Which is odd, considering that U.S. engine design methodology stems from the seminal work of Chung Hua-Wu who was a Chinese expatriate.
He went back to China in the 1950's, like Tsien, and Mao never leveraged what he knew and did.
Now they're making up time by industrial espionage, but it isn't like the people they have can't do it.
Only a matter of time, they'll pass the Russians; they have a 10:1 people advantage, and of course trillions of dollars courtesy of the Free Trade idiots in this country.
Don't know why they bother with Russian jets, except maybe as a political stunt, or historical Communist "solidarity"...except the Russians aren't Communist anymore, and they can't stand the Chinese.
Their domestic turbofan engines are only just beginning to be equipped on their land based fighters. For Navy carrier fighter jets, the engines will have to be significantly more robust than land based fighters.
So their own engines aren’t as good as the Russian ones yet.