Reuters reported on October 21, 2021 (Beijing time 22), according to people familiar with the matter, the Pentagon's hypersonic weapons suffered a heavy setback in the test on Thursday, and the failure of the vehicle booster equipped with hypersonic weapons led to the failure of the test plan to continue, and finally ended in failure!
As a scientific experiment, there are always successes and failures, but this time it happened that on October 18, Chinese Foreign Ministry spokesman Zhao Lijian responded on the 18th to Western public opinion speculating that China conducted a hypersonic "missile" test, saying that "this test is a routine spacecraft test to verify the reusable technology of spacecraft", China succeeded, the United States failed, although the two are not the same concept, but how did the Americans fail?
The Foreign Policy Institute (FPRI), a Think Tank in Philadelphia, held a video discussion on October 21, inviting Laura Grego, a researcher at the MIT Nuclear Safety and Policy Laboratory, and Aaron Stein, director of the FPRI Research Department, to discuss in depth the extremely sonic weapons suspected of being tested by the Chinese side for early warning, missile defense, and What is the effect of nuclear deterrence.
Among them, Greg's statement is very intriguing, first of all, he said that hypersonic technology has existed for decades, and extreme supersonic technology is not stealthy, so there is nothing to worry about, and the success of China's test is not surprising!
Indeed hypersonic technology has been out for a long time, and Gregg said that decades are not excessive! But why did the Americans not succeed, but fail again? The other is that the success of the Chinese test is not unexpected, which is the confidence in Chinese technology? Or a compliment to Chinese technology?
In discussing the warning of hypersonic weapons, Gregg said that although hypersonic weapons are extremely fast at the beginning, they will gradually decrease when they re-enter the atmosphere, so their speed will decrease when they approach the ground, which is 30 to 40 minutes slower than the time for intercontinental missiles to reach the target, but Gregor's words are quite puzzling when it comes to China's attitude towards the development of hypersonic weapons:
China's existing intercontinental ballistic missiles are enough to overwhelm the U.S. missile defense system, and the number is still increasing, so from a technical point of view, China does not need to build a new weapon to avoid the U.S. missile defense system.
This statement seems to have a very complicated mood, all kinds of factors are mixed together, it seems to show disdain, incomprehension, and can not eat grapes to say grape sour meaning, do not know what he thinks! But one thing is clear, he does not intend to explain why the United States should develop hypersonic weapons, the world can not prevent so many missiles from the United States, so why should the Americans develop hypersonic weapons?
Regarding the test of supersonic vehicles, it is estimated that you should have something to say, China seems to have succeeded again and again, but the United States has repeatedly failed, among which on August 25, 2024, when the US Army's hypersonic weapons (ahw) were tested, the missile was forced to detonate due to a malfunction 4 seconds after liftoff, directly blowing up the launch pad, which was very tragic.
How many ways is hypersonic?
The sea level speed of sound is about 340 m / s, generally at 1 to 5 times the speed of sound for supersonic, 5 times or more called supersonic, you read it correctly, the standard statement is supersonic, but now everyone is messing around, hypersonic, or extreme sound, very supersonic, etc., almost all this truth.
There are several ways for a general aircraft to achieve hypersonic speed, one is to send the vehicle to an ultra-high altitude and then glide, similar to the re-entry of spacecraft such as satellites or spacecraft, and the other is to use a scramjet engine to advance to more than 5 times the speed of sound.
Hypersonic glide vehicles
This way is simply a glider, but unlike ordinary gliders, it faces more than ten times the speed of sound, so the first one is a pneumatic shock heating, which is a unique pneumatic heating method under hypersonic speed, which is not the familiar "air friction" at all, but the air at hypersonic speed is too late to avoid the high heat generated by the accumulation and compression in front.
This is the case when a spacecraft re-enters the atmosphere or a meteoroid passes through the atmosphere, such as an article on the science website that says that when re-entering the atmosphere at Mach 25, the pneumatic heating can reach a high temperature of 1400 ° C. Only carbon-carbon composites can withstand such high temperatures.
But everyone knows that the spacecraft returns with a blunt head forward posture, such as the bell-shaped spacecraft that China and Russia prefer, and the United States prefers the outsole cone, but the gliding vehicle cannot be such a shape, and the glider body is needed! But low-speed aerodynamics and hypersonic dynamics are completely different!
In the aerodynamic structure of the gliding vehicle, there are basically two more typical shapes of axisymmetry and multiplication body, and the axially symmetrical winglets can maintain a certain maneuverability and lift-to-drag ratio, but it is obvious that it cannot be compared with the lift-to-drag ratio of the multiplication body, and there is no doubt that the multiplication body is more difficult.
The U.S. Army hypersonic weapon (ahw) above is an axisymmetric gliding hypersonic weapon, the fatal thing is that the test in 2014 also blew up the launch pad, and the DF-17 released by China is that everyone can see that it is like a small plane, which is better or worse, it is self-evident.
The failed agm-183, judging from the propaganda map released by Loma, is a relatively sharp wave-multiplier body, with a total length of about 6.5 meters, a diameter of 0.77 meters, and a length of about 1.7 meters, not big but not small.
The warhead after opening the fairing looks very cool, of course, it is very similar to the head of the DF-17, is this a copycat of our country's DF-17? Of course, even if the Americans copied it, they would not admit it.
Sub-combustion ramjet and scramjet engines
Hypersonic glide weapons are propelled to high altitudes by rocket engines and then separate gliding flight, because the warhead has no power, its maneuvering range and range are limited by the release height and ballistic trajectory, so the scheme of directly advancing to hypersonic with power has also been worked on by scientists.
Hypersonic vehicles require a scramjet engine, although they are all ramjet engines, but the internal airflow of the sub-combustion ramjet is subsonic after compression, and the extreme speed can only accelerate the aircraft to 5 times the speed of sound, and there is no way to go up, and the super-fuel ramjet engine is required to propulse (this article does not discuss the solid fuel ramjet engine).
However, the air flow inside the super-combustion ramjet engine is supersonic, from the engine intake to the tail nozzle discharge, the time is calculated in milliseconds, in this process to complete the compression, injection into the fuel mixture, ignition, expansion workmanship from the tail discharge, this difficulty is very high. The compression heating temperature of the air flow through the ramjet cavity is very high, so gaseous fuels such as liquid hydrogen can cool the incoming air, which not only increases the total amount of air, but also reduces the high temperature resistance requirements for the engine cavity wall.
Therefore, the X-43 verification machine uses liquid hydrogen fuel, the test speed can reach Mach 9.64, but the liquid hydrogen preservation is very troublesome, usually leak, not as convenient as hydrocarbon fuel, so the later requirements have been reduced, after changing to hydrocarbon fuel, the speed will drop to about Mach 6, but this speed is also enough, but until now, it is said that China's hydrocarbon fuel surfloor ramjet engine has made a breakthrough.
X-51 wave-passenger testing machine
A hypersonic vehicle developed by Boeing in the United States completed a 5-fold test of the speed of sound on May 26, 2010, and the last test was on May 1, 2013, a total of four tests, with the goal of completing a 6 times the speed of sound test of 300 seconds, but the longest of the four flights was a 5.1 times the speed of sound on May 1, 2013, which was 3 minutes and 30 seconds (210 seconds).
The 2019 National "Innovation Scramble Award" winner list includes a "hypersonic strong pre-cooled space dynamic research team", Fan Xuejun's team from the Institute of Mechanics of the Chinese Academy of Sciences achieved a continuous running time of 600 seconds in the ground test of the super-fired ramjet engine, breaking the world record of 210 seconds set by the American x-51 engine on May 1, 2013, and it is said that it still uses hydrocarbon fuel!
From the data point of view, this is already 3 times the working limit of the hydrocarbon fuel engine of the US X-51 engine, if you look at the power flight time period, 6 times the speed of sound for 10 minutes, you see how far you can fly? It is about 1200 kilometers, and if you add a booster section to cooperate with the high-altitude high ballistic trajectory, it is estimated that 2000 kilometers is not a big problem, and this distance is enough to be quite practical.
We have reason to believe that China has begun to lead the world in the field of hypersonic speed, which has been concluded since the military parade that year, and the Foreign Ministry spokesman Zhao Lijian said that "it is used to verify the reusable technology of spacecraft, which is of great significance for reducing the cost of spacecraft use, and can provide a convenient and cheap round-trip way for human beings to use space for peaceful use." There are several companies around the world that have conducted similar trials. ”
I believe that we have begun to exert force in the space field, once this breakthrough, the future rockets will be of little use, which is of much greater significance than some kind of supersonic vehicle to achieve a breakthrough.