Alan Baker wrote:
In article ,
"Morgans" wrote:

wrote

Don't bother with center of mass. It's not really relevant.

Indeed

Angling the engine up 3.8 degrees would lead to trouble. That's a lot
of angle.

Absolutely

Thrust works against the center of DRAG, which is much harder
to locate than CG.

Thanks for a verification of my thinking.

Sorry.

But all forces on a body act around it's centre of *mass* when
considering its rotation. You can take the moments about anywhere fixed,
but the CoM is what actually matters.

I know you are trying to be helpful and you know that objects in free space
rotate about their center of mass, but I'm fairly confident that aspects
such as the center of pressure and affects on control surface authority
need to be taken into account when changing the thrust line.

As for angling the engine 3.8 degrees up being a bad idea, how can that
possibly be? When you pull up to a high AOA, does the engine suddenly
explode? No.

A high angle of attack during cruise would presumably place the wings
closer to their stall angle. I presume that is what makes it dangerous.