"Micro Cooling Fan" principle jet engine turboprop engine thrust is limited, while the impact of aircraft flight speed increase. Therefore necessary to improve the efficiency of jet engines. Engine efficiency including thermal efficiency and promote efficiency in two parts. Increase in gas turbine inlet temperature and compressor pressure ratio, you can improve the thermal efficiency. Because of high temperature, high energy density of the gas contained in the larger. However, "Micro Cooling Fan" at the same speed flight conditions, increase turbine inlet temperature, exhaust speed will increase naturally. The flow speed of the gas in the discharge of kinetic energy loss is large. Thus, one-sided increase thermal power, namely to increase the turbine inlet temperature, will lead to a decline in efficiency propulsion. To improve engine efficiency, it is necessary to solve the thermal efficiency and promote the efficiency of this contradiction. Turbo "Micro Cooling Fan" engine beauty lies not only improve turbine inlet temperature, without increasing the exhaust velocity. Turbofan engine structure, in fact, in front of the turbojet engine turbo add a few levels, these turbines drive a certain number of fans.