In preparation for the Pikes Peak International Hill Climb 2018, the Volkswagen Motorsport team has engineered the aerodynamics of the I.D. R Pikes Peak (earlier post)—the brand’s first fully-electric racing car—specifically to tackle the famous hill climb. The goal at the race, which takes place on 24 June in Colorado Springs, CO, is to break the record in the class for electric prototypes, which currently stands at 8:57.118 minutes.
The Pikes Peak start line is located at an altitude just above 9,000 feet, with the finish at 14,115 feet above sea level. The low air pressure up there means that the aerodynamic conditions are different to those at a racetrack on flat land, said François-Xavier Demaison, Technical Director at Volkswagen Motorsport and project manager for developing the I.D. R Pikes Peak. The Pikes Peak race features relatively open regulations, giving the engineers far more leeway to design the chassis and rear wing of the racecar.
During the winding 12.4-mile (20 km) drive to the summit of Pikes Peak, a top speed of around 155 mph (249.5 km/h) is reached—relatively low for a prototype like the I.D. R, as it could theoretically go far faster.
For this reason, we concentrated mainly on achieving optimal cornering speeds. The entire chassis is designed to generate as much downforce as possible, without causing too much aerodynamic drag.—François-Xavier Demaison
The most visually striking result of this strategy is the oversized rear wing on the I.D. R Pikes Peak.
The altitude on Pikes Peak means that the air we are driving through is on average 35% thinner. As a result, we lose 35% of our downforce compared to a racetrack at sea level. The huge rear wing allows us to compensate for some of this lost downforce. The imaginative aerodynamic development means that we will still achieve maximum downforce greater than the weight of the car during the hill climb.— Willy Rampf technical consultant to the project
Volkswagen Motorsport used a half-scale model to test a number of different variants of the Pikes Peak racer in the wind tunnel. The final touches were then put to a full-size chassis on the rolling-road wind tunnel in the Porsche development center in Weissach.
The team used a 3D printer to produce about 2,000 parts, said Dr. Hervé Dechipre, who, as a CFD engineer at Volkswagen Motorsport, is responsible for the aerodynamics on the I.D. R Pikes Peak.
With its two electric motors, which together generate 500 kW (671 horsepower), the I.D. R avoids the cooling issues that face combustion-engined vehicles. This made it possible to reduce the size of the intakes in the chassis, which are traditionally aerodynamic drawbacks. However, the thin air at altitude has a negative effect on the efficiency of the cooling.
Simulation software provided by technology partner ANSYS is used to calculate the ideal compromise.
We could not manage this solely with the data from the wind tunnel, where it is not possible to recreate the thin air. The simulation was a great help in determining the dimensions required for the cooling system.—François-Xavier Demaison
In the meantime, the findings from the development phase have been optimized in great detail in comprehensive tests. The first test run on the original route is planned for the end of May. Driver Romain Dumas and the Volkswagen Motorsport team then begin the final phase of their preparations leading up to race day.