Re:U.S. to ground Boeing 737 Max 8
by teleclimber on Wednesday March 13, 2019 @03:33PM
(#19382709)
The center of thrust moving forward would not have any effect on the pitching moment.
>The center of thrust moving forward would not have any effect on the pitching moment.
Sure it would. Here's a better explanation than I care to make: https://www.quora.com/Where-should-the-center-of-mass-lift-a...
"If the Center of Thrust does not act through the Center of Gravity there will be a moment causing the aircraft to pitch, yaw or roll about the axes of the aircraft and the moment(s) must be counter balanced by design (including provision for trimming when the thrust is varied)."
Boeing chose to counteract that newly induced pitch moment with software, so that they could sell the MAX 8 to airlines as not requiring any new training or type ratings. And now nearly 400 people are dead because of a marketing decision.
Re:U.S. to ground Boeing 737 Max 8
by teleclimber on Wednesday March 13, 2019 @04:16PM
(#19383289)
If you move an engine forwards (or backwards) you are moving it along its thrust vector. Therefore the moment resulting from the distance between the thrust vector and the center of mass is unchanged.
Source: Physics 101
Re:U.S. to ground Boeing 737 Max 8
by AnimalMuppet on Wednesday March 13, 2019 @05:25PM
(#19384009)
Right, but if you increase the power, you increase the moment.
Because the center of thrust is also moved forward, and its effect is much greater than that offset by the center of mass. The 737 airframe was never designed to handle such powerful engines.