Recognize AL-31F and WS-10A engine differences in comparison

The WS-10A or Taihang engine was developed by the Shenyang Liming Aircraft Engine Company and is intended to replace the Russian AL-31F from Lyulka / NPO Saturn in Chinese service. Both engines and their derivatives are in the same class with often contradictory claims as to their relationship.

At the 2012 Zhuhai Airshow, Sergei Kornev, head of the aviation department of Rosonboronexport was questioned on Russia's role in the development of the WS-10A engine. Kornev's answer was that Russian specialists have not been briefed on its design and that Russia has never delivered AL-31F design documentation to China.

The AL-31F and its derivative, the AL-31FN are used in all J-10 and J-11 fighters with the WS-10A and derivatives being used in later versions such as the J-10B, J-11B, J-15 and J-16 alongside the AL-31F(N).

An analysis based on a number of factors, including:

• the number of AL-31 engines delivered by Russia to China
• the number of Su-27 / SU-30 aircraft imported by China
• the estimated number of J-11 / J-10 produced in China
• the estimated number of aircraft in service 
• the estimated aircraft number no longer in service due to retirement etc.
• the average estimated lifespan of J-10 / J-11 aircraft
• the estimated flight hours per aircraft
• the lifespan of each engine

suggest that the number of aircraft currently fitted with WS-10A engines is at least 100 to 125 with number steadily increasing.

Almost all of the WS-10A equipped aircraft are the locally produced J-11B aircraft. None of the Russian produced aircraft have ever been equipped with WS-10A engines.

Despite some claims that the WS-10A engine is a copy of the AL-31F, the two engines have appeared side by side at airshows. The engines are relatively easy to distinguish using their engine nozzles.

J-10B with WS-10A

J-10B with AL-31FN

J-15 with AL-31F

J-15 with WS-10

J-11B with WS-10

The AL-31F to the left and the WS-10A to the right.