Originally Posted by
awblain
HC, I agree: detach the rotors, and you will briefly free fall: there will be weightlessness, which then rapidly (~5s later) returns to normal conditions at the terminal velocity (c.f. AF447).
However, you're not blowing the blades off to experience this, you're pitching them down.
If your clipboard drifts up off a flat surface in the absence of any lateral acceleration to make it bounce off a projecting lip, I agree: that's (briefly) real negative g, with g~-0.0X, where X~1-5. Things "drift" at 0.0Xg; they "fly around" at -0.Xg, and at -Xg they hurt you.
I find this a very interesting discussion - there seems possibly to be a transatlantic polarization developing about old Isaac's ideas, and how air interacts with whirling blades, and that's definitely not based in physical reality. If it's not all just a mix of semantics, cultural difference, sloppy description and misunderstandings, then getting to the bottom of these differences will surely lead to greater awareness of the energetic perils of rotary wing flight, and make everyone's life safer.
Yes as I said, not much below zero. But even at zero g, that means no autorotative effect and the Nr will continue to decay with collective right down, though of course much less quickly than if it was left up. I suspect the difference is less about which side of the Atlantic you live, and more about range of experience. TC's resolve to not grasp my point can I think only arise because of his very formulaic military flying and presumably he has never tried entering auto at 150+ kts. As he himself said, he does it at 120 and there is a bigger difference in the result than the speed difference might suggest.