Who made the stealth clothes worn by the Chinese Air Force J-20 stealth fighter jet

Chinese Air Force J-20 stealth fighter jet

Recently, citing Xinhua News Agency, a research team from the Suzhou Institute of Nanotechnology, Chinese Academy of Sciences, has invented a new infrared stealth material that has significant advantages such as light weight, foldability, and durability. More importantly, compared to traditional products, the newly discovered infrared stealth material can avoid detection by infrared detectors without relying on additional energy, thus having revolutionary significance in the military field, especially in the stealth of fighter jets.

F/A-18 fighter jet from the perspective of infrared detection system

As is well known, all entities in the world produce corresponding infrared radiation, the specific strength of which depends on the surface temperature of the object. Correspondingly, active aircraft using jet engine technology experience a temperature difference of over 1400 ℃ between the tail nozzle and the surrounding environment during flight, making them appear like the "brightest star in the night sky" in front of existing infrared detection equipment.

F-35 fighter jet from infrared perspective

In order to reduce their own infrared characteristics and enhance low detectability, major military powers have begun to manufacture barely usable infrared stealth materials based on the principle of changing thermal radiation characteristics, thus alleviating this urgent need to a certain extent. On the other hand, such products also have a series of significant drawbacks, such as high energy consumption, susceptibility to oxidation, low reaction efficiency, and limited applicability.

The binary rectangular vector engine nozzle used in the F-22A fighter jet

It is precisely because of the limited effectiveness of materials themselves that top aviation powers such as the United States have begun to manufacture complex aviation equipment that can reduce the infrared characteristics of fighter jets. The binary rectangular vector engine nozzle used in the F-22A fighter jet is a typical example: in principle, the device shortens the length of the nozzle core by promoting rapid mixing of the tail flame with the freely flowing air outside, thereby significantly reducing the infrared radiation intensity at the tail of the aircraft. Years of practical application have shown that using a binary rectangular vector nozzle can also increase the contact area between its surface and cold air, which is more conducive to achieving heat dissipation at the tail end. Even according to official data released by the United States, compared to traditional circular nozzles, the binary rectangular vector nozzle used in the F-22A can reduce the infrared radiation intensity at the tail of the aircraft to 40% of its original level, indicating that the effect achieved by this device is still very significant.

F-22 fighter jet from the perspective of Su-35 infrared detection system

However, subsequent evidence has shown that with the continuous improvement of military infrared detection technology, simply reducing the infrared radiation intensity in the nozzle direction is no longer sufficient to meet the stealth requirements of modern air combat. The most typical example is last September, when the Russian Su-35 fighter jet discovered the F-22A fighter jet, which claimed to have "omnidirectional stealth" capability, relying on its onboard OLS-35 infrared tracking and search system. This is because the effective detection target of this system is no longer limited to the engine nozzle with the highest temperature, and even the heat generated by the friction between the surface of the aircraft and the air will be captured in a timely manner. Therefore, this progress has to a considerable extent led to the F-22A fighter jet revealing its true form.

The J-20 equipped with new infrared stealth materials will undoubtedly gain wings like a tiger

The reporter learned from the Suzhou Institute of Nanotechnology, Chinese Academy of Sciences that a research team led by researcher Zhang Xuetong has recently discovered an infrared stealth material. This new material is sturdy, lightweight, and foldable, and can evade the "eye" of infrared detectors without the need for additional energy, with broad application prospects.

They first made a solid but soft nanofiber aerogel film, which has excellent thermal insulation performance. Soaking this film in phase change material polyethylene glycol (PEG) and subjecting it to waterproof treatment results in a lightweight, sturdy, and flexible composite material with excellent infrared stealth performance.

Since the nanofiber aerogel film itself is a good thermal insulation material, while polyethylene glycol will store heat and soften when heated, and then release heat when solidified and harden again. Under simulated sunlight, the composite film covering the target can absorb heat from the sun to achieve the purpose of inhibiting temperature rise, just like the surrounding environment, making the target object "invisible" to the infrared detector. When night falls, the film can slowly release heat to match the surrounding environment. In addition, selecting the appropriate thickness of aerogel film to cover between the heating target and the phase change composite film can also make the heating object "invisible".

The new material can not only be used for infrared stealth, but also for electronic insulation materials, battery separator materials, etc. We predict that its application prospects will be very broad, "said Zhang Xuetong.

Undoubtedly, against the backdrop of increasingly powerful infrared detection methods in various countries, the discovery of new infrared stealth materials in China is like sending charcoal in the snow. In this regard, even domestic scholars have analyzed and pointed out that, on the basis of originally having good radar stealth capabilities, new infrared stealth materials that have sustained effects and do not require additional energy consumption will help the J-20 achieve "all-round, full spectrum" perfect stealth, thus enabling it to better win the sky.