2011 F1 Season Preview - Overtaking: A turbulent topic

For years there has been a perceived lack of overtaking in F1. But is this really the case, and where do you begin to improve it? There are a number of answers…
By Pat Symonds

There are few subjects in motor sport as emotive as overtaking, particularly in the context of Formula 1. It seems as if everyone has an opinion and many have a solution and yet, in spite of the perceived importance of the topic, there has been little true research into what is desired and how to achieve improvement.

One of the first difficulties is separating fact from fiction. It is often stated that there was much more overtaking ‘in the old days’. Is this true? Unfortunately, the truth is not easy to determine. A number of sources have attempted to examine this but the data, particularly before the days of electronic timing, is sparse.

Some years ago, the FIA tasked the late Jabby Crombac, a well-respected journalist who had been following F1 since 1948, to compile some statistics on overtaking. He did this by reference to lap charts, as these were the only source of data prior to electronic timing being introduced in 1983. His analysis, which covered the period from 1955 to 2000, showed a peak in overtaking in 1963, followed by a rapid decline from then until 1975 and a general further decline to 2000.

This may seem logical data from which conclusions can be drawn, but is it? The reality is that while it provides something of an overview, it is not detailed enough to be used to conclude the reasons for the outcomes. For example, if a pass was only determined to have happened by a change of position on a lap chart then anything that may have occurred elsewhere on the lap is automatically ignored. In the early days there was no such thing as sector timing and very little, if any, television coverage with which to enhance the data.

There is also no normalisation of the data; it merely shows the total number of manoeuvres per year. The peak in 1963 occurs in a year when there were just 10 Grands Prix, three more than in 1955 but well short of the 16 that were held in 1984 when a second, smaller peak occurs.

More recently, the advent of sector timing, television coverage and the internet has improved the ability to examine data. One of the best sources is an internet site called Clip The Apex, which has tabulated overtaking manoeuvres since 1983. After 2003 the data is enhanced by reference to television feeds. First-lap overtaking is ignored, as is overtaking backmarkers and position changes that come about as the result of a pitstop. It also adds a vital item of information in showing which races were wet. Unfortunately, even something as simple as this is not clear-cut. For example, if a race starts with the competitors on intermediate tyres but by 10 laps in they are all on dry tyres, should this be counted as a wet race?

Such data can start to give trends but little more than that. Nevertheless, it shows some interesting points which only serve to illustrate the danger of generalisation. For example, it tends to confirm the impression that there had been a general decline in dry race overtaking up to 1996, but from then it was relatively static until 2010. It also shows the generality that more overtaking takes place in wet races than in dry, although it cannot determine the effect of cars being out of position as a result of wet qualifying (Melbourne and Suzuka 2005, for example).

Such generalised statistics, while interesting, do not ultimately help a great deal, nor do they provide clues as to what is desirable.

When FOTA conducted an audience survey in 2009, with respondents ranging from infrequent to avid fans, it found that overtaking was rated the third most significant attractor by all spectators. This, perhaps, is unsurprising, but what was unexpected was that of all types of fans, 62 per cent felt that the amount of overtaking was about right. Even more unanticipated was that occasional fans were less critical of the lack of overtaking than were devoted fans.

I firmly believe that it is possible to have too much overtaking. I think that a well-executed overtaking manoeuvre should be a highlight of an event. It should be compared to a goal scored in a football match, not a basket scored in a basketball match. In cricket terms, it is the fall of a wicket rather than the score of a run. The ideal race should be won by a driver who has fought his rivals to clinch victory. Unfortunately, while races are organised so that the starting grid places the fastest at the front, this is unlikely to happen. Indeed, this ordering of the field inevitably leads to competitors spreading out.

So, if one accepts this thesis, overtaking should not be made too easy. It should remain a challenge and a differentiator of performance that the spectator will applaud rather than just acknowledge. The problem then is how to get the correct recipe – a recipe that allows judicious overtaking while maintaining other aspects of the sport, such as technology, at a suitable level.

In order to do this it’s important to understand the mechanism of overtaking. An F1 car is around five metres long. To execute a clean overtake it therefore needs to gain at least 10m on the car in front. If we consider the entry to the hairpin at Montréal as an example, this is around 610m from the previous corner, with a fast car taking around 8.3 seconds to cover this distance. This equates to an average speed of 265kph (165mph). For a clean pass on a slower car, that slower car should only cover 600m in this time, at an average of 260kph (161.5mph). If this 5kph deficit were taken over the whole lap, it would equate to a huge two-second a lap difference. Herein lies the predicament.

It is a widely held belief that the root of the problem lies in aerodynamics. To some extent, this is true. An F1 car relies on aerodynamic downforce for its remarkable performance and even a small reduction in this downforce will be keenly felt. Racing cars are developed in the assumption that they are running in clean air. Every surface is carefully arranged to maximise downforce and minimise drag under these conditions. Other attributes are also carefully considered such as the sensitivity of the downforce to changes in car attitude. All the time, however, the air is considered to be travelling horizontally and smoothly towards the car. When a car is following another this smooth air is disturbed by the leading car, and not only is its approach to the following car no longer horizontal, it is in fact turbulent.

Now turbulence is an extremely complex phenomenon. Einstein is alleged to have said, “Before I die I hope someone will clarify quantum physics for me. After I die, I hope God will explain turbulence to me.” Complex as it may be, it is well known that it has a significant adverse effect on the aerodynamics of a car. Experiments carried out by Ferrari at Monza in August 2004 showed that turbulence started affecting a following car when it closed to a distance of around 60 metres, and by the time it was on the tail of the leading car up to 30 per cent of downforce could be lost. A 10 per cent loss of downforce translates to a second lost on a lap, and so it is easy to understand why it’s hard to keep close to a rival in a corner.

There can be, however, a positive effect of running in a slipstream and that is reduction in drag. Saloon cars and F1 cars of the ’60s made use of this to gain a slingshot for overtaking. In those days a slipstream gave a positive advantage to the following car; today it is negative.

In the early ’90s, some academic work was done on the effects of slipstreaming. It was not, however, until the Grand Prix Manufacturers Association commissioned a study in 2005 that a professional experimental study of overtaking aerodynamics was made. This in turn formed the basis for a later study by the Overtaking Working Group (OWG) in ’07. This group, of which I was a member, was tasked with devising a set of aerodynamic regulations that would reduce the problems associated with downforce degradation in a wake.

The work was done using two quarter-scale cars in the FondTech wind tunnel in Italy. It would have been better to use a larger scale, but the tunnel size imposed limitations. Each team contributed to the costs, as did the FIA when funds ran short to finish the work. The amount of time spent in the tunnel was very limited at 16 days spread over four months. From this basic understanding a set of rules were written for implementation in 2009 that were intended to both limit downforce and make the wake more benign. Unfortunately, the advent of the double diffuser and the teams’ general inventiveness lifted downforce levels much higher than had been anticipated as well as negating much of the wake flow work that had been done. Nevertheless, statistics show some progress was made, as the amount of overtaking in 2010 reached the highest level for 17 years.

While aerodynamics seem to get the lion’s share of the blame for a lack of overtaking, it is far from the only factor involved. Simple logic shows that F1 cars, each having essentially similar aerodynamic characteristics, ran on 19 different circuits last year with, in the dry, overtaking ranging from just four instances in Monaco to 65 in Montréal. Clearly, there is more to the problem than just aerodynamics. Equally, different categories of cars such as GP2, running on the same circuit, have produced more overtaking than Formula 1.

With the exception of Monaco and Monza, a wet race generally leads to a large increase in overtaking. This belies the theory that increased mechanical grip improves overtaking as the wet track provides just the opposite. I think the very nature of these two circuits, as well as the caution required to drive them, is why they show up as abnormal, but why should lower grip encourage overtaking? Certainly lower and more unpredictable grip will lead to drivers making mistakes, but in the case of the wet track a new and more important attribute is apparent. This is the ability to use more than one line. Unfortunately, with the soft dry tyres used in F1 these days, not only do they shed rubber at an alarming rate but, because they rely a lot on ‘chemical grip’, they are extremely prone to loss of performance when they are not running on clean asphalt. In the wet cars often enhance their grip by running off-line, thereby opening up a further chance for overtaking. Racing in the dry on a harder tyre that both reduces the generation of ‘marbles’ off-line and is less susceptible to grip loss on a dirty track may have a similar effect.

So is this an answer? Unfortunately not, as the tyre would have to be significantly harder and this would mean that the performance profile of all the cars through the race would be similar. With a soft tyre that gives good performance for a few laps and then degrades, there is a significant difference in lap time between cars on new tyres and those on old. It is this that led to the 65 overtaking manoeuvres in Montréal in 2010 and even to Silverstone providing 46 passes in ’03.

Psychology may also be a factor. A GP2 car is essentially a scaled-down F1 car and is likely to have similar aerodynamic characteristics. It also runs on a tyre that is only slightly harder than its F1 equivalent, and yet overtaking in GP2 is much more prevalent. I think this may have a lot to do with incentive. A GP2 driver still has a lot to prove and knows he is being watched and assessed by F1 team principals who are likely to be impressed by aggressive driving. In F1 almost the opposite is true. The race is just a means to an end, with that end being championship position. With a place gain in the midfield only being worth two additional points it is sometimes not worth the risk of overtaking for fear of losing the points that are already in the bag.

Circuit design too has long been recognised as a significant factor and an extremely comprehensive analysis of this was done by Toyota shortly before it left F1.

Its team surmised that a slow corner leading onto a long straight that in turn was followed by a slow corner was likely to lead to a good overtaking opportunity. They then examined every sector of every dry race between 2004-08 to see if they could prove this. Having indeed proven it they then examined the characteristics in more detail to arrive at a favoured geometry for encouraging overtaking. This suggested that the features needed were a slow corner with an apex speed of less than 120kph (74.5mph), leading onto a straight of at least 1000m in length with heavy braking into a corner with an apex speed of less than 100kph (62mph). The second corner required flexibility of driving line and so should not be a chicane. They regarded this as a minimum specification, and that overtaking increased progressively as apex speeds reduced and the length of straight increased. From inspecting their data, I would add that ideally the second corner after the straight should turn in the same direction as the previous corner, so that if the manoeuvre was not completed the overtaking car would still be on the inside line. This is exemplified by turns one and two in Sepang, where the pitstraight barely meets the minimum requirement and so overtaking into Turn 1 is often not completed. The overtaking car, having forced the inside line at Turn 1, is then pushed to the outside at Turn 2 and loses its hard-fought advantage.

So, overtaking is a complex problem. Perhaps, then, we should examine the philosophy more closely. The current competition solely rewards the fastest, most reliable car ensuring that every designer concentrates on ultimate clean air aerodynamic performance with the aim of getting pole and driving away from the opposition. If the fastest car were not guaranteed pole position then a significant proportion of that aerodynamic research would be directed to ensuring good performance in the wake of another car, as this would be a key ingredient of success. Are reverse or semi-random grids really an affront to the meritocracy, or merely a way of ensuring that we supply what we are paid to do – provide entertainment?

With many different facets to the subject, no single one of which will provide a complete solution, it is perhaps time to have a coordinated long-term strategy aimed at embracing all aspects of the topic in a coherent manner for the good of all.