YouTube - ‪Tommi Makinen takes Tiff for a spin.‬‏
Damned link diddnt work:-) I tried google translate but I must have the wrong spelling, it thought it was an italian word.
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YouTube - ‪Tommi Makinen takes Tiff for a spin.‬‏
Damned link diddnt work:-) I tried google translate but I must have the wrong spelling, it thought it was an italian word.
It's spelled "perkele". Good luck. ;)Quote:
Originally Posted by tfp
Oh, this subjects is brought up again, and I'm glad about it.
This excact article was discussed in this forum in 2003 by Pentti, me and many others. I couldn't find that thread anymore. But let's do it again, unfortunately without Pentti.
In my opinion Erkki Pahkinen's article is really interesting but has many contradictions and aggravations.
The article has good points , but drawing conclusions based on some single photos is unprofessional.
There's some laws of physics that can't be won by drivers or engineers.
The basic rule, that counts in any car, is that the sooner you are able to point the driving wheels to the opening straight and accelerate, the faster you are, slow in, fast out that is. That speed of acceleration counts the whole straight, as high speed in counts only that short period of braking in and is usually followed by dramatic loss of speed outside the corner.
How is that done, there's different schools and opinions on that, even on top level of our sport.
Some basics of driving physics: the forces affecting the tyre count. There is certain level of friction to be used in either turning, braking or accelerating. The biggest threat is understeering, and killing that is the core art of driving.
I tend to emphasise my point by discussing a crisis situation. You enter a corner too fast and you have to be able to turn the car throught the corner, and despite that misjudgement entering the corner, you still try to maintain as much speed as possible.
Let's start with fwd where the problem is really acute. Turning is mostly achieved by the front wheels. And in fwd case, sadly, also the acceleration is achieved through the front wheels. That means that those two forces, both turning and accelerating are both "eating" the friction available, that means you can't both turn and accelerate in maximal effect without losing the grip. Everyone of us has probably experienced in my opinion the most unpleasant moment in fast driving, when the front looses grip and car starts to travel straight towards the direction of its mass. Because of that, you have to be able to turn the mass of the car in order to be able to start to accelerate out of the crisis. That might be done by scandinavian flick or left foot braking, which also brings some more mass to the front wheels and allows more grip to be available to accelerate and turn with your front wheels. In fwd the neat driving style is more crucial, as throwing the car around also throws the direction of the mass and center of gravity around, which means that those poor front wheels have a lot more direction of travel to change and less grip available to do it. Other important point of view is that if you concentrate on turning too much there's no room for acceleration, and wise versa. But still in fwd acceleration through a corner is crucial, otherwise the change of direction of travel, i.e. turning the car, is much less effective, you can drive through a corner at about double the speed, if you give some gas!
In rwd, my clear favourite, that case is even more obvious. In rwd the front wheels have a separate tarsk to turn the car and the rear wheels are working on acceleration. Also weight balance is better to give some more stability to rwd cars, that is why they are faster!
In rwd the rule is the same, slow in, fast out. In rwd you have to bring the car to wide angles in order to get the rear wheels point to the opening straight, in 90 degree corner that is 90 degree slide angle in to the corner. But that means also that it should be absolutely straight out of the corner, so no slide after the apex at all. That is the most common mistake, and many drivers ruin their performances by sliding around too much even thought the straight has already began. About Pahkinen's article, these is the point I agree the least. It doesn't matter where the front wheels are pointing in in relation to the car, it matters where they are pointing in relation to the direction of travel! Coming in a 90 degree corner normally requires opposite lock, and that is absolutely normal and "the fastest way" throught the corner, you just give it some gas and opposite lock slide nicely throught the corner accelerating as early as possible. If you don't steer opposite lock, the car spins around immediately, if you don't want to turn the front wheels to opposite direction, you can't accelerate, it is as simple as that! The more you give gas the more you need to adjust the direction of travel with your steering, rwd car is sort of 4 wheel steering car, really agile and rewarding..
In crisis situation the rwd is really good, that is why they are superior in Finnish blind rallies. You enter a corner too fast, you flick the car to wide angle drift and give it some gas, the power of the rear wheels is pointing to the inside of the corner and the turning angle of the car is minimized. I have had several close calls like that and it is absolutely amazing how well a rwd car turns in those situations, I have lost hope manymany times but just amazingly the car turns around the corners by that. Here's an example of another driver, check the BMW at 5:23 on that video:
YouTube - ‪Rantaralli 2.10.2010‬‏
In case of 4wd Pahkinen is absolutely right, in optimal case the car points towards the opening straight as early as possible and all the 4 wheels are accelerating the car at maximal force out of the corner. Still in that case, all the wheels have to bear both the turning and accelerating forces, as the direction of travel is changed.
The problem in 4wd is understeering, if you don't throw the car to point in the corner, the initial effect of acceleration is understeering. That is because the front wheels both accelerate and turn and initially the rear wheels only accelerate. That's why the rear wheels friction is higher and the front wheels loose grip first, so the front wheels have less grip and the rear wheels only push the car forward more and more. That is why 4wd is really challenging in blind rallies, you have to keep some marginal in to the corners. With high power car, the rear wheels loose grip fast and the car goes sideways after that.. But being fast in 4wd car requires a lot of commitment in order to avoid understeering. Ogiers roll in testing is a perfect example of 4wd skillfull driving, he almost saved that situation even though entered the corner 30km/h too fast... http://jannepievilainen.com/Ogier_te...r_testing.html
:) Thankyou, although, I have to say I'm dissapointed :DQuote:
Originally Posted by OldF
@ sami - Good video with the BMW, save of the day from the driver!!
If I understood it correctly, the focus is to first get the car to turn around it’s vertical centre of gravity in a way or another and at the apex minimize the transversal forces that drives the car to the outside of the bend to get the driving wheels (front, rear or all) to point to the direction where the car should go.
What I’ve noticed at least with 4WD cars, is seems that the drivers turn in to a bend turning the steering wheel more than necessary (video in post #23) and in that way get it to controlled slide where the mass is “pushing” the car to the outside of the bend and the wheels driving the car to the inside of the bend.
Can someone explain Petter Solberg's driving style and strategy? I don't get why he is fast on the opening day or gravel rallies when the others slow down, meaning that he has to sweep the roadsf for the following day, often causing him to lose the lead....
Must say I disagree with much of what you write, Sami. But explain this in a language other than my own, is difficult. So try to understand as best.
What we fight against is centrifugal forces. In all cars (except rear Weele drive cars with the engine mounted behind or above the rear wheels), the main part of the weight will be located between or slightly behind the front wheels. This applies even if the car has 50 to 50 weight distribution. It is this point that must be moved as straight as possible with as long arcs as possible to maintain the highest possible speed.
To create the longest arcs as possible through sharp turns, the driver must be able to place the car with great accuracy as close to Apax as possible. This is achieved very rarely with a car that has oversteering, or have a nervous behavior.
THAT'S WHY MOST OF (IF NOT ALL) TOP DRIVERS CHOOSE SETTINGS WHICH MAKES THE CAR TO THE NEUTRAL AS POSSIBLE, BUT TOOWARDS UNDERSTEERING. NEVER TOOWARDS OVERSTEERING.
The more grip the surface gives (asphalt), the less danger if oversteering occurs.
The less grip the surfase Gives ...................
Puh, hard to write in English, take the rest later.
As a private driver his sponsors exposure are essential and I remember Petter saying in some interview that whatever the final result is, it’s important for him and his sponsors that he’s leading a rally at some point to get more exposure.
Thank you for explaining that. It just seemed illogical that he would lose time on purpose. Now I get it. What do you think of this style? Is not not appropriate for this ear?Quote:
Originally Posted by OldF