Airfoil Data
DH4009SM

The dh4009sm is a thin 4.4% chord-thickness airfoil with a maximum camber of 2.2% at 42% 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 -2.2°.

Thin airfoil theory predicts a stall angle near 12.0° and a peak lift-to-drag ratio around 48 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 DH4009SM typically compare it against profiles of similar thickness: S8025 (8%), WORTMANN FX 71-089A AIRFOIL, Eh 1.0/7.0, NASA/AMES A-02 AIRFOIL, NASA/AMES 63A108 MOD C AIRFOIL. The GOE 565 AIRFOIL is another reference profile frequently considered alongside it.