drifting is a controlled slide. sliding is slow. opposite lock means you are using the tire's lateral capacity in such a way that it is not contributing to cornering force (and therefore cornering speed). large slip angles will not mean "sliding" or "drifting". If the tire's max force occurred at a higher slip angle, all you would probably see is more steer angle or less body slip angle.
probably the easiest way is to see more "sliding" is to reduce grip and inertia, make the cars more twitchy. Or, you could just watch professional drifting. probably easier that way.
You won't see drifting or sliding anywhere because:
-Tyres have very small slip angles vs max lateral force to minimize rolling friction in corner (i.e: not loosing too much speed)
-Downforce is greatly affected by large body yaw
-Cornering speeds are so high that a 4 wheels slide means straight in the walls
-Wings allow for far better stability than non winged cars
-Grip levels are so high that this is already a challenge to use the maximum grip for each corner (that is the difference between a high downforce car and a non downforce car; I.E: fight the track vs fight the car)
This is just, for high performance cars, a thing of the past. Now if you want to see 4 wheels sliding, watch nascar on road courses.
F1 drivers drift all the time, but it is inconspicuous because (so-called) slip angles are so small
the term drift is short for four-wheel drift, ie all 4 wheels doing a full job of cornering ie a BALANCED car
in the 50s eg tyres were narrow 'slip' angles were 12-15 deg (mostly distortion, we don't have that today)
so a reasonably balanced 50s car is 'slipping' front and rear about 12 deg, and so POINTS INSIDE the cornering line
the steering angle will be small opposite lock or small same lock or nil (slight oversteer, slight understeer, or neutral)
the cornering process is efficient (insofar as the tyres allow), balance is designed-in more than driver or pitwork adjustable
now for show purposes someone has reinvented pre 30s handling ie POWERSLIDING and called it drifting
this generally exists well below normal cornering speeds (the 'Clarkson'), which shows its inefficiency
(real drifting can be seen in Historic class racing)
powersliding/oversteer etc is advantageous on loose surfaces, their reaction helps the cornering etc
Last edited by Tommy Cookers on 28 Aug 2012, 11:25, edited 1 time in total.
I am not sure I got what you are trying to say. Some punctuation would be nice. But (if I understood you correctly) you are correct. Current performance cars ARE sliding/drifting all the time, because they are at the very edge of adhession. You just don't see it outside of ultra slow slow-motion shots, simply because big slides are a waste of time, energy and rubber. The only time you absolutely want to have a so called "flat" car - i.e. very stable and not sliding with any of the wheels - is when you are accelerating.
if F1 tyres were only 200 mm wide tomorrow there would be visible 4 wheel drifting, as tyre distortion would be much greater
(there would also be powersliding through slower corners and a lot of complaints)
tyre companies would then radically redesign the tyres to reduce distortion, so impoving grip and reducing 'slip' angle
cars would corner faster, and the drift would be less
rubber in the 50s gripped or lost grip as rubber does today, the narrowness (width/height) and structural design of 50s tyres allowed large distortions that were a major contribution to drift
(50s rubber on a current F1 tyre would show little drift)
Sliding in F1 (and every high power-High aero grip car) is nowhere as it was during the 50's and certainly not a technique of driving a modern formula car for the reasons mentionned above; You can't be on the limit of adherence with a modern car, it would result in instant off track experience; You can only approach the limit by the lower side and that's why all drivers are saying modern F1 cars are very hard to exploit at full performance.
That was why i said you are not going to see 50's like drifting/sliding anymore, this is just not safe and efficient with a modern formula car;
On the opposite side, nascar , formula fords/vee/whatever you want with little downforce and narrow tyres they do slide like in 50's because they don't have the features of F1-like cars.
Now if you want to see a good example: Here is a link to one charity race with a 1967 brabham BT26; The car is driven at a very resepctable level and see there's one difference with the original car: It has slick tyres; The car doesn't slide anymore.
I think this supports my views (that the large angles that we recognise as 4 wheel drift are mostly tyre/tread distortion)
and that 4 wheel drift is not sliding (sliding is going beyond the 'slip angle' that gives max grip, 4w drift is not)
and that 'slip angle' would better be called 'apparent slip' angle
any rwd car (with a balanced setup) can be drifted all day without sliding (I should know)
any rwd car(with an unbalanced setup or very high power) can slide all day without drifting
the main point of the slick design is to avoid tread distortion caused by grooves(to have a uniform, hence lower, stress allowing a softer, grippier compound), also the extra width reduces distortion
narrow grooved tyres have much more distortion, hence show more 'slip angle'
as you show, most of this change was around 1965-1970 (Brabham was a leader in this tyre width etc development)
true, large 'slip angles' have a broader range around max grip, which helps any driver
true, with current tyres large angles can only be developed beyond max grip ie sliding
but IMO the cause is not aero, it's 50 years of tyre improvement
Well sliding is a vast term and i'm not qualified enough to speak about tyres dynamics except that for me (and i think for everybody) a car is sliding when tyres can't produce the desired lateral force and thus to me it means the center of gravity "slides" even if there's still grip produced.
And starting from this, new racing tyres allow much less sliding because they have very narrow slip angles windows. When you think that an F1 tyre produces its max lateral grip at 3° slip angles it tells you a lot on how the grip falls past that window.
But this wasn't my main point; My main point is that 4 wheels slide (and to me it was a real slide, but as i said i'm not a tyre expert..) that you saw in the 50's it not possible anymore because mainly of the speeds and the main "culprit" is the downforce because not only it allows for faster cornering but also better braking and better acceleration. Of course tyre developpment has a part in that but driving techniques of modern high level formulas is totally different from the 50's or even nowadays low grip cars cause you can't drive them on the limit, if you do the actual cinetic energy levels will put you in the wall (you just have to think about the size of runoffs now). That was why i said i think you won't see any 50's kind of drifting soon, except of course if you reduce cornering speeds, and any powerslide except of course if you go back in term of stability.
So i wasn't necessarily disagreeing with you, except that i think the modern formula behave very differently from the older one.
I suspect that tires and aero down force are independent but complementary factors in the tidy fashion cars now corner. Even in other types of racing, oversteer is not as prevalent as it was years ago –dirt and similar low-grip racing aside. While it is possible to run fast leaning on the outside rear, tire wear there is greater than with an also fast more balanced setup. Modern tires seem to do better when run sans exaggerated oversteer.
As has been mentioned, F-1 cars have such developed such delicate aero characteristics that yaw upsets the flow and is counterproductive. Using up the tires and losing down force is pretty much the state of things now regarding hung-out racing.
I think much of the visual of old F1 racing is two wheel drift with the rear hung out and all.... which is slow. Don't think you'll find anyone looking to go slow.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.
the modern F1 etc car has a very high power:weight ratio, and uses tracks designed around this ('for safety')
corners are numerous and tight ie just an entry and exit with little/no middle phase
(faster corners are often not roadholding-limited, but limited by V8s lower power)
so corner exit dominates lap time, often the chosen line sacrifices apex speed to ease/improve exit (cornering+acceleration)
(older cars ie lower power:weight ratio often maintain apex speed without affecting exit)
this factor also dominates MotoGP
this is exactly the opposite of the situations that produced real and conspicuous drifting ie the 50s and early 60s
(since when people have complained about its perceived absence)
Lola & Lotus in particular followed Vanwall, dominating with designed-in understeerish drift
(drivers always liked the fun/safety of oversteerish design eg Maserati, or possible setup eg Cooper)
managing understeer allows more power (though unspectacular) through corner exit (eg Prost, Alonso)
(which is where we are today, where data and race engineers dominate setup)
hanging the tail out looks quicker than it is (and always did)
any rwd road car will (4 wheel) drift if you stiffen the rear springs about 20% to kill the standard understeer
on corner exit bring the power in strongly, front and rear slip angles increase together, steering ineffective, that's drift
starting before the apex is the real test, the car must be aimed to run off the inside of the corner, then drift
Last edited by Tommy Cookers on 29 Aug 2012, 11:28, edited 1 time in total.
