Differences, advantages and disadvantages between turbofan engine and turboprop engine. What are the advantages and disadvantages of * * * axis reversal twin-rotor helicopter and traditional helicopte

Differences, advantages and disadvantages between turbofan engine and turboprop engine. What are the advantages and disadvantages of * * * axis reversal twin-rotor helicopter and traditional helicopter? Turbine propeller has gear reduction, and the theoretical thrust of jet is less than 5% due to the blade tension, which is mostly used for large low-speed transport aircraft. To put it simply, a propeller fan is a turbofan without an external duct, with a large number of blades and a small area, and the number of flights is faster than that of a turbofan. The two engines are simply used in different occasions, mainly referring to the design flight speed. Turboprop has large pitch, large thrust and low speed, while propeller fan has the opposite.

Let's talk about propellers,

The tail rotor of a helicopter is mainly used to overcome the reaction torque of the main rotor, so a helicopter with two propellers can cancel the tail rotor. Therefore, the single propeller structure is simple and the double propeller structure is complex, especially the helicopter main propeller is variable pitch. Made a double propeller, the estimated structure is too complicated, the advantages are not obvious, and the significance is not great.