Large fixed wing or rotor, the effects can be deadly. Have a look at the following test. It makes you realise the unseen evil that lurks awaiting the unsuspecting pilot. A PA28 with a friend of mine ended up inverted at Humberside a couple of weeks ago due to the wake vortex from a departing helicopter leaving on runway 20 and he was landing into wind on 27. The westerly breeze blew the vortex towards the threshold just as the piper was approaching to land.
YouTube - NASA Airliner Wing Vortice Tests