Compound Cornering

[Mike Broadbent]

We are producing a whole series of in-depth articles with some professional race drivers discussing Advanced Circuit Driving Techniques.

Here is the first one:

In this article we will be discussing Compound Corners which are common to almost every race circuit, with accomplished race driver and personal coach, Nigel Greensall. You can click on any of the screenshots to view a full size version.

Definition

Compound corner: a series of corners, close enough such that the car is always turning and never travelling in a straight line.

The following data was taken from a Funcup race at Misano in 2009:


Nigel driving in the Funcup Misano 2009

Nigel Greensall- ‘It is a common mistake to treat compound corners as two separate items, whereas they should be tackled as one section, with sacrifices being made in the first corner to gain maximum exit speed. It often seems counter-intuitive not to maximise the speed through the first corner, but the end result is often a faster lap.

There are many examples, but let’s take Misano Circuit which is shown on the left, Turns 12 and 13 which consists of a shallow right hand corner followed by a sharper right hand corner.

On first inspection you may naturally assume that you have to clip apexes of both Turns 12 and 13 to get the best lap-time.

However, there are many other ways to take these corners and I have found that the quickest for me is to almost ignore Turn 12 by missing the apex completely, and set yourself up for a nice wide entry into Turn 13, which seems a little odd at first.


Misano Turns 12 and 13

Two different lines
To see this line in action, have a look at the image on the left, which shows my preferred line in red, and my team mates line in blue.

The red line misses the apex of Turn 12 by almost 2m, but maintains the same apex speed of 105mph as the blue line which clips the apex.

Interestingly, through Turn 12 you are not quite on the limit of grip (a peak of 0.85G), so you can experiment with your lines through here without losing any speed.

This wider line is also slightly shorter, which also gives a small advantage.


Missing the apex of the first corner allows a wider entry into the second

The screenshot below shows the apex point of Turn 12, where both approaches have the same speed, 105mph.

It is after this point where the reason for this wider line becomes clearer.

If you treat Turn 12 as a conventional corner and clip the apex, you cannot get far enough across to use the whole width of the track into Turn 13.


Even though the line on the right misses the apex, the apex speeds are identical

By running wide in Turn 12, you can get much further over to the left for the entry into Turn 13 allowing more speed to be carried around the corner.

Using more screenshots from the in-car video, you can see just how much closer to the edge of the track (just before Turn 13) I could go, whilst carrying 7mph more speed:


I am now 2m further over to the left for my turn in to Turn 13, and carrying 7mph more speed

If we look at the Apex speeds of the second turn using Circuit Tools software, the gain in speed is even greater:


At the apex of Turn 13, I can carry 11mph more speed due to the resulting wider line through the corner

In this screenshot you can see that the wider line allows me to carry 11mph more at the Apex, the upper graph is the speed, and the lower graph is the Delta-T or time difference between the two laps.

The analysis software showed a total gain of 0.67s in this section, which was very simple to achieve, just by taking a slightly wider line through Turn 12, which is very easy to do!’


If you would like to receive the rest of this article as a .pdf, sign up on this page: http://www.videovbox.co.uk/frdb1

[Sider]

Hmmm, interesting, I'm off to read the rest!

[leecavturbo]

very useful. great thread mike

[MichaelJDrost]

Indeed fantastic stuff! Thank you very much! I also loved seeing the Dubai 24h as an example. That event is run by a group of Dutchmen (Gerrie Willems and Ivo Breukers) and the organisation is staffed by people from the DNRT, Huub Vermeulen's Dutch Club Racing organisation.

I guess that means Nigel now knows what a code 60 is

Michael

[Mike Broadbent]

For all you Nordschleife fanatics, there's an excellent thread about this developing on the Northloop forum: http://z8.invisionfree.com/Northloop...pic=26403&st=0

You'll have to register to view it.