A cobra has the same amount and style of chain as a huey. we moved the tail rotors on Hueys and cobras beginning in 1973. it was referred to as a tractor tail rotor because it pulled instead of pushing. I flew one of the very first when I was flying tests at Bell. They were made for the USAF version of the UH-1H and then all hueys and cobras followed as they were upgraded over the years.
BT