What is parasite drag?

Parasite drag refers specifically to the drag that is created by the various exposed surfaces and components of an aircraft as it moves through the air, effectively offering resistance to the airflow. This form of drag is directly related to the shape and condition of the aircraft's surface, as well as any objects that may disrupt the smooth flow of air, such as antennas, landing gear, and rivets.

Parasite drag can be broken down into three subcategories: form drag, skin friction drag, and interference drag. Form drag is caused by the shape of the aircraft and how it displaces air as it moves; skin friction drag occurs due to the surface texture of the aircraft; and interference drag arises when different airflow patterns merge over the aircraft. As the velocity of the aircraft increases, parasite drag tends to increase as well, making it a significant factor for overall drag that pilots and engineers take into account during design and operation. Understanding parasite drag is essential for improving aerodynamic efficiency and optimizing performance in aviation.