Messerschmidt said excitedly: "Shaw, does this mean that we will be able to develop a practical helicopter?" However, in addition to the engine, the flight control of the helicopter is also a big problem. There are insurmountable difficulties in the material and aerodynamic design of the rotors. ”

Xiao Weiguo laughed and said, "Of course I have a way to solve it." At present, the idea of the aviation industry is to use coaxial counterrotating dual rotors to solve the flight control problem, but such a rotor structure is too complicated. Of course, in addition to the coaxial scull, we can also do parallel sculls, but a more practical design, I think, should be a single rotor and tail rotor design. In the case of a coaxial double propeller, the steering is achieved by changing the torque of the upper and lower rotors. This makes it more complicated. However, the design with the main rotor and tail rotor is much simpler. ”

"Rotational motion is the easiest way to keep the paddle in continuous motion. The shape of a helicopter blade is similar to that of an airplane propeller, but the blades on a helicopter rotor are generally narrow and thin because they have to rotate very quickly. The rotating propeller assembly of a helicopter is called the main rotor. If a tiny angle of attack is given to the main rotor blades on the shaft and the shaft rotates, the propellers begin to generate lift. In order for the shaft to rotate, a powerful engine is needed, and the turboshaft engine is the best helicopter power. ”

"Before leaving the ground, the transmission shaft of the engine is connected to the main rotor shaft by means of a transmission. After leaving the ground, the engine will run in sync with the main rotor shaft. In this way, without any resistance, the fuselage will rotate in the opposite direction to the direction of rotation of the main rotors. To suppress the rotation of the fuselage, it is also necessary to apply force to it. The way in which the force is applied to the fuselage is to install another set of rotating paddles on the long tail trusses. These blades are called tail rotors. The tail rotor acts like an aircraft propeller. By creating thrust on the sides, counteracting the tendency of the engines to spin the fuselage, the tail rotor inhibits fuselage rotation. As a rule, the tail rotor is driven by a long propeller shaft. The shaft extends through the main rotor transmission, the tail boom, to a small transmission at the tail rotor. Xiao Weiguo seriously explained to everyone the helicopter he envisioned.

Messerschmitt listened excitedly. He slapped his thigh and said, "yes, why didn't I think of it!" It's still amazing! If we develop a helicopter and bring it to the market, it will be another epoch-making milestone, and it's exciting to think about! ”

Anna looked at Xiao Weiguo and Messerschmidt talking very energetically, and asked, "What's so good about helicopters?" You two are so excited? ”

Xiao Weiguo laughed and said, "Anna." You don't know that! The helicopter can be said to be a new type of aircraft that is no less important than our jets, because it can not only take off and land vertically, but also hover in the air, fly sideways, fly upside down, and turn in place, just like the dragonfly we see, it is even more agile than the dragonfly. Therefore, its application value is very high, because it does not need a runway, and only needs a small open space to take off and land, so it can take off and land in many places. Also, if it is used on the battlefield. Its unconventional maneuvers provide unprecedented tactical flexibility, such as the ability of helicopters to hover below treetops, and at the right time, suddenly emerge to attack enemy targets, especially armored targets, and then quickly descend below treetop height, not only to evade direct fire from opponents, but also to quickly stealthily shift positions. The same tactics apply behind hidden objects such as ridges and buildings. And in rescue and precision fixed-point airborne operations. Helicopters can even play a big role. ”

Messerschmitt laughed: "Of course, helicopters also have drawbacks. That's a lot slower. The slow speed is both its disadvantage and its advantage, so that it can be widely used for short-distance transportation, reconnaissance patrols, emergency rescue, hoisting equipment, etc. ”

Karl thought for a moment and said, "It seems that the helicopter is really an epoch-making aircraft. But what about turbofan engines and turbofan planes? ”

Xiao Weiguo said loudly: "The turbofan engine can also be called a landmark engine. The turbofan engine is a branch of the jet engine, and the turbofan engine should be regarded as a variant of the turbojet engine in terms of kinship. From a structural point of view, the turbofan engine is nothing more than the addition of a fan before the turbojet engine. However, it is this few pages of fans that strictly distinguish a turbojet engine from a turbofan engine. The turbofan engine relied on a few pages of fans on his body, and the fan was also blue. ”

"Part of the air drawn in by the turbofan engine blows backwards from the external duct, the outer duct, and part of it goes to the core of the inner duct. That is, it is equivalent to a pure turbojet engine. The front-end fan acts like a propeller and improves the propulsion efficiency of the jet engine by reducing the exhaust velocity. At the same time, through precise design, more gas energy is transmitted to the outer duct through the fan, which also solves the problem of excessive exhaust speed, thereby reducing the fuel consumption of the engine. Because the fan design should take into account the needs of internal and external ducts. Therefore, the difficulty is much greater than that of a turbojet engine. ”

"With our current technical level of turbojet engine, after the turbojet engine is equipped with a fan and becomes a turbofan engine, its technical performance will be greatly improved. When the air flow of the turbofan engine is equal to that of the core engine, the ground take-off thrust of the engine will increase by about 40 percent, while the fuel consumption during high-altitude cruising can be reduced by 15 percent, and the efficiency of the engine has been greatly improved. What does this mean? It means that the aircraft with turbofan engines will not only be more powerful, but also the fuel consumption will be greatly reduced, and the range of the aircraft will be greatly expanded. For combat aircraft, both energy maneuverability and combat radius will be significantly increased. For civilian passenger and transport aircraft, the economy of aircraft will be greatly improved. Xiao Weiguo said excitedly, of course, he knows how important the turbofan engine is, because it can replace the turbojet engine with high fuel consumption in a large area after it matures, and solve the problem of short legs of jet aircraft.

Messerschmidt said excitedly: "Does that mean that the turbofan engine has the characteristics of low fuel consumption, large take-off thrust, and large windward area, while the high thrust-to-weight ratio and low flow ratio turbofan engine with afterburner can be used as the power of air superiority fighters; And turbofan engines with large flow ratios and high thrust can be used on large passenger aircraft and strategic transport aircraft, and even strategic bombers. ”

Xiao Weiguo laughed and said, "Exactly! (To be continued.) )