This confirms the old and well known Chinese proverb: mechanical engineers build weapons, civil build targets.
I also have a picture for this thread...
Allow me to quote Nick Heidfeld, on Curve 1 at Shanghai.
"You approach the first turn at high speed and enter it flat-out but then the corner increasingly tightens up and you have to shift down to second gear. Making a clean exit will be even more interesting next year when we'll be driving without traction control again."
Now, contrast the many trajectories you can find in this curve at the meleé following the start of the race, compared with a regular curve and conclude something, please.
Take in account that along the whole curve the
side slope is also increasing, which explains in part Heidfeld difficulties, who said that he found the curve very interesting. However, he said he didn't liked it. I think I know why: I think that these curves are not forgiving.
Second point: think again for a moment what it means when I say that
all curves are spiral, only that in this one the spiral is very noticeable, because the designer choose a very long transition.
To me, with all due respect, it means to me that you are not understanding completely the subtleties of the other curves. Of course, I might be mistaken and there could be other reasons behind the designs "correcting" the circuit that I see.
However, I believe that if you really understand how a road is built it could mean a couple of seconds per lap in a kart.
Third and final: again, which one of the curves in the picture I posted before has spiral transitions?
For some people is confusing to learn that the bottom one is the spiral one (the "snail", as you've called it). I also swear on the soul of our Father and Master Terzaghi that
both curves have the same radius.
Notice how the perspective "hides" the steep descent
after the curve, at the bottom of the valley. The descent is the same, but it seems to disappear.
I bet many drivers will make mistakes when judging the braking distance in the second, spiralized curve. Why? Because braking distance increases with slope and if you, as a designer, are able to "hide" the slope a bit, then... you got them, drivers.
Look at what we're losing by omitting this kind of curves. This is a slight curve (30 degrees of deflection or so) and, of course, these effects are magnified at Shanghai #1
I know I have not been able to explain well in this forum how important the sideslope transition is. I also know that most people is not conscious of the steering corrections they make in the first curve (that you can find in MANY old roads made in the 70's or 60's), but they do correct the car. Believe me, you do it, but you have to watch yourself to understand how you do it.
In the second, bottom of the picture curve, you have a different feeling: the lateral acceleration of the slope is proportional to curvature. On the bottom picture curve the rear end is more settled and you don't countersteer intuitively in the entrance.
It is a not so slight difference: in the curve at the top of the image you have to steer to the left during the whole approach, because the sideslope, even in a straight part of the road, is inclining to the right gradually and this lateral twisting of the road is throwing you to the right.
If you watch yourself in an old road, you'll find that when taking the top of the image curve,
during the approach you have to steer toward the left around one eight of a full circle, to keep the car on the road. Not until you reach the actual curve you stop countersteering to the left and then steer to the right to take the curve. The closer you are to the curve, the sharper the left countersteering you are forced to make.
I repeat, next time you drive on an old road, watch yourself. Then you'll understand the difference between spirals and circular curves.
All this is magnified at a "full snail" curve, but it happens at every modern curve, which has those "little snails" in the entrances. The effect depends on the magnitude of the spiralization.
Now, do you really take that in account when racing?
All I say is that
you can do it when designing, to trick the less able drivers.
I know many old tracks with circular curves. Monaco is one. Catalunya is another one. I am pretty sure about the second track, as I've analyzed it a LOT. I've measured each and every curve and I have contacted the track owners to get actual sideslope plans.
Actually Catalunya is quite confusing. The old part of the track has not been modified, so it keeps the old strictly circular curves, with transitions in the straight, but also includes an "experiment" made by the designer which is the exit of Repsol. This is not an spiral but a parabolic curve, a cubic parabola, in orange.
In green, straights; in red pure circular curves; in orange cubic parabola
The design of the sideslope in this curve, surprisingly, follows the rules for railroad tracks, with the end result that an optimal strategy involves to be able to push the throttle strictly
proportional to the length of the curve... tricky, when you consider that the next curve is a strictly circular one with a radius of miserable 30 meters that you have to take at the incredibly slow speed (for an F1 car) of 110 kph.
To summarize, I am, frankly, enchanted every time a car goes off track at some curves in more modern circuits, not because they are pushing to the limit, but because, clearly, the driver, a professional, misjudged the curve. This is what I call a race track design.
Of course, you cannot take this to the limit, because racing tracks are also to be enjoyed by drivers, and it is not the idea to make them so uncomfortable as for them to suffer through the track subtleties, but you I hope you get my idea: being some parts (not all!) of Tilke designs true "first timers", the reception of the public has been frigid. I think they do not get the point, but there is one.
So, puhleeze, I implore you: do not propose to destroy what you don't understand. When I cut daisies I do it by hand...
I think Tilke is an artist. Not the best in the whole world, because then, who is that, but an artist he is, as good as Ed Bargy or Alan Wilson.
I'm sure that over time better designers will pose more intelligent challenges to drivers, but I am also sure that among all the lack of time I have to write a coherent and briefer post, some ideas of Mr. Tilke have now been better understood.
