Airfoil Data
N6409

The NACA6409 9% is a 10.4% chord-thickness airfoil with a maximum camber of 5.2% at 40% chord, suited to general-aviation and UAV wing design. At zero angle of attack the cambered geometry generates positive lift, giving an estimated zero-lift angle of -5.2°.

Thin airfoil theory predicts a stall angle near 11.7° and a peak lift-to-drag ratio around 64 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 10% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the N6409 typically compare it against profiles of similar thickness: HQ 3.5/14 AIRFOIL, WACO COOTIE AIRFOIL, HQ 3.0/15 AIRFOIL, WORTMANN FX 62-K-131 AIRFOIL, EPPLER 338 AIRFOIL. The NACA 5-H-15 AIRFOIL is another reference profile frequently considered alongside it.