nostokäyrä

nostokäyrä is a Finnish term that translates to "lift curve" or "lift characteristic curve" in English. It is a graphical representation used in aerodynamics to illustrate the relationship between the lift coefficient and the angle of attack for a given airfoil or wing. Typically, the lift coefficient is plotted on the vertical axis and the angle of attack, often denoted by the Greek letter alpha ($\alpha$), is plotted on the horizontal axis.

The nostokäyrä shows how the lift generated by an airfoil changes as its angle of attack varies. At low angles of attack, the lift coefficient generally increases linearly with increasing angle of attack. However, as the angle of attack increases further, the airflow over the upper surface of the airfoil can separate, leading to a stall. This stall is characterized by a rapid decrease in the lift coefficient and an increase in drag. The point at which this stall begins is known as the stall angle.

The shape and specific values on the nostokäyrä depend on various factors, including the airfoil's shape, its aspect ratio, and the presence of any high-lift devices like flaps or slats. Understanding the nostokäyrä is crucial for aircraft designers to predict and optimize the aerodynamic performance of wings and other lifting surfaces. It helps in determining the optimal angle of attack for different flight conditions, such as takeoff, cruise, and landing, and in assessing the stall characteristics of an aircraft.