The online racing simulator
Catching a spin in a FOX
2
(46 posts, started )
#26 - Heph
Quote from J.B. :If it works in real life then show me one video clip of a racing driver using it to correct oversteer.

If you want a video showing this technique (and others), try "Bending the Rules". It can get boring but is very informative and was made by english driving instructor (Andrew Walsh) who used to be a F1 test driver...

I might post a short extract from this video but right now I'm moving so my DVDs are packed... And I never tried cutting a short extract out of a DVD
#27 - J.B.
Thx, I found a short clip here. . Looks interesting, would you say it's worth ordering even if you don't a real car to apply the techniques yourself?

BTW if you want to cut part of a DVD the best way is to first save the VOB files to HD using DVD Decrypter and then cutting using Videoredo or Virtualdub.
isnt that short clip just the technique weve been talking about ? catching oversteer by locking the front wheels
The best explanation for a slide in a formula car was given to me by a Jim Russell driving instructor, I'm not sure where it originates.

"A open-wheel formula car acts like a dart flying backwards"

What I got out of that is; once it wants to turn around on you, you're probably already backwards.

Corrections need to be made very early and very smooth. The corrections are usually made before you can visually notice the car sliding, the steering wheel movement is very small and quick. The return of the counter-steer is also important. It needs to be quick as well, but it needs to build up to the original steering angle or the rear will snap again. Concerning the throttle and brakes, unless it is power oversteer (which is not a common issue in the FOX), the pedals shouldn't move. They shouldn't move because you will upset the pitch and fore-aft weight transfer, which will make the cars grip less predictable and much more difficult to correct.

Sometimes the correction or "catch" isn't even counter-steer, rather its just less steering angle and a pause on the pedals. This lets the tires catch up with what your asking them to do, with out upsetting the car too much.

It takes lots of time to get fast and comfortable in a open-wheel car. While its difficult in all cars, open-wheel cars are particularly challenging regarding correcting mistakes without causing extreme negative results. Theres nothing you can read to teach it to you, its muscle memory, hand-eye coordination and just plan experience. After a while you will notice your hands moving with absolutely no apparent thought crossing your mind of a "slide."

I'm no expert, but I'm fairly sure all of that is, more or less, some good advice. Keep driving

Concerning the left foot braking idea, well it might work in LFS, but in real life your more or less asking to continue off the track at that angle right then. No more the bias, brakes transfer weight to the front, increasing the grip of the front and reducing the grip in the rear. Locking the fronts takes away nearly all the grip in the front and by doing that stops the slide because of the balance of grip front to rear. Or, it may stop the slide because it locks up all four tires, which stops and reduces all control and grip the tires had, so the car holds that angle and slides wherever its heading. If you ever talk to any driving instructors, the last thing you want to do is abruptly lift and even worse than that, would be brake "jabbing." If you've ever seen a car spin because a car in front spun its because the car behind abruptly lifted and/or slammed on the brakes, which makes the weight go to the front and thus, spins the car right around. Braking to save a slide should only be used in circumstances where the car is no where near the point of recovery and if it wasn't used the car would for sure quickly loop around and go off the track. Thats why at most driving schools, they pound the idea of two feet in. You start to spin, slam on the brakes and if you can the clutch. This makes the car slide in which ever direction its heading very predictably so that people behind you can make a decision on where to go around you. It more or less eliminates the possibility to smoothly catch a slide in my opinion.
#30 - J.B.
Quote from Shotglass :isnt that short clip just the technique weve been talking about ? catching oversteer by locking the front wheels

Agree. And race cars don't have the forward bias of a road going Elise. That's why I asked earlier for a clip of a racing driver doing something like that in a real race car.

This brings up a question that IMO hasn't been considered enough: Why do LFS cars need so much forward brake bias and so much diff coast locking? (A typical brake balance value for a Formula Renault might be around 55%, in LFS some WR sets have up to 70% + locked diff).

A while ago I posted some thoughts on the issue but no one replied.
i dont think they actually need it per se
id say its either that engine braking has too much of an effect or more likely we can abuse the engines too much by downshifting rapidly to help with trailbraking

i suppose a real engine would give up in a cloud of smoke after 2 corners of lfs downshifting
#32 - Heph
Quote from J.B. :Thx, I found a short clip here. . Looks interesting, would you say it's worth ordering even if you don't a real car to apply the techniques yourself?

Is this DVD worth ordering? If your aim is to decrease your LFS time then No!! That is unless you have a G25 and drive like in a real car: Heel and Toe, LFB ...
Now if you want to learn about driving techniques and cars physics then yes it's worth it. Steering / braking technics are rather basic but Traction circle and slip angles are less commun. There's also laps done with the different technics with hand and feets filmed. The only complain I have about this DVD is that it might have been longer...

There's also books out there that are full of infos but keep in mind all those technics are for real world driving. IMHO, LFS is as close as it gets but there's still a lot of difference.

BTW, thanks for the video editing tips
#33 - Heph
Quote from J.B. :
This brings up a question that IMO hasn't been considered enough: Why do LFS cars need so much forward brake bias and so much diff coast locking? (A typical brake balance value for a Formula Renault might be around 55%, in LFS some WR sets have up to 70% + locked diff).

I wouldn't compare brake Bias from a real car to the one in LFS.
In LFS, brake bias refers to the ratio off braking force applied to front wheels compared to the rear.
On a race car / sport car, brake bias reffers to the ratio of pressure that goes to the rear calipers compared to the front. But the calipers and discs (size) may be different!!!

As an exemple, the Lotus Elise don't have any brake bias so the same pressure goes to the front calipers and to the rears. Discs are the same but calipers are different: 2 pistons front, 1 piston rear. Even the brake pads are different in shape.
In a proper racing car (with adjustable bias via twin master cylinders), the pedal force is biased, so the front and rear will have different line pressures. The front and rear brakes (radius, number & size of pistons, pad surface area, materials etc) will likely also be different as well.

I don't know quite how LFS does the bias - whether it's pedal effort split, line pressure bias, or brake torque bias. I suspect the latter (which is what Heph suggested), and so I agree that the LFS bias might not be comparible to real life bias figures.
#35 - J.B.
Quote from Shotglass :i dont think they actually need it per se
id say its either that engine braking has too much of an effect or more likely we can abuse the engines too much by downshifting rapidly to help with trailbraking

i suppose a real engine would give up in a cloud of smoke after 2 corners of lfs downshifting

Hmm, gave it a thought. So by doing the fast and early LFS-machine-gun-downshifting the brake balance is shifted towards the rear and then after that, when the car is actually turning into the corner, the balance goes back to the front. In reality I think you'd want the opposite. More towards the front initially because of the higher downforce and then back to help the car turn in.

I still feel that the LFS typical diff and brake settings are a workaround to a physics problem although I don't know exactly what. The cars just seem too tail happy on turn in without these tweaks.

Heph and tristan:
Yeah, I'm not 100% positive about the details of the value I mentioned earlier. But I had a look at some RAF data for the FOX and the normal tyre loads under braking are around 65-66%. If you add in tyre load sensitivity the optimal braking balance would be a bit further back than that.

Anyway, I'd still be interested in some comments about my self proclaimed "realistic" setups. For me personally they feel a lot more natural than typical LFS sets. The one attached was good enough for pole and win in OWRL Div B2 with about 20 min practice but I'd love to know what's possible in the hands of a WR driver. Or what someone with RL experience like tristan thinks about the handling.
Attached files
FORMULA XR_AS_Nat.set - 132 B - 226 views
Quote from J.B. :Hmm, gave it a thought. So by doing the fast and early LFS-machine-gun-downshifting the brake balance is shifted towards the rear and then after that, when the car is actually turning into the corner, the balance goes back to the front. In reality I think you'd want the opposite. More towards the front initially because of the higher downforce and then back to help the car turn in.

i dont think you quite got my idea
the corner entry technique you find in lfs usually involves shifting down rapidly followed by a very short trailbrake and a bit with the car coasting torwards the apex

so the result is that you have the high reving engine normalizing the brake torque during the straight part of braking following that the driver "slowly" takes his foot off the brakes shifting the balances further back progressively
the last bit of the entry is a section where the car coasts to the apex ie only the driven wheels are slowing the car down
#37 - J.B.
I still don't get it. Why do say the brake balance gets shifted backwards while the driver gets off the brakes? The decreasing brake pressure shouldn't change the brake balance.

EDIT: I guess you mean that the total normal force balance moves towards the rear. True, but doesn't that support my claim that LFS cars are too loose on turn-in?
it probably does
however since the idea here is that youre basically entering the corner with the handbrake pulled ... shouldnt the cars be tail happy ?
#39 - J.B.
Yeah, using the brakes to make the car tail happy (to help turn in) is how I understand the concept of trail braking. In LFS however the brakes are used to stop the tail hapiness. It's most obvious in the MRT, just try driving it with an open diff. You'll see that you can turn in at a much higher speed if you trail brake. If you don't trail brake you just spin.
the mrt is a bad example since it has all the traits to create a massive weight shift at turn in which will lead to problems with engine braking on an open diff

i honestly dont know if the engines braking effect is overdone in lfs so that it might exaggerate the behaviour but from what little i know about car dynamics i would expect a car like the mrt to be very hard to turn into a corner safely with an open diff (at the limit of traction obviously)
#41 - J.B.
Not quite sure about that. An F1 brakes at 5 G but isn't five times as long as an MRT so weight transfer would also be a big factor there. But that does ignore other factors of course.

Anyway maybe I'll try driving all cars for a bit with open diffs and without trail braking to see if I can get a better understanding of my "too tail happy turn in" feeling. Someday
actaully i meant lateral weight shifts which i suppose should be a significant factorn on a car with very narrow track and very sticky tyres

unloading a wheel under engine braking with an open diff usually isnt a good idea
my guess is if you give it just the tiniest bit of throttle the tail happyness will disappear
i find it quite easy to catch the back end in the FOX and im crap so you should be fine after a lil bit of practice.

the big GTRs on the other hand.....
Quote from gishuk :i find it quite easy to catch the back end in the FOX and im crap so you should be fine after a lil bit of practice.

the big GTRs on the other hand.....

I guess it comes down to a preference but for me FZR and XRR are alot more forgiving than FOX. With FOX the steering corrections have to be really quick and exactly the right amount, especially the moment when you return the steering wheel to center position.

With FOX the steering movement is like "snap--hold--snap" where in GTRs I can much more easily stay in control of the slide with small steering adjustments and as in FZR's case, quickly end it with fast steering movement to opposite direction.
Quote from J.B. :A typical brake balance value for a Formula Renault might be around 55%, in LFS some WR sets have up to 70% + locked diff

Whilst there may be difficulties comparing LFS to real life, including the fact that real world brake bias adjustments do not give an easily measurable ratio, typical brake bias values people reckon they're running seem to range from 70-85% in F4, admittedly it's not precise but I'd of thought the LFS figures are far closer to the real life figures than what you suggested. It should also be noted that you'd expect LFS figures to be lower because a lot of real life drivers would rather have a bit too much front bias than end up with a locked up rear end.
Quote from Crommi :I guess it comes down to a preference but for me FZR and XRR are alot more forgiving than FOX. With FOX the steering corrections have to be really quick and exactly the right amount, especially the moment when you return the steering wheel to center position.

With FOX the steering movement is like "snap--hold--snap" where in GTRs I can much more easily stay in control of the slide with small steering adjustments and as in FZR's case, quickly end it with fast steering movement to opposite direction.

Agreed. The FZR is a heavier vehicle, so once you've corrected for the slide, the vehicle doesn't snap back into place like the FOX does. That's the part that I've noticed EVERY SINGLE person have trouble with who asks to try out the game. They are WAAAY to late in returning the wheel after correcting for a slide.
In the FZR though, you can still save the car if it rotates past the center-mark. The FOX on the other hand - it's a general rule that once you've over corrected - you're screwed. Unless you are really skilled, in which case you rarely ever get into that scenario
2

Catching a spin in a FOX
(46 posts, started )
FGED GREDG RDFGDR GSFDG