What does "airfoil" refer to?

The term "airfoil" specifically refers to the shape of a wing or blade that is designed to create lift when air flows over it. The design of an airfoil is crucial because it determines how effectively the wing or blade can convert airflow into lift, which is essential for an aircraft's ability to fly. The shape of an airfoil typically has a curved upper surface and a flatter lower surface, which helps create a pressure difference that generates lift.

Understanding airfoils is fundamental in aerodynamics, as the efficiency of an aircraft depends heavily on the design of its wings and propellers. Their ability to manipulate airflow is what allows various aircraft to take off, fly, and land effectively.

The other options refer to different components of an aircraft: the landing gear supports the aircraft on the ground, control surfaces are responsible for maneuvering the aircraft, and the overall body encompasses all design aspects. However, none of these directly relate to the focus on shape and lift creation that characterizes an airfoil.