What is parasite drag?

Parasite drag is the resistance an aircraft experiences as it moves through the air, primarily due to its shape and surface characteristics. This type of drag is a function of the aircraft's geometry, including its surface smoothness and aerodynamic design. As the shape of the aircraft becomes less efficient, or if the surface exhibits irregularities such as roughness or contamination, the amount of parasite drag will increase.

Understanding parasite drag is essential for optimizing aircraft design and performance, as it directly affects fuel efficiency and speed. While other forms of drag, such as induced drag, result from lift generated by the wings, parasite drag exists regardless of lift and is a continuous factor, impacting aircraft at all speeds and altitudes.