【Military Sub-Plane】Author: Le Le
In October 2019, the Dongfeng-17 suddenly appeared without leaking the news in advance, and became the focus of the country with its sci-fi appearance and powerful performance. However, in the past two years, the description of the performance of the DF-17 by the outside world is mainly based on the label of "difficult to intercept by the missile defense systems of other countries", and at most "Qian Xuesen ballistics" or "water drifting" will be mentioned. Little has been said about the specific performance of the DF-17 and why it is difficult to be intercepted by missile defense systems. Today, in view of the fact that the DF-17 has appeared for more than two years and the technical sensitivity has declined relatively, the outside world can also glimpse how this epoch-making rocket force equipment, which is known as a self-made anti-ship ballistic missile, has made some countries sleepless at night.
▲ Dongfeng-17 appeared on the scene and shook the world
Before analyzing the performance of the DF-17, it is first necessary to understand what exactly is the "Qian Xuesen Ballistic". In general, the flight attitude of ordinary ballistic missiles is generally similar, and the process is relatively regular, first by the rocket into outer space, and then after a long mid-flight to reach the vicinity of the target, and finally at a high speed to re-enter the atmosphere until it hits the target. During the entire flight, ballistic missiles have a long mid-flight time, generally accounting for 80% or more. The "Qian Xuesen ballistic track" is completely different from the flight trajectory of ordinary ballistic missiles, after entering outer space, only a short mid-flight, the time accounts for only 10% to 20% of the entire flight process, it quickly re-enters the atmosphere (the critical speed is estimated at about Mach 10), and its time in the cruising stage in the atmosphere accounts for 70% to 80% of the entire flight process, and the flight trajectory of this cruise stage is the most well-known "water drift" of the Dongfeng-17.
▲ "Qian Xuesen Ballistic" and "Water Drift" Simple Schematic Diagram
The so-called "water drift" refers to the fact that due to the uneven density of air in the atmosphere, and the front of the Dongfeng-17 is equipped with a wave-riding body warhead, so that in the cruise stage of the atmosphere, the DF-17 can use the asymmetry of speed and aerodynamic performance to jump up and down on the vertical flight surface, through the upward thrust and down speed, subduction growth rate, make full use of the pressure of the gas density change in the atmosphere, realize the vertical jump height gradually shrink, and finally reach the target near the target in a similar way of water drifting. As far as the current level of technology is concerned, due to the rapid change of electromagnetic and infrared signals in the atmosphere, it is very difficult to control the flight attitude of Dongfeng-17, and the resources invested in Dongfeng-17 in China are absolutely massive. The reason why the flight of the DF-17 is so complicated is to make it difficult for the opponent's missile defense system to intercept.
▲ Wave-riding body warheads are critical
At present, some countries have made considerable achievements in the field of advanced missile defense, and the success rate of many anti-missile interception tests has also been very high. However, it should be noted that these tests are mainly aimed at interception during the mid-flight phase of ballistic missiles. During this period, although the flight speed of ballistic missiles was very fast, their attitude was relatively stable, which was conducive to the anti-missile system predicting the trajectory of the ballistic missile in advance, and it could guide the interceptor missile to intercept relatively simply. In fact, since the relative speed of the two is very fast in the final interception, more than 2000 meters per second is commonplace, so the flight attitude of the interceptor missile must be controlled very precisely, often in milliseconds, and the speed can neither be fast nor slow. This is also the fundamental reason why missiles tend to "circle" at low altitude when countries conduct anti-missile system tests, because this is actually in the early stage of missile launch, adjusting the speed of the missile, and consuming excess fuel to ensure that the incoming missile is intercepted with millisecond-level control accuracy. The significance of the DF-17's "water drifting" is that this set of anti-missile interception systems that have gradually matured is actually ineffective against the DF-17.
▲ The wake of the LAUNCH OF THE US "THAAD" CAN BE CLEARLY SEEN AS "CIRCLE"
The interception method of the above-mentioned anti-missile system belongs to the interception method where the interceptor missile and ballistic missile intersect in two straight lines, and essentially belongs to the two-dimensional combat mode. However, DF-17 in the cruise stage, is to "hit the water" way forward, the current anti-missile system is basically impossible to accurately predict its flight trajectory, want to intercept, then the interceptor missile must have a very strong terminal maneuvering capability, in order to theoretically fly near the DF-17, automatically look for targets for interception. However, under the powerful maneuverability of the DF-17, this means that the anti-missile interception operation has been upgraded from the previous linear intersection in the two-dimensional plane to a three-dimensional three-dimensional maneuver everywhere, and the difficulty has increased by 10 times. In addition, the interceptor missile needs to consume a lot of fuel when it moves at the end, which is completely different from the current operational concept of directly consuming fuel in advance when the interceptor missile takes off. In other words, DF-17 completely subverted the design concept of the existing anti-missile system by virtue of the "water drifting" combat method, which belongs to the transcendence of the root cause, which is the root cause of the Dongfeng-17 can be full of confidence, so that the global anti-missile system is basically ineffective, so that the opponent cannot sleep at night.
▲ Single speed does not have absolute significance
Of course, there is no truly perfect weapon in the world. Although the DF-17 has unmatched penetration capabilities in the world, there is still a more obvious deficiency, that is, the range. Ballistic missiles have a long mid-range flight time to ensure that they can reach a range of thousands or even tens of thousands of kilometers. Since the flight time of the DF-17 is extremely short, the range will naturally be limited accordingly. In terms of the current body size and flight trajectory analysis of the DF-17, its range is difficult to exceed 2,000 kilometers, although it can basically meet the needs of the current rocket force, but it is bound to need further development of the range in the future.
▲Intercontinental missiles have a long time to fly far
Just like after the US Air Force launched the groundbreaking F-22 stealth fighter, countries found that the original air defense system could not effectively deal with the F-22, so they chose to develop their own domestic stealth fighters, trying to form an offensive-to-attack model to contain the threat of the US F-22. Now after the appearance of the domestic DF-17, other countries in the world have also begun to exert efforts in the corresponding fields in the current situation that the missile defense system cannot effectively cope with, trying to design and manufacture weapons similar to the DF-17 in order to achieve the purpose of mutual balance.
▲ F-22 appeared at the beginning of the shock also shocked the world
At present, the technical accumulation of European countries such as the United Kingdom and France in this field is very low, and the design and manufacturing level is very far from practical application, so there is no possibility of putting the corresponding weapons into use in the short term. Although Russia has developed hypersonic weapons such as daggers and zircons this year in recent years, from the perspective of its flight trajectory and combat characteristics, it still does not deviate from the design concept of hypersonic missiles in the Soviet era, and there is a qualitative gap with the domestic Dongfeng-17's "water drifting" combat mode.
▲ MiG-31 fighter aircraft mounted with "Dagger" supersonic missiles
Only the United States has accumulated deeply in the field of aviation, has launched a number of hypersonic projects, the design level and target height are also good, the only problem is that the United States did not have the corresponding practical equipment before, and now in the field of hypersonic weapons have failed one after another, and the progress is very unsmooth. Theoretically, it is unlikely that the company will have the ability to equip the corresponding weapons on a large scale before 2025, so the Vostok-17 will still lead the way during this time. In this rare period of domestic technology leadership, how to improve the Dongfang-17 and continue to maintain the technological leadership of other countries is another topic.