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WS15 turbofan

The core engine for the WS-15 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 WS-15 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.

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.




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