RENAULT R31

   In the wake of the Crashgate scandal at the 2008 Singapore Grand Prix, Renault gradually began to withdraw from Formula 1 as a full works constructor, progressively selling a majority stake in the team to Gérard Lopez's investment company, Genii Capital. At the end of 2010, Group Lotus plc, the historic British sports car manufacturer then owned by Malaysia's Proton, ended its association with Tony Fernandes's Team Lotus, with which it had competed during the season just concluded, and acquired a substantial stake in the Renault team. Becoming its title sponsor, the company rebranded the outfit as Lotus Renault GP. Fernandes, however, chose not to change the name of his own team, creating the bizarre situation of two separate constructors competing under the Lotus name on the 2011 grid. The ensuing legal dispute was not resolved until 2012, when Fernandes agreed to rename his outfit Caterham, leaving the Lotus name exclusively to the British team based at Enstone, in Oxfordshire, England. This team was the direct descendant of the original Toleman organisation, subsequently transformed into Benetton before being acquired by Renault in 2000.

RENAULT R31, Nick Heidfeld
Valencia, GP of Europe 2011

   The team's technical staff consisted largely of relatively young engineers, although many of those working at Enstone had been part of the successful Benetton campaigns of the previous decade. The Team Principal was French manager Éric Boullier, who had joined the organisation in 2010 to restructure it in the aftermath of the Crashgate scandal. To oversee financial management and day-to-day operational logistics, team owner Gérard Lopez appointed two trusted colleagues from Genii Capital, Thomas Mayer and Patrick Louis, to the positions of Chief Executive Officer and Chief Operating Officer, respectively. Responsibility for designing the new Renault R31 rested with James Allison, who had previously worked at Ferrari and would later go on to hold a prominent technical role at Mercedes. His deputy was Japanese engineer Naoki Tokunaga, a key figure in the management of the car's electronic systems and in the integration of the power unit with the chassis. Tim Densham served as Chief Designer, assisted by his deputy, Martin Tolliday, who helped develop the structural design of the chassis. The crucial aerodynamics department, whose work was extensively developed through wind-tunnel testing, was headed by South African engineer Dirk de Beer, the Head of Aerodynamics, alongside Britain's David Wheater, Deputy Head of Aerodynamics, and Mike Elliott, Chief Aerodynamicist. Nick Chester was responsible for the car's performance once it reached the circuit, serving as Head of Performance Systems, while Rob White oversaw the performance of the Renault RS16 V8 power unit. One of the most experienced and influential figures at Enstone was Alan Permane, who had been with the team for more than twenty years. As Trackside Operations Director, he was responsible for managing the cars during race weekends. The pit wall also included Paul Seaby, Race Team Manager, and Gavin Hudson, Chief Mechanic. Both played important roles in coordinating garage operations, pit-lane personnel and pit stops.

RENAULT R31, Nick Heidfeld
Hungaroring, Hungarian GP 2011 

   The R31 was, in many respects, a conventional-looking single-seater, featuring a high, relatively flat nose with the characteristic raised ridges along its sides. Its sidepods were fairly bulky, partly because of the demands of a revised cooling system, which had been relocated to an unconventional position to accommodate the car's radical new exhaust arrangement. Indeed, the R31's most distinctive and controversial technical feature was its forward-facing exhaust system, known as FFE (Forward-Facing Exhausts). The exhaust pipes ran through the sidepods before terminating beneath their forward openings, pointing towards the front of the car and directing the exhaust gases outwards along the edges of the flat floor. The gases, expelled at extremely high velocity, were intended to generate a high-energy airflow vortex along the floor's outer edges. This would prevent turbulent air from the surrounding environment from entering beneath the car. By sealing the lateral edges of the underbody, the engineers aimed to reduce the pressure beneath the chassis, creating a more consistent low-pressure region and increasing aerodynamic downforce across the car, including at the front end. Although theoretically promising, the concept proved unsuccessful once the car was put through its paces on the track. When the driver lifted off the throttle on corner entry, the engine produced less exhaust flow, causing the aerodynamic seal along the floor to weaken abruptly. The resulting loss of downforce made the car extremely unstable and unpredictable, particularly through medium- and low-speed corners. Furthermore, the aerodynamic barrier created by the exhaust gases was sensitive to crosswinds and the turbulent wake of other cars. Whenever the vortex broke down, the R31 could suffer a sudden loss of aerodynamic balance. Because the internal arrangement of the radiators, fuel lines and chassis structure had been designed around the forward-facing exhaust pipes, switching to a conventional rearward-facing exhaust system would have required a comprehensive redesign of the chassis, followed by a new homologation process and the successful completion of the FIA crash tests. Such an undertaking was economically and technically impractical during the season. The R31's radical aerodynamic philosophy was so unconventional that it contributed to the FIA's decision to introduce much stricter exhaust-positioning regulations for 2012. The new rules required exhaust outlets to be located at precisely defined points towards the rear of the car, with their exit angles directed upwards. In practice, these measures outlawed both forward-facing exhausts and systems designed to blow exhaust gases directly into the diffuser.

RENAULT R31, Bruno Senna
Spa-Francorchamps, Belgian GP 2011

   Beyond its innovative and extreme exhaust arrangement, the Renault R31 incorporated several significant technical solutions involving chassis construction, suspension geometry, power-unit integration and weight distribution. The chassis presented a series of unusual structural challenges, largely dictated by the need to route the extremely hot exhaust pipes through the sidepods. Constructed from carbon-fibre composite and aluminium honeycomb, the structure incorporated specially designed cavities and ducts, protected by substantial gold-foil and ceramic heat shielding intended to insulate the fuel tank and electronic control modules. Extending the exhaust pipes towards the front of the car added valuable weight to the lower central section of the chassis. This slightly lowered the centre of gravity but also reduced the engineers' freedom to position ballast as required to optimise the car's weight distribution and adapt it to the characteristics of the new Pirelli tyres. To maximise airflow around the rear of the car and compensate for the absence of exhaust gases being blown directly onto the diffuser, the technical team made a series of carefully considered suspension choices. At the rear, the R31 employed a pull-rod suspension layout, a philosophy popularised by Red Bull Racing. This arrangement freed up valuable space in the lower section of the gearbox casing, helping to clean up the airflow directed towards the rear wing and the central channel of the diffuser. At the front, the car retained a more conventional push-rod arrangement, with inclined pushrods operating the springs and dampers housed within the chassis. The geometry was refined to minimise body roll and maintain a consistent ride height, a particularly important consideration for preserving the aerodynamic seal generated by the exhaust system. As previously mentioned, the power unit was identified as the Renault RS16 and was paired with a Kinetic Energy Recovery System (KERS) developed in collaboration with Renault Sport F1. The system featured lithium batteries and a magnet-based motor-generator unit. Cooling also posed a considerable challenge for the engineers at Enstone. The forward-facing exhaust outlets discharged gases at temperatures exceeding 800°C close to the sidepod air intakes, forcing the team to reconsider the arrangement of the oil and water radiators. To prevent hot exhaust gases from being drawn back into the engine's cooling system, the sidepod air intakes were enlarged. However, this solution resulted in a substantial increase in aerodynamic drag, compromising the car's top speed on the straights.

RENAULT R31, Nick Heidfeld
Montecarlo, Monaco GP 2011 

   The Renault R31 was unveiled at the Ricardo Tormo Circuit in Valencia, Spain, on 31 January 2011. Its most striking visual feature was the new black-and-gold livery, evoking the legendary Lotus cars of the 1970s and 1980s. The cars were entrusted to Russian driver Vitaly Petrov and German veteran Nick Heidfeld, with Frenchman Romain Grosjean and Brazilian Bruno Senna appointed as reserve drivers. The man originally expected to lead the team was talented Polish driver Robert Kubica. However, in February, while competing in the Ronde di Andora rally, Kubica suffered a devastating accident. The guardrail penetrated the cockpit of his Škoda Fabia S2000, severely injuring his right forearm and hand and resulting in a near-amputation of both. The Enstone team's season began in spectacular fashion. At the Australian Grand Prix, Petrov delivered a superb performance to claim an unexpected third place, securing his first Formula 1 podium. The R31 demonstrated impressive race pace and an effective ability to manage the new Pirelli tyres. At the following round in Malaysia, Heidfeld, who had been called upon to replace the injured Kubica, secured another third-place finish. A blistering start from sixth on the grid briefly lifted him into second position, laying the foundations for an excellent result. As the season progressed, however, the R31's inherent limitations became increasingly apparent. On circuits demanding high downforce and featuring slow corners, the car struggled badly with rear-end instability, caused in part by the loss of aerodynamic performance under braking. The aerodynamic development programme failed to deliver the anticipated improvements because the entire aerodynamic concept was effectively locked into the fixed position of the forward-facing exhaust pipes. The team had little freedom to make fundamental changes without compromising the architecture around which the car had been designed. Frustration within the organisation eventually led to drastic decisions in the driver line-up. Heidfeld was dropped and replaced by Senna, who scored just two points in the final eight races, compared with the 34 accumulated by the German during the first eleven rounds. At the end of the season, Lotus Renault GP finished fifth in the Constructors' Championship with 73 points. The R31 ultimately demonstrated how an ingenious concept on paper can become a technological dead end when it restricts a car's capacity to evolve over the course of an entire championship.