Experimental studies for determining the profiles of the wing sections with high maximum lift coefficient is described. Observation of flow around the wing sections and measurement of section lift coefficient are carried out in a twodimensional smoke wind-tunnel. Transition in the boundary layer along the wing surfaces is also observed by using evaporated-gas-oil smoke. Additionally, the wing sections with extended trailing-edge are investigated. Maximum lift coefficient up to 2.28 is obtained at Reynolds number of 5.34×105.