Profile drag, also known as skin friction drag, is a type of drag that results from the frictional resistance between the aircraft’s surfaces and the airflow as it moves over those surfaces. It encompasses both form drag and skin friction drag and represents the drag produced by the aircraft’s individual components when isolated from other interference effects.
Formula: The formula for profile drag (Dp) can be expressed as:
- Dp is the profile drag (in newtons, N).
- Cf is the skin friction coefficient (dimensionless).
- ρ (rho) is the air density (in kilograms per cubic meter, kg/m³).
- V is the velocity of the aircraft relative to the air (in meters per second, m/s).
- S is the wetted surface area of the aircraft (in square meters, m²).