What constitutes parasite drag?

Parasite drag is a type of aerodynamic drag that relates to the resistance an aircraft experiences as it moves through the air, which is not directly related to the production of lift. This drag is composed of three components: skin friction, form drag, and interference drag.

Skin friction drag arises from the friction between the aircraft’s surface and the air molecules moving over it. Form drag is caused by the shape of the aircraft and how that shape disrupts airflow. Interference drag occurs when different airstreams meet and interact, often at points where various components of the aircraft (such as wings and fuselage) come together. Together, these factors contribute significantly to the overall parasite drag experienced by the aircraft during flight.

The other choices highlight specific aspects of drag but do not encapsulate the completeness of parasite drag as a whole. Recognizing the collective nature of skin friction, form, and interference drag is essential for a deeper understanding of how aircraft design impacts efficiency and performance in the air.