Stall prevention of an S1223 airfoil using passive bleed

The Selig 1223 airfoil (S1223) is a high-lift airfoil used to obtain short take-off and high load capacity of fixed-wing unmanned aerial vehicles (UAVs) operating at relatively low Reynolds number. However, this airfoil's susceptibility to boundary layer separation at lower Reynolds numbers limits its usefulness in smaller UAVs. Here, we investigate the use of a flow control technique known as passive bleed to prevent boundary layer separation at lower Reynolds numbers. We characterize the modified airfoil's lift coefficient at various angles of attack and values of Reynolds number, and compare this to the performance of an unmodified S1223 airfoil. Prevention of boundary layer separation can allow for the effective use of S1223 airfoils to give a high lift coefficient to wings of small UAVs.