Its not my argument. I did enough of my Aero Eng degree (1.5 years then left, did 2 English degrees and work in IT) to know I can't judge whether he has a point or not. I'd wager the same goes for 95% of the people here.
Arguing he must be wrong because Shenyang engineers are infallible seems... overly patriotic.
Good that you recognize that there’s still the 5% that can judge, because from a basic aerodynamic point of view turning the AMW will give you roll authority as long as there’s flow passing it, period. What else it gives you and how it messes with the overall aerodynamic properties is a whole other story, but having what is essentially a section of the wing at a different AoA will just inherently create momentum.
From your quotes the guy’s point seems to be “because the AMWs are flapping that must mean it has little authority” which doesn’t make sense because he’s making an observation of the final action and oversimplifying the process behind the action when reversing out its cause (no consideration for things like transient flow behavior during a turn, FCS doing weird shit for compensation, possibility of pilot deliberately testing the handling, etc).
No disrespect to people in the industry, but everybody eventually get boxed into their own little niche of specialized skills and knowledge, and this particular engineer’s insight on the behavior of a foreign aircraft based on a 10s video clip could very well have the same credibility as someone playing war thunder.
edit: went and checked the original post on SPF, turns out the guy’s just making a guess instead of trying aggressively to prove he’s totally right and anyone disagreeing doesn’t know their flaps from their slats.
