Downforce Designer

Stall depends on Reynolds number: At HIGH-Re (fast flow, large chord) the boundary layer is turbulent and stall is sharp at ~15°. At LOW-Re (slow flow like your wind tunnel at 3–5 m/s) the boundary layer is laminar — separation is gradual and downforce peaks near 45°. This is why your CFD data and the theory disagreed.

Slot gap effect: Multi-element wings stay attached up to ~35°+ but still stall. Higher angle range is NOT infinite.

Aspect ratio effect: AR = Span ÷ Chord. Higher AR means less induced drag (k decreases) and higher CL — the Prandtl finite-wing correction means a short wing generates less lift than an infinite one. This is why long, narrow wings are more efficient.

Camber = 0% → symmetric airfoil (NACA 00xx). Zero camber means CL = 0 at zero angle of attack — no lift without incidence.

Why doesn't Position affect CL? Thin-airfoil theory proves that CL depends only on the height of camber (m), not where along the chord the peak sits. Position shifts the pressure distribution and pitching moment, but the total lift integral over the chord stays the same.

Thickness affects CD₀ and stall angle, not CL. Thicker profiles have more skin friction (higher parasitic drag) but a rounder leading edge that keeps airflow attached to a higher angle. This is why thickness shifts the stall threshold but not the lift slope.

Cornering dynamics: The downforce adds to the car's weight, pressing the tyres harder into the track. More normal force → more friction force (F = μN). That extra friction is what allows tighter turns: from F = mv²/r, a larger F means smaller r. Increase speed and watch the minimum turn radius grow — this is why fast cars need wings.