Xingkong-2 / Starry Sky 2
China’s first successful flight test 03 August 2018, the Sky Star 2 [there does not appear to be a Xingkong-1] rocket, made significant achievements in the manufacture of self-developed hypersonic weapons. Designed by the China Academy of Aerospace Aerodynamics under China Aerospace Science and Technology Corporation, the Xingkong-2, or Starry Sky-2, was launched in a target range located in Northwest China. According to Chinese media reports, the flight test lasted 10 minutes. During the flight test, the hypersonic vehicle was disengaged from the launch vehicle and several maneuvers were completed. Experts have been paying close attention to the new round of competition in the field of hypersonic weapons for several years. The flight vehicle reached 30 kilometers in altitude at Mach 5.5-6, the academy said.
Some observers said that the booster rocket used in this test flight is a tactical ballistic missile of the Dongfeng-15 campaign. Others believes that the possibility is not great. On the one hand, the Dongfeng-15 has insufficient range, and on the other hand, the volume of both sides is not right. In fact, at present, China's rocket and ballistic missile technology is so developed, and a new type of booster rocket may ba developed.
The test completed after nearly 10 minutes of flight, the rocket completed the active segment turn, the throwing shroud/interstage separation, the test aircraft released the autonomous flight, the ballistic large maneuvering turn, etc., achieving a height of 30,000 meters, with a flight speed of 5.5-6 Mach, autonomous flight for more than 400 seconds, according to the scheduled ballistics into the landing zone. The test flight was a complete success. The video release simply showed the launch of a medium-sized rocket. There was nothing related to the hypersonic flight vehicle - no video, no cartoons, no artwork, nothing.
The China Aerospace Aerodynamics Research Institute, which is responsible for the development of the wave-body hypersonic vehicle, is an important cutting-edge weapon development organization in China. The Fifth Institute of Defense, which was first traced back to 1956, is the first missile research institution in China, and Qian Xuesen is the dean. The third research laboratory of the Fifth Research Institute, the aerodynamic research laboratory, was the first aerodynamic research and experimental base in China under the personal command of Qian Xuesen. In 1964, it was converted into the Beijing Aerodynamics Research Institute. Leaders of the Ministry of Machinery Industry, Aerospace Industry, China Aerospace Industry Corporation, China Aerospace Science and Technology Corporation. In 2004, China Aerospace Aerodynamics Research Institute was established as one of the eight research and production consortiums of the Aerospace Science and Technology Group, and at the same time as the lead unit for the development of the UAV industry.
Waverider is a flight vehicle that flies in the atmosphere and uses shockwaves generated by its own hypersonic flight with the air to glide at high speed. an aircraft traveling at Mach 1 or higher produces a shock wave in air. If the aircraft is tailored correctly, it can be designed to ride this shock wave to produce greater lift, less drag, greater range, and overall improved performance. Such aircraft are commonly referred to as waveriders. Waveriders are particularly useful at high Mach numbers when shock losses (wave drag) become increasingly large. Waveriders reduce shock losses by reducing the shock angle necessary to generate the required lift, which improves the lift-to-drag (UD) ratio of the aircraft and, thus, improves its overall performance.
The "Waverider" concept originated from the fact that at hypersonic speeds a Caret wing will have a planar bow shock wave attached to the edges of its inverted V-shaped plane surfaces. The high pressure region between the wave plane and the wing produces the lift force on this Caret wing which justifies the descriptive term -- "Waverider". It has been suggested to arrange Caret wings in an axi-symmetric geometry to obtain a symmetrical wave-stabilized body for hypersonic flight.
Waveriders are designed to maintain an attached shock along their leading edges. That is, the shock wave is not detached from the leading edge, where detachment would allow high-pressure air that generates lift to spill around the leading edges, reducing lift, thereby requiring an increase in wing angle-of-attack to maintain lift, with an attendant increase in shock angle, wave drag, and induced drag. The wings thus are able to maximize the compression lift created by the shock wave, without adding any unnecessary drag; however, conventional waverider wing designs are only optimized for a single Mach speed and angle of attack condition.
Generally, waverider aircraft provide numerous advantages over conventional aircraft when travelling at high Mach speeds, such as, but not limited to, producing only positive lift; maintaining an attached leading edge shock, which minimizes spillage of high-pressure air from the bottom surface of the wing, thereby minimizing lateral flow losses; and minimizing cross flow, which aids in maintaining natural laminar boundary layer flow, which reduces frictional drag and aerodynamic heating.
Conventional waveriders are typically designed for use at a single, specific Mach number and a specific angle of attack. That is, the bow shock wave created by a typical hypersonic wing, including a waverider, detaches from the wing leading edge when the combination of Mach number and flow incidence angle resolved in a plane normal to the leading edge is outside the range that would yield an attached shock solution on a two-dimensional wedge, as seen in FIG. 2. Under detached shock conditions, flow can spill around the wing leading edge, thereby reducing lower surface pressure and, thus, lift. Accordingly, the particular usefulness of waveriders may be limited to a very small operational envelope--a small range of Mach number and angle of attack. This small operational envelope inhibits high-performance operation outside of the predetermined set of narrow parameters and, thus, limits the versatility and performance of conventional waveriders.
The "Starry Sky-2" rocket, a high-speed supersonic aircraft, is not the first Chinese hypersonic vehicle. But the hypersonic vehicle that China has tested over the past few years belongs to another type, a hypersonic glide vehicle (HGV) that can be used as a ballistic missile head. The carrier of the hypersonic glider is a ballistic missile that performs controlled flight at the supersonic speed at the end of the orbit. Hypersonic gliders may not have their own engine units because ballistic missiles ensure they will accelerate to the necessary level.
China is following the example of Russia and is striving to equip its own ballistic missiles with similarly planned hypersonic warheads to improve its ability to break through enemy anti-missile systems. The Dongfeng-17 (DF-17) medium-range ballistic missile was specially developed for this purpose, but similar equipment may also be manufactured for intercontinental ballistic missiles.
Unlike similar hypersonic vehicles made in China (known as DF-ZF and developed at least for the past five years), the "Starry Sky" rocket uses other aerodynamic principles. The "Starry Sky" rocket can be called a hypersonic cruise missile, which means that it is a specially designed glider that helps to take advantage of the rising force of the shock wave that occurs due to its hypersonic flight. Unlike gliders, this type of aircraft flies at a slightly lower speed ("Starry Sky" rocket up to 6M) and is flying at a relatively low altitude, but its flight path is more unpredictable.
It is understood that the "Starry Sky" rocket is equipped with a supersonic ramjet air jet engine. The news that China developed similar engines has only been known in recent years. The difficulties associated with testing and developing hypersonic vehicles with supersonic ramjet air jet engines should not be underestimated. Successfully starting a flight test does not guarantee that the above system will install troops in the foreseeable future. The United States and Russia have spent decades working on hypersonic vehicles with sound-speed ramjet air jet engines, but problems with failures, accidents, and reliability have been so frequent that no achievements have been made.
The world's first Russian Air Force supersonic cruise missile "dagger" to enter combat duty uses a solid-fuel missile engine, which is actually a specially modified "Iskander" military ballistic missile. Judging from various aspects, there is a similar project in China-- a specially modified Dongfeng-21 (DF-21) ballistic missile based on the bomber-6K (H-6K ).
Compared to this cumbersome system, it may be much more flexible to adopt and install more platforms based on the "Star-2" ballistic missile. Solid fuel missile engines were also used during the accelerated test, but various options may be developed in the future. China has once again proved its position in the leading countries of the hypersonic missile competition, but it still has to go a long way before such missiles are deployed in the army.
Japanese experts believe that the Chinese hypersonic vehicle has a range of about 10,000 kilometers and a speed of 10 times the speed of sound. What is the concept of this distance? Beijing-Washington is 12,000 kilometers; Beijing-Los Angeles is 10,000 kilometers; Shanghai-Washington is 12,000 kilometers; and Shanghai-Los Angeles is 10,500 kilometers.
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