IMO, the stealth of the J-20 is definitely not as good as that of the F-35 and F-22. The frontal stealth of the J-35 is similar to the F-35 and F-22, but rear stealth is obviously inferior. However, the advantage of China's 5th gen fighters lies in their radar and air-to-air missiles. The disadvantage lies in the stealth and the engines, at least until the WS-15 and WS-19 are equipped.
Ask anything Thread (Air Force)
- Thread starter Jeff Head
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The WS-19 is allegedly already equipped on the land based J-35. WS-21 is equipped on the carrier J-35.
WS-15 was equipped earlier but the latest J-20A (third iteration of J-20 single seater) has been photographed with WS-10x engines. WS-15 have allegedly been delayed again possibly due to production rate limits or some other technical snag.
There's little evidence to suggest J-35 and J-20 (similar rear stealth design) is any less than F-35's. F-22's appears to be possibly better than these other three due to a more stealth committed engine petal design with simpler geometry. Russia's IZD.30 adopts this style of TVC nozzle and it appears J-50 and J-36 prototypes both also avoid the circular style of nozzle that is on the current F-35, J-20, Su-57 and J-35. So on rear aspect stealth I think you're right about F-22's but would suggest F-35's rear stealth is not significantly better than J-20 and J-35.
WS-10C and WS-21 do not have a stealthy augmentor so all legacy J-20s and naval J-35s will likely have worse rear stealth. Not sure whether WS-10C2 has them. Also, oddly Chinese LOAN nozzles do not have the pronounced "3D-ness" like US ones, idk how that will affect stealth.
J-20's nozzles are simply circular and lack the angular shape.
My post does state that J-20 and J-35 have inferior rear aspect stealth compared to the F-22 which out of all 5th gen fighters has the best rear aspect stealth. I just don't believe it's that much worse than F-35 which also makes use of circular nozzle.
J-35 engines whether we're talking about the land based variant with WS-19 and the naval variant with WS-21 both feature the stealth augmentation shaping like F-35's F135.
J-20's WS-10x does not. It's lack of this feature would set it further back so if we are to "rank" rear aspect stealth based on observation and guess only it would be; Su-57 << J-20 < J-35 < F-35 << F-22
How much worse your rear aspect stealth is due to the lacking of those petal shaping is unknown. It could be significant, it could also be less than the shaping around other geometries and surfaces. My guess is that it is somewhere in between and the J-20 like all 5th gen fighters, still mostly focus on frontal aspect stealth. The F-22 is the only one in the group of 5 that makes a bit more effect towards all aspect stealth but its tails naturally would limit that effort. Remove the F-22's tails, add DSI and it's as ULO as 6th gen fighters.
Overall I do not believe J-20's other aspects are so much more ahead of its not featuring the stealth augmented nozzles. It's side, top and bottom aspects are probably returning greater signature than rear aspect. So why bother making rear aspect that much better with the WS-10x. Too little pay off for the effort. WS-15 will probably feature that element since it is designed with all these in mind unlike the WS-10. If the WS-15 for the J-20 doesn't even feature this shaping, then we can basically confirm that other angle aspects of J-20 isn't VLO enough to justify so much rear aspect attention and effort.
So for nozzle design the stealth ladder I expect would be F-22 style "paddles" >> augmented circular nozzle a la F-35 and J-35 > circular nozzle with some material effort only but no nozzle shaping
I think the difference between the last two are marginal or for the J-20, not worth the additional effort for the WS-10x version but WS-15 might provide it because while it may not be worth the effort, the WS-15 could be designed to incorporate stealth shaped nozzle from the start unlike the WS-10. After all the WS-15 could become exported some time in the future since VCE is such a difficult thing for nations without the funding and talent pool of US and China.
Round va circular is not as important as use of engine blockers in determining rearward stealth.