Please un-torque my neurons.... Prop effects et al...

[jcomm]

Again, thank you A Squared ! That really was an explanation :-)

Stators, and not slats, was what I wanted to know how to designate, but I'm Portuguese, and my English comes from high-school, long ago, so..., I wrote "slats" instead of "stators" as you correctly put it...

I will have to carefully read your post, make some sketches, and make sure I understand every piece of it, but I tend to have some difficulty in understanding that the torque resulting from the force applied by the engine to the prop, and by the prop to the airflow, aren't somehow scaled down on a free-running turbine because of there being no direct mechanical connection between the turbine and the prop shafts ( of course there are always bearings and the friction, but I assume that they have a very small impact...) other than the air leaving the tubine and entering / going through the stators and turbines of the compressor attached to the prop shaft.

At least a free-running turbine impacts the way FF reacts to prop RPM changes ( there being no FF variation along a long range of prop RPM variations ) contrarily to other types of turbines and reciprocating engines where there is a direct connection between the two...
At a fixed turbine regime, variations in prop RPM will not interact with the turbine rpm, and thus FF will not vary. So, I thought that somehow the same could happen to torque when we vary RPMs in a turboprop...

Ah! Been thinking about that inverted flight showing P-factor can be of more importance than the spiraling slipstream, but, I really think there should be some blending between the contribution of these two "prop effects".

On a taildragger, during the takeoff run P-factor will probably contribute more than the spiraling slipstream because the axis of the prop is at a considerable angle to the relative wind... But, an aircraft flying inverted is also at a higher attitude than it would normally be if flying straight, so, "the descending semi-disk" of the prop will also be at a higher AoA than usual, and that might account for the prevalence of P-factor under such occasions, while probably when flying straight, slipstream will have the higher contribution (?)