This article sets out simplified design laws for cruise, acceleration and initially powered ballistic flight, using various examples (rockets, missiles and aircraft).
Three formulas are used for non-propelled flight (with an initial speed generally obtained by initial propulsion), gliding or ballistic flight.
The other two formulas correspond to two particular cases of propulsion use: acceleration from one speed to another, or cruising flight (with two expressions whose authors have remained famous: the Tsiolkovski and Breguet formulas).
The simplified expressions used in this article thus enable reliable, but estimated, pre-sizing, which will then be confirmed during a project by more precise models and detailed trajectory calculations.
The examples and data provided are taken from the open literature, as the applications of these engines inevitably lead to restrictions on certain particular points of these propulsion systems from a commercial or military point of view.