Xiao Weiguo and Messerschmidt looked at the test aircraft in front of them, and their eyes were full of joy, because once the turboprop engine is successfully tested and put into mass production, it will greatly improve the dominance of the Dragon Soul Ordnance Consortium in the field of aero engines! You must know that although the wind and thunder jet engine has advanced performance, it is only suitable for military aviation weapons, especially fighters and bombers, while transport aircraft and other aircraft are not suitable for the use of turbojet engines, because the fuel consumption of turbojet engines is too large, and such an oil tiger is installed on transport aircraft or passenger planes, and the economy is very bad.

But the turboprop engine is different, its fuel consumption is not higher than that of the piston engine, and its power can be very large, and in the future it will not be a problem to even make a turboprop engine with 10,000 horsepower. But piston engines can't do it. Because the piston engine reaches more than 2,000 horsepower, there will already be a lot of insurmountable technical problems. For example, the weight is too large, take the current piston engine technology, to achieve 2500 horsepower power, then it can only use a star-shaped design, and the number of cylinders will reach an astonishing number, more than a dozen cylinders, or even more than 20 cylinders, so that its weight will reach at least 2000 kilograms, and the wind and thunder turboprop engine is only more than 700 kilograms! Moreover, the piston type high-power engine also has the problem of engine heat dissipation difficulty and easy fire, which has always been a technical problem that is difficult for high-power piston engines to overcome, and the later American B29 bomber is because the 28-cylinder super star-shaped piston engine it uses overheated, resulting in a crash during the test flight, and this problem also exists after mass production.

Xiao Weiguo said with a smile: "Dr. Willy, you see that although our testing machine is weird, it can play a decisive role in the finalization of the wind and thunder turboprop engine!" Without it, the wind and thunder turboprop engine is only afraid that it will be difficult to finalize! ”

Messerschmitt laughs: "It's really weirder than a jet engine testing machine." However, after this change, the risk of the test flight will be greater, and I think you should not go up in person, so as not to cause danger! ”

Xiao Weiguo nodded and said, "Well, this test is very dangerous, so naturally I won't risk it." The turboprop engine has its own unique characteristics in terms of aerodynamics and structure, and the size effect caused by small flow and small channel has an adverse effect on the compressor, turbine performance and cooling. High speed - high speed brings a series of new problems to critical resonance, high-speed bearings, shafting, supports, fatigue strength of vane discs, etc.; Complex flow - the short blade type of small turbine blades increases the flow transition, and the three-dimensional characteristics and viscosity are prominent. Poor cooling efficiency - the small turbine blades are short and thin, and the relative surface area is large, while the internal cooling hole type is difficult to arrange, and the cooling flow is short, so the cooling effect decreases with the decrease of size; Air intake guards are required. I'm not sure if these problems will appear in the sky. Let's hope this test will go as smoothly as a turbojet engine! With turboprop engines, our M40 large transport aircraft will have a better future! ”

Messerschmidt said: "Our Thunder turboprop engine, with its long life, low fuel consumption and high power, is indeed an ideal aviation power!" I think that once it is put into mass production, it can not only be used in military aviation equipment, but also widely used in civil aircraft, benefiting the people of the whole world! ”

Xiao Weiguo said in a deep voice: "At present, our Wind Thunder turboprop engine is still designed based on the Wind Thunder jet engine. Axial compressors are used, but turboprop engines require compressors with a high total boost ratio. to obtain high thermal efficiency and unit power. In order to continuously improve the booster ratio, the structure of the compressor also needs to be transformed from a pure axial flow type to a combined compressor with a large number of axial flow and a centrifugal stage. Because for the turboprop engine with high boost ratio, the increase of the axial compressor stage makes the size effect of the last stages of the compressor more obvious, the airflow loss increases, and the aerodynamic performance decreases significantly. Moreover, the large rotor span of multi-stage axial compressors also brings difficulties in rotor dynamics. Due to the rotor structure of the centrifugal compressor, the rigidity is better and the resistance to foreign objects is stronger. The size effect has little effect on the centrifugal compressor, so it is advantageous to replace the axial compressor at the back. In the case of very small sizes, it is necessary to use a centrifugal compressor system in its entirety. Now that our Thunder turboprop engine power range is on the high side, we also need to continuously replenish the turboprop product line, from 500 hp to 10,000 hp. We need a series of turboprop engine products to meet different needs! ”

Messerschmitt smiled: "I seem to have seen the day when our aero engines will occupy half of the world's aero engines!" ”

Xiao Weiguo nodded and said, "I believe that day will come, but there is still a lot of work to be done now." For example, we should plan as soon as possible, focusing on the research of general core engine technology, with the general core machine, we can develop turboprop, turboshaft, turbojet and even turbofan engine. There are two main advantages of using the existing core machine to develop different types of engines, one is to increase the number of common parts of the engine, improve the interchangeability, improve the reliability of the engine, reduce the cost of use and maintenance, and the other is to shorten the development cycle of the engine, greatly reduce the development cost, and reduce the risk of engine development. ”

Messerschmitt was surprised: "Oh, how can this be? This core machine research seems to be very important! ”

Xiao Weiguo smiled: "That's right! Aviation turboshafts, turboprops, turbofans, and turbojet engines all belong to the category of gas turbine engines, but there are still many differences between turboshafts and turboprop engines and turbojet and turbofan engines because they produce thrust or power respectively, mainly because turbojet and turbofan engines are both heat engines and propulsions, turboshaft engines are only heat engines, and turboprop engines can be considered only heat engines because they only produce a small part of the thrust. The flight speed of the aircraft mounted on the turboshaft and turboprop engines is relatively low, and the slightly larger windward area of the engine will not cause serious problems; In a variety of higher speed aircraft, the turbofan (turbojet) engine, especially the turbojet engine, is required to have a smaller windward area, and the turboshaft, turboprop, and turbojet engine only have 2 thermal cycle parameters, namely the total pressure ratio and the pre-turbine temperature, while the turbofan engine has 4 thermal cycle parameters, namely the total pressure ratio, the pre-turbine temperature, the bypass ratio and the fan pressure ratio, and the turbofan and turbojet engines are different from the rotating parts of the turboshaft/turboprop engine and other moving parts outside the engine, such as helicopter transmission system, rotor or propeller, There are also mechanical connections. So with the core machine, there is still a lot of work to be done, especially basic research work! (To be continued.) )