I will repeat myself (as I enjoy nagging
) that
we probably will not see J-20 in yellow primer on the tarmac, ever.
We have seen two color schemes of J-20, 2001 and 2002 in dark green, 2011 and onwards in lighter grayish green. We have seen all other prototypes of J-10 and J-11 in yellow primer but never J-20, why?
Some say that J-20 is painted in its final state to test stealthiness which is unique from all other types of planes. That is only true to 2011 and later, which are clearly equipped with radar and avionics. But not to 2001 and 2002 which do not have these stuff and only meant for aerodynamic and flight characteristic verification just like all other non-stealthy planes, but they are still fully painted.
I remember some say that J-20's fully painting has something to do with pride of the PLA. I am skeptical about it. That is not the kind of mentality of Chinese state/millitary that I know of.
One possibility of the "final painting" approach is to conceal the material composition of the whole fuselage, so it makes it very difficult (if it is even possible) to estimate some parameters of the plane, such as weight, strengh (therefor) load, G numbers in different flight regimes. One good example is that the DSI bump getting lighter (composite?) paint has suggested some electronical devices/sensors inside, if they could have managed to conceal that we wouldn't know these extra sensors.
