Checkboard,
You're absolutely correct. Most texts quote the "lowest safe flying speed above unstick speed".
I'd hate to be responsible for any smoking holes caused by people investigating climb performance at VS.
Thank you for that.
The crux of the original question is that ram effect follows an exponential curve. propeller aircraft don't go fast enough to get very far up the curve, but do suffer from loss of thrust and propulsive power due to decreasing propeller efficiency. The question of what exactly is driving the prop (piston or turbine) doesn't really change this much.