I Russian pennant design bureau R-73 shooter missile
In fact, the R-73 is not a real fourth-generation air-to-air missile. It ranks first not because of its strength, but because of its unique position in the development of the fourth generation air-to-air missiles. R-73, like a fierce catfish, led the arrival of the fourth generation air-to-air missile era. Its development laid a lot of technical foundation for the fourth generation air-to-air missile, and even divided a clear and accurate technical threshold. R-73 was originally a new generation substitute designed by the Soviet Union to further improve and enhance the capability of the R-60 aphid missile. The old aphid missile was too ingenious in design. Although it is small, the fighter can carry a lot, but the R-60 warhead is too small, with less than 6 kilograms of charge and many fragments. However, under the weight limit, the debris produced is of small mass and insufficient damage. In addition, the rocket engine has a small total impulse and a long range. When R-60 Aphids intercepted a small propeller airliner with twin-piston engines in Africa, the missile hit the side of the engine accurately, but the aircraft did not suffer any major damage, and still relied on one engine to complete the task. This battle made the Soviet Air Force lose confidence and decided to give up aphids with almost no potential to dig and develop a new generation of air-to-air missiles with new MiG fighters.
The main air combat equipment of the Soviet Union in the 1970s, the R-60 missile called AA-8 Aphid by NATO, was an attempt by the Soviet Union to turn to light and small combat weapons, which was completely different from the bulky weapons of the Soviet Union at the same time. The weight of only 55kg is 30% lighter than that of the western rattlesnake missile at the same time, but it is not very successful because of its small warhead and short range.
The missile R-73 under the wing of MIG -29 was named AA- 1 1 Sagittarius by the West. The red cover on the head is a traditional accessory of Soviet weapons to protect the seeker window. This 1986 suit, which appeared at the Paris Air Show, gave the West a strong shock.
The design of R-73 did not abandon the technical system of aphids. On the contrary, its layout was formed after some amplification and innovation on the basis of aphids. The length of R-73 is 2900mm, the projectile diameter is 160mm, the wingspan is 5 10mm, the weight is 105kg, and the warhead weighs 7.4kg. The design is quite complicated, which is somewhat contrary to the Soviet Union's habit of acquiring weapons by simple technical means. As a measure of the fourth generation missile in the west, it has laid several key technologies for the development of short-range air-to-air missiles in the future:
① The pneumatic layout is complex and the pneumatic control is simple.
The R-73 has an extremely complicated aerodynamic layout. There are some shortcomings in the traditional canard layout, such as the attack angle of the rudder surface of the front wing is greater than that of the missile, and the early stall phenomenon is easy to occur at large maneuvering attack angle. This problem must be considered in missile design, and the rudder deflection angle is small. For example, the rudder deflection angle of the front wing of the early rattlesnake missile was only 65438 02 degrees, which limited the improvement of the missile's maneuverability. Aphids use compound front wings. A fixed wing is added in front of the rudder, and the downwash airflow generated by the fixed wing is used to reduce the real angle of attack of the rudder surface of the front wing, thus expanding the available angle of attack of the rudder. The rudder deflection angle can reach 65438 08 degrees. In addition, the lift generated by the curved wing composed of the fixed wing and the rudder surface is greater than that generated by a single rudder surface, which further enhances the control force. Many third-generation high-mobility air-to-air missiles in the west have also adopted this design. In addition, the R-73 added a movable weather vane on the conical surface of the warhead in front of the front wing. The movable weather vane has two functions. Firstly, it can provide accurate and dynamic reference position of attack angle for the front wing, so that the missile control computer can always control the rudder surface of the front wing to work at the maximum aerodynamic angle without stalling; Secondly, the wind vane itself is a front wing, and the combination of its angle in the airflow and the rear wing can also produce an extra lift. The maximum lift increment can reach 6- 1 1%, which is also very impressive. The result of the combination is that the R-73 can obtain much greater maneuverability through the aerodynamic surface than the third generation close air-to-air missile in the west. At that time, the maximum overload of AIM-9L, the main western rattlesnake, was about 22g, while AIM-9M, known as the super rattlesnake, was only 30g, while R-73 could reach 40G. In the envelope area where AIM-9M deals with 7g maneuvering targets, R-73 can deal with 12G targets. The tail wing of the R-73 also uses a strip wing with a small aspect ratio, which is close to the strip because of its high maneuverability. On the one hand, it has a larger wing area to obtain greater aerodynamic lift, on the other hand, a longer chord length can also strengthen the structural strength of the missile tail, which is very effective for increasing the thrust control of the R-73. R-73 does not use gyro rudder servo aileron commonly used in western missiles, but uses damping servo aileron to control the roll of canard layout with less resistance.
The front of R-73 has complex aerodynamic design, and the movable winglet of the wind vane can not only provide reference angle of attack for the wing, but also provide partial lift effect. The wingspan of the fixed wing is very small, only half that of the wing, but the chord length is equivalent to a side strip, which provides a strong vortex to enhance the lift of the wing and also produces a partial downwash airflow to reduce the real angle of attack of the wing.
MIG -29 and its equipped helmet sight, the standard MIG -29 air superiority mount carries two R-27 semi-active guided medium-range air-to-air missiles and four R-73 short-range air-to-air missiles. The main design object is to defeat the American f 15 fighter. The merger of Germany and Germany has given the United States the opportunity to directly test this air combat system, which has a far-reaching impact. Helmet sight and large off-axis missile can improve the exchange ratio to 4: 65438.
The use of large off-axis launch and helmet sight further subverts the traditional occupation theory of energy air combat. Because the nose field of view is blocked, the occupation of aircraft does not need to be higher than that of enemy aircraft, and it is easier to reach the shooting condition if it is slightly lower. At the same time, it is very important to link the rolling speed with the goal. Up to now, helmet sight is the only technical way to develop the large off-axis capability of air-to-air missiles, and it is also the necessary standard for the fourth generation air-to-air missiles.
③ Engine thrust control vector technology
The large off-axis launch capability greatly expands the kill zone of the missile, but the larger the off-axis angle, the greater the maneuvering overload the missile needs to bear after launch. Complex and advanced pneumatic layout and control can achieve higher maneuverability, but the missile's initial weight is relatively large, and the missile's weight should be reduced by at least 30% after the rocket engine is completely burned. In addition, the missile is often slow at the initial stage of launch, and the engine is not completely burned, so it is heavy, and it depends on the wing to provide maneuvering control. In addition to the complicated aerodynamic layout, the R-73 also adds thrust vector control to the missile, so that the missile has a steering angular velocity close to 42 degrees/second in the initial stage of launch.
The aerodynamic layout of R-73 is canard layout, so it is relatively easy to design thrust vector control technology, because the thrust vector direction is consistent with the lift direction of canard. Considering the space layout of the tail and the energy loss of the rocket engine, the designer of the pennant chose to arrange four spoilers at the tail to control the rocket jet. The advantage of spoiler technology is that the existence of spoiler will not interfere with the airflow work of rocket nozzle if vector control is not needed. There is almost no thrust loss, so that the basic performance of the missile will not be weakened when long-range is needed. When the thrust vector control is needed to provide additional external force, the spoiler in the direction of the required force will cut into the jet, and the deflection angle of the jet will be obtained by the spoiler deflection. Spoiler can get a jet deflection angle close to 20 degrees, generally around 15 degrees, and the thrust loss of rocket engine will be 8-8 depending on the cutting degree of spoiler.
For the thrust vector details of the R-73 tail, the spoiler is the airflow cut into the tail nozzle by micro-hydraulic equipment, and the four channels can be controlled independently. The spoiler is made of nickel-based superalloy with high reliability.
Thrust vector control technology is very effective in the early stage of launch and when the aircraft is at low speed, which can give the missile many previously unimaginable capabilities, such as the over-the-shoulder shooting capability pioneered by R-73, which can make the missile draw a small circle in the air and launch forward but attack the target behind the tail. Thrust vector control greatly increases the initial maneuverability of the missile, and the combined control force with pneumatic control surface also increases the maximum maneuverability of the missile, which has become a technical standard of the fourth generation air-to-air missile, thus causing a series of changes in the design of choosing low-resistance pneumatic layout configuration and long-burning rocket engine.
④ Advanced infrared seeker.
In the third generation short-range air-to-air missile, the structure of indium antimonide refrigeration point target angle tracking seeker is popularized, which can be extremely sensitive to the infrared band of 3-5 microns. The third generation infrared short-range missile, starting from AIM-9L, has the ability to attack in all directions, but it is difficult to be found at a distance far exceeding 1000m unless the force is applied to the target nose. This distance is less than the time required for the missile to aim in the head-on flight. In fact, it is impossible to attack in a large angle range in the head-on direction of the target. Therefore, it is only a missile with false omni-directional capability, and omni-directional only needs to enter the second generation.
Dial-modulated infrared goniometer manufactured by Sidewinder Company is the structure of the third generation infrared missile. There is a partially opaque rotating dial on the optical path focused by the lens, which will halve the radiation energy of the target. In addition, when the missile axis is facing the target at zero, there is another shielding problem, which is called signal zero. R-73 adopts a new eccentric optical scanner and 4 yuan's cross indium antimonide refrigeration device, which not only eliminates the modulation disc that will block infrared signals, but also enhances the detection ability, so there is no blind eye phenomenon of signal zeroing, and the anti-interference ability is greatly enhanced. Among the western missiles, the third-generation missiles of France and Israel have adopted similar designs. The infrared seeker of R-73 basically reaches the limit of point tracking seeker, and with the complex digital processing technology in the later stage, the anti-jamming ability also reaches the limit of this structure. In terms of range, both R-73 and AIM-9M have the ability to head-on 4.5 (and h=500m) to 18km(h= 15000m), but in fact, the range at this time is only theoretical, and this missile can only be launched after the seeker locks the target. Under this condition, it takes only 2 seconds to aim at two planes flying head-on at Mach 0.9 and fly to the minimum shooting boundary of the missile. It is very bad that the rattlesnake seeker needs at least 2 seconds to lock the target, so it is impossible to hit the target. Under this condition, the R-73 can detect the target 22% farther than the rattlesnake, and the locking and launching speed is fast, which can be completed within 1.4 seconds, and it can barely achieve a real all-round attack. Later, the R-73 is going to use the improved D80 seeker, which has the dual-color infrared function and the anti-jamming ability is further enhanced. The digital circuit of seeker has also added programmable electronic circuit, and it is said that infrared imaging seeker is also in the experiment.