Airfoil Data
B540OLS

The BELL 540 AIRFOIL (MODIFIED NACA 0012) is a thin 4.9% chord-thickness airfoil with a maximum camber of 2.4% at 22% chord, suited to high-speed UAVs, sailplane tip sections, and propeller blade design. At zero angle of attack the cambered geometry generates positive lift, giving an estimated zero-lift angle of -2.4°.

Thin airfoil theory predicts a stall angle near 12.0° and a peak lift-to-drag ratio around 49 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The slim profile minimises pressure drag at higher speeds but leaves limited spar depth for structural integration.

Designers evaluating the B540OLS typically compare it against profiles of similar thickness: S6063 7.05%, EPPLER 874 HYDROFOIL AIRFOIL, AG18, RAF 27 AIRFOIL, RG 14A-1.4/7.0 AIRFOIL. The GOE 174 (ALBATROS 5020) AIRFOIL is another reference profile frequently considered alongside it.