021 Before the Zhuhai Air Show, someone exposed the picture of an American aircraft in transportation online. Judging from the pictures, the aircraft has a dark appearance, streamlined appearance and sharp edges. It seems to be a new model of stealth combat aircraft or a drone model.
new stealth aircraft in the United States swayed in the city
1970s, a US TV series "Wonder Woman" (Wonder Woman) was a hit. In the play, "Super Woman" Diana was flying a crystal-transparent jet saved the handsome pilot Major Steve Trevor. The hero and heroine and the " stealth aircraft " captured the hearts of countless Americans.
beauty flying a transparent plane to save heroes
Glass is transparent. We use it to make doors and windows to shelter the wind and rain, and at the same time let the light penetrate in without obstruction to provide lighting. Sometimes I suffer because the glass doors and windows are wiped too clean, causing many jokes.
Many people have hit the glass. This guy is a bit ruthless
So, like "Wonder Woman", is it feasible to use transparent glass to make airplanes? After all, "I can beat you, you can't see me" is the highest goal that military strategists always dream of!
glass is too heavy and too brittle. As early as World War I , German scientists tried to use a cellulose acetate material called "Cellon" to make the fighter matte. At that time, the Folk E. III single-wing fighter, the Albatross C.I biplane two-seater reconnaissance aircraft and the Link Hoffmann R.I bomber used this transparent "Cellon" skin, which looked very transparent on the ground, but these aircraft would reflect sunlight in the sky, which was easier to expose themselves. In addition, cellulose acetate quickly aged and degraded under certain temperature and humidity and sunlight, making the dream of German stealth aircraft ended up in vain.
Link Hoffmann R.I bomber
886, German physicists discovered that radio waves can be reflected back by solid objects; at about the same time, Russian scientists also discovered this, and he believed that electromagnetic wave reflection phenomenon can be used to detect objects in distant places.
Before World War II , radio technology had gradually matured, and European and American countries began to manufacture radar , making the aircraft nowhere to hide under electromagnetic waves.
Radar principle
electromagnetic wave fills the entire universe, and in fact all light is electromagnetic wave of a certain frequency. The frequency range that our human eyes can feel is very narrow. We cannot see ultraviolet rays with higher frequencies, X rays with lower frequencies, and infrared light, microwaves and radio waves with lower frequencies can only be detected by electronic instruments.
light is electromagnetic wave
In the dark night, we turn on the flashlight, and the light emitted by the flashlight is reflected back, so we can see the object in front clearly. Radar also has the same principle: it emits electromagnetic waves forward at a certain frequency. When part of the electromagnetic waves are reflected back by the aircraft, the radar receiver will receive the reflected signal, and then multiplies the time difference between the signal transmission and reflection by the speed of light, so that we can know the orientation and distance of the aircraft.
Air highlights on radar screen
In this way, even if you use fully transparent crystal to create an aircraft, it cannot escape the radar tracking. Radar is sharper than human eyes. It can detect and track aircraft hundreds of kilometers away. Once locked by the radar, it is the beginning of a pilot's nightmare. How can
be "stealthy" so that the radar cannot discover itself?
If you want to avoid being discovered by radar, the usual practice is nothing more than three ways: let the radar wave penetrate, refract, or absorb the radar wave. Penetration means transparency, like a clean glass. But the problem is that the surface of the aircraft is transparent, and the structural parts, engines, weapons and people inside cannot be transparent. They will still reflect electromagnetic waves back and are detected by radar. It's like a dazzling array of windows, and the other party can see it at a glance.
Can airplanes become transparent? The second way to invisible
is to refract: I do not reflect the electromagnetic wave you emit, but let it deflect to other directions, so that the reflected signal you can receive is very weak and it is not easy to find me.
U.S. F-117A attack aircraft is a combat aircraft that fully utilizes the principle of radar wave refraction to achieve radar "stealth". Unlike most aircraft we commonly use, the surface of F-117A has no arc transition. It is an aircraft composed of almost planes and looks very sci-fi.
When the radar wave illuminates the surface of the aircraft, since no plane is facing the direction of the electromagnetic wave emitted, no beam of electromagnetic wave will be reflected back to the radar receiver for a long time. It is said that the light spot on the radar of F-117 is comparable to a bird. It is easy to hide in the clutter of the sky, and it is difficult for you to find it.
F-117A has a weird appearance
Since the entire body is composed of a plane, the F-117A not only has a weird appearance, but also has poor aerodynamic performance, does not fly fast, and has poor maneuverability. And as long as the bullet casing is opened, all kinds of complex pipelines and parts inside it will be exposed, and it is still easy to be captured by the radar. When the United States and NATO bombed Yugoslav in 1999, Yugoslav air defense forces used the former Soviet Union's "old antique" S-125 surface-to-air missile to shoot down an invading F-117A and seriously injured another one. This proves that as long as the right method is used, the " Nighthawk " is not completely invisible or impossible to kill. In 2008, the aircraft was retired. The surface of the fuselage is made of special paint, which can absorb some frequency radar waves, thereby further reducing the reflectance. The B-2 bomber, , which was first flew in 1989, brought the technology of absorbing radar waves to the extreme. Its entire fuselage skin was specially designed to absorb radar waves.
B-2 bomber Guibi Gold
B-2 bomber adopts a flying wing layout. In order to reduce the reflection surface, it cut off the vertical tail wing and instead uses the horizontal flap at the rear end of the wing to control balance and change the flight direction. Unlike the F-117, the fuselage surface of B-2 is smooth and streamlined, with the front edge of the wings very sharp, minimizing the forward reflected electromagnetic waves. The stealth aircraft in service in
is similar to the B-2. In addition to achieving the maximum electromagnetic wave refraction from its appearance, it also puts a lot of effort into surface skin and wave absorbing materials. Due to the use of a large number of advanced technology and metamaterials, the price of stealth aircraft is comparable to that of gold of the same weight, which is quite expensive. The wave absorbing panel of
B-2 is made of multi-layer carbon fiber, each layer is conductive, and the outermost layer is coated with graphite coating containing tiny iron beads. When the radar electromagnetic waves illuminate the skin, the iron beads will first absorb some of the electromagnetic waves and convert them into heat and consume them; the other part of the electromagnetic waves will penetrate the coating, constantly scattering in the pores between the multi-layer carbon fibers and deplete energy. Electromagnetic waves can enter and not exit, so it will naturally be difficult for the opponent's radar to receive reflected signals.
J20
Although scientists from various countries have invested a lot of money and technology in the development of stealth fighter , so far no type of fighter has truly achieved stealth. The characteristics of electromagnetic waves determine that aircraft can only refract or absorb radar signals of certain wavelengths, but are powerless to do anything to electromagnetic waves in other frequency bands. The path is one foot higher and the magic is one foot higher. In the foreseeable future, the fight between fighter jets and radar will continue.
surface-to-air missiles and multi-band radar
