Airfoil Data
E339

The EPPLER 339 AIRFOIL is a 11.0% chord-thickness airfoil with a maximum camber of 5.5% at 29% 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 -5.5°.

Thin airfoil theory predicts a stall angle near 11.7° and a peak lift-to-drag ratio around 66 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 11% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the E339 typically compare it against profiles of similar thickness: GOE 207 (AVIATIK V8) AIRFOIL, GOE 363 AIRFOIL, GOE 239 (MVA H.31) AIRFOIL, GOE 365 AIRFOIL, EPPLER 434 AIRFOIL. The Dayton-Wright T-1 is another reference profile frequently considered alongside it.