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Y-20 Kunpeng - Design

Preliminary estimates suggested that the Y-20 had about the same range - about 4,500 kilometers or 2,000 miles - as the the medium size medium range Y-8 transport aircraft [each aircraft would thus have an operational radius of about 1,000 miles]. The Y-8 is a version of the Russian Antonov An-12 built produced by Shanxi Aircraft Company in China [the Chinese and Russian counterpart to the American C-130]. The Y-20 is assessed to have about three times the payload of the Y-8 - 60 tons versus 40 tons, and the turbojet powered Y-20 is estimated to be somewhat faster than the turboprop powered Y-8, with a maximum speed of 750-800 km/hr versus 660 km/hour.

According to a mid-2016 technical evaluation in the Chinese journal Aerospace Knowledge, the plane has a maximum payload of 66 metric tons and a maximum takeoff weight of more than 200 tons, according to military sources. The high payload means it can carry the PLA's heaviest tank, the 58-ton Type-99A2. The Y-20 when fully fueled and carrying a payload of 51 tons can fly for 5,200 kilometers. This means it can reach everywhere in Europe and Asia, the US state of Alaska, Australia and North Africa. With its maximum payload, it has a range of 3,700 km, enabling it to fly nonstop from Harbin in Heilongjiang province to Lhasa in the Tibet autonomous region.

The most noteworthy advance of the Y-20 over the Y-8 is not seen in the initial public photographs, but it quite striking in the artwork that surfaced at the same time. Four of the five artist concepts of the Y-20 feature a dorsal refueling probe above the cockpit. Aerial refueling could substantially extend the operational radius of the Y-20 versus that of the Y-8, an aircraft that does not have such a capability. And the Y-20 itself would be a nice aerial refueling platform. A single refueling could double the operational radius of the Y-20. Without refueling, the Y-20 could support paratroop airdrops in all of Indo-China and the South China Sea. With a single out-bound and in-bound refueling, all of South East Asia [save New Guinea] would be within reach of round-trip airborne assault operations. A second refueling [that is, four in all] would bring Australia within reach of Chinese paratroopers.

The actual dimensions of the Y-20 were initially somewhat uncertain, so it was difficult to assign relative capacities with any great precision. But preliminary data indicates a cargo compartment appreciably smaller than that of the American C-17, and generally comparable to the Ukrainian An-70, which did not enter production. Compared with the Il-76, the Y-20 seemed to have a shorter wingspan and a shorter, but slightly wider, fuselage [5.4 meters versus 4.8 meters]. The Y-20 is larger than the Airbus A400M and has about the same fuselage diameter, but is much smaller than the Boeing C-17.

The Y-20 design addressed some of the shortcomings of the IL-76 design. The IL-76 fuselage and cargo hold is relatively narrow, which is a significant drawback in the transport role. In general, most cargo tends to bulk out before they hit their weight limit. The Y-20 fuselage and cargo hold was made wider and more efficient than the IL-76, allowing larger cargo dimensions. The IL-76 has a narrow cargo compartment that limits the size of the load. The Xian Y-20 is closer to the of C-17 cabins, i.e. within 4.0-4.5 meters height and width and approximately 20-25 meters in length.

Russian sources suggested the Y-20 underwent a redesign in 2010 to enable it to lift the PLAs heaviest armored vehicle, the 58 ton Type 99A2 main battle tank. This would place the Y-20s payload capacity around that of the IL-76 MF (60 tons payload capacity) and perhaps between the IL-76 MF and C-17 Globemaster (77.5 tons maximum payload), depending on the power of the engines available.

In terms of appearance, the Yun-20 is very close to the Russian Il-76 and the US C-17, both of which have single-wing layouts that suspend four engines. This situation made many people think that the Yun-20 was the product of plagiarism. In fact, this is not the case. In order to achieve the same goal, in many cases, the optimal solution of each country may be almost the same.

In a similar aerodynamic layout, the avionics system determines the gap in the performance of the transport aircraft. Thanks to years of development, China's electronic equipment has reached world-class levels, so the use of vitrified cockpits is not a problem. The exposure of the Yun-20 cockpit did not surprise the majority of netizens, because China's current strength should be like this.

The biggest feature of the Soviet transport aircraft is that there is a huge glass observation window under the nose, which is the position of the pilot. The pilot needs to navigate according to the observation window on the ground. This World War II technology also shows from the side that the Soviet Union was forced to design this way. Because there was no high-precision satellite navigation similar to GPS, it had to use the most primitive navigation methods. This design makes an additional pilot configuration on the aircraft, and at the same time the pilot cabin takes up a lot of nose space, so it can not be based on a large number of electronic equipment.

Yun-20 does not have this problem, because after nearly 20 years of development, Beidou satellite navigation has covered the world, and the positioning accuracy is not worse than the US GPS. The Yun-20 only needs to be equipped with a Beidou satellite receiver to easily achieve accurate navigation, and the space saved in the navigator cabin can be equipped with more antennas and more powerful radars. More importantly, compared to the Il-76, it has reduced staffing, reduced crew member training, and reduced manpower consumption.

From the perspective of the glass cockpit, only two members of the Yun-20 crew can suffice. Compared with the Il-76, there are at least four crew members and as many as seven crew members, and the staffing is much more flexible. The display can also make the pilot a lot easier when performing tasks than densely packed instruments. The pilot no longer needs to spend a lot of effort to find the instrument with the corresponding function, and only needs to use the touch screen to display it according to his needs.

Yun-20 adopts the conventional layout, the wings are cantilever upper single wings, the main wings are large aspect ratio, medium swept wings, the leading edge of the wing has a constant swept angle (a quarter chord swept angle of about 24 to 26 degrees), and the trailing edge of the wing adopts two sweep modes-the trailing edge of the middle and outer wings The sweep angle is larger, while the sweep angle of the inner wing section of the wing is significantly reduced, without winglets. The cantilevered T-tail has a small dorsal fin extending forward from the vertical stabilizer to the fuselage. The built-in rudder is divided into upper and lower sections, and the elevator is divided into two sections.

Hydraulically retractable three-point landing gear has reliable gravity emergency lowering. The front landing gear is two wheels and the main landing gear is six wheels. The front landing gear enters the fuselage forward, and the main landing gear rotates 90 inward to enter the fairings on both sides of the fuselage.

The aircraft has a large aspect ratio supercritical airfoil and uses lifting devices including leading edge slats and blown-out flap systems. The Yun-20 is based on the design of the Il-76 transport aircraft, but with a larger volume, stronger carrying capacity, and advanced electronic equipment. In addition, the Yun-20 also refers to some designs of the US C-17 "Global Overlord" transport aircraft, such as vertical tail and supercritical wings.

Yun-20 uses supercritical wings and increase the proportion of composite materials, which can reduce the structural weight of the machine. As the lift of the aircraft increases and the lift-drag ratio increases, even if the engine thrust and maximum take-off weight remain unchanged, its load will increase. The Il-76 uses a critical wing with a low launch / takeoff weight ratio. In response to the requirements of the Chinese Air Force, the Yun-20 widened and heightened its cargo bays on the basis of the Il-76 in order to adapt to the emergence of a large number of ultra-wide and ultra-high cargoes in the new era. The Il-76 cargo bay has a small width and height, and its loading adaptability is poor, while the cargo volume of the Yun-20 has increased to 320 cubic meters, which is more than one-third of the Il-76. Therefore, the Yun-20 transport aircraft will look relatively short and thick, which is also a common appearance feature of military transport aircraft in the new era.

In terms of power system, the Yun-20 prototype uses imported Russian D-30KP2 engine, for a maximum take-off weight of 220 tons.. The motive power will then adopt the turbofan 18 (WS-18, D-30KP2 imitation model) engine imitation of Chengdu Engine Co., Ltd. With the same fuel capacity, the range of the domestic military large transport aircraft is obviously larger than that of the Il-76. Or carry more than the same voyage. The engine used in the Yun-20 is a Russian-made 12-ton thrust D-30KP-2 engine. Next step Yun-20 uses a turbofan-18A (WS-18A) engine manufactured by Chengdu Engine (Group) Co., Ltd.-a copy of D-30KP-2. It is expected that Yun-20 will eventually use turbofan engine turbofan-20 (WS-20) with 14-ton thrust. If the Yun-20 is replaced with a new domestically produced large-thrust, high-bypass, turbofan-20 engine, its performance will be further improved.

Il-76's avionics system is backward, and the instruments are mostly traditional pointer instruments and avionics are backward. In response to this problem, Yun-20 uses a domestic integrated avionics system, taking ARINC429 as the backbone, connecting electronic flight instruments, flight control, navigation, communication, meteorology, and engine data and instructions to achieve comprehensive data processing, and is displayed on the cockpit's color display. In addition, self-defense jamming systems may be added, including missile approach warning systems, jamming transmitters, and launch racks.

The maximum load capacity exceeds 60 tons, representing the latest level of China's aviation industry. The Yun-20 draws on its strengths in design, and its overall performance exceeds that of the Il-76 , reflecting the huge leap in China's large aircraft research and development capabilities. The advanced performance of the aircraft mainly has three aspects:

First, the body layout is reasonable. The Yun-20 uses a wide-body design that looks relatively short and thick. It has the common appearance characteristics of a new generation of military transport aircraft. Its widened and heightened cargo compartment makes it convenient to transport a large number of ultra-wide and ultra-high cargo. The design of the Yun-20 on the body structure, weight reduction and aerodynamic layout is superior to the Il-76, and its fuel consumption is 20% lower than the latter. In the same voyage, the carrying capacity of Yun-20 will be greater.

Compared with the C-17, the Yun-20's overhead wing box keeps the center wing higher than the body, keeping the inside diameter of the body intact. Because the wings are not inserted into the cabin, a unique "humpback" appearance is formed. The net height under the wing is much higher than that of the C-17, which is conducive to loading a single piece of excess cargo at the maximum cabin height. And other heavy ultra-wide equipment. This unique loading capability enables it to carry most of our army's large vehicles.

The second is strong adaptability to takeoff and landing sites. The Yun-20 adopts a conventional layout, with a large aspect ratio than the main wing, a constant sweep of the leading edge of the wing, a cantilevered T-shaped vertical tail, and a complex three-slot flap design. Its hydraulically retractable front three-point landing gear can be freely lowered by gravity in an emergency, making it adaptable to take-off and landing sites and excellent take-off and landing performance on short runways.

The third is to apply a large number of advanced technologies. Yun-20 uses lightweight materials and uses 3D printing. Parts produced by the printing technology have broken through hundreds of key technologies. Major breakthroughs have been made in aerodynamics, large-scale structural design, supercritical wing, integrated avionics systems, and high-reliability control systems. This reduces the structural weight of the aircraft and increases the lift-to-drag ratio. Therefore, the pilot described the Yun-20's feeling of flight as: the plane is stable, with excellent aerodynamic characteristics, take-off and landing characteristics, and carrying capacity.

The Yun-20 is similar to the aerodynamic shape and body structure of the Russian Il-76, and integrates some features of the US C-17. Has high extensibility, high reliability and security. The development of this aircraft broke through hundreds of key technologies, marking China's entry into the ranks of the world's largest aircraft.

The Yun-20 uses supercritical wings, lightweight composite materials, and has made major breakthroughs in aerodynamics, design and manufacture of large structures, development of airborne equipment, and high-reliability control systems. The technical level of avionics system has reached the advanced level in the world today. The performance of the Yun-20 is better than that of the Russian Il-76, which is equivalent to its latest improved Il-476. It is slightly lower than the American C-17 in carrying capacity, but significantly ahead of the Japanese C-2 and European A-400M transport aircraft. The Yun-20 has latecomer advantages in terms of technology. Regardless of airframe design technology, load technology, and flight control technology, it should be in the first echelon.

The Yun-20 aircraft is a strategic and iconic equipment of the Air Force, marking a breakthrough in the design and manufacturing capabilities of China s large aircraft. It promotes China s economic and national defense modernization, responds to emergency situations such as rescue and disaster relief, and humanitarian relief, and improves the Air Force s strategic investment. The sending ability and the ability of the Chinese army to fulfill missions and missions are of great significance.

The Yun-20 has the characteristics of long range, heavy load, fast flight speed, high cruising altitude, and good low-speed performance. It can perform long-distance air transport missions under complex weather conditions. For the Chinese Air Force, which has previously relied on imported large-scale transport aircraft and has a limited number of product options, the Yun-20 is not only a "aircraft" to verify the level of the aviation industry, but also a key model to meet the number of large-scale transport aircraft of the Chinese Air Force. For the Chinese military, in addition to meeting daily material transportation tasks, the first use of large and medium-sized transport aircraft is undoubtedly to transport airborne troops to perform large-scale airborne operations.

Since the launch of the Y-20 large transport aircraft, a certain division of the Air Force has actively explored a series of practical trainings such as night navigation, cross-domain delivery, air-drop airborne, and low-altitude maneuvering. The dense formation flight of large transport aircraft also has practical significance for emergency delivery.

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Page last modified: 22-11-2020 20:22:40 ZULU