Chapter 2160: YF120 Relay

For the Eagles, they also have their own reasons. Although the J58 is a cross-age engine with variable cycle design, this engine was produced in the 1960s, and it is now in the late 1980s. Ten years have passed, and the once-advanced engine is already behind. This is also one of the reasons they can come up with it.
Of course, this is only on the one hand, and on the other hand, the Yingguo people already have a newer variable cycle engine!
This early engine has many shortcomings. As a combination of a turbojet engine and a ramjet engine, it has many problems in the connection of high and low speeds. At that time, there was no advanced digital control technology, and the entire engine control was difficult to achieve very precise. For Yingguo, this engine was only an introduction.
General Electric has become obsessed with variable cycle engines. Now, in Eagle Country’s new generation of fighters, two prototypes are competing. These are the YF22 and YF23. The YF23 is more sci-fi, in addition to more styling. In addition to the avant-garde, such as the unique V-shaped vertical tail, it also uses a newer engine.
"General Qin is right. Our intelligence personnel have obtained some information from Eagle Country." General Lin said: "England people have prepared two engines for the selection of next-generation aircraft, one is a conventional turbo Fan engine, code name YF119, one is a variable cycle engine, code name YF120."
General Lin waited for Qin Guan to come here before throwing out the news. Obviously, he also supported it. The Yingguo people were willing to give him this engine because they already had more advanced engines.
This news made Qin Guan stunned, not because Qin Guan didn’t know it, but Qin Guan didn’t expect that the information from his own intelligence department was so well-informed that he had explored so much about the engineering of the fourth-generation aircraft of Ying Guoren. You know, this is still a secret now.
It is funny to say that in this competition, Lockheed YF-22 and Pratt & Whitney's YF119 won, becoming F-22 fighter jets and F119 engines. The Eagle State Air Force was originally pursuing advanced technology and pursuing loftyness. As a result, the YF23, whose technology is like science fiction, and this super advanced YF120, were rejected.
The Eagles must have suffered enough from the F-15 engine. Once they were bitten by a snake for ten years, they were afraid of well ropes.
Now, General Lin has stated that we must not fall behind!
Variable cycle engines are about to become a trend in the future!
Although both are variable cycles, YF120 and J58 are still different. J58 is a turbojet engine. When the cycle is changed, the airflow does not pass through the compressor in front, but only the combustion chamber at the back. At high speed, the air itself It has been compressed, this is the variable cycle of turbojet and ramjet.
The YF120 is for fighter jets. It circulates between turbojet and turbofan engines.
Turbojet engines are commonly used in the past. This type of engine has a small frontal area, so it has very good high altitude performance. An aircraft as small as the MiG 21 can also achieve a maximum speed of Mach 2, which is inseparable from turbojet engines. Yes, but this kind of engine has its shortcomings. This is fuel-consuming. Adding an external duct on the outside becomes a turbofan. The fuel consumption rate has been greatly reduced. The third-generation engine must It is a turbofan, otherwise the range will be a mess, and at the same time, the thrust is much greater than that of the turbojet.
However, not all turbofans have advantages. Due to the addition of external ducts, the windward area of ​​this engine is larger, which increases resistance, especially at high speeds. External ducts have no advantage. Instead, it will become a kind of resistance.
Therefore, the high-altitude performance of the Spey engine is a mess, which is the reason for the front fan. The MiG 31 engine is upgraded to a turbofan. Although the range is improved, the maximum speed is slowed down, but it is lower than the MiG 25 using turbojet This is the truth.
In order to develop advanced fourth-generation aircraft, Yingguo people also used all the power of science and technology. In terms of their engines, the YF120 engine is obviously a more sci-fi one.
The F119 engine uses a lot of the most advanced technology and is the world's first engine with a thrust-to-weight ratio of 10, but it is still just a conventional low bypass ratio turbofan engine.
And YF120? It adopts valve control, which can open the outer duct when needed to realize the turbofan function; after closing the outer duct, the turbojet function is realized. In particular, there are two groups of such valves. One group is in the front, which divides part of the fan exhaust to the outer duct, and the other group is behind, which divides the exhaust of the high-pressure compressor to the outer duct.
This design that changes the engine is obviously more advanced. In this way, at low speeds, the engine is a turbofan engine, which can provide a lot of power. At high speeds, closing the outer duct is a turbojet engine. At this time, the windward area is small, which is convenient for sprinting. What is more ingenious is that this engine can smoothly transition between the turbojet state and the turbofan state, taking into account the fuel-saving characteristics of the turbofan at subsonic speeds and the high-speed characteristics of turbojet at supersonic speeds. It can be said that this engine embodies the scientific and technological power of Eagle Country.
Unfortunately, it was precisely because it was too advanced, too sci-fi, and in order to avoid being too avant-garde and failing, the Eagle Air Force gave up this engine.
Of course, it’s not really giving up. It’s just that they haven’t used it on their fourth-generation machines, and this engine has continued to be allocated for research and development. The F-15 hangar queen’s nightmare is still in my memory. Therefore, they are also funding this new engine. When the F-35 was developed, this engine changed and became YF136. Competing with YF135, the result failed again. Until this time, the engine was finally abandoned.
By this time, this kind of engine is not just a simple cycle change, but also an adaptive level. In addition to the variable cycle between turbojet and turbofan work, it further automatically adapts to the working environment.
Now, when General Lin mentioned this news, in Qin Guan’s brain, there was a flash of inspiration. The J58 engine given by the other party was just an introduction. If you use other engine technologies, such as YF120 or even YF136, If the technology is taken over and absorbed by one's own side, can it greatly promote the development of one's own aviation power system?
If it is really done, then domestic aviation technology will scorn the global level.