I'll toss in my last with a ditto on the idea that VMC has nothing to do with climb rates during an engine failure; and the 10 factors that you are thinking of are merely 10 standards that the FAA has mandated designers to use when designating a number to put a redline on the airspeed indicator. The speed at which directional control is not possible is not constant, it changes; that is why the feds made up the 10. The 10/7 discrepancy comes from the manufacturer's guidelines having 10, and the pilot training references having only 7. For instance, pilot training references omit that the force on the rudder pedal must be no more than 150 lbs... etc. To get back to the p-factor point, I'll tell you that the best way that I have seen to demonstrate p-factor is with the good old prop-on-a stick. You can find these in toy stores, and to a simple mind like my own, they are loads of fun. You spin the stick between your hands, and the whole thing flies away. If you tilt it forward for the launch, it will fly away, but as it moves along, it will begin to "pitch" up, changing the angle between the stick and the horizon. This is a really easy way to actually "see" p-factor for yourself. The explanation is that each blade of the prop has its own airspeed, due to rotation. Let's say that is 20 mph. When the stick starts moving forward at 5 kts, then the advancing blade is 25, and the retreating blade is 15 (or close to it). Thus, the advancing blade produces more lift, and since the lift occurs 90 degrees early, the resulting change is that the stick reverses its angle. Try it, but be prepared to spend all day playing with the little prop thing... at least that is what I do. You can have contests to try and make the stick land in a coffee cup, or if you get two, you can juggle them with another person. If you stand in an elevated place and spin it backwards, it will autorotate, and actually pick up rotational speed on the way down. Very fascinating, if you ask me. Thanks for all the fun discussion.