This is from 2021:
View attachment 258007
The IL-76 FTB has a new engine (covered in yellow tarp) for testing on its inboard portside pylon. This is believed to be either the WS-19 or WS-21 from its size and date. WS-13E was already on JF-17 and FC-31 testbeds at the time so it is unlikely to be a WS-13 family type. WS-15 is too big and is already on fighter testbeds. So if the WS-21 is just the WS-13E (or WS-13 variant) then the test engine has to be the WS-19 unless China has another fighter engine we do not know about.
The yellow Y-20 in front is the 7810 prototype that did four-engine testing of the WS-20 after transition from Il-76 FTB:
View attachment 258011
View attachment 258012
There is a confusion above with V1 & V2.
Outside China very little info is available. Certain websites don't open in certain countries. Different sites state different info.
Some sites demand paid premium option for preliminary unconfirmed data.
----------------------------------------------------------------------------------------------------------
The following website confidently links J-35 35003 (spotted in 2022) with WS-21/13E engine, maning WS-19 not tested yet on J-35.
(
https://jetlinemarvel.net/china-dis...-stealth-fighter-with-a-new-jet-engine-ws-21/)
I don't know how famous & credible this website is.
-----------------------------------------------------------------------------------------------------
Although Russian MiG official said that on 31st Oct'2012, FC-31 V1 31001 used RD-93.
another website says that on 1st July 2016, FC-31 V1 31001/PT-01 used 2 different engines together -
RD-33 + WS-13E/21. So RD-93 used for 1st flight was replaced with RD-33???
(
https://inf.news/en/military/c4ef2d0ea68f1181c22ed294919a2d84.html)
So FC-31 V2 31003 may have also used the above combo or both WS-13E/21, not WS-13.
So photograph says RD-33 & Russian MiG official says RD-93, who is right?
Now the timeline looks like following -
31 Oct 2012 - FC-31 V1, black, 31001, both RD-93 engines.
1st July 2016 - FC-31 V1, black, 31001, RD-33
+ WS-13E/21 engine.
December 2016 - FC-31 V2, yellow-green, 31003, [{(RD-33 or RD-93)+WS-21/13E} OR both WS-21/13E engine].
29 Oct 2021 - J-35, green, 35001, either [{(RD-33 or RD-93)+WS-21/13E} OR both WS-21/13E engine].
2022 - J-35, grey, 35003, assuming both WS-21/13E engine.
2024 - J-35, grey, 3505, assuming {both WS-21/13E or (WS-19 + WS-21/13E)} engine.
2024 - J-31 rumored, grey, no data yet for engines.
Do you wan't to make any corrections?