# Aerodynamics Essay

853 Words4 Pages
1.) What is lift and how is it developed over a typical airfoil? Be sure to address both applicable theorems, and how each contributes to the development of lift. Additionally, compare and contrast symmetrical and cambered airfoils and how the development of lift varies over each one. Be sure to address the concepts of center of pressure and aerodynamic center, as well as any pitching moments occurring on the airfoils Lift is the force that directly opposes the weight of the airplane. The first theorem addressing lift is Bernoulli’s principle. The airfoil travels through the air the shape of the airfoil creates a lower pressure above the wing and a higher pressure below the wing. This pressure differential causes the airfoil to be pushed upward and lift is a result. The second theorem is simply Newton’s third law where air is forced downward so there is a reaction of the airfoil being pushed upward (lift). On a symmetrical airfoil there can be no moment developed about the CP, and do not generate pitching moments at any AOA. This also means that the CP does NOT move with a change in AOA for a symmetrical airfoil. In a cambered airfoil the CP moves along the chord line with a change in AOA, as the AOA increases the CP moves forward and vice versa. The pitching moment at the AC will be constant with changing AOA if velocity is constant. The AC does NOT move with changes in AOA 2.) The nature of the boundary layer determines the maximum lift coefficient and stalling characteristics of an airfoil. Define stall and state what the boundary layer is. Name and describe/define the two forces that act on the airflow in the boundary layer and how the two forces contribute to the development of stall. What characterizes a stall and which is the most common type of stall? A stall is a separation of the boundary layer from the lifting surface (airfoil). The boundary