Reminders and definitions
Aerospace propulsion

Let's start by recalling the forces at play and the conventional axes associated with flight [1].

The simplified equations (in three degrees of freedom) of external ballistics (as used in artillery and rockets) or flight mechanics (as used in aircraft) allow us to decompose the forces and accelerations of the mobile under consideration along different axes. The sum of the force torso (aerodynamic resultant of lift and drag, thrust, weight mg) is equal to the acceleration vector. Note that in this simplified representation, known as the balanced material point, all forces are assumed to apply at the same point.

The aerodynamic drag force (drag and lift) can be decomposed...