On what sources do you base this superiority in stealth and multirole capability of the J-35A over the J-20 (leaving the J-20A out here completely for a bit)?
As others have said, there are official hints (or straight-up confirmations) that the J-35A had higher stealth parameters compared to the J-20, new generations of RAM, etc.
Even assuming that the J-20A will use the same RAM, by default the J-35A should be stealthier - it's literally the closest to a textbook perfect stealth fighter in terms of shaping.
1.) DSI. It doesn't have the splitter gaps of the F-22's caret intakes as a massive reflecting source that takes great pain and a whole lotta hair to deal with.
2.) Conventional wing layout. Although with great efforts, layouts like the J-20's canard-delta can be as stealthy as conventional wing designs, the J-35A doesn't have to deal with that. In equal conditions (which is a MASSIVE caveat), a canard-delta can only be *as* stealthy as a conventional wing, not more. Fortunately for the J-20, most of the other aircrafts have some sort of flaw to equalise the field (F-22 with the splitter plate gaps, F-35 with the bumpy underside + relatively lower wing sweep angle). However not with the J-35A.
3.) Relatively high wing sweep angle. A higher wing sweep angle means that your horizontal degree range without RCS spikes will be larger than that of a lower wing sweep angle (*cough, F-35, cough*). The J-35A's wing sweep angle is almost identical to that of the Raptor.
4.) Flat and smooth underside. Same as the F-22 and the J-20.
5.) Clipped wings and stabilisers to deal with edge scattering. Also found on the F-22 and the J-20.
6.) Smaller vertical stabilisers (with no strakes). The F-22 had to use massive vertical stabilisers IIRC because of some supersonic performance requirements and something with fluttering (although I'm not sure if it's because of the fluttering that they had to enlarge the stabilisers or because the stabilisers were so large that there we fluttering issues). IIRC the J-35A got around it with using an addictively manufactured frame which is stiffer. Hence from the sides, smaller stabilisers would reflect less radar waves. Strakes can be made with composites, but it's better to have nothing there at all.
7.) Relatively small airframe. Of course larger airframes can be as stealthy as smaller ones, but you literally start with an inherently smaller RCS.
etc.
But, as close to textbook perfect as the J-35A is, it's still not perfect. The F-22 beats it at rear IR stealth with the 2D TVC nozzles. However I've been told that circular nozzles are actually stealthier on radar. The J-35A is rumoured to get 2D TVC too though, so if that turned out to be true I think it can rightfully claim the top spot in terms of overall stealth.
For all we know the J-35 is just getting started to become operational. Information is pretty scarce and it was developed from a cheapish, privately funded, export oriented demonstrator (FC-31). The J-20 on the other hand was a ground up new design, from the outset intended to be the cutting edge, high performs stealth fighter for the PLAAF.
And since the program revamp supported by the PLAN, the FC-31 has transformed to also a cutting edge, high performance fighter. Seriously, it underwent extensive redesign, to the point that it might as well been a new aircraft. They took the best of the FC-31 (extensive application of additive manufacturing, new approach of airframe design, etc.) and made it even better and more capable (shifting the engine bays a bit upwards so the intake ductings would take up as less space of the IWB as possible, IRST/EOTS, EODAS, redesigned how the control surfaces are clipped for even better control of edge scattering, etc.).
In fact initially the PLAAF wasn't even interested in the FC-31/J-35.
The JH-7 all over again. This isn't the first time the PLAAF did this.
So I find it hard to believe that anything but the smaller price tag and seperate assembly line (thus not putting more pressure on the assembly of the J-20) were driving factors for the PLAAF.
I told you repeatedly - the 35A fills the gaps that the J-20 shouldn't or couldn't fill, called being multirole.
Just like it's cousin in name, the F-35, it seems to be the cheaper, strike oriented, complementary fighter for it's respective air force.
Why is cheaper somehow a derogatory term? It's an advantage. Nothing wrong with being complimentary, it's still a force multiplier.
While the J-20 is evidently the favorite of the PLAAF.
And the PLAAF is a player. Just look at how they're asking for the 35As to be delivered earlier.
