[KNS]

Originally Posted by svandamme

But does that density not change , the second the disk transitions from open mountain air, eg 300 feet of nothing below
to just hovering over the mountain top, 10 feet to hard rock?

eg ground effect gives the disk something to"push" off?
causing increase in torque

I mean, the Disk is in fact a big old fan, that moves air down
If the air below the disk can't get away, it will compress

Obviously we aren't talking compressors here, the air can get away..
But Ground effect , is a thing, right?

Hence an overloaded Huey in Nam had to fly circles in an opening
To first gain transitional lift and not just go straight up.


Now if you cross the cliff.. you go from NO ground effect
to Ground effect, in a flash

The tail rotor however, hangs free , no ground effect there.
and due to altitude density.. NO capacity to increase its output. The engine is at mechanical limits.


To me it looks like that is exactly what happened in this video

And as soon as he went back over the clif, both disk and tail rotor in thin air again
control was regained.

Ugh...where on earth do you find all this stuff? Get some seat time in the the real thing. If you're going to educate yourself, get off the internet and do some reading by Ray Prouty.