Like you said it is to defend against weapons like single stage HEAT rounds. Like an RPG-7. You can basically use a rubber side skirt. It is so cheap and effective against those widespread weapons that it would be foolish not to use it.
I think the major issue with the Type 099, well with T-72 models in general, is the carousel loader rounds are located in that part of the chassis. In modern T-72 variants the Russians have tried to mitigate the issue by reinforcing armor in that specific area and adding blowout panels to the tank.
But much like I said in this thread before. I think Chinese main battle tanks are just simply outdated. I even proposed the Chinese to buy Russian Omsk design bureau's Black Eagle tank design and modernize it. Then use that as their main battle tank. It would have bustle mounted ammunition, blow out panels, a larger turret which can possibly carry a larger gun in the future. Only thing I do not like about that tank design is the gas turbine engine. But it is based on the T-80 tank chassis and there are versions of it with diesel engines. The Chinese have a good high power 1500hp diesel power pack of their own production which they can use.
I think they need a new main battle tank design, a new gun, a more network centric distributed comms architecture, plus a CVT transmission in the tank.
Uh?? What?
The Type 99A and Russian T90MS or whatever come from entirely different schools of design and lineages
The gun on the 99A is an upsized version of the Type 89 tank destroyer 120mm, which in turn was based on the imported L7 105mm. In contrast, the 2A48 descends from the original T72 gun.
Armor philosophy and hull design is entirely different too. No T72 variant ever reached the weight and size of the Type 99A, neither did the black eagle design. The only common point is sharing 3 crew members, and even then the motivation is different.
Type 99A has it in order to fit more armor and because reload rate is not a huge concern compared to the ease of protecting 3 crew members vs 4. T90MS uses it so the tank can go faster/present smaller profile.
99A was designed with defensive war in mind, while the T72 variants excel in armored charges. They’re almost opposites in how they’re meant to be employed.
The Black Eagle too, is an offensive tank, which doesn’t fit the doctrine. At 48 tons, it is not nearly as well protected as the Type 99A, and would be just as old a design.
Unlike the Type 99A which has been kept relevant through the years with continuous updates, the Black Eagle would take heavy work to become PLA standard. And the final result would be an inferior tank, based on the T80U with it’s catastrophic performance. The Type 99A already has a large turret that can fit larger guns.
If China and Russia should make a joint tank project, it would be better to upsize the Armata, add the 99A’s gun, armor, APS and power plant to it.