Airfoil Data
FX74MODSM

The FX 74-Cl5-140 MOD (smoothed) is a thick 15.9% chord-thickness airfoil with a maximum camber of 8.0% at 34% 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 -8.0°.

Thin airfoil theory predicts a stall angle near 10.2° and a peak lift-to-drag ratio around 74 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 16% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the FX74MODSM typically compare it against profiles of similar thickness: USA 32 AIRFOIL, GOE 382 AIRFOIL, EPPLER 858 AIRFOIL, UA(2)-180 smoothed, original ycoord oscillate +-0.0003, UA(2)-180 (University of Alberta/Marsden). The FX74_CL5_140 is another reference profile frequently considered alongside it.