Aircraft specific energy

Aircraft specific energy is a measure of the energy available to an aircraft per unit mass. It is often expressed in units such as joules per kilogram (J/kg) or foot-pounds per pound (ft-lb/lb). Specific energy is an important concept in aerodynamics and aviation engineering because it provides a way to evaluate an aircraft's performance and efficiency in terms of the energy required for flight maneuvers, climbing, cruising, and descending.