Military

Can the design of maneuverability and stealth fighter achieve a win-win situation

2023-05-29   

Not long ago, it was reported that the South Korean KF-21 fighter jet successfully conducted missile launch tests and machine gun tests. Since its first flight in July last year, the KF-21 has conducted approximately 150 test flights, verifying its supersonic cruise capability and the performance of advanced avionics such as radar. When it comes to the fifth generation aircraft, stealth, supersonic cruising ability, super maneuverability, and super information advantages are essential features. These capabilities not only provide strong combat power for the fifth generation aircraft, but also significantly increase the difficulty of developing the fifth generation aircraft. The development of the fifth generation aircraft often constrains its stealth and maneuverability. Balancing various aspects of performance is the core task that runs through the entire development process for researchers in designing fighter jets. So, where does the contradiction between invisibility and mobility come from? The answer lies in the aerodynamic layout - in order to avoid obvious echo signals caused by radar waves, stealth fighter jets have strict requirements for their appearance design, which is "clean and smooth appearance". But it also brings two problems: firstly, the appearance of fighter jets is limited. As is well known, the canard wing layout has unique advantages in maneuverability, but it directly damages stealth, making it difficult for third-generation and fourth-generation fighter jets with canard wings to develop into stealth fighters. The tailless flying wing layout is completely opposite to the canard wing layout, with excellent stealth performance, but poor control ability, almost losing supersonic maneuvering and short takeoff and landing capabilities, and is only suitable for B-2 and other aircraft models. Currently, the fifth generation aircraft in active service worldwide do not adopt a tailless flying wing layout. The second is that the difficulty of designing fighter inlet ports has increased. Taking the F-117 fighter jet as an example, in order to avoid strong cavity reflection in the inlet, the designer used a grille filled with holes to seal the inlet to achieve stealth. This design affected the aircraft's intake capacity, resulting in the F-117 being unable to achieve rapid maneuvering flight. After the MiG-31, there will be no high-altitude high-speed interceptors. With the development of reconnaissance and detection technology, it is obviously unreasonable to blindly pursue the flight speed of fighter planes. Once a fighter plane is locked by an anti-aircraft missile, it is difficult to escape the fate of being shot down. Therefore, in the development process of fighter jets, researchers have prioritized stealth and abandoned some maneuverability. Even the most advanced stealth fighter aircraft currently have a significant difference in flight speed compared to high-altitude high-speed interceptors. However, researchers have not given up on technological exploration for improving the maneuverability of fighter jets. While emphasizing stealth, try various methods to enhance the maneuverability of fighter jets. One is to improve the intake duct. The advancement of electromagnetic computing capabilities has to some extent solved the problem of poor maneuverability of stealth fighter jets. Researchers have designed twisted spaces with irregular cross-sections, allowing radar waves to enter the intake duct like falling into a black hole, constantly being absorbed and attenuated during the internal reflection process. The second is to change the pneumatic layout. By ejecting high-speed airflow at specific locations to replace aerodynamic surfaces such as flaps, the maneuverability of stealth fighters is enhanced. However, this method can cause significant engine consumption and is currently only used on small-scale unmanned aerial vehicles. The third is to develop stealth materials. With the progress of material technology, the new term "metamaterial" has come into people's vision. Metamaterial is a newer and more powerful stealth material, which is expected to achieve real stealth. By changing the structure of metamaterial, researchers can adjust the electromagnetic wave arbitrarily

Edit:qihang Responsible editor:xinglan

Source:81.cn

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