Arm out da Window said:
Re the asymmetric vortex ring thing - differential collective for control in multi-rotor types is hardly new, being used in the Chinook for pitch, so surely it's not insurmountable.
The big difference is that the tilt-rotors asymmVR is out on the end of lateral moment arms. When the Osprey pilot hits asymmVR and a wing starts to drop, his instinctive "pick up the dropped wing" control input embeds the condition even deeper and ensures a worsening snap-roll rate.There is no recovery when you hit the condition. It's always destined to be a repeat of the Marana profile.