Hansar,
As Geeser stated YES, depending on the size (weight) of the helicopter they can generate a tremendous amount of rotor wash. Granted that the wake turbelence generated by a helicopter doesn't have as large of a foot print as a large or heavy acft, a pilot in a small acft would be wise to give any helicopter a wide berth.
I have seen several small acft flipped over when a CH-53 taxied near a row of small acft.
Mike
NATCA FWA