OBR26 Side Wing

The side wing consists of three main elements: the mainplane and two supporting flaps. The main-element airfoil is fully custom, while the flaps are modified S1223 profiles optimised to work with the mainplane. The mainplane has a chord length of 750 mm and an angle of attack of 4 degrees. The following elements have chord lengths of 190 mm and 170 mm, and angles of attack of 28 and 58 degrees respectively. Flap 2 is tapered inboard, with its inner profile almost two times smaller in chord than the outer profile. This reduces upwash in that section of the flow; keeping the element straight produced an 8 N downforce loss at the rear wing.

Overall, this combination stays attached throughout the operating conditions, except at very low ride heights or during aggressive pitching and squatting. It achieves a pressure peak of -3.6 and a 0.76 ClA increase compared with the initial OBR25 baseline. The mainplane has three strakes that spool strong vortices with low-pressure cores, improving suction. These vortices merge downstream and help the flow remain attached to the supporting flaps, allowing a high effective angle of attack across the whole wing.

The side-wing side panel is curved to build high pressure behind the tyre and drive low-energy air away from the underfloor. At the front, a turning vane reduces tyre-wake ingress, especially in yaw and crosswind conditions. The lofted geometry was developed through multiple iterations for the largest performance gain.

A C-channel runs through almost the entire length of the elements and maintains a vortex that leaves the outboard edge through a circular tunnel. This vortex limits ambient-air leakage into the underbody and low-pressure flow leakage out of it. At the rear, a vertical wall constrains the rear-tyre stagnation flow and creates outwash.