malabo
Turbulence and Wake are two different things. I fail to understand how a rotor disk which has one half in rapidly up moving air, and the other half in rapidly down moving air, is going to fail to flip upside down very rapidly, regardless of how fast it's rotors are moving. I'm guessing you have never seen video footage of such an event?
I've taken off in a 747 behind another 747, and had full aileron control just to prevent the roll upon encountering the preceding aircraft's wake. It is true that I was taking off exactly along his takeoff profile, but it is also true that I had the inertia of 340 tonnes behind me, so I had a lot more time to react than a lightweight aircraft such as a helicopter.
A helicopter will generally not fly through a plane's wake, because of the totally different takeoff profiles. A helicopter's approach to land is far steeper than a plane's, and wake descends, so you are even more unlikely to experience problems on landing.
Hit a full blown wake vortex low down in a helicopter, and you are unlikely to survive to tell the tale.