Peugeot has revealed the aero concept of its Le Mans Hypercar that will compete in the 2022 FIA World Endurance Championship and at Le Mans, the 9X8. Powered by a 2.6-litre twin-turbo V6 engine, with a 900V battery built by Saft and with a maximum power output of 500kW, the car was unveiled to the world with a striking aerodynamic concept that harks back to the ground effect era of Formula 1 in the late 1970s.
Each of the manufacturers that have built a car to the LMH regulations, including Toyota’s GR010 and the Glickenhaus 007C, confirm that the aero targets of lift/drag are not that challenging to meet. With an upper limit of downforce permitted by the regulations, the calculations have become simpler for the development team, and innovation can go instead into the most efficient method of developing the required downforce levels.
Peugeot has clearly gone for underfloor generation of downforce with a large rear diffuser and no rear wing, although it does say that the upper and lower body work together to generate the required forces.
‘It is a combination of ground effect and upper rear bodywork that has been worked out in a bit of a different way compared to the old LMP1,’ confirms Peugeot Sport Technical Director Oliver Jansonnie. ‘With the new LMH regulation, there is a lot more freedom on many things. The underfloor is freer and with the upper bodywork there is more freedom plus there is an upper limit on the downforce, and how much we are allowed to generate and we felt that was achievable without the rear wing.
‘We basically have a combination of the front splitter and rear diffuser. The front of the car is much more traditional. We are allowed to have one device to adjust the aero balance of the car, and this is one key element for us. We have several options and that is something that we will decide during the first test of the car.’
While both Toyota and Glickenhaus have stuck with the engine cover fin and large rear endplates to help with yaw stability, Peugeot has opted for a totally different approach. A slender fin is mounted on the centreline of the engine cover, and yaw stability is further helped by vertical fins on the inside of the rear wheel arches.
‘We have to demonstrate in a calculation that the car is stable in a side wind, [so from] 0-180 degrees,’ confirms Jansonnie. ‘To be fair it is the most challenging part of the regulation and it took us quite a lot of time to achieve that. In concept, we had a much bigger fin plate at the back, and it is possible that we have to extend that on the race car once again. In LMP1 the dimension was specified while here we are free to do what we like but we have to prove the stability. We have the vertical winglets on the inner part of the rear wheel arches which are also helping to stabilise the car. As a total, we have a similar effect with a smaller engine cover fin.’
The team is reluctant to make the underfloor too complicated with winglets and turning vanes, as they are conscious that the car will endure a battering over a 24-hour race, as well as in sprint races over the high kerbs. While the front section of the floor will have to work hard to channel air into the desired areas, it cannot, therefore, be too complicated. ‘We have to be careful to avoid too many fragile parts on the underside of the car and that can get damaged and change the balance,’ admits Jansonnie. ‘It is part of the game to keep something that is in terms of performance strong enough, reliable enough and robust enough for the 24 hours and the other races.’
Unlike a traditional prototype, where the front and rear can be tuned separately, this will require a whole new way of thinking with the whole car designed to feed the rear diffuser. Air is channelled out of the front via exit ducts mid-ships and then is attached to the outside rear bodywork to create a curtain and prevent air from flowing into the diffuser from the side.
While Lotus was able to use the now-famous sliding skirts to achieve the same effect with its 78 and 79 in the late 1970s, the regulations do not allow LMH manufacturers to do the same, hence the reliance on air to do a similar job.
Cooling ducts over the body are cavernous compared to traditional prototypes, due to the requirements of the twin-turbo engine and MGU. The issue with such large ducts, other than the drag penalty, is that they could more easily capture debris and lose efficiency.
‘On cooling, we have an air pick up for the radiator that is quite forward and high and that is something that we need to avoid debris,’ admits Jansonnie. ‘We had a bad experience from that in the past. You need a lot of cooling required on the cars when you put together the ERS system, the 500kW engine, and so on.’ The engine intake is above the roof and that will serve a single function.
There is little to be made of the front crash structure and chassis design from the rendering. The driver will sit more upright than in an LMP1 design, which means the feet will be lower down and that reduces the freedom to channel air under the car, Formula 1 style.
The final specification of the car has not yet been finalised and will not be until the car begins track testing at the end of the year. For example, the gap between the top of the rear diffuser and the engine cover is closed in the rendering, but the race car will be open as is more traditional in a prototype, allowing the hot air to escape.
The car’s engine has been tested on the dyno since April, while the front-mounted 200kW MGU, the seven-speed sequential gearbox and the battery are in the process of being assembled, in keeping with the bench-testing validation schedule. ‘Our target with regard to our energy requirements is flawless reliability and perfect control,’ says Stellantis Motorsport Director, Jean-Marc Finot in the accompanying press release. ‘Le Mans has become a 24-hour sprint race that can be won or lost by the number of times you pit. The exceptional energy efficiency of the new Hypercars prefigures what we will see shortly in the world of road cars. Consideration had a fundamental influence on our work on the Peugeot 9X8 package, every aspect of which needs to contribute to achieving hyper-efficiency from its powertrain and aerodynamics.’