Kamov Ka-15

The Kamov Ka-15 (NATO reporting name Hen) was a Soviet two-seat utility helicopter with coaxial rotors, which first flew on 14 April 1952 at the hands of test pilot D. K. Yefremov. It was the world's first mass-produced coaxial helicopter. State acceptance trials were completed in 1955, and the helicopter entered production the following year at aircraft factory No. 99 in Ulan-Ude. It was a precursor to the Ka-18 and was fitted with the M-14 engine (helicopter version). It was primarily used for bush patrol, agricultural purposes and fishery control.