The old saying about absence of evidence not being evidence of absence applies. It is of course prudent not to jump to conclusions, but that works *both* ways.
Take the Su-57, it is actually a case in point, but not in the way you portray. While it's NOT officially in service (contrary to what you say), it clearly isn't as far along as the manufacturer and customer hoped it would be at this time. Nonetheless, the assumption - based simply on an absence of milestone announcements - that it still is nothing more than an empty shell, and testing very limited, is also false. For example, even if the 2018 Syrian deployment was likely nothing more than a propaganda exercise (I can't think of any useful contribution to the test programme...), it did demonstrate capabilities that speak to a certain progress.
There were plenty of skeptics who were convinced its internal bays were non-functional, even though in 2017 a milestone slide (not intended for public consumption) dating to 2014 was leaked which stated they had been opened in flight by then. Even ignoring the aforementioned leak (which in itself proves milestones can happen without disclosure to the public!), is it credible to assume the launch of the Kh-59MK2 was the first time any weapon had been dropped? We are only talking about the bulkiest and heaviest payload planned for internal carriage on the Su-57...
... and the missile itself is actually another case in point: until the release of that footage, it had been only seen as a plastic trade-show mock-up. It was not even certain that it was an active project of record with the Russian air force, and given the deafening silence since its debut at MAKS 2015 one might have been forgiven for considering it vapourware by 2018. There had never been photos of a flight-worthy unit or even press releases about so much as an external captive carry on an aircraft other than the Su-57. Yet suddenly there is footage of a launch from the tight confines of the internal bay (and the rear one too, where the CoG shift is probably most problematic), followed by the wings and fins popping out for a full flight.
Nice post Trident, much more introspective and logical, even Gentlemanly post questioning Mr. Brumby's position. Now, I'm rather more confidant that the J-20 has indeed conducted a supersonic launch, than my esteemed co-hort Mr. Brumby, but once again I'm going to defend his concern, and his right to be skeptical.
The J-20 is progressing nicely in its development, however, the J-20 is indeed China's first clean sheet attempt to develop, prototype, and begin LRIP of a large twin engine Hi end fighter of the 4th Generation for China. Zhuhai 2018 provided each of us with amazing, even clinical evidence of the very fine flying qualities of the J-20, China wouldn't place the J-20 "out there" if there were major flaws or even concerns about its present developmental status...
He did provide more than ample evidence to support his position that weapons release is a rather more complex undertaking than the average SDF poster seemed to realize.. He also pointed out the many, and varied issues faced by the X-35/F-35 in bringing that aircraft into production.... the F-35 is NOT unusual, nor is it extraordinary in having these types of issues in the numbers that it has, not unusual at all...
No rational individual with knowledge of aircraft development, prototyping, and preproduction, production would be offended, nor would they deem his question somehow "out of bounds"? the truth is not a single soul on this forum, or even in the aviation press? have a definitive answer to his question.. the only accurate answer for those of us here is? "I don't know, but, give your own logical reasoning behind your own suppositions...
I'm only responding to the very personally negative, even insulting responses Mr. Brumby received from fellow posters....
I'm a fan of the J-20 as well, I took no offense at Mr. Brumby's concern, or question about where exactly do people suspect the J-20 is presently in its developmental process. I'm rather more concerned that J-20 production seems to be hanging right at 20 developmental and LRIP aircraft, I could be completely wrong about that, but that appears to be the case with the evidence we have at hand....
Finally going back to your Su-57 analysis, in your concerns about the CG with a fore and aft weapons bay, you would of necessity load the forward bay with the heaviest weapons, and you would also release weapons from the aft bay first, particularly if they were the same or nearly the same weight as those weapons in the forward weapons bay.... To release weapons in the forward weapons bay, and retain a heavy weapon in the aft bay would leave you with an extremely dangerous aft CG, which is likely out of the safe "flight envelope", and would lead to some very dangerous characteristics were you to accidentally "depart" the aircraft in air combat maneuvering, in fact its likely that you might not be able to recover the aircraft at all....
