Airfoil Data
NACA66209

The NACA 66-209 is a thin 5.6% chord-thickness airfoil with a maximum camber of 2.8% at 45% 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 -2.8°.

Thin airfoil theory predicts a stall angle near 11.9° and a peak lift-to-drag ratio around 51 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 NACA66209 typically compare it against profiles of similar thickness: S2062 8%, MH 30 7.84%, GIII BL332 AIRFOIL, NACA 65-209, RAF 15 AIRFOIL. The NACA 66,2-(1.8)12 A=.6 P-51 TIP AIRFOIL is another reference profile frequently considered alongside it.