Propulsive Efficiency (Paperback)

High Quality Content by WIKIPEDIA articles! In aircraft and rocket design, overall propulsive efficiency is the efficiency, in percent, with which the energy contained in a vehicle's propellant is converted into useful energy, to replace losses due to air drag, or gravity, or to accelerate the vehicle. The cycle efficiency, in percent, is the proportion of energy that can be derived from the energy source that is converted to mechanical energy by the engine. In the case of heat engines, it is always less than the Carnot efficiency because of heat that is necessarily lost in the engine exhaust and internal inefficiencies such as friction losses, power to drive accessories like compressors and generators, etc. These typically generate waste heat that represents loss of power. The propulsive efficiency, in percent, is the proportion of that mechanical energy that is actually used to propel the aircraft.