On the matter of PLA Transport/Tanker aircraft -- one thing that I've been consistently thought was a good idea, was for all new Y-20Bs once they enter mass production, to be capable of doubling up as tanker aircraft by having removable wingtip air refuelling pods and the necessary plumbing to carry out air refuelling.
Similar to how A400Ms are all designed with air refuelling compatibility as standard.
The PLA's lack of large tanker aircraft is obviously a major deficiency that everyone has noted, and they are obviously going to rectify this by building Y-20Us (based on Y-20A and Y-20B), and that is important, as Y-20U aircraft will be dedicated tankers with sealed ramps, three air refeulling positions (including a central fuselage position), and likely with an internal cargo hold redesigned to permanently be capable of carrying more fuel.
However, annual induction of Y-20U airframes will be limited by overall Y-20 airframe production, and the PLA will still need a large fleet of standard transport Y-20s that will put a ceiling on how many Y-20U tankers could be built over its lifetime.
But the vanilla Y-20 should have an internal fuel capacity similar or greater than that of Il-76, and I think a standard non-tanker Y-20 would make a good tanker on its own, certainly with an internal fuel capacity multiple that of a standard H-6U, and approaching that of the KC-46/KC-135.
The problem with Chinese tanker capability in the future is fleet size and availability. It will take time for a sizable, dedicated fleet of Y-20U to enter service and even then they will be high value assets that an opfor will seek to target and destroy.
But if every Y-20B also has the ability to carry a refuelling pod on each wing, it will not only significantly enhance the refuelling capacity of the air force overall, but also make the overall air refuelling fleet more resilient to attrition. Like the A400M, the pods can be easily removable and attached only when needed, and the only other modifications to a standard Y-20B will be a side fuselage camera on each side and some rewiring and software to allow the copilot to monitor the two refuelling drogues during operation.
Otherwise, during standard airlift operations the normal Y-20 fleet does not to be equipped with refuelling pods, but for operations or conflicts where air refuelling is important, they will be able to equip themselves with refuelling pods while also retaining the internal cargo bay for airlift.
Annually, a production ratio of 3:1 Y-20 between standard transport/tanker variant airframes to dedicated tanker variant airframes could prove sustainable in the long run.
If some eventual 160 Y-20B airframes are built, then that would be some 120 Y-20B transport/tanker aircraft, with 40 dedicated Y-20BU tanker aircraft.
In a conflict where tankers are in high demand and strategic transport is deemed slightly less important, then the core of those 40 dedicated Y-20BUs could be supported by a large fraction of those Y-20Bs operating in the tanker role. Obviously the Y-20B tanker will have less fuel capacity than a dedicated Y-20BU, but they'll still be fairly capable and able to haul a lot more gas than H-6U, and more importantly it means more tanker airframes are available in general.
