Aha! its good to see some aviation updates. A two seater finally.
Questions
1. Is it a trainer variant with combat capabilities?
2. Usually inclusion of a twin seat incurs fuel penalties, or structural lengthen changes, can you show some schematics of the new variant where the fuel is stored?
3. Is the twin seater variant more focused towards AEW&C & Battle Management?
4. Does it comes with the enhanced WS-10 engine considering its improves its fairly average T/W performance of early WS-10s which will solve its super-cruising problem?
5. How is the WS-15 development going on?
6. If the former question is true, what is the Taiwan invasion strategy for the new J20 variant?
ANSWERS (to the best of my knowledge)
1. It is easier and cheaper to conduct pilot training on dedicated new generation trainers such as the L15 and JL9 in China's case and Boeings new supersonic trainer in the USAFs case.
What I believe the twin seat J20S(?) brings to the table for the PLAAF is first and foremost is the forward air control mission.
An added advantage of 5th gens demonstrated in declassified accounts of Red Flag exercises hosted by the USAF is the F35s and to a lesser degree the F22s ability to passively (0 signature) vector other 5 th gens and 4th gens away from hazardous airspace targeted by the red (aggressor team) and make the best use of air assets in the battlespace while placing them in the least danger of interception by the enemy and remaining undetected themselves. Altogether an invaluable asset in congested Electromagenticly dense contested airspace with dozens or 100+ enemy and friendly assets.
Many have pointed to the two seater variant
as a sign of deficient levels of automation and AI application on the J20 (which may be true, I honestly don't know). BUUUUT. MY contention is:
Even if the J20s automation (level of pilot workload) is higher than the F35 (unlikely but possible), equal to the F35(probable), or less than the F35(more likely); the addition of a second pilot for vectoring of other air assets in the battlespace reduces pilot workload to levels lower than other single seat 5th gens (F22, F35 and SU57).
Which is the main reason I believe the IAF included a requirement for a twin seat SU57 for their suspended (or dead) FGFA programme.
Other more novel missions that still apply the same are command and control of friendly unmanned reconnaissance or strike platforms (HALE, MALE and next gen stealthy drones like the GJ11 or the mysterious aircraft identified by satellite on CAAC grounds recently) passively within congested airspace. Again emphasis being on Stealth as these platforms can be commanded or controlled via vulnerable, large wing AEW&C platforms like the KJ2000, KJ200 and KJ500 or smaller 4+ gen fighter types like the J16.
I emphasize use of manned platforms for C&C of unmanned aerial vehicles because even if they can be controlled by ground stations via satellite links; those satellite data links will probably be jammed or degraded in actual EMI heavy combat.
The J20S (twin seat) provides a platform to allow C&C capability with a lower chance of enemy interception due to its inherently lower IR and Radar signature.
Again, the same function will be provided to the USAF via the single seat F35 for comms and reconnaissance nodes like the new RQ180 stealth UAV. BUT again, I believe a 2 seat platform allows for more capacity for this function than a single seat platform.
Just as for example the Growler in USN service uses the twin seat variant of the F/A18 (F) as base platform as it provides more capacity for collection and analysis of electronic signatures and pursuit of Jamming targets than a single seat would.
Another function that may be performed by the J20S more effeciently than a single seat J20A. Signals intelligence and jamming, but again in a low signature platform as opposed to the 4th gen F/A18G.
2. I don't have any schematics as there is literally only 1 video and 2 pics of the J20s prototype (2031).
Usually twin seats have a more pronounced fuselage aft of the cockpit to accommodate avionics displaced by the second seat to maintain the same fuel capacity as a single seater. But we'll know more as better imagery of the J20s is released.
3. See answer in 1.
4. We haven't had clear imagery of the engines installed. It might revert to the AL31s used in the first J20 prototypes and LRIP airframes, or the WS10Cs on production airframe produced post 2019, or (highly unlikely) WS15s. Don't want to speculate.
5. I don't know for sure. We've seen blurry pics of a purported J20 prototype with 1 WS15 installed for testing but that has not been verified yet. We've seen rumors from reliable sources claiming a J20 prototype has been observed over Chengdu flying high energy maneuvers on 2 WS15s (still not verified...
Soooo, I don't know and wouldn't want to speculate.
6. In the Taiwan scenario, I believe the PLAAFs precious few (for now) J20s would be prioritized for a contingency where US assets would intervene. Or they'd be used to neuter the Republic of China Airforces meger (as compared to the numbers available to the PLAAF) assets at the very onset of hostilities.
Either way the platform offers large fuel and thus range capabilities which would enhance loiter time which would contribute to its availability serve in the functions detailed at answer 1. Facilitating better use of PLAAF 4th and 4+ gen aircraft in the TW strait and around the island.
That's all my opinion mate. I can't claim to know what the PLAAF brass have planned for actual operations, but that's my best guess and the opinions of those I highly rate amongst the PLA watcher community.
Sorry for the very long post.