The Xian Y-20 (Chinese: 运 -20) is a heavy military transport aircraft being built by Xi'an Aircraft Industry (Group), a part of Aviation Industry Corporation of China (AVIC), for the People's Liberation Army Air Force (PLAAF). The official codename of the aircraft is Kunpeng (Chinese: 鲲鹏) after the mythical bird of ancient China that can fly for thousands of kilometres.
However, within the Chinese aviation industry itself, the aircraft is more commonly known by its nickname Chubby Girl (Chinese: 胖妞), because its wide fuselage in comparison to other Chinese aircraft previously developed in China.
The aircraft can be deployed in the transportation of personnel and heavy equipment during military assault, and humanitarian assistance and peacekeeping missions. It can also be configured for airborne early warning and control (AEW&C), anti-submarine warfare (ASW) and aerial refuelling missions.
The first Xian Y-20 prototype successfully made its first flight at Shaanxi Yanliang Aviation Base in January 2013. The second prototype took into skies in December 2013. The aircraft was displayed at China International Aviation & Aerospace Exhibition 2014 (Airshow China) held in Zhuhai.
Development
The Y-20's general designer is Tang Changhong (Chinese: 唐长红), (the general designer of Xian JH-7), and the deputy general designer is Guo Zhaodian (Chinese: 郭兆电). The aircraft was primarily designed and developed in China under Xi'an Aircraft Industrial Corporation.
It was reported that the Y-20 started ground testing from December 2012, including runway taxi tests. The aircraft made its maiden flight lasting one hour on January 26, 2013. During landing in first flight, it was reported that the Y-20 prototype bounced once before finally settling on runway due to high landing speed. In December 2013, a new Y-20 prototype took to the sky.
On 6 February 2016 the Y-20 was flown for the first time and pictures of the fifth prototype (bort number 788) in flight appeared on Chinese military webpages. Other known prototypes carry identification numbers 781, 783 and 785. On 27 January 2016, former Chinese test pilot Xu Yongling had reported in a Xinhua article that Chinese aviation industry officials had stated that the Y-20 "completed development" at the end of 2015. Xu, who participated in the Chengdu Aircraft Corporation J-10 fighter test programme, suggested that the Y-20 could enter service with the People's Liberation Army Air Force (PLAAF)in 2016.
Design and features of Y-20 heavy airlifter
The Y-20 uses components made of composite materials. The composites are produced in China, whereas in the past they had to be imported. The Y-20's cabin incorporates flame-retardant composites developed by the 703 Institute of the China Aerospace Science and Technology Corporation (CASC). The 703 Institute was created in March 2009 with development taking three years. The performance of the composites is reportedly comparable to those that fulfill FAR Part 25.835.
The 703 Institute achieved another milestone by establishing a comprehensive Chinese evaluation and certification system for aircraft composite materials based on international standards.
The Y-20 is the first cargo aircraft to use 3-D printing technology to speed up its development and to lower its manufacturing cost. Model-based definition (MBD) is also used, and it's the 3rd aircraft to utilize MBD technology in the world, after Boeing 787 (2005) and Airbus A380 (2007). A project team to implement MBD for Y-20 program was formally formed in October 2009, and after the initial success in application on the main landing gear, MBD application was expanded to the entire aircraft and became mandatory for all contractors and sub contractors of the Y-20 program. The implementation of MBD was initially met with strong resistance, with only a third of suppliers agreed to implement MBD, but the general designer of Y-20 declared those who refuse to do so will be banned from participating in Y-20 program, thus forcing everyone to comply, resulting in increase in productivity. The implementation of MBD greatly shortened the time required, for example, without MBD, installation of wings takes a month or two, but with MBD adopted, the time is drastically shortened to just a few hours, and in general, the design work reduced by 40%, preparation for production reduced by 75%, and manufacturing cycle reduced by 30%.
The aircraft features deep and wide fuselage for cargo section and T-tail empennage configuration with high-mounted horizontal surfaces on the vertical stabiliser. The centre fuselage is hinged with moderately sweptback, high-mounted monoplane wings integrating triple-slotted trailing-edge flaps. A pair of engine nacelle is fitted under each wing.
The Y-20 airlifter has a glass cockpit, which accommodates three crew members. It features a rear cargo-loading assembly allowing the loading / unloading of large-sized cargo and equipment.
In addition to 3-D printing, Y-20 is also the first aircraft in China adopting associative design technology (ADT) in its development, the second aircraft to do so in the world, after Boeing 787. Headed by the deputy general designer of structural design, Mr. Feng Jun (??), the initial attempt to implement ADT actually failed after two months spent on application on the nose section. It was only after the second attempt that took another three months on the application on wings did ADT became successful. The adaptation of ADT greatly shortened the development time by at least eight months, and modification of wing design that previously took a week is shortened to half a day.
The aircraft is expected to measure 44m to 47m in length and 18m in height and have a wingspan of 50m. The maximum takeoff weight of the aircraft is approximately 220t and the maximum payload carrying capacity is 66t.
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Shenyang WS-20 |
The power plant of the Y-20 prototypes integrates four D-30KP-2 turbofan engines, whereas the production aircraft is expected to be equipped with 14-ton thrust WS-20 engines. WS-20 is the most powerful aircraft engine developed by China. The Shenyang WS-20 is derived from the core of the Shenyang WS-10A, an indigenous Chinese turbofan engine for fighter aircraft.
The engine develops a power output of 14-tons and offers a higher bypass ratio for fuel efficiency. It will replace the less powerful and less efficient Russian D-30KP, which generates 10.5t of thrust. The WS-20 turbofan has been under trail on Il-76 test aircraft since 2014. The aerial testing is expected to conclude in late 2015, paving the way for service entry on Y-20 aircraft.
The Y-20 aircraft can perform missions in adverse weather conditions and can also land at small airports in mountainous regions.
In 2013, Shenyang Engine Design and Research Institute was reportedly developing the SF-A, a 28700-pound thrust engine, for the Y-20 and the Comac C919. The SF-A is derived from the core of the WS-15. Compared to the WS-20, the SF-A is a conservative design that does not seek to match the technology of more modern engines.
Landing gear
The aircraft is equipped with a retractable landing gear comprising two main landing gear units and a nose unit. Each of the two main units on either side of under-fuselage features six wheels, which are arranged in a two-two-two layout from front-to back.
The steerable nose gear includes a standard twin-wheel leg unit. The landing gear allows take-offs and landings on rough airfields or unpaved runways.