Airfoil Data
E864

The EPPLER 864 STRUT AIRFOIL is a thick 19.4% chord-thickness airfoil with a maximum camber of 9.7% at 33% 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 -9.7°.

Thin airfoil theory predicts a stall angle near 9.0° and a peak lift-to-drag ratio around 78 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 19% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the E864 typically compare it against profiles of similar thickness: MH 126 25.0%, S9104, S9104BTE, FX 69-PR-281, GOE 531 AIRFOIL. The EPPLER 856 AIRFOIL is another reference profile frequently considered alongside it.