Germany Preview Quotes: Renault

Jarno Trulli

Q. Jarno, Hockenheim holds good memories for you: are you looking forward to racing there?

JT:

I am definitely looking forward to arriving in Germany. I have always enjoyed racing at Hockenheim, ever since I was in German Formula 3, and even since the changes, it is a circuit I enjoy. It is technical again, because although most of the corners are low speed, you really need to concentrate on good performance through them and also responsiveness through the quicker sections, so the correct compromise can be quite difficult to find. There is a big physical challenge with the heat which is a good test and, of course, I scored my first podium there for Renault in 2003.

Q. Are there any after-effects from your Silverstone crash?

JT:

Not at all. The car did an excellent job protecting me, and I felt fine immediately after the race. I just want to get back in the car, and put in a more positive weekend than we had in Silverstone. We didn't achieve the performance we wanted in the race, and that was a disappointment, so we must step up and take the fight to our immediate competitors.

Q. How optimistic do you feel ahead of the race?

JT:

Predictions are becoming so hard to make - we really have to wait until Friday in order to judge where we stand, once we have tried the tyres. Getting that choice right will be absolutely critical, as it seems that each weekend, it is a different Michelin team challenging Ferrari: for this race, we will be working hard to ensure it is us so that we can consolidate our championship position. We have updates to the engine and the aerodynamics, and they will definitely help us with these objectives.

Fernando Alonso

Q. Fernando, what are the challenges for the drivers in Hockenheim?

FA:

Hockenheim is often all about concentration for the drivers. It is usually very hot there, so the conditions in the cockpit are quite demanding, and to be quick we need to be very precise in how we drive. There is a lot of heavy braking into slow corners, and especially on heavy fuel loads or in the race on worn tyres, the slightest slip can mean that competitors will get by you on the exit of the corner. This is a circuit where overtaking is quite easy at certain points, and if you make mistakes, the cars behind will often punish you.

Q. What about the car: what areas does it need to be strong in?

FA:

Well, with the current layout, the most important areas are getting good mechanical grip, and also very good traction - but keeping the top speed quite high into the hairpin at turn 4. The R24 has been strong in these areas, as we have seen at circuits like Monaco and Montreal, so I think we should be optimistic. Equally, the team will be looking to bounce back from Silverstone with a good result.

Q. In terms of performance, what can we expect?

FA:

Personally, I was pretty frustrated after Silverstone, because I spent the whole race following slower cars and just couldn't find any clear track. So hopefully, we will have a problem-free weekend so that we can run at our proper pace. However, this year, it has become more and more difficult to predict who will be strong at which circuits: we have expected to be good in some places where we were not, and have had a nice surprise at other circuits, like France. A lot will depend on the tyres, of course, but we will hope to be one of the main challengers to Ferrari on Sunday afternoon. We need to start scoring points again to maintain our championship position.

Bob Bell, Technical Director

Q. Bob, how well do you feel the Silverstone race reflected the true level of performance of the car?

BB:

We knew Fernando would struggle to make an impression from his grid position, and that was borne out in reality. Admittedly, he was not running in free air when his tyres and fuel load were optimum, but whatever the circumstances, we were not as competitive in reality as we should have been, and that was particularly true in Jarno's case. However, what we were particularly reminded of was that any unreliability will cost us: every team's reliability is up, and only one car running ahead of Fernando retired during the race. It is imperative we maintain our hitherto good record in the coming races.

Q. Overall, how delicately poised do you believe the championship situation to be?

BB:

We have seen a number of teams challenging Ferrari this season, including ourselves, but nobody has been unable to do so consistently. That no doubt reflects the fact that while we, and our direct competitors, have particular strengths, Ferrari have achieved an extremely high standard in every area of vehicle performance. McLaren have now joined the battle at the front: while many people were very quick to write them off this year, we have never taken that view, but it now remains to be seen whether they can turn their Silverstone pace into consistent race by race speed.

Q. Looking ahead to Hockenheim, what are your performance expectations?

BB:

Firstly, I think we will all appreciate getting back into the normal fortnightly rhythm of races after a frantic mid-season period. In terms of performance, Hockenheim could prove a good circuit for us. We ran well there last year, taking third and fourth, and the R24 has been strong at circuits featuring lots of traction events and heavy braking, as Hockenheim does. The cooling on the R24 is extremely good, and this will be important in the high temperatures, plus we will also introduce further aerodynamic developments. Both drivers performed strongly in Germany last year, and we will certainly be hoping to start scoring points again.

Rob White, Engine Technical Director

Q. An engine update is planned for Hockenheim: what can you tell us about it?

RW:

In Hockenheim, we plan to race a further evolution of the RS24B. This concludes a cycle of development based on knowledge and experience accrued since the introduction of the RS24B at Imola earlier in the season. Specifically for the German Grand Prix, there are new pieces in the bottom end, and engine operating conditions are customised for the Hockenheim circuit. Further small steps will follow, based on a revised cylinder head from Hungary onwards.

Q. Silverstone saw the first engine failure of the year: what happened, and is it a source of worry?

RW:

The failure of the engine in Fernando's car at the end of practice on Saturday came without warning. There was a problem concerning the timing gears that drive the camshafts that had not previously emerged in dyno and track testing. Rapid analysis at Viry allowed a countermeasure to be implemented and dyno tested on the engines for Hockenheim. The engine build group responded fantastically to the inevitable disruption and we are optimistic we have fixed the problem, despite the accelerated approval process.

Q. Hockenheim demands good torque from low engine speeds and the last circuit with this dominant characteristic, Montreal, suited us very well. Is torque a particular strength of the RS24?

RW:

The continuous improvements in chassis and tyre performance add relentlessly to the demands on the engine. The search for increased power continuously drives engine speeds upwards, yet low and medium speed performance remains important too. The RS24 has a torque curve and power delivery that is well liked by the drivers. This is a result of well-focussed development by the Viry team and good work by the track engineers in calibrating the engine control systems to the drivers' needs and preferences. However, Silverstone also reinforced the importance of achieving faultless reliability. The target for Hockenheim is to conduct a race weekend without incident, which is always the best starting point for a good race result.

The Engineer's View, Pat Symonds

One often hears Formula One engineers, and others, talking about tyre degradation. But exactly what is it, and why does it matter?

In simple terms, there are two main factors affecting race strategy: the amount a car is slowed down by carrying a heavy fuel load, the 'fuel effect' (usually represented as a penalty of x seconds for 10kg of fuel), and the amount the car is slowed down as the tyres 'wear'. Tyre degradation is a complex subject because not only does it vary circuit to circuit, but also year to year at any given circuit, and even day to day. The reason for this is that there are three fundamental types of tyre degradation.

The first of these is linear degradation: this is similar for both front and rear tyres, and dependent on their wear. In other words, if tyre performance is such that the car loses 0.1 second of lap time between the second and third laps, it will also lose 0.1 second between laps 22 and 23. During a race, the level of linear degradation can vary from nothing up to 0.15s depending on the circuit and the conditions. Linear degradation does not cause any change in the car balance, provoking neither understeer nor oversteer.

The second type of degradation is graining. This is a phenomenon that has become much more prevalent since the introduction of grooved tyres, although even slicks can suffer from it. Graining occurs when the surface of the tyre grips sideways and rolls up due to the shear force on the rubber. It is very easy to spot as the rolled-up rubber remains on the tread. In most cases, graining is seen laterally on the front tyres although on some circuits, it can occur longtitudinally on the rear tyres. This happens when there are a lot of traction events, such as in Canada. However it is much more common for it to be seen at the front at circuits such as Imola which are 'front-limited' (where the front tyres are under greater stress than the rears). Tyres are prone to graining when temperatures are low and the rubber is perhaps stiffer than is ideal for the conditions. The result is an increase in understeer, but as the tyre wears, the graining disappears (the 'loose' rubber is cleaned off the tread) and the tyre behaves normally. The performance curve created by graining is illustrated by the second line.

The final type of degradation encountered is the type we will be more concerned with at Hockenheim. Blistering is so-called because the tyre does literally form heat blisters which are then ripped off the surface. This is commonly seen on the rear tyres, and is generally due to a combination of high acceleration and hard cornering forces through long, slow and medium speed corners With this type of degradation, the tyre behaves normally at the beginning, suffering only from linear degradation, until it gets to the point when the rear tyres blister, which can be quite sudden. The car then starts to lose lap time through oversteer and a loss of traction caused by the loss of rear grip.

The propensity of the tyre to blister is very much a function of the core temperature of the tyre, in other words the temperature of the rubber below the surface. While the surface temperature of a tyre can build up quite quickly, particularly through the tyre sliding, the fact that rubber is a good insulator means the high surface temperatures do not penetrate quickly to the core. Core temperature increases occur more from the work the tyre does and these temperatures, even under arduous race tyre conditions, can take 8 to 10 laps to stabilise. A blistering tyre therefore will behave well until the core temperatures reach the critical point, and the tyre starts to lose its tread as the blisters occur. Blisters are generally of similar size, and 'bad' blistering is therefore the consequence of a higher number of blisters on the tyre.

Since the circuit revisions at Hockenheim, the demands the circuit places on the tyres have changed significantly. The new tarmac has significantly higher grip levels than the old surface, and the nature of the circuit is radically different: previously composed almost exclusively of heavy braking and traction events, it now includes a much higher number of medium speed corners. As such, the set-up compromise required has altered radically, and the circuit now requires much higher downforce levels. The result is much higher speeds through the stadium section (an average rise of 16%), and for the tyres, the numerous acceleration phases out of these corners have made Hockenheim a 'rear-limited' circuit.

Once these factors have been taken into account, our data analysed and the delicate choice of tyre compound and construction has been made, we then hope that the only unknowns left are the ambient factors. However, the weather is such that it can make a finely-balanced choice look like inspired genius, or over-ambitious miscalculation.

The Engineer's View, Denis Chevrier

Given that we are now reaching our twelfth circuit of the season, Hockenheim does not stand out in any particular sense. The profile of the circuit is at the upper end of the average mid-season circuits: the engine spends 63% of the lap at full throttle (season average is 55%) and the longest continuous period is 14.9 seconds (against 13 seconds on average).

The salient characteristic of Hockenheim is that it includes numerous periods of acceleration from low speeds, exiting the slow corners. These demand an engine that accelerates strongly, and power throughout the rev range - ie, torque - is more important than the peak power that can be achieved. Indeed, the technical definition of torque is the product of the power produced, and the engine speed at which it is produced.

These frequent accelerative phases also mean the engine is frequently under relatively light loads. The loads the moving parts must withstand are intermittent, rather than continuous, and this makes the circuit easier for certain among them, such as the pistons.

In order to best adapt the engine to suit these circuit characteristics, we work to optimise the driver's control by concentrating on driveability and power delivery.

However, while torque is important, the single longest period at full throttle is sufficiently long that obtaining a competitive top speed is still a crucial factor. This need for top-end performance, while not predominant, does nevertheless mean that building a 'Hockenheim special' is out of the question.

Temperatures at Hockenheim are often very high, but we have already had to deal with this factor at circuits such as Sepang - this is not usually a major challenge for the any car-engine package at this stage of a season. Indeed, temperature is a phenomenon that can be quite easily simulated and, as such, reproduced and predicted with relative accuracy. Although we will be introducing an engine development in these high temperatures, it should not pose a problem for us. The homologation procedures are particularly stringent this year, and we also tested in high temperatures last week in Jerez.