Airfoil Data
E551

The EPPLER 551 AIRFOIL is a 11.5% chord-thickness airfoil with a maximum camber of 5.8% at 35% chord, suited to general-aviation and UAV wing design. At zero angle of attack the cambered geometry generates positive lift, giving an estimated zero-lift angle of -5.8°.

Thin airfoil theory predicts a stall angle near 11.6° and a peak lift-to-drag ratio around 68 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 E551 typically compare it against profiles of similar thickness: NACA 64(4)-221, MUE 139, FX 62-K-153/20 AIRFOIL, AH 94-156, EPPLER 793 AIRFOIL. The S8055 (12%) is another reference profile frequently considered alongside it.