RE: Right thrust and 3D
Ernie,
Proximity to the ground also has an effect; a very profound one, in fact.
The prop-wash is in the form of a spiral, which with the plane 'out of ground effect', goes directly backward along the plane's thrust-line.
As a result, with the prop spinning in the normal direction; clock-wise, when viewed from the cockpit, the 'over' prop-wash will hit the vertical stabilizer and the rudder from the left; in turn causing the plane to veer to the left. The 'under' prop-wash hits nothing, thus causing no change in the plane's heading.
But, what happens if the plane is a tail-dragger and is in the normal three-point attitude, on the runway, in the beginning of the take-off run? The prop-wash obviously cannot go into the runway... so, it deflected, becoming runway-hugging and parallel...
But where does the 'under' prop-wash go now???
It hits the vertical stabilizer and the rudder from the right, causing the plane to veer to the right; the exact opposite to what it does with the plane in level attitude (the 'over' prop-wash will hit nothing, now going over the vertical stabilizer and the rudder...
This effect reversal, as the plane's tail rises, used to cause beginners in WWII fighters to do the notorious 'ground-loop'... It was usually blamed on 'Torque'...
The would-be pilot would have a bit of trouble explaining what he encountered, from the world he now resides in...
When you are hovering near the ground, deflected prop-wash has mysterious ways of causing your plane to react...
EDIT: Correction of 'directional error' following Red B.'s remark.