【FS-2020】“鷹獅”戰機的隱形版FS-2020，爲什麼以失敗告終？|被下馬的FS-2020戰鬥機，它的隱身性能有多強大？

At the beginning of 2020 , I got news from the Swedish media "Express" that a fifth-generation fighter developed by Saab itself could not meet the requirements of the Swedish military in terms of comprehensive performance and the existing technology could not be improved , so it was decided to use this fighter. The related projects are dismantled. Saab is a company that is as famous as Bofors, Sierses and other arms dealers. Its military weapons are very famous in the international arms trade market. The previous JAS-39 "Gripen" fighter is a very good one. Example But why did the research and development of this fifth-generation fighter fail to continue in the end? Why did Sweden, which was able to successfully develop the fourth-generation aircraft, make such a big somersault on the fifth-generation aircraft? This starts with this FS-2020 fighter . In addition, Sweden, as a small country with a small population and a small land area , cannot be compared with China, the United States and Russia in terms of the research and development strength of fighter aircraft. Although it has successfully developed the fourth-generation aircraft, and its fighter aircraft is in aerodynamic layout and overall design. It is very good, but the overall strength is obviously not that strong. During the research and development process of FS-2020, this point was completely exposed. FS-2020 is the 2020 aviation system project. This is Sweden's plan for the development of fifth-generation fighters. From the plan We can see that the FS-2020 adopts the close-coupled layout of the canard-delta wing. Its canard trailing edge is swept forward, and the leading and trailing edges of the canard and delta wing are parallel. This principle is strictly followed because the main wing returns The wave can be used to hide the reflection of the canard and merge the two lobes together. Not only that , the design of the tail of the FS-2020 is also very special. It uses a V-tail design . What is a V-tail design? Only the YF-23 "Black Widow" has used the design. It replaces the horizontal tail and vertical tail with two tail fins with a V-shaped angle. It kills two birds with one stone . The tail structure is very simple, the weight is relatively light, and the resistance is very small , so it The stealth performance of the FS-2020 is particularly good, so from the above aspects , the stealth performance of the FS-2020 is still very powerful, but no matter everything has two sides, both advantages and disadvantages , so the design of the FS-2020 also has some unsatisfactory places . In terms of the coupling layout of the canard and delta wings of the FS-2020, this is actually a very complicated project. When Sweden was developing and manufacturing the fourth-generation "Gripen" fighter, it encountered a bottleneck in the fly-by-wire flight control. If it wasn't for the United States at that time I am afraid that the fate of the "Gripen" will be the same as the current FS-2020. It can be seen that the duck-style layout of the fifth-generation aircraft is a difficult project . The requirements it needs to meet can be described as abnormal, except for the super cruise and super maneuver. In addition, it also needs to deal with the reflection relationship between the canard and the main wing, and also need to deal with the stealth details of the action mechanism and the gap of the canard's rotating shaft. A little carelessness and negligence will lead to the deterioration of the stealth performance of the entire aircraft, losing it as the fifth generation. The most fundamental respect of the machine Yan FS-2020's more invisible forward swept design of the canard 's trailing edge makes the center of lift very forward. On this basis, its combination with the diamond-shaped fuselage of the fourth-generation aircraft puts the aircraft in danger of aerodynamic upward divergence. The solution of this problem itself has its own advantages. It is very difficult, which is a big challenge for the designer. The V-tail design of the multi-purpose tail of the aircraft is actually equivalent to the engineering that originally belonged to hardware. Now it is replaced by software . Difficulty This is not at the same level as the flight control difficulty of the " Gripen " fighter. The problem should be the biggest problem of the FS-2020. This problem is its single-engine design. This design has very high thrust requirements . At present, in addition to the FS-2020 in Sweden, the fifth-generation aircraft developed by other countries are used . They are all dual-engine designs , so that the problem of insufficient power can be solved to a certain extent. However, the FS-2020 abandoned the dual-engine solution. The reason can only be that Sweden did not put the issue of the structural weight of the fifth-generation aircraft in the first place. You must know that in order to be able to generate enough thrust, the FS-2020 requires multiple additional bomb bays and larger internal fuel tanks . The weight of a single-engine fifth-generation aircraft on empty weight alone is far more than a single-engine fourth-generation aircraft. For example The empty weight of the F-16 is 8.5 tons , but by the time of the F-35, the empty weight has almost risen in a straight line, reaching 13.3 tons . Therefore, in the selection of the F-35 engine, the United States uses the F135 engine with a thrust of up to 19 tons. Coincidentally , it is the same as The single-engine fifth-generation Su- 75 also uses 30 engines with a thrust of 18 tons. Therefore , even if the take-off weight of the FS-2020 was originally designed to be 16 tons , if you want to have the most basic combat capability, overweight is inevitable. From the strength of Sweden Judging from the fact that it does not have enough ability to solve the power problem of fighter jets, it once used the RM-8 turbofan engine developed on the basis of the Boeing 737 civil turbofan engine JT8D on the Saab 37 "Thunder" fighter and this The engine reflects a high level of aero-engine design. However, after the "Gripen" fighter booster chose the American GE-400 engine, Sweden 's own domestic engine project disappeared, so the FS-2020 engine can only rely on external purchases . The high-power single-engine fifth-generation aircraft requires at least high-thrust turbofan engines. This technology has basically been monopolized by developed countries, and the internal bomb bay of a single- engine fighter is very small . The size of the FS-2020 is similar to that of the "Xiaolong" fighter. There is not much difference, so its bomb bay can only be designed on the abdomen , which leads to its loading capacity of only 4 pieces. As for air-to-air missiles, don’t even think about it. Even if there are many difficulties , FS-2020 completed its first flight. At that time , it used F The thrust of the 414G engine obviously cannot match the speed, maneuverability and thrust-to-weight ratio of the aircraft with the design indicators. In the end, the fifth-generation aircraft developed since 2005 was forced to announce its dismantling . The results achieved in the middle can only be converted into technology. Reserve In the research and development of the fifth-generation aircraft, Sweden not only made a prototype, but also allowed it to complete the test flight. This is already a big breakthrough. Why did Sweden successfully develop the fourth-generation aircraft, but suddenly overturned on the FS-2020 project ? I have to go back to the fourth-generation "Gripen" fighter developed by Sweden. That fighter was not completely independently developed by Sweden. We said earlier that its fly-by-wire flight control system was built with the help of the United States. The F404 engine and air-to-air missiles on the configuration also came from the United States . When the "Gripen" improved, it adopted the British avionics configuration. That is to say , the "Gripen" fighter is actually the product of the collective cooperation of many Western countries. As for why at that time The answer to the question that so many Western countries want to help Sweden is actually very realistic . You must know that the "Gripen" fighter jet appeared before the Cold War, and during that time, various NATO countries were in great need . When I use you, I should help you. When I don't use you, we don't break the river . After the end of the Cold War, the United States has become a military superpower . Its F-35 is used to suppress Russia's Su-57. There is no problem at all . Need the help of Sweden , and the FS-2020 overlaps with their own F-35 export market, which itself poses a threat to the United States, so he would rather help South Korea develop the KF-21 than support Sweden's fifth-generation aircraft The end result is that Sweden cannot buy high-tech products because it has lost the support of the United States. Even if it can purchase ready-made products from other countries , most of the same type of products on the market use American technology. No wonder the FS-2020 engine can only be used. The research and development cost of the fifth - generation aircraft is incomparable with the third- and fourth-generation aircraft. The research and development cost of the F-22 20 years ago has reached 28 billion US dollars, which is high for Sweden, whose military expenditure in 2021 is only 7.48 billion US dollars. It is not only a little bit that the death of the Swedish FS-2020 has once again confirmed that a small country can't play the fifth-generation aircraft. Thinking about it , France, which is relatively strong, has begun to concentrate on the development of stealth UAVs and gave up the research and development of the fifth-generation aircraft , not to mention Is it Sweden? However , the consequences of FS-2020’s dismantling are still very serious for Sweden. The technology that has been accumulated through hard work is also faced with the risk of losing the talents cultivated in this project. There is no place for Sweden , which makes Sweden not hesitate to sell the "Gripen" fighter production line to develop the FS-2020. Unfortunately, the project still failed in the end . After this development failure After that, Sweden also realized that seeking multinational cooperation is an effective way to obtain fifth-generation aircraft, so it participated in the "Storm" fighter project. This project was jointly developed by Italy and the United Kingdom and was led by the United Kingdom. Although it is known as the sixth-generation aircraft, there are only fifth-generation aircraft. Even if Sweden participated in this fighter, it did not adopt the design of the Swedish FS-2020. I am afraid that FS-2020 can only be used as a history of the independent development of the fifth-generation aircraft by small and medium-sized countries. In this issue , the introduction of this FS-2020 fighter is here. Please continue to pay attention to us, you can watch the latest videos and browse past highlights . Please leave a message in the comment area . See you in the next issue