). When you do a very noticeable slide, its probably not the fastest way because you are above the limit, not on it.

 

I'm afraid I think it's the car/s in this case, though I normally drive the GTR, and it has an excellent front end and brakes, but the rear grip is wrong IMO.

 

What do you actually mean by that? I'm asking because naturally you can't go above 100% grip, because 100% is all there is. Are you referring to something specific and perhaps phrased it badly, or just exaggerating to make a point? Just want to understand the though behind this.

 

As a former engineer doing mechanical and fluidal finite element calculations I consider car simulation a highly complex problem: contact problems, high accelerations (the 3rd dimension is present and very nasty), aero effects near ground and a lot of turbulent air flow, 6 DoF too.

BTT, about NKP: I don't consider myself expert enough to judge about the right simulation, but NKP had flat spots you can feel and dirt building up on the tires, which I really miss in rF2. A good measure against cutters and brake smoke generators and that sort of realism I can see and feel.

 

I think the point he was getting at and the thing I was trying to draw attention to is that in real life you can be driving bad and yet the car is very stable.

So say you are over driving the car and skidding all over the place with the back end swinging out obviously your lap time will suffer but its there as an option and is part of the physics of a car that have an effect all the way up to when you are only in 0.01% of a slide and so can work with it.

In reality when the car is in one of these slides as a driver you are largely in control even at quite extreme slip angles ( obviously depends on the car and the setup ) and it should be a very gradual transition from near perfect corner maintaining grip to wasting speed by getting into a skid.

I think in general the cars in RF2 are quite unstable compared to the real world counterparts , and when skidding you have less ability to steer and control the car than you do in real life or NKP that's not to say you cannot race them you can , and when I race on-line I'm normally in the top 5 or so drivers on any given server.

But that lack of feel and depth takes away some aspects intrinsic to driving and can make competitive racing more clinical.

Granted the 1960s cars don't tend to suffer from this issue as they in general drive as if they are always in a slide and have such lurchy suspension and Wight that they are too unresponsive to shift the car within the grip profile of the tire ( I think grip profile would be correct term not sure? )

To be clear I'm not saying you cannot control the 1960s cars well on the contrary you can control them incredibly well because they are 100% predictable linear and communicative.

I'm also not saying you cannot skid the gripy cars like the megin or the FISI you can and you can recover them from quite extreme skids , its more that you cannot have precise control over the skid as you are in it , or do things like a powered low speed drift with a basic set-up of the car.

In NKP and real life even with a set-up for racing you can still do powered drifts although obviously allot harder than if you actually set a car up for drifting.

Some of you keep using the counter argument "You should not be drifting and power sliding around corners in a race " and that is correct but the piont is that aspect of the cars handling translates all the way up through the physics up to where you are barely in a skid and hence driving the car on the limit.

Other people have said "which car is it , all cars are different" That is also correct every car and every car around every corner is different , but this nature of how the cars grip and lose grip applies to all the grippy cars in RF2.

If I put it this way In RF2 I can very clearly define that the cars physics state has changed from griped in to skid it is very sudden change and its as if the tires are made out of some ridiculously hard compound that just gives out without any flex.

In NKP and reality it is near imposable to define the "exact" moment that transition happens its almost seamless ontop of the communication of the flex of the tire and the point at which you move into a slide.

I can feel and tell that i am at a slip angle or in a skid but its a very gradual transition from when the tire loses its bite. Ontp of that for a good proportion of slip angle I can control the car using steering , throttle , brake (exactly as you can with the 1960s cars) all the car characteristcs as the tires change in grip are infact very gradual , with no worry or sudden unpredictability ( other than track verables , wet patch , bumps , camber) the car is still smooth and when given the opertunity the tires are eager to return back to there state of normal grip


NKP still has a bite point and there is a give before you start to get into any slide but once any slip angle or slide happens its incredibly smooth and gradual.


If ISI can get this right in RF2 then it will blow my mind that + mods + tracks + league races , drying line weather and everything else.

I don't understand why it seems allot of people don't seem to notice this Its ether a case of

1) I am totally wrong and making it all up ( I'd love to be proven right or wrong )

2) grippy cars in RF2 are accentually the same as real world cars when it comes to these aspects of sliding and again I am wrong

3) some people don't have the same feel for driving / balancing the grip in the same way , they might still be fast drivers but they just learn the defined limits of the track. That Might also explain why so many drivers in real life struggle to drive in the wet (on-top of the obvious lack of grip )

4) Grippy cars in NKP are in fact less like real cars than the grippy cars in RF2 ( would seem strange to me from my personal opinion and then that the general consensus from people I know in leagues seem to think NKP is more realistic in the way cars grip. I think i racing is allso closer to NKP in the way the cars perchise and lose grip than it is to RF2 and again most people i belive would regard iracings tire model to be of a higher stranded to that of RF1 and RF2.

5) Instead of doing work , I am chatting on a forum about car tire simulation.

Again Yes RF2 in beta Yes RF2 tire model not finished

Maybe when ISI finish the tire model it will be more like and better than NKP ? !!!!!!!!!!!!

 

So false it isn't even funny. Let a physicist explain it. Starting at about the 3:30 mark, extending to around 18 minutes. For starters cars can and do move in the exact same three dimensions.

The physics governing flight are incredibly simple to calculate compared to the physics involved in racing. Like Brian Beckmann points out we could do flight simulation with all the basics in there in 1982 and even before that, really simulating cars didn't happen until much later, before that it was just kinematics. Airplane simulations have been pretty much perfect from a physics standpoint since the 90s, what has happened after that has been relatively small tweaking compared to how much the simulation of cars has developed even in the last few years. Like Beckmann says, cars have a much bigger target audience, if it really was simpler to do cars properly they would've done them before flight sims.

Physicists still are not 100% sure how tyres work, they don't work according to the simple friction physics we're taught in schools. Figuring out slipcurves and contact patch behavior is hard, let alone actually making them interact with the ground in a realistic manner. Factor in that the tyre and the rim are to a large extent separate entities, moving and behaving very differently even though they're connected. Now factor in that all of this is linked to the by a huge variety of different complex (some simpler, many not by a long shot) linkages, affecting how the rim, the tyre and the contact patch all behave, if they're in contact at all. Now multiply that by four wheels, which can all move more (or less, depending on the linkages) independently from each other in relation to the body of the car and the ground below, and then factor in that the body itself can move around the same three axes as the plane, how all of that affects the tyres. And then factor in that the ground isn't a consistent flat plane, but full of bumps, kerbs, inclinations, elevations, everything. And then factor in that modern racing cars actually generate the same kind of lift and ground force effects as planes do, just that the wings are upside down.

And even after all that it's just a box on wheels, there's a lot more to do still.

 

jubuttib
I know it sounds irrational, By 100% grip I mean the last point where no slip occurs, where tyre is still firmly on the ground, no understeer or oversteer. Or in other words, where the rotational speed of the tyre corresponds to the acceleration. But you are the fastest when you break this point, where some slip occurs.
Mathematically it would be better to call those 105-110% the real 100%, but in that case the point where the tyre stops being firmly on the ground would become 90.9-95%. Even if actually incorrect, I like to imagine in my head in such way as to call the "break point" 100%, and some slip call over 100%.

 

Technically slip occurs all the time, tyres work like that. Every time you accelerate, brake or turn there is some slip. 100% of grip is achieved at the optimum slip. So yeah, you meant what I thought you meant, you just phrased it in a weird way. Carry on! =)

 

In general i think the FFB is often better in RF2 More direct in many ways , I think playing rf2 you are getting more out of expensive FFB wheels than you do with NKP.

But then the underlying way in which the cars gain and lose grip and maintain stability is better to me in NKP than RF2 , and NKP's FFB is more than enough to describe what the car is doing to the player .

 

In the sense that it produces (negative) lift it is similar but that's where the similarity ends.

For example, the moments caused by the control surfaces (ailerons, elevators, flaps, v-stab, etc.) on the CoG at a certain AoA is many times more complicated than any changes in moments you'd experience in a car.

 

No, they're not. Watch the video I linked to in post #89.

 

Agree with jubuttib, I also heard racing physics is even more complicated than flight.
Its 2012 but how tyres work is still a huge mystery. Even real world tyre manufacturers improve their tyres hugely by trial and error, theres no reliable predictive methods.

Edit: There is a tyre formula which is literally called magic http://www.racer.nl/reference/pacejka.htm which gives relatively accurate results but unlike all the physics stuff that is taught at schools it is NOT theoretically provable. It just fits some numbers.