Originally Posted by
Azgalor
How the engines do that? What is supposed to be a problem? I expected that power and placement of engines creates this pitch up moment. Is it something aerodynamics related?
Underwing-mounted engines, being under the center of gravity, create a pitch-up moment when adding thrust. Pitch-down when reducing thrust. Easy to picture: letter T. Push the lower end of the vertical line, pushing force being the thrust vector forward. The junction of the T (where vertical meets horizontal axis) being the CG - The whole thing swings clockwise (nose up).