Newey, Willis & Lom on the RB5 and the 2009 rule changes 09 Feb 2009
As the Renault-powered Red Bull RB5 is launched in Spain on Monday, the cars designer Adrian Newey, Red Bull technical director Geoff Willis and Renault F1s technical coordinator Fabrice Lom take us through the impact the revised regulations for the coming season have had on the new machine
Newey on the 2009 regulations:
2009 arguably sees the biggest rule change since flat bottoms were introduced in 1983, a very major change. We have taken a clean sheet, blue-sky approach, looking at the implications of these rules and how to interpret them, while not changing things simply for the sake of it. Apart from the gearbox internals, there is hardly any carry-over from RB4.
Newey on the challenge of KERS:
We use a battery storage system, which is heavy and therefore affects weight distribution on the car. After everything is packaged in the usual manner, driver, fuel cell, engine, gearbox, you then have to find somewhere for KERS, while maintaining fuel tank capacity and achieving the weight distribution target. RB5 carries its KERS in the base of the fuel tank.
Willis on KERS:
KERS is a big engineering challenge. Looking at the extent of the changes to the car design required, we made the decision not to test a KERS mule car at the end of the 2008 season but to test it only on the new 09 car. The high-power, high-voltage motors and batteries are new technologies to F1 and much lab testing has been needed to understand the technology and develop a safe and reliable solution. While there have been some safety concerns in early testing by a few teams, fundamentally safe operation is dependent on good design and proper procedures. F1 has learned to deal safely with a lot of potentially dangerous systems - this is just a new technology to learn to deal with. The additional challenges for KERS are to minimise the detrimental effects to chassis performance resulting from the additional weight, compromised braking stability and increased cooling requirements. The teams will judge where and when to use KERS by balancing these chassis performance penalties with the obvious gains.
Newey on the return of slick tyres:
The main area of change with going back to slick tyres was in terms of weight distribution, as it will put greater strain on the rear tyres, so at the design stage, we moved the weight distribution forward a bit.
Willis on slicks:
The conversion from grooved to slick tyres of the same dimensions has led to a substantial mismatch with the front tyres too strong for the rears. However, there was some resistance to changing this since the new aerodynamic regulations had been developed around the existing tyre sizes. This leaves a big challenge for the teams to match the cars weight distribution to suit the tyre characteristics as well as a challenge for the drivers to deal with the rear tyres going off faster than the fronts. Well only have four compounds to choose from this year and we wont have two adjacent compounds in terms of their characteristics, so we will either have compounds 1 and 3 or compounds 2 and 4 on a sliding scale of soft to hard. The new regulations have hit both downforce and aero efficiency. While the gains from the tyres will make up for this, it will be interesting to see how close to 2008 levels the teams can get.
Newey on reduced engine cooling:
Apart from the little gap around the exhausts, all the cooling air has to come out the back of the car, which is a more difficult solution. It means you have to make the back of the car bigger, while the situation is further complicated by KERS, which increases cooling requirement by 10 percent.
Willis on engine cooling:
Up until now its always been fairly easy to modify cooling by fitting top panels with gills or having other ventilated panels. Now we can only vary cooling by changing the rear exit of the bodywork. This clearly places the emphasis on the teams getting their cooling calculations right first time. Given that the early races are usually hot, some teams may find themselves struggling to engineer their way out of an under-cooled car.
Newey on the new-look aero package:
The rear wing is narrower and higher, the aim being to reduce its effect on a following car. Its a bit like a mushroom cloud, in that the narrower and taller you make it, the less effect it has behind it. (The front wing is) oddly proportioned! Its lower and wider and to my eye looks like an indoor go-kart. The idea is that the centre of the front wing is most susceptible to disturbance and this solution makes the centre very neutral, while the tips of the wide span wing are heavily loaded with this design. The lack of appendages such as winglets, barge boards and so on causes a loss of downforce, but they dont affect the fundamental behaviour of the car. However, the behaviour will be different, because of the front wing and the diffuser, which is now moved further back and is higher. Being alongside the rear wheels, instead of in front of them, it now works in a different way.
Does Newey think the changes will lead to more overtaking?
A bit more, but not a huge amount as people overlook the fact that circuit layout is the most important factor for generating passing moves. Last year the entire field was very close, with a very tight grid and five different chassis manufacturers winning races. A major rule change is likely to have the opposite effect, just one or two teams get it right and do all the winning.
Lom on the 2009 regulations:
We have eight engines per driver to last through all 17 grands prix, including Friday practice, so penalties are only incurred once any driver uses a ninth engine. On average, therefore, an engine has to last around three grands prix plus the equivalent of one extra grand prix to cover Fridays free practice sessions. However, there is no stipulation that the engine used on a Friday must then be used for the remaining two days, so one can juggle the engines around within the eight engine limit.
Lom on power outputs:
We will see a significant drop in power from all the engines on the grid, because of the rev limit being lowered from 19,000 to 18,000rpm. As the engines were designed to run at 19,000rpm, we had our work cut out to ensure they worked as effectively as possible with a thousand fewer revs per minute.
Lom on the challenge of KERS:
We are allowed to make modifications to the engine aimed at incorporating the arrival of KERS as this system changes the areas on the engine which are subject to vibrational stresses. We have carried out modifications allowed within the rules to guard against an engine breaking, simply because the car uses a KERS system. The useable rev range of the engine also needs to be different to adapt to KERS, to cope with the fact that inevitably, gear ratios will be too long for the power on offer from the engine when the energy stored by KERS is not being released. The system impacts on the engine in that it affects its driveability, but operationally at the race track, the management of the Renault-developed KERS is entirely in the hands of Red Bull Racing.