Aviation & Aeronautics
Intermediate

Drag Equation

Aerodynamic drag force on the aircraft, analogous to lift with a drag coefficient.

Formula

D=12ρv2SCDD = \tfrac{1}{2}\rho v^2 S C_D

Variables

DDrag
\rhoAir density
vAirspeed
SReference area
C_DDrag coefficient

Example

Doubling airspeed quadruples aerodynamic drag — which is why cruise fuel burn climbs fast.

Did You Know?

Drag also rises with the square of speed — which is why fuel burn soars at high cruise speeds.

dragaerodynamicsperformance