Airfoil Data
USNPS4

The USNPS4 (smoothed) is a 11.0% chord-thickness airfoil with a maximum camber of 5.5% at 34% 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 USNPS4 typically compare it against profiles of similar thickness: EPPLER 434 AIRFOIL, RONCZ 1082T VOYAGER TIP OUTER AFT WING AIRFOIL, GOE 363 AIRFOIL, GOE 239 (MVA H.31) AIRFOIL, GOE 207 (AVIATIK V8) AIRFOIL. The EPPLER 340 AIRFOIL is another reference profile frequently considered alongside it.