Shameless update from Dale Kramer

"Multirotors come down very quickly and very stable with a good controller, not like the limitations of the 1950's tail sitters (all manual control)."

Vortex ring state can occur when settling under power with helicopters as the rotor settles into its own downwash. This has caused a number of crashes including the V-22 Osprey. So there is risk in "coming down very quickly". Once this occurs in helicopters (and I've only personally hovered models and real ones in forward flight :c) adding power simply feeds into the vortex problem. The save is to apply cyclic and move off into clean air. Is that an option with a tail sitter? Is there a "save"?

Another question is that once pitched up to land, would Rotax failure have a recovery mode?