Airfoil Section Characteristics at a Low Reynolds Number

The aerodynamic characteristics of airfoils operating at Re = 4 × 103 were examined, varying the parameters related to the airfoil shape such as thickness, camber, and roughness. Airfoils with good aerodynamic performance at this Re have the following shape characteristics: (1) they are thinner than airfoils for higher Re numbers, (2) they have a sharp leading edge, and (3) they have a camber of about five percent with its maximum camber at about mid-chord. The characteristics of airfoils are strongly affected by leading edge vortices. The measured two-dimensional airfoil characteristics indicate that the planform, which greatly affects the flight performance of the three-dimensional wing at high Reynolds numbers, has little effect on the flight performance at this Reynolds number.