The increasingly deteriorating air combat environment puts forward higher requirements for the technical and tactical performance of fighter aircraft, such as ultra-maneuverability, vertical, short-range rapid take-off and landing performance, stealth performance, etc. In order to adapt to the needs of modern air combat, fighter jets must adopt corresponding high and new technologies in their design to improve and improve the technical and tactical performance of modern fighter jets. The use of thrust vector control technology is a major technology to improve the technical and tactical performance of fighter jets.
Development of vector technology
Thrust vector control technology is also known as thrust steering technology. It controls the aircraft's maneuver flight by controlling the direction of the engine tail jet, that is, it can supplement or replace the aerodynamic generated by the conventional flight control surface to control the aircraft flight. After using thrust vector control technology, fighter jets can significantly improve the maneuverability of fighter jets. The technology of vertical and short-range takeoff and other technologies and tactical performance was used as early as the early 1940s, but was used on rockets, not on aircraft. For example, in the later stage of World War II , the German bombing of London, England, the V-2 rocket was equipped with a controllable deflection at the rocket's nozzle, and used the deflection of the jet stream to control the rocket's flight trajectory. Until now, some new air-to-air missiles, such as Russia's R-73 and France's " Mika ", have adopted similar methods to improve the maneuverability of the missile .
Generally, fighter jets rely on various rudder surfaces to control the flight direction. Under conditions such as large elevation angle and supersonic maneuver, the ability of rudder surface to control the direction will be affected by factors such as external airflow and pressure, and will be affected to a certain extent. If a vector nozzle is used, the flight attitude of the fighter will be adjusted very carefully, and even very maneuverable actions will be possible. This is also the main reason why scientists use vector technology on fighter jets.
F22 fighter As the main force of the US Air Force, is the world's first fifth-generation fighter to serve, with supersonic cruise, over-visual attack, stealth and supermaneuverability. F22 equipped F119 engine is a two-dimensional vector propulsion engine.
After the United States adopted vector technology, it was found that in addition to improving the maneuverability of fighters, it could also increase the stealth performance of fighters. We know that the aircraft's vertical tail wing is a main RCS source. Especially when exposed to the side of the radar wave, the RCS value generated by its vertical tail is even 3-4 times higher than that in front or rear, which is very unfavorable to improving the stealth performance of the aircraft. However, during the test flight of the X-3I verification aircraft, the United States found that thrust vector control can replace the role of the vertical tail wing in all or most.
In addition, aircraft using binary nozzle thrust vectors, since their nozzles are far from the center of gravity of the aircraft, the thrust vector can provide a large longitudinal maneuvering torque and does not change with the angle of attack. When the binary nozzle thrust vector is used for transverse f-directional maneuvering, the low-speed maneuvering efficiency can be doubled, especially at large angles of attack, which is very conducive to the improvement of the aircraft's subsonic and supersonic maneuverability.
China's vector technology is gradually maturing
At present, China's Taihang engine has made three- and binary vector thrust nozzle engines. In fact, as early as a few years ago, Academician Yang Wei expressed his confidence in an interview that year. We have vector engine and it is completely autonomous. In extreme airflow conditions, the aerodynamic energy of the aircraft is well matched with the engine. This technology (thrust vector technology) is a general technology, so once any type of aircraft needs to apply this technology, we will not hesitate to apply this technology to new aircraft.
binary vector technology and ternary vector technology have their own advantages and disadvantages. The engine tail nozzle of the binary system can only swing up and down, and high-temperature and high-pressure gas can only change the up and down directions. The biggest advantage of binary vector technology lies in its good stealth performance, which has a shading effect on the turbine blades of jet engines, and can reduce infrared characteristics and reduce rear fuselage resistance.
The biggest feature of the engine of the three-way system is that the engine tail nozzle and the engine are spherical articulated. The nozzle can deflect at full range of 360 degrees, and can swing in all directions. The high-temperature and high-pressure gas can also change directions in all directions. can bring very good maneuverability to the aircraft, but in order to take into account the multiple nozzles, the engine's nozzle cannot be covered, which sacrifices some of the stealth ability.
Now, the J-10B fighter has equipped a vector engine. The J-10B fighter equipped with a vector tail nozzle engine can display high-difficulty maneuvering such as "cobra" maneuvering and "falling leaves floating". The J-10B uses an omnidirectional axisymmetric vector nozzle, which is the ternary vector technology. This also shows that my country's thrust vector engine is gradually maturing, its output is gradually increasing, and its performance is gradually optimizing. The application of vector engines will also greatly improve the maneuverability and combat effectiveness of fighter jets.
When asked "will J-20 be replaced with vector engine in the future?" Yang Wei said, "Your question is when can it be used, but how do you know it is not used?" Does this mean that J-20 or binary vector engine can be replaced with binary vector engine completely surpass the US F35?
China's current aerodynamic layout is already the optimal solution
In fact, the current aerodynamic layout design of the J-20 does not require the use of binary vector engines. This is why the J-10B fighter has adopted vector engines, and the evolution of the J-20 is developing towards a two-seat version, which is China's original J-20 commands drone operations.
Chief Yang Wei’s meaning is more that vector technology is already very mature, and vector technology can also be used on our J-20, but this does not mean that we must use it.
We can see from another interview with Chief Yang Wei that he said that in extreme airflow conditions, the aerodynamic energy of the aircraft is well matched with the engine. This technology (thrust vector technology) is a general technology, so once any type of aircraft needs to apply this technology, we will not hesitate to apply this technology to a new aircraft.
means that fighter jets only use this technology when they need to use this technology.
In fact, China's J-20 has created the lift body side strip wing duck-style layout, and uses candle wing and wing front strips. This not only maintains the lifting effect when using the two lifting devices separately, but also allows a higher lift coefficient. This shows that some advantageous coupling effect is created between the canard, the front bar and the wing. The lift body layout with the wing body fusion can use the fuselage to generate lift, and increase the internal volume and improve the stealth characteristics at the cost of less resistance.
When using candle wings, the J-20 candle wings can be flipped 90 degrees, and the vertical tail wings have a large angle flip. No fighter can be achieved at present in the United States.
This is China's original design. The purpose is to achieve the J-20 stealth performance, large range, highlight supersonic maneuverability, highly informatized, omnidirectional threat perception and enhanced multi-spectrum stealth capability through a new aerodynamic layout.
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That is to say, the layout scheme of side strip wing double vertical tail, the vertical tail will experience relatively serious vibration under the conditions of large angle of attack flight; at the same time, the existence of the vertical tail will significantly reduce the maximum lift, accompanied by adverse headlift torque. This is also why the F22 needs to use a vector engine to make up for the insufficient maneuverability of the F22.
However, the aerodynamic layout adopted by the J-20 has reached the optimal solution. In fact, there is no perfect aircraft in this world to make various choices in various parts of the aircraft due to various problems encountered. The use of vector technology will actually reduce the thrust of this J-20.
Of course, with the continuous development of vector technology and the continuous upgrading of J-20, perhaps in the future, there will indeed be a J-20 engine that adopts new vector technology.
From this I have actually answered this question. Binary vector technology is not the icing on the cake for the current J-20, so this question naturally does not hold.
In fact, as fifth-generation fighter jets, F22, F35 and J-20 all have their own advantages and disadvantages. The key depends on which aspect of the performance of the fighter is focused more on.
As foreign media commented:
, supported by advanced omnidirectional sensors and systematic combat data links, cooperates with the world's best power performance long-range air-to-air missile 9, plus the excellent high-speed performance J-20 is likely to be the most powerful fighter in the world with the strongest capabilities of BVR in the world, and its excellent aerodynamic design is of great significance.
Reference:
Sang Jianhua: "Aircraft Stealth Technology"
Song Wencong: The development of duck-style aircraft
