The propulsive efficiency as defined in the Wikipedia article is the product of the cycle efficiency (the efficiency turning heat into mechanical power) and the

The propulsive efficiency as defined in the Wikipedia article is the product of the cycle efficiency (the efficiency turning heat into mechanical power) and the mechanical efficiency (the efficiency turning the mechanical power generated by the engine into movement of the airplane). The mechanical efficiency can be close to 100%, but the cycle efficiency is only 40% or so.