Airfoil Data
E657

The EPPLER 657 AIRFOIL is a 12.4% chord-thickness airfoil with a maximum camber of 6.2% at 42% 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 -6.2°.

Thin airfoil theory predicts a stall angle near 11.5° and a peak lift-to-drag ratio around 69 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 12% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the E657 typically compare it against profiles of similar thickness: GOE 654 AIRFOIL, EPPLER 587 AIRFOIL, NACA M18, N-22, RONCZ 1082 VOYAGER ROOT OUTER AFT WING AIRFOIL. The W1011 is another reference profile frequently considered alongside it.