Airfoil Data
AH81131

The AH 81-131 is a 9.3% chord-thickness airfoil with a maximum camber of 4.7% at 40% 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 -4.7°.

Thin airfoil theory predicts a stall angle near 11.7° and a peak lift-to-drag ratio around 62 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The slim profile minimises pressure drag at higher speeds but leaves limited spar depth for structural integration.

Designers evaluating the AH81131 typically compare it against profiles of similar thickness: HQ 3.5/12 AIRFOIL, MH 80 12.72%, MH 95 15.86%, HQ 3.0/13 AIRFOIL, USA 25 AIRFOIL. The NACA M12 AIRFOIL is another reference profile frequently considered alongside it.