Re-typing it is a pain but since it got removed from the KF-21 thread, I'll manually move it over here to anyone who would like to inform themselves on current Chinese engine progress.
In the paper posted in this thread, the turbofan it was describing is suspected to be the WS-19 or something thereof. It has an estimated reliability increase of up to 50% compared to it's predecessor unnamed T/W ratio of 8 engine. This unnamed engine is presumed to be the WS-13E/WS-21, a interim of sorts to the WS-19.
Despite wielding the WS-13 namesake, the WS-21 is completely different than the WS-13 in design. The WS-13 is similar to the RD-33, with 4 Low pressure stages and 8 high pressure stages, while the WS-21 has 3 low pressure and 7 high pressure stages, a design reminiscent of the F414. Thus it would be foolish to even extrapolate anything from the base WS-13 for the WS-21. But to give an absolute baseline floor value to stop people from uneducatedly quoting the lifespan of Chinese engines being 500 hours, something I often see. The WS-13 has an estimated TBO of around 810 hours, a 50% increase from here would be an absolute floor value of 1200 hours.
For a more realistic estimate I will assume the WS-21 should belong in the same technological area as engines such as the WS-10B. From what I could scavenge online, the WS-10B should have a hot section TBO of 1200-1500 hours. Extrapolating this number for the WS-21, we should get a TBO of around 1800-2200 hours for the WS-19. This is a realistic estimate inline with other 5th gen engines, like the F119 with a hot section TBO of 2000 hours.
Therefore I would take pause to anyone trying to diminish the Chinese engine development program by downplaying their lifespans. Yes in the past Chinese engines were not doing so great on this front. But the mental gymnastics needed to jump around assuming Chinese engines would forever remain unreliable is a cope, plain and simple.
@insidersource @BonPlan2
10 years ago, if you had argued that Chinese engines were unreliable I would have assuredly agreed with you, today however is different than 10 years ago.