WS15 turbofan

The engine is the heart of the aircraft. Its manufacturing process is complex and its design technology is complex. The WS15 "Emei" aero engine is a low bypass ratio thrust vector engine developed by China for the fourth generation of fighters. It is organized by experts from 606, 624, 614, 410, 430 and 113 intitutes. The first station was successfully commissioned in May 2006. In 2011, AVIC completed the delivery of the WS-15 verification machine. The maintenance node was completed in 2020 and mass production equipment began in 2021.

It can be said that China's engine technology is about 30 years behind the United States. The American F119 has a maximum diameter of 1.13 meters and a weight of 1360 kg. In such a small volume, it contains multiple components such as a 3-stage fan, a 6-stage high-pressure compressor, and a combustion chamber. It has to withstand the test of high temperature resistance during operation. In terms of service life, the service life of F119 is as high as 6,800 hours, while the service life of China's turbofan 15 is only 3,600 hours, which is almost half that of the United States. The American F119 has been around for about 30 years, with a thrust-to-weight ratio of about 10, and the F135's thrust-to-weight ratio is as high as 10-12. China’s J-20 was previously equipped with the Russian AL31F engine which was also developed more than 20 years ago, with a thrust-to-weight ratio of less than 8. It was later replaced with China’s self-developed turbofan 10 with a thrust-to-weight ratio of about 8. The highly anticipated turbofan 15 is said to have a thrust-to-weight ratio of nearly 10, which is also far behind the F135.

In terms of production capacity, due to difficult production and high requirements, the production cycle is long, and the current domestic production capacity is not enough to meet installed demand. Even the aircraft is often built, but operators still have to wait for the engine. These are the difficulties of engine manufacturing, and current technology is still unable to break through these barriers. All because of the relatively late development of China's aerospace industry and the relatively weak foundation, the early reverse research methods were mostly adopted.

The parts and components produced by China's manufacturing equipment are less precise than those produced by foreign equipment. Therefore, China also needs to purchase foreign manufacturing equipment. However, not all manufacturing equipment involving armaments will be sold to China. There are no drawings, the measurements are wrong, the production is not detailed enough, and the gap between the finished product and Russia and the United States can be imagined.

The core engine for the WS15 engine was first tested in April 2005. The demonstrater was developed successfully and the prototype WS-15 was running smoothly. China is undoubtedly far behind Russian engine technology. Nonetheless, China has produced the WS-9 engine for the JH-7, the WS-10A engine for J-10, and the WS15 for the new J-20 fourth generation stealth fighter. The WS-9 and WS-10A were both usable, and without the WS-10A China would not have negotiated J-10 orders with PAF.

Since the founding of New China, the country has achieved fruitful results in the aviation field. In the aerodynamic layout design, electronic equipment, weapon systems, radar systems, etc. have been close to or have reached the world's leading level, but have been criticized in aviation engines, due to Western technology blockade, Russia restrictions on technology transfer, the development of China's aviation engine It can be said that it is difficult. However, the aero-engine is an important equipment related to national security and highlighting the status of a powerful country. China is aware that the importance of this is the great development of China's economy after the reform and opening up, and it has begun to invest heavily in research and development.

Although specifications of the Russian T-50 fifth-generation fighter remain undisclosed, prototypes and the first production aircraft will be fitted with 117S (AL-41F1A) turbofan engines, a major upgrade of the AL-31F engine from Russian aircraft engine manufacturer NPO Saturn. The most advanced fighter engine is the that of the F-22 which has a T/W ratio of 11, while the engine of the EF2000 and Refale has a T/W ratio of 9-10. These engines are usually called the 4rd generation engines. The 3rd generation engine of the SU-27 variants has a T/W ratio of less than 8, while the engine of the Mirage 2000 has a T/W ratio of 6.5, the poorest performance of an engine adopted by a 3rd generation aircraft.

Production for current generation, design for next generation and advanced research for future generation are running through the central line of China's armament development, so it is can be affirmed that China is developing a more powerful engine from WS-10 for a chrysalis? China's fourth generation fighter, counterparts to the F-22 and F-35 made in China.

The well-known AL-31F is from Soviet source and notorious for low MTBF. The UK plans to cooperate with U.S in the F119 engine which will be used in F-35. However, these two countries are in dispute for technology transformation. After the M-88-3 for Rafael, there are no engine development projects in France's schedule. The fewer players in the fighter engine competition tell a truth that no one single country can endure the black hole of money and time for engine development. Russia, UK and France have to quit the game or cooperate with others. By holding abundant financing and advanced technologies, The US has been being the strongest player who is investing on future aviation engines. Now a new player participate this expensive game.

China's GPD has become the 2nd in the world and its foreign exchange reserve has surpassed Japan and became the Top one. China's air transport is growing in double digits. Besides, China's geopolitics condition, like in Korean peninsula and Taiwan Strait, wwere serious bad to breaking military conflicts in any moments. Therefor, China had motivation and power (money) to develop aviation engine from the strategic view. China and United States may be the only two nations who provide more fund to engine projects. From WS-10 engine, the great ambitious strategy of China is so clear.

But China's road to great engine manufacturer is still long. The WS-10, whose thrust to weight ratio is likely under 8, it as a whole better than the AL-31F. Even the WS-10 catches up the F-110, it is still a product of 1980s level technology. China's gap with the US remains at least 20 years. In the production of materials for engine, China has countless problems to be solved. The more serious factor is from the unchanged disadvantages of China's military industry. For a long time, rigidified managing structure of the state owned military enterprises, compared with Chinese private companies, were terrible in production efficiency and quality control. Several severe accidents were all caused by those soft spots. Although the investment grew after 1999, the state's manufacturers need a long time to become competitive enterprises.

A military industrial journal, Aviation Engine, once published an article that there are totally 24 WS-10 demonstration engines after 15 years's production in 2001, less two per year. It also said that the processing period of WS-10 first stage fan blade requires 10-12 months in China, and similar product only 6-8 months in Rolls-Royce. Even thought WS-10's success is not a propaganda trick, people have doubt if Chinese enterprises can satisfy the need of PLA Airforce. In case China decided to enter mass-production, WS-10 possibly shows poor quality, and otherwise low performance. As a matter of fact, after the bearing failures accident in 2004, AVIC I Deputy General Manager Lin Zuoming who was in charge of WS-10 project, once told research staff to produce an available WS-10 engine to end this hard and long project. Perhaps, today's WS-10 doesn't have the expected performance and will be continuously improved.

Chinese state owned manufacturers have lots of disadvantages, but they find ways to become contractors for oversea aviation giants, like Boeing and Airbus, and learn too much in project management. Besides, China armed forces now can open some equipment production to private companies, even some foreign registered companies owned by Chinese people. The significance of WS-10 which is like China's first Atomic Bomb in 1966. It proved that China has ability to produce turbofan engine. If China can keep its economic growth and unswervingly invest on an opening and healthy aviation industry, her aviation engine manufacturing level will likely to exceed Russian, France and Germany, then narrow to tiny gap with United Stages in next 15 to 20 years.

Current turbine engines are optimized for either high performance, as in the case of a low bypass fighter engine, or fuel efficiency, as delivered by a high bypass transport engine.

In a turbofan aircraft gas turbine engine, air is pressurized in a fan module, an optional booster module and a compression module during operation. A portion of the air passing through the fan module is passed into a by-pass stream and used for generating a portion of the thrust needed for propelling an aircraft in flight. The air channeled through the optional booster module and compression module is mixed with fuel in a combustor and ignited, generating hot combustion gases which flow through turbine stages that extract energy therefrom for powering the fan, booster and compressor rotors.

The fan, booster and compressor modules have a series of rotor stages and stator stages. The fan and booster rotors are typically driven by a low-pressure turbine (LPT) and the compressor rotor is driven by a high-pressure turbine (HPT). The fan and booster rotors are aerodynamically coupled to the compressor rotor although the fan rotor and compressor rotor normally operate at different mechanical speeds.

It is often desirable to use an engine core comprising the compressor, combustor, high-pressure turbine (HPT) and low-pressure turbine (LPT) from a high bypass commercial engine or a medium bypass engine with a moderate fan pressure ratio as a building block for lower bypass ratio engines with higher fan pressure ratios. The boost pressure and temperature into the high-pressure compressor (HPC) is usually significantly higher in the low-bypass derivative engine than in the original high-bypass engine.

This typically requires that the maximum operating airflow in the core be limited below its full design corrected airflow capacity due to mechanical limitations of the maximum physical core speed and/or the maximum compressor discharge temperature capability of the core. It is desirable to find a way to operate the original engine core airflow at its full potential while significantly increasing the fan pressure ratio to the bypass stream to maximize the thrust potential of the derivative engine.

At present, China's "Turbofan-10" Taihang engine has a thrust-to-weight ratio of around 8, while the latest "Turbofan-15" Emei engine has a thrust-to-weight ratio of around 10, which still has a gap compared with internationally advanced aero engines. For example, the F119 engine used in the US F22 has a thrust-to-weight ratio of 10.2, while the F35 uses a F135 engine that has reached 11.7.

The maximum thrust of the WS-15 "Emei" engine is 16 tons, the intermediate thrust is 10 tons, the afterburning fuel consumption rate is 2.02kg/daN/h, the intermediate fuel consumption rate is 0.665kg/daN/h, and the thrust-to-weight ratio is 8.86~10. The air flow rate is 138kg/s, the bypass ratio is 0.382, the total pressure ratio is 28.71, the turbine inlet temperature is 1477 degrees Celsius, the maximum diameter is 1.02m, the length is 5.05m, and the mass is 1862.3kg. Compare with the world's similar products: WS-15 has a push-to-weight ratio of 10 and a maximum thrust of 16 tons; the F119 engine of the US F-22 is equipped with a thrust-to-weight ratio of 11.7 and a maximum thrust of 15.5 tons; the Russian Su 57 is equipped with AL. The -41 engine has a thrust-to-weight ratio of 11.1 and a maximum thrust of 14 tons. The F-135 engine of the US F-35 is equipped with a thrust-to-weight ratio of 10+ and a maximum thrust of 17 tons. Through the above comparison, the WSs-15 has reached the world advanced level.

On Chinese observer wrote : "The development of the WS-15 has opened up China's counterattack in the world of aero-engines. The "heart disease" that has been criticized by Chinese fighters has ceased to exist. If the aero engine is the jewel in the crown of modern industry, then China will inevitably let this pearl release a dazzling light..."

Emeishan / Mount Emei

As usual, the WS-15 engine is named after a mountain in China, like WS-9 is named after "Qing Lin", a mountian near Xian where the WS9 is manufactured. Mount Emei is located in Emeishan City, Leshan City, Sichuan Province , China. It is one of the “Four Buddhism Famous Mountains” in China. It has a steep terrain and beautiful scenery. It is known as the “ Emei World Show ” and the highest in the mountain. 3099 meters, more than 2,700 meters above the Emei Plain. "Emei County Zhi" cloud: "Cloud Rosary Verdant, bushy black hair Dai away makeup, really the first cicada Crescent, thin and long, the United States and Yan also, named Mount Emei."

the Samantabhadra Bodhisattva reveals the true meaning to the ordinary people, and it is also called "optical phase". In fact, Buddha light is a natural phenomenon of planting light, which is formed by the diffracting effect of sunlight on the surface of clouds. The Chinese scientist named it "Emei Baoguang". According to the report, Emeishan Foguang appears every month, with the most frequent occurrences in summer and early winter, and the most is visible about 100 times a year.

Emei Mountain is located in the intersection of various natural elements. The composition of the fauna is complex, the species is rich, the endemic species are numerous, and the complete subtropical vegetation system is preserved. There are more than 3,200 species of plants, accounting for about one-tenth of the total number of Chinese plant species. Mount Emei is also home to a variety of rare animals , with more than 2,300 species of animals. There are more monkeys along the mountain road, and the team often asks for tourists to eat, which is a major feature of the mountain.

Mount Emei is the dojo of the Samantabhadra. Religious culture, especially Buddhism culture, constitutes the main body of Emei Mountain's history and culture. All architecture, statues, instruments, etiquette, music, paintings, etc. all show the rich flavor of religious culture. There are many ancient monuments and temples on the mountain , such as Baoguo Temple, Fuhu Temple, Washing Pool, Longmen Cave, She's Cliff, and Emei Buddha Light. It is one of the destinations for tourism, recuperation and summer vacation in China.

The best time to see the magical Buddha light is 2-5 pm. The best place is at Shuguangtai and the body rock. In the afternoon, under the rock, the rock is covered with white clouds, and a seven-color halo of red, orange, yellow, green, blue, blue and purple suddenly appears in the clouds. It is about one or two meters in size and the center is as bright as a mirror. The golden dome is thunderous. The viewers are facing the sun in the west, sometimes they will find their own figure in the aura, just like facing the mirror, raising their hands and throwing their feet, the shadows are all the same, strange, even if hundreds of people are watching at the same time, the viewer is also I can only see myself and I will not see others.

It should not be confused with Emei Township, Hsinchu County in Taiwan.