Airfoil Data
STCYR171

The St. CYR 171 (Royer) is a thin 5.5% chord-thickness airfoil with a maximum camber of 2.8% at 30% 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 STCYR171 typically compare it against profiles of similar thickness: AG44ct -02f, NACA 63-209, DSMA-523B AIRFOIL, DSMA-523A AIRFOIL, SIKORSKY SC1095 AIRFOIL. The NACA M3 AIRFOIL is another reference profile frequently considered alongside it.