CR929 has a long story.
the actual issue was, Russia demanded IP rights and R&D center in Moscow.
in 2019 UAC completed full scale model testing in high speed wind tunnel and designed composite wing of CR929.. this project was bound to fail as two different mindset of people and requirements. this was even admitted by Irkut's chief designer. but in 2021 both parties decided to have put differences aside in relation and confirmed plans to start first prototype. but this time Russia launched Ukraine operation. in 2023 COMAC decided to go alone as they have gained enough experience with C919 development and domestic suppliers too gained experience with Y-20B/AG-600.
Russia was still interested to supply composite wing but COMAC said, no thanks. C929 composite wing contract gave to Shanghai aircraft industry group. its fuselage contain 51 percent of composite and all high end composite materials sourced from local suppliers. C929 engine mounts, vertical tail and rudder contract given to SAC. majority of onboard airborne systems are from domestic suppliers too.
all thanks to geopolitics and current USA trade policies regarding export control.
What is Russian fabulous black wing made of? I know it's carbon fiber but could Russian produce any carbon fiber for the wings of CR929 or even its own MC21-310 then? Here is the answer:
Which means Russian only began producing T-700 grade carbon fiber in 2026. Back to 2022-2023, under the west sanction, Russian has nothing to make wings for CR929 which was planned to have its first flight in 2025 then. And I suppose members of this forum know what T-700 means and thus know where the most of the 5.75t overweight of MC21-310 come from.
In early 2026, when Russian finally announced they could produce T-700 grade carbon fiber, China began to produce T-1200. If you were the chief designer or project manger, who would you choose to make the wings for C929?
How could Russia make wings for C929 if they even couldn't make wings for their own MC21-310 then? This is why we began to hear all these excuses from Russian side during this period of time.