Re: Shenyang J-21 / J-31 revealed!
It's not a mockup or carrier fighter, because clearly the wings are structurally integral to the fuselage, has no mid span folding capability, and are not readily removable.
No mockup would have bothered with fabricating a single indivisible, awkward piece like this. No structural test prototype would need to have its folding wings installed and locked down for transport.
So we might conclude its a genuine prototype, probably with a fully or mostly composite mid-fuselage with integral wing box
I think the Chinese would very reasonably think in terms of a high-low mix in any future force strategy. Clearly j-10 is not an adaquately basis for any low end that would have to compete with f35. So it is not at all surprising they should complement j20 with a lighter twin engined G5 fighter like the soviets complemented su27 with Mig29.
Also if the conventional wisdom about j20 is right, then the j20 is actually operationally even more like what was intended for su27 than merely a generic air superiority fighter like f22 or f22. Specifically it was meant to perform exotic missions like penetrating enemy held airspace by its combination of great range and stealth, and take out awacs and tankers. In other words, j20's ability to tangle with other G5 fighters was subsidiary to its ability to penetrate defended airspace. This make it all the more important for the Chinese to have a real tactical air superiority fighter meant to fight over the front lines and compete with enemy tactical aviation, like the mig 29 was meant to do. So it ought to be no surprise they came up with something that might seem to be aimed half way between f22 and f35, as mig29 was meant to split the difference between f15 and f16
I will venture to guess this j21 will have substantially lower fuel fraction than f35 in order to achieve better maneuverability, while j20 will have substantially higher fuel fraction than f22 in order to achieve greater range and more sustained supercruise capability.
I will guess the Chinese force structure in, say 2025, will consist of j20 in long range air superiority patrol and deep aerial interdiction role, j21 in swarm front line air superiority role, and j-10 and j-11 in versatile tactical bomb truck roles.
