Airfoil Data
NPL9626

The NPL 9626 AIRFOIL is a thin 6.8% chord-thickness airfoil with a maximum camber of 3.4% at 31% 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 -3.4°.

Thin airfoil theory predicts a stall angle near 11.9° and a peak lift-to-drag ratio around 54 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 NPL9626 typically compare it against profiles of similar thickness: LOCKHEED C-141 BL426.57 AIRFOIL, HUGHES HELICOPTERS HH-02 AIRFOIL, LOCKHEED C-5A BL758.6 AIRFOIL, LOCKHEED C-5A BL488.2 AIRFOIL, BOEING BACXXX AIRFOIL. The EH 2.5/10 is another reference profile frequently considered alongside it.