Aeroloss

[n1lyn]

i don't know how difficult it is to fix this aerodynamics, but somethin really has to change as soon as possible. there is no more important improvement around that i can think of. this ruins races, this ruins the whole racing thing. if u cant stay behind other cars in turns because u will definetly spin with the cars with wings then something is wrong. also the slipstream is a lot too strong. but thats what we all know already. plz scawen make this the first thing on your to do list.

[AndroidXP]

I'm pretty sure an more advanced aero model is pretty high on Scawen's list, especially after we discovered the high nose bug. But you have to keep in mind that any of these updates are incompatible ones, so I wouldn't expect anything mayor before next year.

[[RCG]Boosted]

slipstream too long? i would say its to short.
just for example, GTI vs GTI im behind him on 180 KMH.
i wont get faster until im at least 5 Meters behind him. thats unreal.
on this speed u get slipstream for at least 40 M. a bit.
but i think u talk bout the formula cars. well not unreal there too.
high speed = longer stream.
but the point with spinning in slipstream is really crazy. last time i was behind a FZR with my FO8, then in the middle of the street my car spun. no clue why. i didnt steer or something.

[XCNuse]

if u cant stay behind other cars in turns because u will definetly spin with the cars
er.. how could you? with no downforce you SHOULD spin (not so easily, but lets also keep in mind LFS has weird handling at <40 mph

[Gunn]

if u cant stay behind other cars in turns because u will definetly spin with the cars with wings then something is wrong.With less air resistance how do you expect the aerodynamics to provide downforce? This really does occur in real life when a car (dependant on aerodymaic dowforce for high speed cornering) is travelling in the slipstream of another car through a curve. Aerodynamic devices just don't function very well in the "dirty" air behind another car.

[sil3ntwar]

You have to change the way you take the corner when following someone. Its a skill you need to learn and its part of racing.

[Tweaker]

But the main affect it should have on your car is understeer, not oversteer. We all just have cars losing their rear ends even at slow speeds... that is certaintly not correct --- unless you have huge bus-sized rear wings to give the trailing car no downforce whatsoever. But the main portion of the car that should be affected is the front when trailing a car... it should be understeer in my opinion.

Because we have oversteer, it just shows that the air coming off the car and coming in towards the car behind does NOT flow like real air should. Imagine what we have now as just a block of straight-lined dirty air that dissipates the farther you are away. Very simplistic, and that is how I think it is done, resulting in low front dowforce, and ultra-low rear downforce. When it should actually be something where you get low rear downforce, and not so heavy dirty air on the rear wing --- depending on the speed of course.

Even some real race car drivers here have noted that it is WAY too extreme, even the slipstream. It is just a far too heavy amount of dirty air.

Maybe some more knowledgeable physics guys here can expand on this, but... it has been said before that what we have now is partially real/correct, however some things are a bit odd at the moment, and need to be fixed. Because I have had way too many occurances of where dirty air is just absolutely absurd at slow speeds, causing really good races... it is just so frustrating.

And some say that even the F1 drivers back off from slipstreams because they might slide out... partially true... but the most important reason why they do so is because of heat, their cars can heat up dramatically if they stay sucked in behind another hot car.

[Nick_ll]

In F1 it's AFAIK only because of heat that they back off.
They can't drive very very very close to a car in front because the FRONT washes out because of dirty air. What they loose it FRONT downforce and therefore aero balance. Not all sorts of downforce front and rear whatsoever.
Also it might be good to note that the air density is lower when air is at higher temperature and therefore if I'm not mistaken, if you follow a hot car with a car powered with an internal combustion engine, you will most definitely loose power, which is why clean air is better.

[Nitemare]

In F1 it's AFAIK only because of heat that they back off.
They can't drive very very very close to a car in front because the FRONT washes out because of dirty air. What they loose it FRONT downforce and therefore aero balance. Not all sorts of downforce front and rear whatsoever.
Also it might be good to note that the air density is lower when air is at higher temperature and therefore if I'm not mistaken, if you follow a hot car with a car powered with an internal combustion engine, you will most definitely loose power, which is why clean air is better.i'm pretty sure that heat has a negligible effect in this case...

the f1 car has huge tyres and rear wing, and that creates an area of low pressure behind the car, that extends qute far behind it... if the other car follows very closely, it loses downforce on both wings - but much more on the front one...

this is why FIA proposed a new rear wing for f1 in 2008, to reduce the low pressure area behind the car, and thus (hopefully) introduce more overtaking
http://vne-resource.iol.co.za/30/picdb/5/0/62408...on this graph you can clearly see low pressure area behind car:
http://www.f1m.com/images/fia_plan_drag.jpg

currently the aero model in lfs is not wrong, but very simplified... slipstream reduces overall downforce, not front / rear separately... but i believe that it will be sorted out for s2 final..

[sil3ntwar]

On a slightly off topic note...does the wing height from the ground affect downforce? I would have thought so but i have done some jumps in the FO8 and seen no change in downforce in forces view.

[Chaos]

Those who say the slipstream effect is ok now are imo wrong, the effect is far too strong. Have you seen DTM or WTCC races? They drive bumper to bumper (literally) and have almost no problems with the cars spinning... I have been watching races for two seasons now on the race track I work at, which has the longest finish straight in europe and I have not seen such drafting as in LFS, the most prestige races run in the Czech Republic are done with cars very close to the FXO (only with slicks) and if they want to pass on the finish straight they have to be almost on the bumper of the leader while exiting the corner and with slipstreaming they only manage to get about half of the car to overlap (chaser's car's front bumper is near the front door's of the leader) before starting to brake... And this is not regulary... Who want's to pass usually does not succeed at the first try... So no way we see the drafting as it is in LFS where you can be 2 car lengths behind the leader and then about in 3/4 of the straigh you zooom past him with no effort...

I agree with n1lyn, because of this "exaggerated" efect its nearly impossible to have close races in the aero cars. Should the drivers be of an equall (top) skill (jet, n1lyn, rudi, etc.) I think it would be nearly impossible for them to pass each other in a race with aero cars... I guess they would have to drive just as far to be out of the reach of the slipstream effect of the leading car, just waiting for the leader to make a mistake... Any getting closer and they would spin... You may say they can drive another line, but when the leading driver sees this, it's no prob for him to change lines and effectively get rid of his attacker by "stealing" his downforce, resulting in a spectacular spin of the attacker...

Not long ago I suggested the same> LINK (http://www.lfsforum.net/showthread.php?t=1454)

[Chaos]

On a slightly off topic note...does the wing height from the ground affect downforce? I would have thought so but i have done some jumps in the FO8 and seen no change in downforce in forces view.
no, the groundeffect is not yet implemented...

[AndroidXP]

Yeah, don't use the aero in LFS to judge anything from RL. It's very very simplistic right now. Hence the high nose bug.

[tristancliffe]

That FIA Center Hogwash Generator will NOT work in real life. The graphics they produced show the aero state in 2 dimensions over a snapshot in time. Apparently, according to F1 Aerodynamisists, it's not gonna do diddly squat at 170mph in a curve with the following car not being the perfect distance away.

I say fat slicks, no wings (or maybe very small ones), and groud effect. Same lap times, no dirty air. If the sponsers want space for logos, maybe allow a rear 'wing' with no aerofoil section, and it must be mounted a, say, 20 degrees to the reference plane at all times. It won't do much, other than produce drag, but still allow visible logos.

[Nitemare]

i agree that banning wings altogether would be the best idea - apart from better racing, it will lead to developments in mechanical grip, which is more useful in real life than playing with winglets to gain bit more downforce...

..but a simple solution would be to reduce rear wing size, and allow diffusers...
look at a1gp, there's a lot of overtaking, without a need for stupid split rear wings..

[tristancliffe]

Yeah, but A1GP is filled with second rate drivers (still better than me though). Only 3 or 4 of the drivers are any good, and half of those are in crappy cars.

If you have a wide range of talent, then you are bound to get passing. I think Ron Dennis said a couple of months ago, that if the F1 drivers were all in GP2 together, it wouldn't be anywhere near as good because they are superior drivers, don't make as many mistakes, and wouldn't leave doors open. So it's not just the cars causing the problem, but the fact that all the F1 drivers are pretty special, and pretty even. What we need is a rubbish driver in a top team to spice it up.

Oh, we already do --> Montoya. :razz:

[Nitemare]

Yeah, but A1GP is filled with second rate drivers (still better than me though). Only 3 or 4 of the drivers are any good, and half of those are in crappy cars. well, if you saw a last race in sepang, drivers were overtaking in places where f1 cars couldn't even get close to each other...

and a battle for first place in sprint race... when was the last time you saw an f1 car following a car ahead so close?

problem in f1 is that drivers most of the time cant even try to overtake...

[tristancliffe]

I'm not denying the cars are more capable of following closely. I'm just saying it's not ALL down to the car. Driver skill is a big factor y'know ;)

[inCogNito]

please, i can't believe some of you really say it's realistic!
Have you ever seen a F1 car spin behind another one because of sudden aeroloss? I don't, but in LFS it happens all the time.
The major problem F1 cars have behind another car is the amount of air they get for the intakes, that's why they can't slipstream on the straights and therefore can't overtake.
Of course it affects the aredynamics in the corners, but they don't lose downforce at all like in LFS.

And an even better example is the DTM. They have highly developed aerodynamics (looks at all those silly flaps), and they can race behind each other with 1m distance. looks at the fight between ekström and paffet in oschersleben.
And then look at a GTR race in lfs, it's just not realistic.


Boosted']slipstream too long? i would say its to short.
just for example, GTI vs GTI im behind him on 180 KMH.

he said it's too strong, not too long ;)

[xaotik]

Have you ever seen a F1 car spin behind another one because of sudden aeroloss?

Hmm, I've seen them lose frontal downforce and lock up the front wheels when braking if someone infront of them is too close - usually happens after an overtake if the overtaker gets infront of the overtakee directly after the pass (I think Montoya did that once when lapping someone (http://www.grandprix.com/ns/ns15555.html)). But you don't see them up close to someone on sweeping turns (there's also the instict of self-preservation in that one [and the paycheque too]).

[inCogNito]

yes, and i think we can agree, that understeer and locked wheels is not the problem in LFS. That's how it should be!

[ORION]

he said it's too strong, not too long ;)
It's the same - a stronger slipstream will also "last" longer.
With an infinitely strong splipstream, the observer car can also be infinetaly far away without leaving it ;)

[Barroso]

what makes me mad about this is that you can spin out easily if the driver in front wants it to happen, just keeping a bit slower speed out of a corner will make the next car coming out of the corner loose aero, even if he was keeping distance, so its really frustrating to spin out basicly when the other driver makes a mistake.

[sinbad]

It's the same - a stronger slipstream will also "last" longer.
With an infinitely strong splipstream, the observer car can also be infinetaly far away without leaving it ;)

That would only be true if the ratio of "slipstream effect:distance it trails the vehicle" is spot on. I don't think it is, both things need to be looked at seperately. If you reduce both things (or increase them) by the same amount, the problem will not be fixed, just changed.

[avih]

The "no airo on turns while nehind another car" has happened to me too while driving the FO8 mostely, but since I don't have any RL experience with formula cars I don't know how real it is on LFS. Also, I don't know what's the relation, if at all it exists, between the high-nose bug and the described behaviour during turns.

So we're talking about few issues i think:

1. slipstream effect is too strong and/or exists for too long distance (they're not neccessarily the same i think) and/or not applied properly as a function of speed (it might have a non-linear effect i think).

2. "high-nose" bug, where the force applied by the wing is calculated wrongly (or at least some vectors of it). Obviously, this one would be fixed quite straight forward.

3. together with possibly low-speed grip bug, it may result in the impossible to turn bug.

Maybe we can try and collect some numbers and/or evidence and/or practical experience about this matter?

i.e. On F1 races that i've seen on TV, it seems like they gain less speed from slip than we get on LFS, or at least it's much harder to utilize it properly. Also, they're able to keep quite close through turns and chicanes.

[inCogNito]

It's the same - a stronger slipstream will also "last" longer.
With an infinitely strong splipstream, the observer car can also be infinetaly far away without leaving it ;)

he wasn't talking about the duration. And most racetracks aren't just a straight line.

[ORION]

it's the same lol...
Slipstream is baisically moving air, and a pressure difference.
And if the "intensity" is higher, the cars which are lets say 20m aways will also get more slipstream.

But like sinbad said: Simulating those streams is highly complicated and only possible with very ineffective numerical mathematics nowadays (iterations), so it's impossible to simulate correct airflow at a acceptable accuracy in realtime.
Im sure those shots there from the F1 cars took some hours to "render" :)

And it's also difficult to measure the correct values, because 1. the forces are rather small, and piezo-elements might not be exact enough (not really sure though, as I dont have one :) ), and 2. because Scawen has no race car and no racetrack :D

[avih]

What I ment when I said they're not neccessarily the same is that the model which is used to calculate the effect in LFS probably has several parameters which are not tightly correlated (in contrast to real life where there's "absolute" correlation because it's actual physics).

I.e. the model might work like this:
- for car X the there exist a slipstream effect in <deg> degrees angle behind the car with <max> effect right behind it degrading over distance as a function of 1/distance calculated for upto <dist> meters behind it, etc. There could be more parameters that use the movement vector of the car, the orientation of the car towards the movement vector etc.

So, in that model, you could change either <max> or the function (replacing 1/distance with something else, or even a precalculated table) and in both cases you'll have different effect. Of course, if you change the max effect, it *might* effect the distance in a model. But it comes down to the model used.

[Hyperactive]

Didn't read all posts (sorry) but there are some things I find hard to comment (but I still do) regarding the aero effects.

1) dirty air behind the cars. This is not directly a problem whether the LFS simulates this correct or not. It's more about the aerodynamics properties the LFS cars are meant have. (how the rear end of the car creates dirty air and how the front wing uses it). Though the high nose gain is a "bug".

2)I have no real life racing experience (like most of you too) so it's impossible to comment this. But I still try :). The slipstream force seems to be too big. In F1 couple of years ago there was less dirty air and more slipstream. But it still took a long straight to even get aside with equal car. In LFS, like in ovals this gets odd measures as the cars with little downforce pass others all the time (though the high speeds compensate little for the smaller downforce)

3) The car in front should also gain some more speed. Don't know does it.

4) Currently driving in the slipstream makes the car much more loose on the rear. I thought in F1 they can't drive close because the front wing loses the airflow and therefore the downforce gets smaller in front. So the car pushes as a result. Though under braking this is currently right(ish), but still the rear get more happy than front. Maybe because more oversteery aero setup, but...

Just my 4 cents :shy:

[AndroidXP]

Ok, I've just driven some FOX @ BL1 and the current downforce/slipstream model is really starting to piss me off :mad:

As soon as you enter the slipstream there's suddenly no more downforce at the rear... which isn't exactly what I need when I'm cornering at 160km/h...

[DodgeRacer]

Well that aspect of it is fairly realistic, just needs to be toned down a hair..or clump of hair

[AndroidXP]

Well, emphasis was on the NO more downforce. The problem is that front and back wing suffer equally from downforce loss, but it should mostly be the front one only. Which would have a vastly different result.

[Hyperactive]

I say fat slicks, no wings (or maybe very small ones), and groud effect. Same lap times, no dirty air. If the sponsers want space for logos, maybe allow a rear 'wing' with no aerofoil section, and it must be mounted a, say, 20 degrees to the reference plane at all times. It won't do much, other than produce drag, but still allow visible logos.

I saw a document about Sennas accident and it was said that ground effect is very strong when driving straight line and while cornering. But it was also said that if your rear end just slides even a little bit you suddenly loose all ground effect. And in Senna's case he lost the ground effect and had no way of recovering from it (not my opinion, it was said in the document. It's long time since I saw it so I may remember it wrong. And there is the theory of broken steering axle, or something, too).

But no downforce (just ground effect) in F1 is a suggestion that I can't take seriously. Like putting a manual clutch in F1...


Maybe someone make a test: make a very low-front-aero setup for the F08 and drive behind an F08 with very low-rear-aero setup. How do the forces change when the distance gets smaller? And has the front runner any gain in speed when the other is only 1 inch from him?

EDIT. Added a link to site offering some info about the downforce: http://www.nas.nasa.gov/About/Education/Racecar/

[AndroidXP]

No, I think currently only the drafters get a speed boost.

[Tweaker]

what makes me mad about this is that you can spin out easily if the driver in front wants it to happen, just keeping a bit slower speed out of a corner will make the next car coming out of the corner loose aero, even if he was keeping distance, so its really frustrating to spin out basicly when the other driver makes a mistake.

I know.... dissapoints me that some good drivers can setup a situation where you spin out or lose it JUST to have them get you off their arse (or so you lose and they win, obviously).... really stupid tactics by exploiting a bug in the game :chairs:

[Shotglass]

has anybody tried putting the fo8 into a cfd tool yet to simulate the hell out of it until we have some realistic values for how long and strong the trail should be ?

[tristancliffe]

About Senna's crash documentary - I downloaded it the other day. It's totally correct, but one solution is to make the use of magnesium skid blocks at certain points, so the actual floor can never touch the floor, and hence ground effect isn't lost easily.

And it has the positive side effect of the dramatic sparks returning to F1, rather than saw dust :S

[OPK]

EPS race on monday...I was slipstreaming Jay on the main straight of SO4, pulled out of his slipstream to pass him - and almost spun Oo
This is in no way realistic, since the rear wing is affected much too much atm -.-

[Hyperactive]

has anybody tried putting the fo8 into a cfd tool yet to simulate the hell out of it until we have some realistic values for how long and strong the trail should be ?

Well, you need a CFD tool, exact model of the F08 in right file format and person to understand the results. I guess we need someone to make the 3d model first and then someone willing to spend lots of time. And I don't know how exact the results would be...

And I don't even think the 3d model we see have actually anything to do with aero effects coded in game. That is not a bad thing as it is impossible to simulate 3d model's aero effects real time. As far as I can tell it is just a good guess.

[Shotglass]

And I don't even think the 3d model we see have actually anything to do with aero effects coded in game. That is not a bad thing as it is impossible to simulate 3d model's aero effects real time. As far as I can tell it is just a good guess.

they should have a lot to do with the forces in game ... of course not in the sense of a real time cfd but in the sense that the aero model applied to the car should simulate the aerodynamic properties of the cars body as we see it in game as closely as possible

[tristancliffe]

Only if Scawen has access to CFD, which I doubt. Most likely he's using very rough approximations based on 'facts' he read somewhere. It might be quite close, but it might just be a simple case of

slipstream length = speed^2 * Cd

or something equally easy.

If I had the time I'd look at importing the cars into CFD at uni, but time to do projects like that is not going to be easy to find... It's hard enough doing 2D problems :S

[Hyperactive]

Well first the devs just decide what kind of car they are going to have...
I think Eric has just made the models looking at the F3000 and such to have some equal characteristics in them. At the same time Scawen has been researching the aero data about different kinds of formula cars (similar in power and layout) and then the devs just decide what is the real life counterpart(s) of the F08 for example and how they react. Then they probably just try to take the most useful data out of it. But finding this data must be extremely hard, maybe we need some Gp2 organization to sponsor LFS by providing some info about the car and physics related.


If I had the time I'd look at importing the cars into CFD at uni, but time to do projects like that is not going to be easy to find... It's hard enough doing 2D problems :S

Well that kind of stuff needs a lot of expertise as even the simplest structural analysises I have made need a lot thought before they can be used.

OT: BTW. tristan (or anyone), you study mechanical engineering in UK...might you have any downloadable PDFs or stuff about anything automotive related designing? What I'd like to have is some studying material they give you at school. I understand if you don't want to give me anything as I guess university education is expensive in UK (?) and therefore you've paid for the material :). In Finland it's free :). I really wouldn't like to buy any expensive books about it and at my uni there isn't really anything automotive related courses.

[RacingSimFan]

All I know is that the draft in the FO8 is way too 'potent'. The physical size of the slipstream is actually pretty spot on but the burst of speed the trailing driver gets from it is way too much.

I haven't raced on the oval in ages because its all about the draft. You are royally screwed without the draft. I watch real-life Indy car racing on high speed ovals and a fast car with a good setup IS capable of gaining on a group because the draft just does not produce that slingshot effect with such low-downforce wings.