n flight mechanics and aerodynamics, the thrust drag coefficient, often denoted as , is a dimensionless parameter that relates the thrust generated by an aircraft’s engines to the drag it experiences during flight. It’s a useful metric for assessing the efficiency of an aircraft’s propulsion system in overcoming drag and maintaining or changing its velocity.
- is the thrust produced by the aircraft’s engines.
- is the air density at the given altitude and conditions.
- is the velocity of the aircraft relative to the air.
- S is wing area