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#21 [url]

Dec 23 11 9:25 PM

gonzas wrote:


wouldn't be better to change the name to "tonsofgripracing" instead of nogripracing ?



Well, as an official person of nogripracing I can tell that we generally do love this mod and it's physics.

I haven't driven a vintage race car, but I've driven some vintage cars of '60s and '70s era, and can tell that the physics is very believable. For me personally, it is big improvement since version 1; as I spoke earlier I've always felt the lack of sharpness in the cars like Cobra. Never driven the real thing, but i always expected it to be more agile and sharp - and my expectations finally have been proven in v1.9

And I do not have problems with grip, also want to mention that making stiff suspension setup and a stiffen the roll bar improves the feel of a car, it gives more info and feedback.

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#22 [url]

Dec 23 11 9:37 PM

fanlebowski wrote:
Niels_at_home wrote:
Looking at just the TBC file it seems we used weird numbers. However, you always must see the bigger picture.



The 40 degrees slip angle is only at loads that do not occur. In practise for the 1965 cars slip reaches its maximum grip between 12 and 24 degrees.



that's why i did say "start" and "finish" ;)

So in practise the peak slip angle is about the same as on the bigger cars.


maybe you don't need to set the peak depending a load we'll never have on track. i mean a slip angle moove on few degrees at the beginning and "blow up" after, generally. put a large range make something too linear i think.

on wich load is setting the graph you put ?


The load is 4448 Newton which is 1000lbs; pretty high load for most of these cars.

The LatPeak was chosen because of something technical; the shape how LatPeak changes with increasing load is a half Sine wave. So if LatPeak=(0 , 1 , 1000) the slip changes between 0 and 1 in a sine wave shape

That means the slip angle changes the fastest when loads are near 500. I chose the final load to be at least 2x the occuring load, so as you load the tire more within the occuring load range, the change of peak slip angle gets larger and larger, replicating the bias ply data that is floating around.

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#23 [url]

Dec 23 11 9:54 PM

Is it just me or the Ferrari 330 P (all of them) handles too 'approximately'. It feels like a 70-s engine in a 50-s chassis. I mean, even the Cobra Daytona feels more sorted, let alone Ford GT. But P3s and P4s are just happy to pop their noses up and prance away in a random direction while accelerating in 3rd gear in a straight line There's a choice of tires between Dunlop and Firestone, but both feel like Haribo. Or maybe it's the suspension?
The nose always floats about too much. That pretty much negates the huge power advantage of 330 P vs. Porsche 906 anywhere but at Le Mans.

Is that supposed to be so? How come Ford GT is so much more precise and predictable?

edit: typos

There's nothing wrong with the car, except it's on fire...

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#24 [url]

Dec 23 11 10:01 PM

Pandamasque wrote:


Is that supposed to be so? How come Ford GT is so much more precise and predictable?

Who won the Le Mans four times in a row in the late 60s?

Also, some p3/p4's have a spare wheel on the back, targa florio p4 for example. It increases the disbalance a little more.

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#26 [url]

Dec 23 11 10:23 PM

Thanks for the explanations Niels, they clarify several things

I think that two different things are coming together here in order to cause a surprising feel on the drivers:

1) We were after all used to HX 1.0 for a long time, and when a change comes everything seems weird until you adapt to it

2) Sometimes getting more realistic or closer to how the real thing works, is confusing in simulators with a relatively reduced ability to transmit sensations and reduced output. Most probably, a real driver with real slip angles working under his butt feels it all very differently, and while replicating a physical procedure might be possible, replicating a subjective and kinestatic feel is way more complicated.

My prediction is that with time and working around the setups, people will learn to live and enjoy this as much as 1.0

Thanks for your dedicated work that you gave for free to all of us, we are indebt with you all, guys. !!

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#27 [url]

Dec 23 11 10:41 PM

I haven't tested all cars, most of them felt really good but the Pantera LM72 (haven't tried the others yet) and the Porsche 911 2.4 have a big issue in high speed turns, they just let go without warning, and no way to catch them back, or to fix that in the setup. Try them at Zandvoort 67 and you'll see what I mean.

image

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#28 [url]

Dec 24 11 10:57 AM

Guillaume Siebert wrote:
I haven't tested all cars, most of them felt really good but the Pantera LM72 (haven't tried the others yet) and the Porsche 911 2.4 have a big issue in high speed turns, they just let go without warning, and no way to catch them back, or to fix that in the setup. Try them at Zandvoort 67 and you'll see what I mean.


Do you mean that those cars have nasty lift off oversteer? You know ... when you realize that you are too fast (understeer) then lift off for a moment in the middle of the corner?
If that so I belive the only cure is left foot braking (just touch) without lift off. OK you can ease little bit on throttle but just forget throttle lift off.
On modern cars (and vintage race legal because of allowed modifications) you can deal with it by adjusting engine braking and that will not comletely change nasty part of character to those cars but make life little bit easier ...

btw I think that grip level is tiny bit too low but I can live with that as long it behaves right - like old car.

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#29 [url]

Dec 24 11 1:52 PM

I have to agree with Ed. In the 60s & 70s I owned a number of 'tuned' cars, Minis, Cortinas, Jaguars, a Porsche & a BMW. The Cortina's included a Mk1 Lotus, a Mk1 which I fitted a far to fragile, (and too powerful for road use) virtually full race engine. I had a 4.2 E-Type coupe & a couple of XJ6s (also 4.2 litres, but automatics), I also had a couple of v8 Rovers which aren't really relevant & I drove one of the American Motors AMXs that competed in the London to Sidney marathon in 1968 (only from Heathrow to the factory in West London, but it was fully race prepared at the time) . I feel that the Historix cars exhibit a very similar 'feeling' to how I remember they were in real life. the obvious thing is that the real thing would kill you, something that does not temper one's driving on a computer. The Cortina was absolutely terrifying over 100mph, the BMW although only a 320 would swap ends under the slightest provocation. The E-Type had a distinct tendency to wander and follow any ridges on the road & you just had to pray when applying the brakes hard as it was difficult to predict what the resulting reaction would be as each individual brake could apply slightly different pressure in slowing it's wheel, so it could cause the car to snake, veer to one side, lock a front wheel & under-steer or lock a back wheel and over-steer, this was a characteristic that applied to most cars of the period, as braking effort relied purely on hydraulics with no electronic intervention.
So if you take the 911 in the mod & drive it like it could actually hurt you, use engine braking by changing down as you approach a corner(not bang down 3 gears as you reach the corner, like you can in a modern car), plan ahead & use the brakes as if there was an eggshell on the pedal & don't (above all else) lift off more than 10% once committed to a corner. Also be aware that bumps and crest in the road will unsettle the car much more & need to be accommodated for by knowing where they are & adjusting speed & gear before you hit them.

Sorry for such a long post but I think that the physics feel pretty good to me & I think there is a lot more satisfaction/enjoyment to be gained by mastering these cars. I'll shut up now.

image

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#30 [url]

Dec 24 11 2:44 PM

I agree with the post above... Being a bit of an older dude, I had that luck to drive some of the early 70's cars, more or less tuned for racing and believe me when you are driving them on the edge they are pretty unpredictable and shaky, and you have to put all your skills and guts in fighting with the steering wheel, to put that car wher you want it... Most of the cars in this mod are simply FANTASTIC! I think that the creators took the most out of our good ole rF to produce this vintage mod as realistic as possible within the rF limits... Although there is a few cars that need some psychics/tires tweak, like I said most of them feels, sounds, and look great... Being a sworn Alfista I just love the feel of GTAm, the way it slides in corners, the controlled oversteers and drifts, and overall feel of the car is IMO just great, in all time I have perfect feedback from the car, I always know when I'm close to the limit. Being said that, I'll just say one more thing - Job well done HistorX Mod Team! Keep on the good work, hope to see you in rF2.

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#31 [url]

Dec 24 11 3:17 PM

Do you mean that those cars have nasty lift off oversteer? You know ... when you realize that you are too fast (understeer) then lift off for a moment in the middle of the corner?


I don't know what he means, but I also experience that oversteer at high speed turns, not just when lifting but also simply when forcing the car a bit into the turn. At high speeds aero can influence a lot in the car behaviour, and looking at the files I see that they have downforce in the front, but lift on the rear. IIRC in HGT 1 it was just downforce or nothing at all. But in any case, things will get sure nasty at high speeds with that built-in lift in the rear. Wether -despite being realistic- this was overdone in the mod or not, I leave to the experts. ??

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#32 [url]

Dec 24 11 4:11 PM

Aerodynamics is a combination of downforce or lift, and drag that apply on a few points on the car. Drag pushes the car down on its rear tires because it applies above the ground. Rear wings could have 'lift' values but overall the car might have rear downforce.

The RSR 3.0 for example has 3kg downforce at the front and 12.5kg downforce at the rear axle at 200km/h

Some cars have some lift, but you are talking the same ish amount, just a few kg.. Put that into perspective; the cars are usually about 1000kg, so with 10kg downforce at the rear, that is 1% of the car weight. Downforce / lift is a very small part of the handling of the cars.

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#33 [url]

Dec 24 11 4:56 PM

Hitman_M3 wrote:
Do you mean that those cars have nasty lift off oversteer? You know ... when you realize that you are too fast (understeer) then lift off for a moment in the middle of the corner?


I don't know what he means, but I also experience that oversteer at high speed turns, not just when lifting but also simply when forcing the car a bit into the turn. At high speeds aero can influence a lot in the car behaviour, and looking at the files I see that they have downforce in the front, but lift on the rear. IIRC in HGT 1 it was just downforce or nothing at all. But in any case, things will get sure nasty at high speeds with that built-in lift in the rear. Wether -despite being realistic- this was overdone in the mod or not, I leave to the experts. ??


I did few laps with those cars on Zandvoort 67 and, to me it only happens when I liftoff ... or hit the bump.
I don`t think that it is aero related "problem" regardless easy fix for that kind of behavior by todays standards is to "give more wing" - modern approach for an old car problem. IMO it`s more suspensions problem (dynamic weight distribution related) ... as you see I`m not trying to find reason by opening any mod file because I wouldn`t understand any of data (maybe I would - don`t know) - just what might be reason for that kind of problem with real car.

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#34 [url]

Dec 24 11 7:15 PM

Aerodynamics is a combination of downforce or lift, and drag that apply on a few points on the car. Drag pushes the car down on its rear tires because it applies above the ground. Rear wings could have 'lift' values but overall the car might have rear downforce.

The RSR 3.0 for example has 3kg downforce at the front and 12.5kg downforce at the rear axle at 200km/h

Some cars have some lift, but you are talking the same ish amount, just a few kg.. Put that into perspective; the cars are usually about 1000kg, so with 10kg downforce at the rear, that is 1% of the car weight. Downforce / lift is a very small part of the handling of the cars.


Now I put the values better into perspective, I didn't know that rfactor actually calculated the effect of aero drag as transmitted to the ground via tires and previously thought it was only used in 2 dimensions. Impressive ...

Thus I thought before that the rear wing lift implemented was actually meant to represent car body lift with more accurancy than what is normally available with the [BODY] section. Using only that body section in the hdv one can't put downforce in one point (f.e. front of the body due to hood and windscreen angle) and lift on another (f.e. rear, representing the final high pressure area above the rear hood and window), so there is a need to use the front and rear wing sections for that (And eventually the diffuser), which complicates things a bit more unless one simplifies and calculates all values to the axis (And take acount yourself of the cantilevering added by the real location of the pressure centre)

Anyway in rFactor i have always found aero grossly exagerated. Maybe it was just a matter of the mods I have seen so far, but small changes seem to have too big effects.

But after getting more used to the car, and as I predicted, I start to like it much more and understand that the behaviour is truly more realistic.

Thanks again for your explanations Niels

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#35 [url]

Dec 25 11 4:15 AM

Niels_at_home wrote:
Looking at just the TBC file it seems we used weird numbers. However, you always must see the bigger picture.

First, our curves start very 'steep' but then take a long time to reach maximum grip. If the maximum is at 20 degrees, you have like 92% grip already at 10 degrees.

The 40 degrees slip angle is only at loads that do not occur. In practise for the 1965 cars slip reaches its maximum grip between 12 and 24 degrees. The Mini and Abart have the biggest slip angles, but also the lightest tire loads. So in practise the peak slip angle is about the same as on the bigger cars.

Longitudinal slip also has these curves; so 90% grip is reaches a LONG time before the LongPeak values in the TBC file. But it is very believable for tires to have peak longitudinal slip ratio between 10% and 20%.

There is some tire data for the 1970s. Those are newer tires than on our 1965 cars! So they might be 'stiffer'. The chart below compares this real data to our TC65 Mustang. As you can see they are about identical.

There will be things wrong with our cars, and tire data is not always reliable. But this data shows that we might be in the realistic range of slip angles.

image


Please forgive my ignorance when it comes to the data, I'm more of a racer than an engineer. But are you trying to say that although you used the most accurate tire data possible, rfactor's engine doesn't allow this real life data to show when you go on track? If so, do you believe rFactor2's engine is a more 'reliable' one in this respect? Is this a sign that rF1's engine has come of age?

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#36 [url]

Dec 25 11 10:33 AM

Let me ask you something rafa. Do you know what "vintage race legal" means? Are you aware that those cars in clips that you choose have modern shock absorbers, springs, gearboxes (GT350 in clip) even engine can be changed ... after all that changes and precise balancing with todays technology and knowledge, do you really belive that it was like this in those clips?
With what would you be happier - to have mod with cars as they were at that time or mod with cars as they could be with todays know how?
And I found two better clips...
this http://www.youtube.com/watch?v=zNG8Aj7DEic

and especially this
http://www.youtube.com/watch?v=L3yscKttdoI&feature=player_embedded

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#37 [url]

Dec 25 11 11:14 AM

rafa79 wrote:
Niels_at_home wrote:


image


Please forgive my ignorance when it comes to the data, I'm more of a racer than an engineer. But are you trying to say that although you used the most accurate tire data possible, rfactor's engine doesn't allow this real life data to show when you go on track? If so, do you believe rFactor2's engine is a more 'reliable' one in this respect? Is this a sign that rF1's engine has come of age?


rFactor works perfectly well with 'real data'.. I showed an example that we seem to be in the area of real data for the TC65 type cars, but we could still be off.

rFactor also responds to aero just fine, it really is very very solid; but people don't trust it for some reason. Lots of people say it can't do this or that, where in fact it can do it quite well!

Its only the modders who can't always get it to work, and that will include us up to a point as well.

Now of course you can not like the result and how the cars handle. Of course things aren't perfect but nothing is bugged or flawed to a HUGE extend with rFactor. The exact same approach to physics is taken for all the cars, and that includes real single seaters that I've reproduced. The handling of these cars is also very believable and the telemetry that they produce nearly identical to the real car. I trust rFactor, just build the cars to the known real specificaitons and live with the outcome.

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#39 [url]

Dec 26 11 4:43 AM

Animal Ed wrote:
Let me ask you something rafa. Do you know what "vintage race legal" means? Are you aware that those cars in clips that you choose have modern shock absorbers, springs, gearboxes (GT350 in clip) even engine can be changed ... after all that changes and precise balancing with todays technology and knowledge, do you really belive that it was like this in those clips?
With what would you be happier - to have mod with cars as they were at that time or mod with cars as they could be with todays know how?
And I found two better clips...
this http://www.youtube.com/watch?v=zNG8Aj7DEic

and especially this
http://www.youtube.com/watch?v=L3yscKttdoI&feature=player_embedded


Your videos are very good, they really show what those cars behaved like back in the day, I didn't know what "vintage race legal" meant until I saw those videos, the one from Goodwood is awsome!!!

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#40 [url]

Dec 26 11 4:49 AM

Niels_at_home wrote:
rafa79 wrote:
Niels_at_home wrote:


image


Please forgive my ignorance when it comes to the data, I'm more of a racer than an engineer. But are you trying to say that although you used the most accurate tire data possible, rfactor's engine doesn't allow this real life data to show when you go on track? If so, do you believe rFactor2's engine is a more 'reliable' one in this respect? Is this a sign that rF1's engine has come of age?


rFactor works perfectly well with 'real data'.. I showed an example that we seem to be in the area of real data for the TC65 type cars, but we could still be off.

rFactor also responds to aero just fine, it really is very very solid; but people don't trust it for some reason. Lots of people say it can't do this or that, where in fact it can do it quite well!

Its only the modders who can't always get it to work, and that will include us up to a point as well.

Now of course you can not like the result and how the cars handle. Of course things aren't perfect but nothing is bugged or flawed to a HUGE extend with rFactor. The exact same approach to physics is taken for all the cars, and that includes real single seaters that I've reproduced. The handling of these cars is also very believable and the telemetry that they produce nearly identical to the real car. I trust rFactor, just build the cars to the known real specificaitons and live with the outcome.


Niels, your mod to me, has always had the best physics of any for rfactor, I could be wrong but I believe that if you can't do a sustained drift with most RWD street cars or those monsters from the 60's and 70's then the physics aren't really that good. Not if you're a good driver anyway.

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