This is not meant to start a LFS vs. iRacing argument, I would just like a comparison of the two in regards to aero downforce. When I was subscribing to iRacing I didn't buy any of the downforce cars because I didn't think I would enjoy them. The management of the weight transfer of a car under dynamic loads is one of the things that I like best about driving. For example, there are a couple of turns at Aston Club at which the track has a little hill in the middle of them so that one has to make adjustments as the car first presses down on the track and then gets light after the hump. This a bit of the a challenge in cars like the LX6 whereas, in the FO8, the changes in elevation are hardly noticeable because of the aero downforce. In the winged cars, because of the downforce and stiff springs, I don't experience as much the weight transfer under braking, acceleration and cornering loads. My question to those who have tried the winged cars in iRacing (I don't count the Skip Barber 2000 in this group because there doesn't seem to have much downforce), do you consider the formula cars in LFS to be a good representation of what downforce feels like or do you think I would have come to a different conclusion if I had tried the aero cars in iRacing?

Try netkar pro as comparison as well. It mainly has Formula cars and 2 with downforce.

Can't really say much about iRacing or netKar, but the aero model in LFS is still quite simple as far as I know. The wings are probably simulated well enough, but the ground effect is only simulated for race cars that have an undertray/diffusor and it isn't influenced by ride height at all. In a real car if you go very fast and get air under the car not only is the ground effect gone/diminished, but if you're unlucky your whole car can act as a wing which can flip you over - no such thing in LFS.

Non-downforce cars are also lacking the negative downforce (lift) at high speeds, though IIRC that's the case because Scawen doesn't have good reference data on just how much lift is actually produced for cars similar to LFS' ones, so he just set the lift to 0 instead of using wrong values.

Quote from AndroidXP :

Non-downforce cars are also lacking the negative downforce (lift) at high speeds, though IIRC that's the case because Scawen doesn't have good reference data on just how much lift is actually produced for cars similar to LFS' ones, so he just set the lift to 0 instead of using wrong values.

its certainly not a problem with the model (not since the high nose fix at least) as theres some very noticeable lift if you flip the bf1 upside down at high speeds

Also I don't think it's an issue with data. There are several car magazines out there that regularly test the lift on cars.
E.g. according to the german "Sport Auto" the latest M3 generates 102 N of lift at the front respectively 227 N at the rear axle, each at 200 km/h.
Since F_lift = c_lift * density * area * velocity² and the area is given with 2.17 m² c_lift is:
c_lift_front = 102 N / 1.2 kg/m³ * 2.17 m² * (55 m/s)² = 0.013
c_lift_rear = 227N / (the same as above) = 0.028
c_lift_combined = (102 N + 227 N)/(the same as above) = 0.041
Source is here on the fourth page of the tab "Wertung".
They do this test to about every car they test, so there really should be enough data available.

Vain

Quote from Shotglass :

its certainly not a problem with the model (not since the high nose fix at least) as theres some very noticeable lift if you flip the bf1 upside down at high speeds

The BF1 'flying' while upside down is the act of downforce from the wings. That force is still applied exactly the same as if the car was right-side up, but since the car is upside down it flies. It may not be a problem with the model, as Android pointed out it could be set to 0 eliminating the lift from those cars without downforce. It would be interesting to race when the car gets lighter the faster you go!

One would have to assume that the slipstream effect would have a positive effect on grip on a such a car.

That would be an assumption that I believe would be correct including the the real world physics of such an effect, correct?

I assume it is a realistic effect, yes.

Quote from blackbird04217 :

That force is still applied exactly the same as if the car was right-side up, but since the car is upside down it flies.

ever since whichever patch fixed the high nose exploit the aero forces are applied in the world coordinates so no they arent applied in exactly the same way and the vertical force calculation most certainly is already signed as it is

Quote from Forbin :

One would have to assume that the slipstream effect would have a positive effect on grip on a such a car.

negative id assume
in the same way that dirty air decreases downforce at the front (the excuse for having f1 cars that resemble snowplows these days yet still arent any better at overtaking) i presume it would reduce lift at the front increasing oversteer
nice to have in an fwd but positively deadly in anything worth driving

I was thinking positive in the mathematical sense. It would increase grip, even if it isn't necessarily where you want it.

Quote from Shotglass :

ever since whichever patch fixed the high nose exploit the aero forces are applied in the world coordinates so no they arent applied in exactly the same way and the vertical force calculation most certainly is already signed as it is

I don't think I was around with that exploit, if so I don't remember it well enough - possibly back when I was demo?

Anyways, even without this fix I am not sure how the lifting effect of the BF1 while upside down is not the same as the downward force that is pushing it against the road? Surely the same force is causing both effects here, I can't think of another reason for it.

A wing, as designed on the BF1, at speed will press downwards. If you keep the speed the same, except turn the BF1 upside down the wing will now press upwards. That is where I am coming from, so I don't see how its not the same force?

because as i said the force is calculated in world coordinates which means that in the calculation it is pointing up (which is the relevant bit which bit on the car causes it makes no difference) as opposed to the earlier versions of lfs where the aero forces used to be calculated in the cars coordinate system so the force would always point down (in relation to the car and its coordinates) as its being calculated which means an unsinged variable would suffice and may have been used at that point