RE: APC 8x10 prop question
From experience I can tell you that the OS.46AX can spin an APC 8.75x8.25NN pylon prop, at over 16,000 RPM.
However, the P-Box muffler disintegrated very shortly and repeatedly. You will see RPM approaching this number.
This was demonstrated on a Diamond Dust delta plane.
You can get to this RPM, but you must substitute the P-Box for a suitable after-market muffler.
This prop will give you very little forward static thrust. I am not sure about a vertical hand launch...