The two helicopters you mentioned are Russian-made Mi -17 and Chinese-made Zhi-9 (also imitating French dolphin helicopter).
The Mi-17 helicopter is a medium-sized transport helicopter with single rotor and tail rotor developed by Miri Design Bureau of the former Soviet Union, and produced by Kazan and Ulan-Ude aviation factories respectively. The North Atlantic Treaty Organization nicknamed it "Hippo" -H(Hip-H). China has bought hundreds of aircraft in recent 2 years.
Mi -17 is an aerodynamic layout with a single rotor and a conventional tail rotor, with the tail rotor on the left.
Zhi -9 light multi-purpose helicopter is developed and produced by Harbin Aircraft Manufacturing Company with French patents.
The tail rotor of Zhi -9 is special, and it is the layout of ducted fan tail rotor.
The advantage of the ducted tail rotor is that the fan is wrapped, so the risk to the surrounding area is relatively small. In addition, the fan flow field inside the ducted tail rotor is relatively clean due to the ducted rectification, so it is not easily disturbed by external factors.
-The aircraft in Avatar is actually a kind of ducted blade.