vstol cost
VRS is NOT COMMON to ALL helicopters and tiltrotors. This
appears to be a marketing ploy. Helicopters, which have lighter disk loading usually settle with power and can readily be controlled to either exit the situation or make a controlled landing. A tiltrotor which has much stiffer blades (props) also begins to settle with power , however it can each a state where severe flow changes result in vortex near mid span, produce abrubt and sometimes violent vibrations and loss of control ( rapid pitch down and roll to inversion) -- and CRASH BIG difference!!!