High-lift low Reynolds number airfoil design

A new high-lift airfoil design philosophy has been developed and experimentally validated through wind-tunnel tests. A key element of the high-lift design philosophy was to make use of a concave pressure recovery with aft loading. Three codes for airfoil design and analysis (PROFOIL, the Eppler code, and ISES) were used to design the example S1223 high-lift airfoil for a Reynolds number of 2 × 10⁵. In wind-tunnel tests, the new airfoil yielded a maximum lift coefficient of 2.2. With vortex generators and a 1 % chord Gurney flap (used separately), the C_l,max increased to 2.3. The airfoil demonstrates the rather dramatic gains in C_l,max over those airfoils previously used for high-lift low Reynolds number applications.