AFAIK speed limits in WT are usually based off of what the manufacturer / manual allows operationally, rather than what was tested / demonstrated to be possible in real life.
But just as an starting point, to at least prove that the aircraft can even go supersonic near ground level (even if for testing or demonstration rather than operationally), perhaps you could provide a picture or video of it doing so …
The absurdity of 1400 kph (Old documents) or 1450 kph (in the game) max speed @ ground/sea level for Su-34 is made even more clear by the fact that the much less draggy Su-30MK and Su-30MK2 have max speed of 1350 kph near ground level (according to UAC the manufacturer, and FSVTS the Russian Federal Service for Military-Technical Cooperation).
And even Su-35, which is even less draggy and more streamlined, and has improved engines with higher thrust, has a maximum speed of 1400 kph at sea/ground level (according to UAC the manufacturer, and FSVTS the Russian Federal Service for Military-Technical Cooperation).
So it’s obvious that the declassified 1100 kph figure given for the Su-34 by UAC (the manufacturer) since around March 2023, given that the aircraft is a lot more draggy than Su-35 and has weaker engines, actually makes sense.
Just because they are the middle ground of new and old figure doesn’t mean they are the “most correct”.
It absolutely does not matter what engine was installed on it. It will not make it go from 1100 kph to 1450 kph on the deck …
Drag is proportional to the velocity squared and a small increase in velocity requires a massive increase in thrust.
But since the Mach 1.45 (From ROE) / 1500 kph (From UAC) at altitude and 1100 kph (From all three sources) on deck figure seems to be with the 125kN engines (as per UAC’s website), the devs could account for the increased thrust (to 135kN) of the better engines.
UAC’s website also lists a 2% reduction for installed thrust. So given that the drag is proportional to the velocity squared:
Again, UAC saying that the flight performance specification are “Classified”, until around March 2023, makes it clear that the old 1900 / 1400 kph figures (which were given since at least 2005) are fake …
I do not know from what date or by whose order they changed all the numbers there…
This is some kind of planned action, the UAC didn’t open last year either!
By the order of whomever ordered to declassify the real speeds, most likely because there’s no reason to fake it anymore since the aircraft and its performance was being observed by radars in [redacted] for quite some time now …
UAC’s website not opening is likely related to sanctions etc
They most likely want to hide the company’s structure and (high ranking) people to avoid sanctions on them …
As for ROE website, there is a bug with it
You have to open the link in my report twice … The first time it will not load the page, the second time it will … (Or you could simply navigate to the aircraft’s page from the website’s menu).
The answer is no, and that’s why they could put fake numbers in public ROE brochures and placards etc, for so long, without any consequence …
Actually, the fact that the real buyers will ask for classified information rather than deciding based on public brochures and placards could be the reason why nobody actually bought the aircraft … I.e. they asked for performance data and when they were shown the real performance data, it dissuaded them …