To generate front downforce efficiently, to balance the aerodynamic center of pressure against the undertray and rear wing, and to condition the air that reaches the undertray inlets and the front tires.
A dual main element wing using Eppler-series airfoils, chosen because they perform well in the low-speed high-lift regime an FSAE car actually operates in. Each side carries a stack of flap airfoils behind the main elements. The endplates do two jobs: half-tubes seal the bottom of the endplate to preserve the low-pressure region on the underside of the wing, and the endplate curve directs air outboard away from the front tire, which cuts tire drag.
Development targets high-efficiency CL gain, not maximum CL. The wing is constrained at the bottom by minimum ride height and by roll angle in dynamic conditions, so more angle is not always available. The endplate is treated as a design element in its own right rather than a closeout. The CR26I sweep is explicit about this: flat endplate gave FW CLA 1.16 with 0.241 tire CDA; fence and half-tube together gave 1.34 CLA with 0.225 tire CDA, so the combination bought downforce and cut tire drag at the same time. 1. 2D CFD sweeps in ANSYS to place elements and set angle of attack cheaply. CR26E ran 153 two-element and 148 three-element sweeps for the rear wing on the same method. 2. Move promising 2D results into a 3D half-car model at 35 mph, chosen as a representative competition corner speed. 3. Iterate in the half-car model, tracking CLA, CDA, CoP and tire drag in an iteration tracker. 4. Run the best candidates in the performance map (PMAP) full-car model for yaw, roll and cornering. 5. Validate on track with constant-speed testing, tufting and Flo-Vis oil.
- Hold or grow front wing CLA while keeping CDA flat. CR25 to CR26I: CLA 1.34 to 1.35, CDA 0.15 both years, weight 6.44 to 6.38 lb. - Keep the wing inside the aero no-go surface at worst-case heave and roll. - Keep mounting accessible for quick attachment and release, with longitudinal adjustment for balance. - Survive a cone impact. CR26I mounts are analysed at 216 lbf lift, 28 lbf drag and an approximated 640 lbf cone impact, giving 23.3 ksi peak stress and FoS 1.71.
- Upper flaps and cascades. CR26E investigated them and found they add mass, strain performance and move the center of pressure rearward, with the flap pressure field interfering with the main element (Iter001 lost 12.21% of front wing lift). Only the turning vane case helped, and only for outwash. - Interior endplates creating a separated region. Addressed with a curved leading edge on the interior endplate, a floating endplate, or using a vertical airfoil as the endplate. - Leakage around elements from manufacturing tolerance, visible in Flo-Vis. Addressed with 3D printed bonding jigs and glass alignment beads to control bond gap.
ANSYS Fluent: 2D element position sweeps, 3D half-car iteration at 35 mph, full-car PMAP for dynamic conditions, poly-hexacore volume meshing, k-omega SST turbulence with a pressure-based coupled solver. Ahmed body runs validate the mesh and model setup against published wind tunnel data. SolidWorks FEA for mounting. Constant-speed on-track testing using bellcrank rotation and known weights to back out CL.