@Airborne Viking
Wouldn't that apply to the turning moment of the remaining engine(s) as well?
Less abrupt yaw, - better rudder control, if you (read me!) are a little slow applying rudder?
Basically, I would think, the yaw moment (force X arm), with assymetric thrust is not dependent upon CG, and the yaw moment of the rudder would only be dependent upon deflection and speed? Aft CG would only result in a slower yaw (tail sideways) acceleration?
Wow, this was complicated, and it's getting worse!
Nope.
The moment due to the engine is basically net thrust of the asymmetric live engine * the distance from centreline - which is essentially independent of forward or aft cg.
The rudder moment is taken about the cg, so must be affected by fore/aft cg movement. So the rudder is less effective as the cg goes aft.
There are secondary effects (the aircraft will be less directionally stiff at aft cg, and likely have more weight on mainwheels, both of which will have a small effect on the motion) but the big effect is aft cg = less effective rudder control, so harder to fight the engine yawing moment.