What technology is used in the Russian Kinzhal hypersonic missile, and why is it so difficult to intercept?

Defense Minister Sergei Shoigu said that Russia has used three-time Kinzhal hypersonic missiles so far in Ukraine and they have worked very well.

On March 19, Russia first announced the use of Kh-47M2 Kinzhal (Dagger) air-launched high-velocity ballistic missiles against a target in Ukraine. A video allegedly released by the Russian Federation’s Ministry of Defense (MoD) shows the missile being used to strike a Ukrainian ammunition depot in the western part of the country.

A high-precision missile attack destroyed an arsenal of the Ukrainian Armed Forces. We can see the exact impact of an underground hangar with weapons and ammunition,” the Russian Defense Ministry said on its official Twitter page.

Kinzhal missiles are one of a series of new advanced weapons that Russian President Vladimir Putin announced in 2018. According to Russian media, they can hit almost any point in the world and penetrate air defense systems. America.

K-47M2 “Kinzhal” (Dagger in Russian) is a hypersonic ballistic missile capable of carrying a nuclear warhead and being fired from an aircraft.

Although Russia has kept the Kinzhal development process a secret and has not released many details, open information indicates that the missile can carry both conventional and nuclear warheads, with a payload of up to 480 kg.

Kinzhal is designed to be fired from a MiG-31 fighter at an altitude of about 18 km and can travel at a speed of at least 5 times the speed of sound or Mach 5. Many sources believe that Kinzhal’s top speed is capable of up to Mach 10 (12,350 km/h). The range from Mach 5 to Mach 10 is called hypersonic speed.

mig-31k with Kh-47M2 Kinzhal
Mig-31k with Kh-47M2 Kinzhal Hypersonic missile

Russia said that the Kinzhal missile can reach a range of more than 2,000 km if fired from a Tu-22M strategic bomber.

Kinzhal is a terrifying new-generation weapon because with a speed of up to 12,000 km / h and a tricky flight trajectory, defense seems to be an impossible task, even with top anti-missile systems of the world.

Russia is believed to have used Kinzhal missiles for the first time about a month after opening a special military operation in Ukraine at the end of February, targeting a large arsenal in the Ivano-Frankivsk region in the west. Ukraine.

Dagger Hypersonic Missile

According to wiki information, this missile can attack static and dynamic targets, including destroyers and aircraft carriers, and no weapon can intercept it at 10 times the speed of sound. Its cruising kinetic energy is 432 times that of the Tomahawk missile, and high-speed penetration can destroy the target even if it does not explode.

According to Tass, the first launch of Kinzhal was in mid-November 2019. The carrier was a MiG-31K from Olenia Air Force Base. The missile hit a ground target at the “Bloomberg” test site at a speed of Mach 10.

Trajectory of a hypersonic manoeuvrable glide vehicle
Trajectory of a hypersonic manoeuvrable glide vehicle

It was used in actual combat for the first time on March 18, 2022, destroying the underground arsenal of the Ukrainian Armed Forces in Deliatyn. Judging from the released video, a big explosion occurred after the hypersonic missile penetrated directly into the ground, and the explosion was larger than that of a conventional missile. The middle and rear are slightly larger, but looking at the scale of the explosion, it seems that the ammunition did not explode.

What kind of hypersonic technology does the Dagger missile use?

The key technology of hypersonic missiles is undoubtedly how to achieve hypersonic speed. Generally, hypersonic technology has the following ways:

  • Rocket violent propulsion
  • Gliding at hypersonic speeds
  • Scrambling hypersonic speed

First of all, we must make sure that there is a difference between supersonic speed and hypersonic speed. The definition of hypersonic speed is at least 5 times the speed of sound, so many so-called pseudo-hypersonic speeds have been revealed.

Disadvantages of rocket propulsion

It is easiest for a rocket to achieve hypersonic speed. A rocket that launches a satellite into space needs at least the end-to-orbit speed of about 7.8 kilometers per second, which is about 23 times the speed of sound at sea level. Therefore, countries that can launch satellites should able to build hypersonic missiles without any trouble?

In fact, this is not the case at all, because the rocket has its own fuel and oxidant, and can only carry half of the fuel, while the other half is taken up by the “useless” oxidant. Because the rocket has to leave the atmosphere, it can only carry the oxidant, but the missile does not need it, so a plane carrying the same mass of “fuel” with atmospheric oxygen has a much higher range.

The difficulty of gliding hypersonic speed

The rocket is an unqualified hypersonic propulsion engine, but it can propel the target warhead to a high altitude, and then use the gliding method to reach the target. This is the gliding hypersonic technology, which uses the control of the glide angle and trajectory until it hits the target. 

hypersonic glide vehicle
hypersonic glide vehicle

It has a feature that the threshold is relatively low (there is no hypersonic engine technology), but it has high requirements for aerodynamic gliding technology, and the thermal insulation and high temperature resistance technology of the body is also very high, because of the extreme friction at hypersonic speed ( In fact, hypersonic shock heating) will heat the shell to more than 600 degrees.

Difficulty of scramjets

It is estimated that everyone has heard of the ramjet engine. This kind of super simple structure has great thrust, and the engine that can adapt to supersonic speed is simply ideal power, but its disadvantage is that it can only be started under supersonic conditions.

What Is A Scramjet Engine? How Does A Scramjet Work?

Through the compression of the intake port, the airflow through the combustion chamber is reduced to below the speed of sound. At this time, fuel is injected, ignited, and ejected from the tail nozzle. This is the work process of the sub-combustion ramjet.

Typically, a sub-combustion ramjet can travel at 5 times the speed of sound, but at speeds higher than that, the combustion chamber becomes unstable and the engine cannot continue to operate. As a result, it was necessary to develop a supersonic combustion chamber airflow, which gave rise to the scramjet.

The distance between the combustion chamber is less than one meter, and the time for supersonic airflow to pass through is only a few milliseconds. It is really difficult to complete the mixing of fuel and ignite it in such a short time!

Rotating detonation engine (RDE) 

The rotary detonation engine is not described above. This kind of engine is an engine that is separated from the combustion mechanism and turns the combustion of fuel into a process of detonation. Its advantages are that it can be started at 0 speed and can also adapt to hypersonic speeds. But so far the test results have been announced, but it has not actually been equipped with some kind of aircraft or missile.

What kind of engine does the Dagger missile use?

If it weren’t for gliding hypersonic speed and violent rocket propulsion, hypersonic missiles must have an air intake. For example, the X-51 tested in the United States is of this type:

But from the appearance of the dagger, there is no air intake at all, such as the missile mounted on the MiG-31:

It doesn’t seem like it really looks like a missile with a scramjet, but this is the window sill before the launch. It’s not clear what happens after the launch. If it’s a scramjet, the first step in the launch is to start the rocket engine and push it forward to the speed that the scramjet can ignite, while exposing the intake port, because the scramjet uses oxygen in the atmosphere as an oxidant.

From the structure of this unidentified Dagger missile, it can be seen that it is a solid fuel engine, with an air inlet in the middle, and the airflow entering from the front passes through the holes in the fuel column, and then ignites and occurs with the solid fuel. After the oxidation reaction, it is ejected from the tail nozzle at a high speed.

However, I still can’t see where the intake port is located. From the analysis of the starting structure, it is either hidden in the nose cone (axisymmetric intake port, somewhat similar to the structure of the Brahmos missile), or hidden in the fairing structure, such as the following A structure like this:

Indian BrahMos missiles structure
Indian BrahMos missiles structure

The nose cone of the ramjet isolates the shock wave, because the destructive force of the shock wave is too great, and the supersonic airflow enters the air intake for compression, and finally reaches the combustion chamber is the combustion chamber.

Difficulties of hypersonic weapons

Some people say that the most difficult thing for hypersonic weapons is not the scramjet, but how to guide it, because the hypersonic shock wave heating will cause the temperature at the nose cone to rise to hundreds of degrees high temperature, modern materials that can transmit waves and have good high temperature resistance But it’s hard to find, so the problem is to achieve hypersonic speed only to find that the guidance is blocked.

It is no problem to inject guidance commands from the rear. After all, the temperature of other positions except the nose cone is still relatively low, but for missiles attacking moving targets, post-launch guidance is required, and the distance is limited because the rear Airborne radar is affected by the curvature of the earth. Secondly, it cannot be ignored after the launch. The carrier aircraft is exposed to the dangerous airspace for too long, and the consequences are unimaginable.

It is said that both China and Russia have solved this problem. It seems that the United States has encountered some problems. While India also tested many times its Hypersonic missile test bed and in next 4-5 years could achieve the success.

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