As one of the earliest domestic aviation lubricants that meets the US military MIL-PRF-23699 implementation standard, and as one of the earliest Class II medium-viscosity aviation lubricants that passed China's official appraisal, 4050 high-temperature synthetic aviation lubricant is now a household name in the industry. However, its 27-year development and service history is only a long and unknown journey at night. The pain and sadness in it can only be deeply understood by the Chinese aviation people who are forging ahead in difficulties.

 

Trident aircraft introduced in turbulent times.

 

 

The Republic of China in 1970 was in a precarious era. The development of the Chinese Air Force at that time was basically at a standstill. Even supporting daily necessities such as aviation lubricants were far from international standards and could not even meet its own needs.

That year, the Chinese Air Force introduced four second-hand "Trident" aircraft from Pakistan as special aircraft for the chief. Along with the Trident came Esso's Esso 2380 aviation lubricant. Just like the aircraft, 2380 oil was also the earliest advanced Western aviation lubricant that China came into contact with. In order to solve the problem of aviation lubricant use at that time and in the future, the military took the lead and began to imitate 2380 oil.

 

According to the analysis of researchers, the main components of Esso 2380 aviation lubricant are: 70% trimethylolpropane mixed acid ester and 30% trimethylolpropane adipate. The additives are 1% diisooctyl diphenylamine, 1% phenyl-a-naphthylamine antioxidant, 2% trimethyl phosphate anti-wear agent, and 0.09% indolizine preservative. Therefore, according to this composition, the Institute of Petroleum Science and Technology began the development plan of a new type of oil, and successfully developed it in 1972, which was named No. 4050 high-temperature synthetic aviation lubricant.

 

From March 1972 to November 1974, 4050 oil began to be used in the test flights of Trident airliners. However, the number of Trident airliners, only 39, was far from enough to support the production of a special aviation lubricant. Later, 6 more crashed, with a loss rate of 15.4%, which was unprecedented. The new 4050 oil faced the risk of inorganic compatibility.

 

The Tragedy of a Great Power: The Rise and Fall of the Y-10 Passenger Aircraft.

 

 

In August 1970, the Y-10 large passenger aircraft was officially launched, and was managed by Shanghai Aircraft Manufacturing Plant (now COMAC). The Y-10 aircraft was the first attempt made by China's aviation industry to catch up with the world's first-class level. Hundreds of units of all sizes across the country participated in it, and the newly born 4050 aviation lubricant also became the standard oil for its plan.

 

In order to meet the needs of JT3D-3B aircraft engines, Sinopec Chongqing Yiping Refinery improved it in 1975, improving thermal oxidation stability and lead corrosion resistance, and the base oil formula was changed to trimethylolpropane C5 ~ C9 mixed acid esters. At the same time, Yiping Plant also withdrew from 4106 aviation lubricant. This type of lubricant, together with 4050 oil, became the best lubricant material support for the dream of Yun-10, and was successively tested on the JT3D-3B aircraft engine.

 

However, the reality did not match expectations. A high-tech large passenger aircraft was far beyond the capabilities of the Chinese aviation industry at that time. After struggling for more than 10 years, the Yun-10 was finally discontinued. 4050 aviation lubricant once again faced the embarrassing situation of inorganic applicability.