Multi-objective optimization design of lowreynolds- number airfoils S1223

For the design of a high-performance propeller for low-dynamic aircraft in Near Space, it is very important to have low-Reynolds-number airfoils which are supposed to have high liftdrag ratio at cruising attack angle along with a good property of stall characteristics. The paper is having a hierarchical multi-objective optimization on the basis of the high-lift airfoil S1223 by combing direct search optimization algorithm EXTREM and airfoil flow field solver XFOIL to automatically and quick calculate aerodynamic performance function of airfoil by computer. The aerodynamic characteristic results of the optimized airfoil S1223_OPT2 meet the design requirements. So the optimized airfoil presented here is propsed as the selected airfoil reference for the high-efficiency propeller of low dynamic vehicles in stratosphere.