A LOW-DOWNFORCE STREET CIRCUIT
Paradoxically, the Baku City Circuit does not share many similarities with other street racetracks like Monaco or Singapore. Despite featuring characteristic tight and twisty sectors, the Azerbaijan layout also includes two long straights and several fast corners.
Williams performance chief Rob Smedley revealed that teams opted for downforce levels close to Spa-Francorchamps. Post-race, Red Bull team principal Christian Horner even drew comparisons with Monza’s ‘Temple of Speed’.
Concretely, most teams mounted low-downforce, low-drag rear wings in Baku (i.e. the exact opposite of Monaco) in order to keep a healthy top-end speed, even though it meant sliding around in slow corners.
Compared to the standard spec of rear wing, the low-downforce version features a main plane with a lower angle of incidence. In other words, the plane is less tilted and sits higher (compare white arrows), while the upper flap is slightly shorter.
As the plane has a flatter placement, the speed differential between the air above the board and the air underneath it is less important. This lowers the pressure differential between both sides of the wing, which in turn weakens the vortex generated at the joint area of the endplate and wing tip.
Ferrari, McLaren, Force India, Red Bull, and Toro Rosso all went for this design, which implies reducing the number of fences pierced in the endplate. By comparing the yellow arrows, you can notice that these went down from five to three on the SF16-H, from four to five on the MP4-31, etc.
Mercedes decided to follow another path in order to generate the same effect. The reigning Constructors’ champions mounted a spec of rear wing on the W07 that was similar to the curved ‘spoon’ version they had first introduced at last year’s Belgian Grand Prix.
The angle of incidence is fairly low on both ends of the main plane, while it remains quite high in the middle section, this in order to keep some level of downforce. Such compromise was made possible thanks to Mercedes’ powerful, yet efficient, PU106C engine.
One could also note that no team kept a ‘monkey seat’ winglet above the exhaust in Baku. This did not come as a surprise, for the device was rendered moot by the rear wing’s lower angle of incidence. Indeed, the Y100 element is used to prevent the airflow from stalling under a rear wing that has a high angle of attack.