Imola this time around

[Ciro Pabón]

Sorry, this is going to be long.

I agree: putting a "mild" chicane with high kerbs in a track is stupid. You could as well put a speed bump in the middle of the road. I would close my eyes every time I entered the curve, I bet.

I have suggested before blending a little mechanical and civil engineering knowledge: every little spec in the car is subject of animated debate but road changes are good as long as they do not break a couple of teeth of the pilots! Millions are invested in the cars but pennies on the road.

I ask for full correction of defective curves:

If a curve is giving you problems because it is too fast and long for the tire temperature, or too narrow for the degree of curvature and the speed, (you can pass in any curve if you make the road wide enough, guys!) then correct the curve. But no: the answer is always to put a chicane before the curve!

Good way of thinking: with a couple of empty oil barrels on the straight you do not have to spend some tens of thousands of dollars on the curve. Do not worry if you spend more money on practice tires...

If you have to make a chicane, try to make it like the one in the photo posted in this thread. Chicanes that deviate you barely a track width from your trajectory are, well, hard to understand.

I do not know if the tracks are the Cinderella of F1 and I am not happy with so much hairpins and chicanes. You have 900 hp or whatever cars optimized for aero down force at 150 kph because this is the curve radius they'll get! F1 is almost (well, I may be exaggerating ) a braking contest, like a stop-and-go drag race with several quarter mile tracks joined by flimsy curves. Just four words: too much down force! Of course, I find that Karts are fun because you can slide, I guess.

Some of my colleagues are surprised seeing that a four radius curve is a novelty for F1 fans... This kind of curves went extinct around the 1950's in public road design.

Modern road design emphasizes spiral transitions, with almost no fixed radius curves, so you can have smooth super elevation transitions and the axis of the road follows the optimal trajectory. Take a look at my avatar...

This gives you plenty of trajectories if you calculate the width ample enough for two cars side by side and a “bumpless” road (relative to a circular curve track design) because the side slope is always proportional to curve radius.

Most people is not aware of this, but take a look at your steering wheel next time you are on a really old road: you have to turn left when you are on a straight entering a right hand curve, because the side slope is increasing while you are still straight. For the suspension guys, this increments your “natural” under steering at the beginning of the curve.

I would appreciate if anybody can explain to me why the principles of road design do not apply to F1 tracks. Am I mistaken trying to extrapolate my road design experience to tracks? I have only worked in two racetracks (Rosario and Tocancipá), and not very important...

I am not sure, because I am looking at track layout from Google Earth photos, but I could swear that Catalunya has several curves without transitions (I have spent several hours with the satellite photos in AutoCAD) I do not think so, because this would imply major ignorance. Does anybody knows if I am wrong?

Sorry, it touched a sore spot. I will never, ever make posts this long. :^o

[jaslfc]

dont care what they do to the track.. just as long the race is still exciting

[zac510]

Ciro, I think the problem with multi-radius turns in modern F1 stems from the movement of the C of P upsetting the balance of the car.

That said, turn 1 at Shanghai...

[Ciro Pabón]

Ciro, I think the problem with multi-radius turns in modern F1 stems from the movement of the C of P upsetting the balance of the car.

That said, turn 1 at Shanghai...

Exactly: that is why I advocate for pure spiral curves. This, with an appropiate superelevation, should give you a constant load on the suspension. Am I wrong?

[dumrick]

To Ciro:
Isn't there a huge difference between designing roads and tracks, in the sense that in the earlier you must make it comply with the dynamic abilities of the cars and, in a racetrack, you are supposed to challenge them?

[zac510]

Good point dumrick, designing the tracks is probably becoming more like designing a road!

Ciro, but as the speed changes through the corner, the CofP will change. Now I understand your avatar at least

[Ciro Pabón]

This is just one example of what intrigues me: compare the entry and exit curves of Repsol, at Catalunya: it is (maybe) only important to have transition (yellow) on the exit? Only when you are accelerating?

What about the entrance (red)? The geometric designer supposed that you could go from straight to curve in an instant at the entrance, because you go from straight (green) to circular (red) without any apparent transition (and I worked with 5000x3600 pixel photos; if this red thing is not circular I will swallow my hat. Well, my hard hat).



Nobody will take the entrance to this curve following the inner kerb, not even Superman. You should flick your wheel from straight to curve in the blink of an eye.

Besides, imagine the frontal view: the green entrance (to the left, of course) is flat (well, almost). The red curve has superelevation. Where is the transition from flat to inclined made? In the straight. What about the lateral displacement of COG at the entrance? This is the kind of design I do not understand. I would not make the humbler road in Colombia like this...

Can somebody explain this (apparently) poor design?

[manchild]

...Nobody will take the entrance to this curve following the inner kerb, not even Superman...

I agree, driver must keep car outside approximately all the way to that yellow mark 112,91.

[Ciro Pabón]

To Ciro:
Isn't there a huge difference between designing roads and tracks, in the sense that in the earlier you must make it comply with the dynamic abilities of the cars and, in a racetrack, you are supposed to challenge them?

Yes, you could challenge them, instead of ignoring them (apparently)...

Ciro, but as the speed changes through the corner, the CofP will change. Now I understand your avatar at least

Well, I think that for you to understand it completely you could take a look at this:



It is funny that F1 cars (as Manchild says) follow the curves of nautilus or the growing of plants. Beauty is in the eye of the beholder...

And, yes Virginia, there is braking at the entrance and acceleration at the exit and CofP change. This is the point: you have to change the sideslope at this points, not in the straight, preferably while you are changing the radius from infinity (straight) to the value for the curve.

Well, enough of going out of the thread.

[zac510]

Can somebody explain this (apparently) poor design?

Ciro, who said the corner is of poor design?

It is not unlike the famous Parabolica!

[Ciro Pabón]

Ciro, who said the corner is of poor design?

It is not unlike the famous Parabolica!

I say so. I may be mistaken, of course. Please, try to imagine the vertical view of the road... there are problems with the superelevation, as I tried to explain (without succes, I guess). You have superelevation on a straight!

The Parabolica is precisely a long, long transition curve: hence its name, even if, at that time, logarithmic spirals were still waiting to be applied to road design. And I think it is a really dangerous curve, if you ask me, because it is not well suited to modern cars. http://www.f1technical.net/articles/20 This, or modern cars are not well suited to the curve, make your pick.

I guess the difference is small to the untrained eye... Actually, to "correct" Repsol you should move the curve less than a meter or so. But you have to do it along the whole curve.

[zac510]

The challenge of Repsol must be the hidden apex. If you miss it you would lose a lot of speed.

[Ciro Pabón]

The challenge of Repsol must be the hidden apex. If you miss it you would lose a lot of speed.

Good point. You are right. The apex is actually at the line marked 104.52 (which is actually the length of the curve in meters), in the middle of the red curve.

It is not closer to the point of union of the red and yellow lines, at the top of the photograph, as you could think at first sight.

Actually, this depends heavily on the yellow part of the track: I think it depends on how you regulate your acceleration at the exit what indicates if you are going to exit with understeer or not. A more powerful car should take an earlier apex.

[DaveKillens]

It is my philosophy that a racing track should be quite different than one used for day to day traffic. In road engineering, it's a responsible engineer who designs a roadway that throws no hidden or unwanted surprises at an unwary driver. A good example would be an on ramp for an expressway. Uusally they are 270 degrees, and take the vehicle from 50 kph to 100 kph. So as the driver turns and accelerates, the road slowly unwinds and gently feed them towards the main artery. To have a sudden diminishing radius corner would be a definite source of accidents.
But on a racing track, it should be just the the opposite. In the history of tracks, they were first adopted from local roads, which at that time were just laid out as the locals and terrarin allowed. And the drivers just had to deal with whatever was there. Yes, there were definitely some very unsafeplaces, and sadly, to this day there are still some being used. The Isle Of Man be historic, but as dangerous as they come.
But my own personal definition of racing is to have the drivers deal with difficult terrain, that is one of the deciding factors in skill. If you designed a track that did not challenge the driver, you wind up something called "Talladega".
Safety must never take a back seat to anything else, but for me, to design in awkward and challenging sections is what I prefer. The old Watkins Glens track had a long straight, followed by a drop in elevation, followed immediately by a high speed right turn. Get it anwhere just a bit off, and you were in very serious trouble. To eliminate that section for fast cars is logical and safe.
Personally I like tracks that challenge a driver, force them to deal with awkward and challenging sections. Off cambers, esses that unbalance the car, things that force mistakes, and separate the drivers.

[dumrick]

My point exactly. I understand Ciro's view from a point of view of someone interested in minimizing the risks involved in road car operation. However, that's not the same the philosophy as that of a race track. If that was the case, any road would be testing the dynamic abilities of cars as good as a race track, and the Nordschleife (if it was designed under road engineering best principles) would be an ordinary place (just to give an example).