You got it right in the first line "pitching moment" the actual thrust angle dos'nt change, if the turbines tail is point down and as thrust is a reaction force then the thrust is up.
It is this up thrust that causes a planes nose to PITCH down if mounted behind the CG and Pitch up if mounted in front, that is why we normally add down thrust on our conventional tractor engine models.
You cant call it down thrust at the front and down thrust at the rear if the engine/turbine is mounted at a different angle.
Dont blame me blame Newton
And by the way I dont use pusher props on my rear engine aircraft, I change the timing of the engine so they can run in reverse and so use conventional tractor props
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