Since the late 1960s, many countries have begun to study stealth aircraft technology, among which the United States is the most famous. Its stealth fighter F- 1 17 and stealth bomber B-2 have been in service for many years. In recent years, the fifth generation stealth fighters F-22 and F-35 have been introduced.
I. Definition
The concept of "invisibility" itself is not a proper term for aircraft. Its essence is to make the reflection on the surface of the object as close to zero as possible to avoid being found by electronic detection systems such as radar. In the military field, "stealth" means that the aircraft can obtain low observability and avoid being found and tracked by the other radar, thus ensuring its confidentiality and attack ability.
Second, the technical characteristics
1. shape design: stealth aircraft usually adopt streamlined shape design as the primary guarantee of its stealth.
2. Vertical tail control: stealth aircraft relies on rudder control and jet vector orientation to achieve directional stability and maneuverability. The vertical engine can generate a very powerful steering thrust, so that the stealth fighter can turn flexibly like a big plane.
3. Feature control: stealth aircraft often recognize radar, because it is on the surface that can't reflect radar waves, which limits the radar task of the aircraft. For example, for the traditional radar, the electromagnetic wave without reflection will find echoes with a long time interval at the receiving end, which is called "echo missing area".
The leading engineer of stealth aircraft regards the "echo-missing area" as the breakthrough point of both offensive and defensive sides. By improving the surface material, shape and layout of aircraft, the reflection ability of aircraft electromagnetic waves received by radar from different angles is reduced.
4. Electronic warfare: Stealth aircraft often need to be equipped with advanced electronic warfare systems to counter ground radar and target tracking systems. These systems can be prevented from being detected by radar by jamming, cheating, exhausting the energy of the target radar and fabricating camouflage signals.
Third, the development process
Since the 1960s, the United States has been secretly researching stealth aircraft technology, because the early prototype machines were subject to many restrictions, and the first stealth aircraft did not appear until the 1980s.
1977, American Loma company and the military began to develop YF- 1 17A fighter-bomber. Later 1990, the United States launched the B-2 stealth bomber, and in 2005, the F-22 Predator fighter entered service.