Skin friction drag is a component of parasite drag in aircraft design that results from the resistance of air molecules as they rub against the surface of an aircraft’s components, such as the fuselage and wings. This type of drag is related to the frictional forces between the moving air and the aircraft’s surfaces.
Formula: The formula for skin friction drag (Dsf) can be expressed as:
- Dsf is the skin friction 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).