The philosophy behind this car was very much one of evolution. Its predecessor, the R24 and R24B had a compromised mechanical architecture by the late change of engine angle. Renault decided at that time that a 72° angle would be a better solution then 90°. The new RS25 engine is once more a 72° design but has a lower centre of gravity, and a much stiffer installation than with the R24. Thefocus has been on optimising each detail to improve stiffness, reduce weight and package the components very tightly to give the aerodynamicists as much freedom as possible.
2005 was also the year of new aerodynamic rules to reduce downforce. RenaultF1 allocated wind tunnel resources as soon as the regulation changes were announced last July. That decision was a risk, and cost performance at the end of 2004 where the R24 could not get on the podium in the last races. The team made big step forward from its initial downforce loss of approximately 25%.
The car's major innovation is an all-new electronic system integrating the engine and chassis controllers, named Step 11. It is physically lighter, representing a quarter of the total weight saving in the new car, and brings a concrete advantage in terms of the scope of development: it allows a four times’ greater processing power, and ten times’ more data acquisition capacity, all of which will contribute to improvements in the control systems.
The other new feature of the car is the ‘v keel’ front suspension.
Technical director Bob Bell: "In recent years, we have seen two schools of thought evolve in front suspension design: the traditional single keel, with a single front lower wishbone, and the twin keel, which brings a measurable aerodynamic gain but can also have a structural penalty outweighing the benefit. We believe the v-keel is a very elegant solution to this dilemma, as it combines the virtues of both systems: we have obtained an aerodynamic advantage for minimal structural penalty, while maintaining our preferred mechanical configuration for the front suspension."
Chassis: Moulded carbon fibre and aluminium honeycomb composite monocoque, manufactured by the Renault F1 Team and designed for maximum strength and stiffness with minimum weight. Engine installed as a fully-stressed member.
The car is known for its elaborative implementation of the 'shark gills' which were previously used by Ferrari on a smaller scale. Although being usually slower than the McLaren MP4-20 in the second half of the season, Renault took the advantage in the first half of the season where they won the first 6 grand prix.
Cars of 2013