22.10 Drag

22.10.2 Identify and explain the components of total drag.

Total drag consists of two main components:

• parasite drag and
• induced drag.

Parasite drag includes different types of drag that occur due to the aircraft's shape and external factors.

There are three types of parasite drag:

• form drag,
• skin friction drag, and
• interference drag.

Form drag is caused by the shape of the aircraft.

Skin friction drag is caused by the friction between the air and the aircraft's surface.

Interference drag arises when different parts of the aircraft interact and create turbulence.

Induced drag is generated as a result of the production of lift.

When an aircraft generates lift, it also creates a downwash of air, which leads to induced drag.

This drag is directly related to the angle of attack and the span of the wings.

Higher angles of attack and shorter wingspan contribute to higher induced drag.

22.10.4 Explain the term boundary layer.

The boundary layer is a thin layer of air that forms on the surface of an object, like an aircraft wing, as it moves through the air.

This layer of air sticks to the surface due to friction, and its behaviour can affect the overall aerodynamics of the object.