Airfoil Data
S1223

The S1223 is a 13.5% chord-thickness airfoil with a maximum camber of 6.8% at 31% chord, suited to high-lift UAV wings, RC sailplanes, and low-Reynolds-number slow-flyers. At zero angle of attack the cambered geometry generates positive lift, giving an estimated zero-lift angle of -6.8°.

Thin airfoil theory predicts a stall angle near 11.1° and a peak lift-to-drag ratio around 71 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 14% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the S1223 typically compare it against profiles of similar thickness: GOE 513 AIRFOIL, GOE 423 AIRFOIL, GOE 573 AIRFOIL, NACA 23024, EPPLER 748 AIRFOIL. The GOE 570 AIRFOIL is another reference profile frequently considered alongside it.