FIA Formula Two Williams JPH1B Released

CordellCahill said:
Why?
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I'm going to copy+paste a post from iRacing forums about FFB/mechanical trail/pneumatic trail/caster etc, it's pretty well explained by Jeremy Spiering:

A majority of the forces you feel at the steering wheel arises from aligning torque at the tires. Aligning torque is caused by the tires tendency to face in the direction they are traveling. In general, slip angle is what causes the majority of aligning torque. Aligning torque arises from total trail, which is the sum of pneumatic trail and mechanical trail. Pneumatic trail is the distance from the center of the contact patch to the center of tire. The center of the contact patch is behind the center of the tire and this creates a moment arm (which is the pneumatic trail). The lateral force the tire produces acts at center of the patch (at least it does in our virtual world when simulating, but in real life of course it is acting to varying levels at all points of the contact patch), and since the center of the patch is not in the center of the tire, a force arises, which causes a torque about the center axis of the wheel. This torque is PART of the aligning torque that works it's way to the steering rack.

Mechanical trail is caused by suspension geometry, namely caster. When looking at the steering pivot from the side view (so the upper and lower ball joints) if you connect a line between them and look at where the line intersects the ground plane, and then take the distance from the center of the tire and subtract the pneumatic trail, you would have the mechanical trail. Now mechanical trail is generally orders of magnitude higher than pneumatic trail. So the forces you are feeling at the steering wheel are often 75+% due to the mechanical trail.

Ok, so now that is explained, I will try to response to your statement and question. You seem to be thinking that the torques on the steering wheel in real life are giving the driver the best possible feedback for the handling of the vehicle. In reality, the best possible feedback is completely subjective. Let's break down what causes aligning torque again and see what is happening and why...

Pneumatic Trail - This is purely determined by the location of the center of the contact patch. This varies from tire to tire and changes with velocity, pressure, and many other factors. Pneumatic trail isn't a primary specification that a tire is designed around it is more a byproduct. In other words, the pneumatic trail, while it helps a driver with feedback about what the tire is doing, certainly doesn't give the driver the best possible feedback, it is just a perk that it helps. Also, realize that even though pneumatic trail is generally much smaller than mechanical trail, it is the pneumatic trail that helps the driver to feel the grip of the tires the most.

Mechanical Trail - For simplicity, let's just say mechanical trail is all based on caster, and that the caster is static. Say 75% of the aligning torque is caused by mechanical trail, and 25% for pneumatic trail. So now 75% of the torque at the steering is caused by caster. This makes the steering wheel feel more solid and comfortable to the driver. It isn't however directly aiding the driver in feeling the grip of the front tires. In fact, if anything it is reducing the drivers ability to feel subtle changes in the pneumatic trail. However mechanical trail is necessary to make the driver comfortable, especially if the pneumatic trail changes signs which (in the absence of mechanical trail) would cause the steering wheel to actually steer INTO the corner (similar to reversing your FFB in iRacing). This is why I stated in my previous post the mechanical trail is essentially damping the effects of the feedback the driver is getting from the pneumatic trail.
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And pay attention especially here:

However mechanical trail is necessary to make the driver comfortable, especially if the pneumatic trail changes signs which (in the absence of mechanical trail) would cause the steering wheel to actually steer INTO the corner (similar to reversing your FFB in iRacing).
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Which is something pretty similar to what happens in the F2, or at least it did when it was released. You can also test this even in rF with realfeel, make a suspension with no caster / mech trail and see what happens :)
 
Domi said:
I'm going to copy+paste a post from iRacing forums about FFB/mechanical trail/pneumatic trail/caster etc, it's pretty well explained by Jeremy Spiering:



And pay attention especially here:



Which is something pretty similar to what happens in the F2, or at least it did when it was released. You can also test this even in rF with realfeel, make a suspension with no caster / mech trail and see what happens :)
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You didn't answer the question. Your statement was that the mechanical trail is wrong. Why is it wrong? Your iRacing qoute is only proof that it is physically possible for the self aligning torque to go negative....it happens with some cars and some setups, that doesn't make it wrong.
 
It is wrong because it is either too low, or the pneumatic trail insanely high in this car.

If the mod hadn't encrypted files, we could figure out the SAT with the tire tool :)
 
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Dude, because it has almost 0 resistence past 90º of steering rotation. If you believe this is right ok, I don't believe it. There are also tons of evidences of open wheelers running much higher caster settings, in order or x2-x3 higher.
 
Domi said:
Dude, because it has almost 0 resistence past 90º of steering rotation. If you believe this is right ok, I don't believe it.
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DUDE, you should reread your iRacing qoute. You don't seem to understand that what it's saying is that 0 resistance is possible

Domi said:
There are also tons of evidences of open wheelers running much higher caster settings, in order or x2-x3 higher.
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I'm not doubting this. Now do you have evidence that their self aligning torque never changes signs?
 
I can read perfectly, I know it's possible to have 0 and even negative resistance, I'm just saying that I do not expect such thing in a car like this, I simply don't believe that a Formula Two car has 0 resistance.

CordellCahill said:
I'm not doubting this. Now do you have evidence that their self aligning torque never changes signs?
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No I dont have evidence, and I wouldn't be surprised if the SAT changes signs as there are graphs showing this around the Internet, but the SAT is only part of the picture, not all. They are the aligning forces coming only from the tire, measured in a tire machine without any suspension.
 
Domi said:
but the SAT is only part of the picture, not all. They are the aligning forces coming only from the tire, measured in a tire machine without any suspension.
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This is why you need to reread your iRacing qoute. Self aligning torque is the SUM of the forces coming from pnuematic AND mechnical trail. Now put that together with whatelse you said

Domi said:
I wouldn't be surprised if the SAT changes signs as there are graphs showing this around the Internet
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You've said it yourself, resistance(SAT, the sum of mechnical and pnuematic trail) can be equal to 0 or be negative.
 
Well the real life f2 runs an insanely low amount of caster supposedly. So maybe what was described in the iracing article is what's happening with the F2 (whenever the f2's front tyres steer sharply enough and/or have enough slip angle) therefore making this how it's supposed to be??

Also, most people use way too little ffb, and therefore when the resistance lowers it's going to really be limp and dead because you already don't even use much ffb resistance normally, nevermind when it lessens.

Just speculating, I don't really know much about pneumatic trail, suspension geometries, steering columns, etc
 
CordellCahill said:
This is why you need to reread your iRacing qoute. Self aligning torque is the SUM of the forces coming from pnuematic AND mechnical trail. Now put that together with whatelse you said



You've said it yourself, resistance(SAT, the sum of mechnical and pnuematic trail) can be equal to 0 or be negative.
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The aligning torque comes from the tires, the sum of both trails gives the steering torque.

What I meant is that I do expect things like this:

http://oi19.tinypic.com/4y7l0ys.jpg

But this comes alone from the tires, without the mechanical trail. What I tried to say is that I hardly believe that the sum of them would give almost 0 resistance in a modern open wheeler like this. I wasn't saying that this effect is impossible to achieve, as it is indeed possible with certain suspension geometries :)
 
Spinelli said:
Well the real life f2 runs an insanely low amount of caster supposedly. So maybe what was described in the iracing article is what's happening with the F2 (whenever the f2's front tyres steer sharply enough and/or have enough slip angle) therefore making this how it's supposed to be??

Also, most people use way too little ffb, and therefore when the resistance lowers it's going to really be limp and dead because you already don't even use much ffb resistance normally, nevermind when it lessens.

Just speculating, I don't really know much about pneumatic trail, suspension geometries, steering columns, etc
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I don't think it's about little FFB, the FFB forces are scaled anyway.... so they increase/decrease in the same proportion. Anyway I remember having a bit of clipping with that car, so certainly the FFB wasn't low... there is something odd there, but perhaps I am totally wrong and F2 drivers have 0 resistence past certain slip angles :)
 
I have almost 0 resistance in some road cars when I have understeered badly (not slight understeer, but BAD understeer lol). Not saying F2 is correct, but it certainly can happen on certain cars.

I also had almost no steering resistance and almost no steering returning to centre one time when my F2000 was setup wrong. That felt horrible, it was like playing a sim with your FFB set to 0, no resistance, no centering forces, no centering spring, nothing. It resulted as a cause of someone messing up something on the front end. Think it was caster, or something on the front suspension that affects steering. This happened my entire run, not just at a certain steering angle or slip angle, but every second. When I would use the curbs on entry the freaking curbs would almost shoot me off the track (they already sucked you in when the steering was normal, but it was even worse with the super dead, light steering I had that session). Totally different situation than the RF2 F2, but just thought I'd share the story with everyone :).
 
"The new 'F1-style' system shares similarities with the DRS feature used in Formula One. Each driver has up to eight shots of overboost available to them - increasing power output of the F2 car from 425bhp to 500bhp for a period of six seconds - but can only use them if they're within one second of the car ahead." *

Has this feature been activated in the game?

*Wikipedia article.
 
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Tim Wheatley said:
No. They know about it, that's all I know at the moment. There was mention that tire camber could cause the effect though.
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It seems to be the only car in ISI's garage that to me feels like it's got almost no f/f when using a G27, all I get is a very light rumble going over the kerbs - no weighting up of the wheel when turning, I'm really no expert - first to admit that :rolleyes: - but it still doesn't feel right when all the other cars feel good
 
Although these options should be vehicle specific maybe try altering your PLR. It woke the game up nicely for my CSR e. Be mindful of FFB clipping though.

Rumble strip magnitude="0.20000"
Off-road multiplier="0.75000"
Steering torque sensitivity="1.50000"
Rumble strip wave type="3"
 
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