F-135 paid a price for higher thrust, which is much higher bypass ratio.
F-135 0.56:1
F-119 0.30:1
F135-PW-100 dry trust 128 kN
F119-PW-100 dry trust 116 kN
China can sacrifice bypass ratio to improve dry trust, but is it what we need?
I think they should just investigate variable cycle. If WS15 first trial was done just when J-20 was ready and they decided to restart so many of its components then I suspect newer WS15 for 2025 or around then is variable cycle. Or I hope it is. Even if it is higher bypass ratios similar to F135/6 levels, I will be so amazed. China will have super high thrust level turbofan which is only limited by variability in bypass ratio. Even then it will hopefully become obsolete technology in coming decades.
I divide military low bypass turbofans in five thrust levels:
1. Weak - For garage enthusiasts and various experiment concept levels useless for military fighters and generally we ignore for this purpose.
2. Low thrust - Honeywell engine etc or WS-5 WS-11 etc of various low thrusts for drones and up to very small light fighters requiring two of such engines in higher end like FCK-1.
3. Medium thrust - M88, RD-33 series up to higher end of EJ200, F414, M53 - European low bypass turbofan achieve these highest thrust level but of course this doesn't mean they cannot produce higher thrust levels but there are challenges certainly and a lot of time and money to spend if they want to.
4. High thrust - AL-31, WS10, F100, F110 these are Russian, American, and Chinese now with WS10 being mature enough with over 10 years of flying service with J-11B series and now applied to J-10 and various other kinds even including thrust vectoring forms.
5. Super high thrust - F119 to higher end of F135 F136. So far only USA has this level of technology already accomplished and conquered. This is our Himalaya peak to conquer because it represent the level when we can sit side by side with the best if we achieve this before they achieve their next breakthroughs which will be variable cycle and even higher thrust than F135. Even if we can do this by around 2025, it is going to be amazing for us who just 70s years ago was struggling to feed ourselves with full bellies. WS15 hopefully considers variable cycle and I suspect the reason for total complete redesign was to incorporate variable cycle so in one leap we can get to the next stage anyway because the core design and materials for F135 is actually already there since years. For variable cycle it is not so much. About Russia's project type 30, who knows. Their latest report suggest roughly ready around 2025 as well.
The word ‘close coupled‘ implies an interaction between the canard and the wing typically to generate lift. The Rafale and the J20 both are close coupled designs. But weirdly the J20 designers coupled the canard with a high mounted wing, while the Rafale has mid mounted wing. This design choice for the J20 further illustrates my point, the J20 is designed to carry large payload for long range undetected penetration into contested airspace. It wasn’t designed for close combat ..period.
Well let's finish this argument we both disagree but one thing I personally think is correct is J-20 is not designed for close combat. It doesn't even have a gun. PL-10 is must in case for close combat and is helmet guided and very high off boresight anyway. J-20 uses long arm canard we can disagree here but reality is whatever it is and one of us is right about it. Long arm canard is generally for good supersonic turning and mechanical stability. Eurofighter is also famous for supercruising and supersonic turning. F-22 is also fantastic in its own way and can use thrust vectoring to full advantage due to advanced incorporation of its thrust vectoring and flight control. J-20 hopes to get 3D thrust vectoring here so minimal canard movement is required. This can help with stealth too but right now canard movements are not as important to stealth because again it is 90% material and electromagnetic now.
