Airfoil Data
N66021

The NACA 66-021 AIRFOIL is a 10.5% chord-thickness airfoil with a maximum camber of 5.3% at 45% 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 -5.3°.

Thin airfoil theory predicts a stall angle near 11.7° and a peak lift-to-drag ratio around 65 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 N66021 typically compare it against profiles of similar thickness: NASA/LANGLEY LS(1)-0417 (GA(W)-1) AIRFOIL, NACA 16-021, NACA 747A415, NACA 0021, EPPLER 545 AIRFOIL. The NACA 65(4)-221 is another reference profile frequently considered alongside it.